Merge branch 'master' into docking

# Conflicts:
#	docs/CHANGELOG.txt

.github/workflows/build.yml

@@ -25,8 +25,8 @@ jobs:
         working-directory: ${{ github.workspace }}/imgui
 
     env:
-      VS_PATH: C:\Program Files\Microsoft Visual Studio\18\Enterprise
-      MSBUILD_PATH: C:\Program Files\Microsoft Visual Studio\18\Enterprise\MSBuild\Current\Bin\
+      VS_PATH: C:\Program Files\Microsoft Visual Studio\2022\Enterprise\
+      MSBUILD_PATH: C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\
     steps:
       - uses: actions/checkout@v6
         with:
@@ -116,7 +116,7 @@ jobs:
           cl.exe /D_USRDLL /D_WINDLL /I. example_single_file.cpp /LD /FeImGui.dll /link
           cl.exe /DIMGUI_API=__declspec(dllimport) -DIMGUI_IMPL_API= /I. ImGui.lib /Feexample_null.exe examples/example_null/main.cpp
 
-      # Win64 examples are more frequently compiled than the Win32 examples.
+      # Win64 examples are more frequently compilted than the Win32 examples.
       # More of the Win32 examples requires 'workflow_run' to reduce waste.
       - name: Build Win32 example_glfw_opengl2
         shell: cmd
@@ -160,7 +160,6 @@ jobs:
       - name: Build Win32 example_sdl3_opengl3
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_opengl3/example_sdl3_opengl3.vcxproj /p:Platform=Win32 /p:Configuration=Release'
-        if: github.event_name == 'workflow_run'
 
       - name: Build Win32 example_sdl3_sdlgpu3
         shell: cmd
@@ -201,7 +200,6 @@ jobs:
       - name: Build Win64 example_glfw_opengl3
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_glfw_opengl3/example_glfw_opengl3.vcxproj /p:Platform=x64 /p:Configuration=Release'
-        if: github.event_name == 'workflow_run'
 
       - name: Build Win64 example_glfw_vulkan
         shell: cmd
@@ -230,7 +228,6 @@ jobs:
       - name: Build Win64 example_sdl2_directx11
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_directx11/example_sdl2_directx11.vcxproj /p:Platform=x64 /p:Configuration=Release'
-        if: github.event_name == 'workflow_run'
 
       - name: Build Win64 example_sdl3_opengl3
         shell: cmd
@@ -575,9 +572,6 @@ jobs:
     - name: Build macOS example_sdl2_metal
       run: make -C examples/example_sdl2_metal
 
-    #- name: Build macOS example_sdl3_metal4
-    #  run: make -C examples/example_sdl3_metal4
-
     - name: Build macOS example_sdl2_opengl2
       run: make -C examples/example_sdl2_opengl2
       if: github.event_name == 'workflow_run'
@@ -657,12 +651,8 @@ jobs:
     name: Build - Android
 
     steps:
-    #- name: Setup Gradle
-    #  uses: gradle/actions/setup-gradle@v6
-    #  with:
-    #    gradle-version: '8.14.5'
-
     - uses: actions/checkout@v6
+
     - name: Build example_android_opengl3
       run: |
         cd examples/example_android_opengl3/android
@@ -677,7 +667,7 @@ jobs:
         working-directory: ${{ github.workspace }}/imgui
 
     env:
-      MSBUILD_PATH: C:\Program Files\Microsoft Visual Studio\18\Enterprise\MSBuild\Current\Bin\
+      MSBUILD_PATH: C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\
 
     steps:
       - uses: actions/checkout@v6

.github/workflows/static-analysis.yml

@@ -23,9 +23,9 @@ jobs:
         run: |
           if [[ "$PVS_STUDIO_LICENSE" != "" ]];
           then
-            wget -q https://files.pvs-studio.com/etc/pubkey.txt
+            wget -q https://files.viva64.com/etc/pubkey.txt
             sudo apt-key add pubkey.txt
-            sudo wget -O /etc/apt/sources.list.d/viva64.list https://files.pvs-studio.com/etc/viva64.list
+            sudo wget -O /etc/apt/sources.list.d/viva64.list https://files.viva64.com/etc/viva64.list
             sudo apt-get update
             sudo apt-get install -y pvs-studio
             pvs-studio-analyzer credentials -o pvs-studio.lic $PVS_STUDIO_LICENSE

.gitignore

@@ -1,7 +1,5 @@
-## Misc artifacts
+## OSX artifacts
 .DS_Store
-.claude
-.vscode
 
 ## Dear ImGui artifacts
 imgui.ini
@@ -57,6 +55,9 @@ examples/example_sdl3_wgpu/web/*
 .idea
 cmake-build-*
 
+## VS code artifacts
+.vscode
+
 ## Unix executables from our example Makefiles
 examples/example_apple_metal/example_apple_metal
 examples/example_apple_opengl2/example_apple_opengl2
@@ -72,7 +73,6 @@ examples/example_sdl2_opengl3/example_sdl2_opengl3
 examples/example_sdl2_sdlrenderer2/example_sdl2_sdlrenderer2
 examples/example_sdl2_vulkan/example_sdl2_vulkan
 examples/example_sdl3_metal/example_sdl3_metal
-examples/example_sdl3_metal4/example_sdl3_metal4
 examples/example_sdl3_opengl3/example_sdl3_opengl3
 examples/example_sdl3_sdlgpu3/example_sdl3_sdlgpu3
 examples/example_sdl3_sdlrenderer3/example_sdl3_sdlrenderer3

backends/imgui_impl_allegro5.cpp

@@ -9,8 +9,8 @@
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 // Missing features or Issues:
 //  [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert vertices manually.
-//  [ ] Renderer: Missing support for DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest callbacks: Allegro5 cannot enable/disable LINEAR bitmap flags after creation.
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -22,7 +22,6 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState (others cannot be supported by Allegro5). (#9378)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() and platform_io.ClearPlatformHandlers() on shutdown.
 //  2025-08-12: Inputs: fixed missing support for ImGuiKey_PrintScreen under Windows, as raw Allegro 5 does not receive it.
 //  2025-08-12: Added ImGui_ImplAllegro5_SetDisplay() function to change current ALLEGRO_DISPLAY, as Allegro applications often need to do that.
@@ -138,10 +137,7 @@ static void ImGui_ImplAllegro5_SetupRenderState(ImDrawData* draw_data)
     }
 }
 
-// Draw callbacks
-static void ImGui_ImplAllegro5_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*) {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-
-// Render function
+// Render function.
 void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
 {
     // Avoid rendering when minimized
@@ -157,7 +153,6 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
 
     // Backup Allegro state that will be modified
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     ALLEGRO_TRANSFORM last_transform = *al_get_current_transform();
     ALLEGRO_TRANSFORM last_projection_transform = *al_get_current_projection_transform();
     int last_clip_x, last_clip_y, last_clip_w, last_clip_h;
@@ -214,7 +209,8 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
             if (pcmd->UserCallback)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplAllegro5_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplAllegro5_SetupRenderState(draw_data);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -491,12 +487,11 @@ bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
 
     ImGui_ImplAllegro5_SetDisplay(display);
 
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 #if ALLEGRO_HAS_CLIPBOARD
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Platform_SetClipboardTextFn = ImGui_ImplAllegro5_SetClipboardText;
     platform_io.Platform_GetClipboardTextFn = ImGui_ImplAllegro5_GetClipboardText;
 #endif
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplAllegro5_DrawCallback_ResetRenderState;
 
     return true;
 }

backends/imgui_impl_allegro5.h

@@ -9,8 +9,8 @@
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 // Missing features or Issues:
 //  [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert vertices manually.
-//  [ ] Renderer: Missing support for DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest callbacks: Allegro5 cannot enable/disable LINEAR bitmap flags after creation.
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_android.cpp

@@ -8,6 +8,7 @@
 //  [ ] Platform: Clipboard support.
 //  [ ] Platform: Gamepad support.
 //  [ ] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'. FIXME: Check if this is even possible with Android.
+//  [ ] Platform: Multi-viewport support (multiple windows). Not meaningful on Android.
 // Important:
 //  - Consider using SDL or GLFW backend on Android, which will be more full-featured than this.
 //  - FIXME: On-screen keyboard currently needs to be enabled by the application (see examples/ and issue #3446)

backends/imgui_impl_android.h

@@ -8,6 +8,7 @@
 //  [ ] Platform: Clipboard support.
 //  [ ] Platform: Gamepad support.
 //  [ ] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'. FIXME: Check if this is even possible with Android.
+//  [ ] Platform: Multi-viewport support (multiple windows). Not meaningful on Android.
 // Important:
 //  - Consider using SDL or GLFW backend on Android, which will be more full-featured than this.
 //  - FIXME: On-screen keyboard currently needs to be enabled by the application (see examples/ and issue #3446)

backends/imgui_impl_dx10.cpp

@@ -5,6 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -16,8 +17,8 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: DirectX10: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. Obsoleting samplers from ImGui_ImplDX10_RenderState. (#9378)
-//  2026-01-19: DirectX10: Added 'SamplerNearest' in ImGui_ImplDX10_RenderState. Renamed 'SamplerDefault' to 'SamplerLinear'. 
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2026-01-19: DirectX11: Added 'SamplerNearest' in ImGui_ImplDX11_RenderState. Renamed 'SamplerDefault' to 'SamplerLinear'. 
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: DirectX10: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
 //  2025-05-07: DirectX10: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
@@ -99,6 +100,10 @@ static ImGui_ImplDX10_Data* ImGui_ImplDX10_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX10_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX10_InitMultiViewportSupport();
+static void ImGui_ImplDX10_ShutdownMultiViewportSupport();
+
 // Functions
 static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device* device)
 {
@@ -154,11 +159,6 @@ static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device*
     device->RSSetState(bd->pRasterizerState);
 }
 
-// Draw callbacks
-static void ImGui_ImplDX10_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)       {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplDX10_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)       { ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData(); bd->pd3dDevice->PSSetSamplers(0, 1, &bd->pTexSamplerLinear); }
-static void ImGui_ImplDX10_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)      { ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData(); bd->pd3dDevice->PSSetSamplers(0, 1, &bd->pTexSamplerNearest); }
-
 // Render function
 void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
 {
@@ -183,7 +183,7 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
         bd->VertexBufferSize = draw_data->TotalVtxCount + 5000;
         D3D10_BUFFER_DESC desc = {};
         desc.Usage = D3D10_USAGE_DYNAMIC;
-        desc.ByteWidth = (UINT)bd->VertexBufferSize * sizeof(ImDrawVert);
+        desc.ByteWidth = bd->VertexBufferSize * sizeof(ImDrawVert);
         desc.BindFlags = D3D10_BIND_VERTEX_BUFFER;
         desc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
         desc.MiscFlags = 0;
@@ -197,7 +197,7 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
         bd->IndexBufferSize = draw_data->TotalIdxCount + 10000;
         D3D10_BUFFER_DESC desc = {};
         desc.Usage = D3D10_USAGE_DYNAMIC;
-        desc.ByteWidth = (UINT)bd->IndexBufferSize * sizeof(ImDrawIdx);
+        desc.ByteWidth = bd->IndexBufferSize * sizeof(ImDrawIdx);
         desc.BindFlags = D3D10_BIND_INDEX_BUFFER;
         desc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
         if (device->CreateBuffer(&desc, nullptr, &bd->pIB) < 0)
@@ -266,6 +266,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     ImGui_ImplDX10_RenderState render_state;
     render_state.Device = bd->pd3dDevice;
+    render_state.SamplerLinear = bd->pTexSamplerLinear;
+    render_state.SamplerNearest = bd->pTexSamplerNearest;
     render_state.VertexConstantBuffer = bd->pVertexConstantBuffer;
     platform_io.Renderer_RenderState = &render_state;
 
@@ -283,7 +285,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
             if (pcmd->UserCallback != nullptr)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplDX10_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplDX10_SetupRenderState(draw_data, device);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -613,12 +616,10 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
     io.BackendRendererName = "imgui_impl_dx10";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
     io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = D3D10_REQ_TEXTURE2D_U_OR_V_DIMENSION;
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplDX10_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplDX10_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplDX10_DrawCallback_SetSamplerNearest;
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = nullptr;
@@ -635,6 +636,8 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
     if (pDXGIAdapter) pDXGIAdapter->Release();
     bd->pd3dDevice->AddRef();
 
+    ImGui_ImplDX10_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -645,13 +648,14 @@ void ImGui_ImplDX10_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ImGui_ImplDX10_ShutdownMultiViewportSupport();
     ImGui_ImplDX10_InvalidateDeviceObjects();
     if (bd->pFactory) { bd->pFactory->Release(); }
     if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     platform_io.ClearRendererHandlers();
     IM_DELETE(bd);
 }
@@ -666,6 +670,131 @@ void ImGui_ImplDX10_NewFrame()
             IM_ASSERT(0 && "ImGui_ImplDX10_CreateDeviceObjects() failed!");
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplDX10_ViewportData
+{
+    IDXGISwapChain*         SwapChain;
+    ID3D10RenderTargetView* RTView;
+
+    ImGui_ImplDX10_ViewportData()   { SwapChain = nullptr; RTView = nullptr; }
+    ~ImGui_ImplDX10_ViewportData()  { IM_ASSERT(SwapChain == nullptr && RTView == nullptr); }
+};
+
+static void ImGui_ImplDX10_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    ImGui_ImplDX10_ViewportData* vd = IM_NEW(ImGui_ImplDX10_ViewportData)();
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+
+    // Create swap chain
+    DXGI_SWAP_CHAIN_DESC sd;
+    ZeroMemory(&sd, sizeof(sd));
+    sd.BufferDesc.Width = (UINT)viewport->Size.x;
+    sd.BufferDesc.Height = (UINT)viewport->Size.y;
+    sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
+    sd.SampleDesc.Count = 1;
+    sd.SampleDesc.Quality = 0;
+    sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
+    sd.BufferCount = 1;
+    sd.OutputWindow = hwnd;
+    sd.Windowed = TRUE;
+    sd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
+    sd.Flags = 0;
+
+    IM_ASSERT(vd->SwapChain == nullptr && vd->RTView == nullptr);
+    bd->pFactory->CreateSwapChain(bd->pd3dDevice, &sd, &vd->SwapChain);
+    bd->pFactory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_WINDOW_CHANGES); // Disable e.g. Alt+Enter
+
+    // Create the render target
+    if (vd->SwapChain)
+    {
+        ID3D10Texture2D* pBackBuffer;
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX10_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 here since we didn't create the data for it.
+    if (ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData)
+    {
+        if (vd->SwapChain)
+            vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        if (vd->RTView)
+            vd->RTView->Release();
+        vd->RTView = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX10_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData;
+    if (vd->RTView)
+    {
+        vd->RTView->Release();
+        vd->RTView = nullptr;
+    }
+    if (vd->SwapChain)
+    {
+        ID3D10Texture2D* pBackBuffer = nullptr;
+        vd->SwapChain->ResizeBuffers(0, (UINT)size.x, (UINT)size.y, DXGI_FORMAT_UNKNOWN, 0);
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        if (pBackBuffer == nullptr) { fprintf(stderr, "ImGui_ImplDX10_SetWindowSize() failed creating buffers.\n"); return; }
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX10_RenderViewport(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData;
+    ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+    bd->pd3dDevice->OMSetRenderTargets(1, &vd->RTView, nullptr);
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+        bd->pd3dDevice->ClearRenderTargetView(vd->RTView, (float*)&clear_color);
+    ImGui_ImplDX10_RenderDrawData(viewport->DrawData);
+}
+
+static void ImGui_ImplDX10_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData;
+    if (vd->SwapChain)
+        vd->SwapChain->Present(0, 0); // Present without vsync
+}
+
+void ImGui_ImplDX10_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX10_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX10_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX10_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX10_RenderViewport;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX10_SwapBuffers;
+}
+
+void ImGui_ImplDX10_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx10.h

@@ -5,6 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -41,9 +42,9 @@ IMGUI_IMPL_API void     ImGui_ImplDX10_UpdateTexture(ImTextureData* tex);
 struct ImGui_ImplDX10_RenderState
 {
     ID3D10Device*           Device;
+    ID3D10SamplerState*     SamplerLinear;
+    ID3D10SamplerState*     SamplerNearest;
     ID3D10Buffer*           VertexConstantBuffer;
-    //ID3D10SamplerState*   SamplerLinear;          // Use ImDrawList::AddCallback(ImGui::GetPlatform().DrawCallback_SetSamplerLinear)
-    //ID3D10SamplerState*   SamplerNearest;         // Use ImDrawList::AddCallback(ImGui::GetPlatform().DrawCallback_SetSamplerNearest)
 };
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx11.cpp

@@ -6,6 +6,7 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -17,11 +18,12 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: DirectX11: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. Obsoleting samplers from ImGui_ImplDX11_RenderState. (#9378)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-01-19: DirectX11: Added 'SamplerNearest' in ImGui_ImplDX11_RenderState. Renamed 'SamplerDefault' to 'SamplerLinear'.
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: DirectX11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
 //  2025-05-07: DirectX11: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
+//  2025-02-24: [Docking] Added undocumented ImGui_ImplDX11_SetSwapChainDescs() to configure swap chain creation for secondary viewports.
 //  2025-01-06: DirectX11: Expose VertexConstantBuffer in ImGui_ImplDX11_RenderState. Reset projection matrix in ImDrawCallback_ResetRenderState handler.
 //  2024-10-07: DirectX11: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2024-10-07: DirectX11: Expose selected render state in ImGui_ImplDX11_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
@@ -86,7 +88,7 @@ struct ImGui_ImplDX11_Data
     ID3D11DepthStencilState*    pDepthStencilState;
     int                         VertexBufferSize;
     int                         IndexBufferSize;
-    ImGui_ImplDX11_RenderState* RenderState;            // == (ImGui_ImplDX11_RenderState*)ImGui::GetPlatformIO().Renderer_RenderState during rendering.
+    ImVector<DXGI_SWAP_CHAIN_DESC> SwapChainDescsForViewports;
 
     ImGui_ImplDX11_Data()       { memset((void*)this, 0, sizeof(*this)); VertexBufferSize = 5000; IndexBufferSize = 10000; }
 };
@@ -103,6 +105,10 @@ static ImGui_ImplDX11_Data* ImGui_ImplDX11_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX11_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX11_InitMultiViewportSupport();
+static void ImGui_ImplDX11_ShutdownMultiViewportSupport();
+
 // Functions
 static void ImGui_ImplDX11_SetupRenderState(const ImDrawData* draw_data, ID3D11DeviceContext* device_ctx)
 {
@@ -161,11 +167,6 @@ static void ImGui_ImplDX11_SetupRenderState(const ImDrawData* draw_data, ID3D11D
     device_ctx->RSSetState(bd->pRasterizerState);
 }
 
-// Draw callbacks
-static void ImGui_ImplDX11_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)       {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplDX11_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)       { ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData(); bd->RenderState->DeviceContext->PSSetSamplers(0, 1, &bd->pTexSamplerLinear); }
-static void ImGui_ImplDX11_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)      { ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData(); bd->RenderState->DeviceContext->PSSetSamplers(0, 1, &bd->pTexSamplerNearest); }
-
 // Render function
 void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
 {
@@ -190,7 +191,7 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
         bd->VertexBufferSize = draw_data->TotalVtxCount + 5000;
         D3D11_BUFFER_DESC desc = {};
         desc.Usage = D3D11_USAGE_DYNAMIC;
-        desc.ByteWidth = (UINT)bd->VertexBufferSize * sizeof(ImDrawVert);
+        desc.ByteWidth = bd->VertexBufferSize * sizeof(ImDrawVert);
         desc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
         desc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
         desc.MiscFlags = 0;
@@ -203,7 +204,7 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
         bd->IndexBufferSize = draw_data->TotalIdxCount + 10000;
         D3D11_BUFFER_DESC desc = {};
         desc.Usage = D3D11_USAGE_DYNAMIC;
-        desc.ByteWidth = (UINT)bd->IndexBufferSize * sizeof(ImDrawIdx);
+        desc.ByteWidth = bd->IndexBufferSize * sizeof(ImDrawIdx);
         desc.BindFlags = D3D11_BIND_INDEX_BUFFER;
         desc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
         if (bd->pd3dDevice->CreateBuffer(&desc, nullptr, &bd->pIB) < 0)
@@ -281,8 +282,10 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX11_RenderState render_state;
     render_state.Device = bd->pd3dDevice;
     render_state.DeviceContext = bd->pd3dDeviceContext;
+    render_state.SamplerLinear = bd->pTexSamplerLinear;
+    render_state.SamplerNearest = bd->pTexSamplerNearest;
     render_state.VertexConstantBuffer = bd->pVertexConstantBuffer;
-    platform_io.Renderer_RenderState = bd->RenderState = &render_state;
+    platform_io.Renderer_RenderState = &render_state;
 
     // Render command lists
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
@@ -298,7 +301,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
             if (pcmd->UserCallback != nullptr)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplDX11_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplDX11_SetupRenderState(draw_data, device);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -324,7 +328,7 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
         global_idx_offset += draw_list->IdxBuffer.Size;
         global_vtx_offset += draw_list->VtxBuffer.Size;
     }
-    platform_io.Renderer_RenderState = bd->RenderState = nullptr;
+    platform_io.Renderer_RenderState = nullptr;
 
     // Restore modified DX state
     device->RSSetScissorRects(old.ScissorRectsCount, old.ScissorRects);
@@ -630,12 +634,10 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
     io.BackendRendererName = "imgui_impl_dx11";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
     io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION;
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplDX11_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplDX11_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplDX11_DrawCallback_SetSamplerNearest;
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = nullptr;
@@ -655,6 +657,8 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
     bd->pd3dDevice->AddRef();
     bd->pd3dDeviceContext->AddRef();
 
+    ImGui_ImplDX11_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -665,6 +669,7 @@ void ImGui_ImplDX11_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ImGui_ImplDX11_ShutdownMultiViewportSupport();
     ImGui_ImplDX11_InvalidateDeviceObjects();
     if (bd->pFactory)             { bd->pFactory->Release(); }
     if (bd->pd3dDevice)           { bd->pd3dDevice->Release(); }
@@ -672,7 +677,7 @@ void ImGui_ImplDX11_Shutdown()
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     platform_io.ClearRendererHandlers();
     IM_DELETE(bd);
 }
@@ -687,6 +692,152 @@ void ImGui_ImplDX11_NewFrame()
             IM_ASSERT(0 && "ImGui_ImplDX11_CreateDeviceObjects() failed!");
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplDX11_ViewportData
+{
+    IDXGISwapChain*                 SwapChain;
+    ID3D11RenderTargetView*         RTView;
+
+    ImGui_ImplDX11_ViewportData()   { SwapChain = nullptr; RTView = nullptr; }
+    ~ImGui_ImplDX11_ViewportData()  { IM_ASSERT(SwapChain == nullptr && RTView == nullptr); }
+};
+
+// Multi-Viewports: configure templates used when creating swapchains for secondary viewports. Will try them in order.
+// This is intentionally not declared in the .h file yet, so you will need to copy this declaration:
+void ImGui_ImplDX11_SetSwapChainDescs(const DXGI_SWAP_CHAIN_DESC* desc_templates, int desc_templates_count);
+void ImGui_ImplDX11_SetSwapChainDescs(const DXGI_SWAP_CHAIN_DESC* desc_templates, int desc_templates_count)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    bd->SwapChainDescsForViewports.resize(desc_templates_count);
+    memcpy(bd->SwapChainDescsForViewports.Data, desc_templates, sizeof(DXGI_SWAP_CHAIN_DESC));
+}
+
+static void ImGui_ImplDX11_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    ImGui_ImplDX11_ViewportData* vd = IM_NEW(ImGui_ImplDX11_ViewportData)();
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+    IM_ASSERT(vd->SwapChain == nullptr && vd->RTView == nullptr);
+
+    // Create swap chain
+    HRESULT hr = DXGI_ERROR_UNSUPPORTED;
+    for (const DXGI_SWAP_CHAIN_DESC& sd_template : bd->SwapChainDescsForViewports)
+    {
+        IM_ASSERT(sd_template.BufferDesc.Width == 0 && sd_template.BufferDesc.Height == 0 && sd_template.OutputWindow == nullptr);
+        DXGI_SWAP_CHAIN_DESC sd = sd_template;
+        sd.BufferDesc.Width = (UINT)viewport->Size.x;
+        sd.BufferDesc.Height = (UINT)viewport->Size.y;
+        sd.OutputWindow = hwnd;
+        hr = bd->pFactory->CreateSwapChain(bd->pd3dDevice, &sd, &vd->SwapChain);
+        if (SUCCEEDED(hr))
+            break;
+    }
+    IM_ASSERT(SUCCEEDED(hr));
+    bd->pFactory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_WINDOW_CHANGES); // Disable e.g. Alt+Enter
+
+    // Create the render target
+    if (vd->SwapChain != nullptr)
+    {
+        ID3D11Texture2D* pBackBuffer;
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX11_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == nullptr since we didn't create the data for it.
+    if (ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData)
+    {
+        if (vd->SwapChain)
+            vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        if (vd->RTView)
+            vd->RTView->Release();
+        vd->RTView = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX11_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData;
+    if (vd->RTView)
+    {
+        vd->RTView->Release();
+        vd->RTView = nullptr;
+    }
+    if (vd->SwapChain)
+    {
+        ID3D11Texture2D* pBackBuffer = nullptr;
+        vd->SwapChain->ResizeBuffers(0, (UINT)size.x, (UINT)size.y, DXGI_FORMAT_UNKNOWN, 0);
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        if (pBackBuffer == nullptr) { fprintf(stderr, "ImGui_ImplDX11_SetWindowSize() failed creating buffers.\n"); return; }
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX11_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData;
+    ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+    bd->pd3dDeviceContext->OMSetRenderTargets(1, &vd->RTView, nullptr);
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+        bd->pd3dDeviceContext->ClearRenderTargetView(vd->RTView, (float*)&clear_color);
+    ImGui_ImplDX11_RenderDrawData(viewport->DrawData);
+}
+
+static void ImGui_ImplDX11_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData;
+    if (vd->SwapChain)
+        vd->SwapChain->Present(0, 0); // Present without vsync
+}
+
+static void ImGui_ImplDX11_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX11_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX11_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX11_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX11_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX11_SwapBuffers;
+
+    // Default swapchain format
+    DXGI_SWAP_CHAIN_DESC sd;
+    ZeroMemory(&sd, sizeof(sd));
+    sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
+    sd.SampleDesc.Count = 1;
+    sd.SampleDesc.Quality = 0;
+    sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
+    sd.BufferCount = 1;
+    sd.Windowed = TRUE;
+    sd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
+    sd.Flags = 0;
+    ImGui_ImplDX11_SetSwapChainDescs(&sd, 1);
+}
+
+static void ImGui_ImplDX11_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx11.h

@@ -6,6 +6,7 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -44,9 +45,9 @@ struct ImGui_ImplDX11_RenderState
 {
     ID3D11Device*           Device;
     ID3D11DeviceContext*    DeviceContext;
+    ID3D11SamplerState*     SamplerLinear;
+    ID3D11SamplerState*     SamplerNearest;
     ID3D11Buffer*           VertexConstantBuffer;
-    //ID3D11SamplerState*   SamplerLinear;          // Use ImDrawList::AddCallback(ImGui::GetPlatform().DrawCallback_SetSamplerLinear)
-    //ID3D11SamplerState*   SamplerNearest;         // Use ImDrawList::AddCallback(ImGui::GetPlatform().DrawCallback_SetSamplerNearest)
 };
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx12.cpp

@@ -6,6 +6,8 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//      FIXME: The transition from removing a viewport and moving the window in an existing hosted viewport tends to flicker.
 
 // The aim of imgui_impl_dx12.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -20,7 +22,8 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-10-23: [Docking] DirectX12: Fixed an issue in synchronization logic improving rendering throughput for secondary viewports. (#8961, #9025)
 //  2025-10-11: DirectX12: Reuse texture upload buffer and grow it only when necessary. (#9002)
 //  2025-09-29: DirectX12: Rework synchronization logic. (#8961)
 //  2025-09-29: DirectX12: Enable swapchain tearing to eliminate viewports framerate throttling. (#8965)
@@ -92,8 +95,6 @@ struct ImGui_ImplDX12_Texture
 struct ImGui_ImplDX12_Data
 {
     ImGui_ImplDX12_InitInfo     InitInfo;
-    ImGui_ImplDX12_RenderState* RenderState;
-        
     IDXGIFactory5*              pdxgiFactory;
     ID3D12Device*               pd3dDevice;
     ID3D12RootSignature*        pRootSignatureLinear;
@@ -118,9 +119,6 @@ struct ImGui_ImplDX12_Data
     UINT                        pTexUploadBufferSize;
     void*                       pTexUploadBufferMapped;
 
-    ImGui_ImplDX12_RenderBuffers* pFrameResources;
-    UINT                        frameIndex;
-
     ImGui_ImplDX12_Data()       { memset((void*)this, 0, sizeof(*this)); }
 };
 
@@ -140,20 +138,98 @@ struct ImGui_ImplDX12_RenderBuffers
     int                 VertexBufferSize;
 };
 
+// Buffers used for secondary viewports created by the multi-viewports systems
+struct ImGui_ImplDX12_FrameContext
+{
+    UINT64                          FenceValue;
+    ID3D12CommandAllocator*         CommandAllocator;
+    ID3D12Resource*                 RenderTarget;
+    D3D12_CPU_DESCRIPTOR_HANDLE     RenderTargetCpuDescriptors;
+};
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+// Main viewport created by application will only use the Resources field.
+// Secondary viewports created by this backend will use all the fields (including Window fields),
+struct ImGui_ImplDX12_ViewportData
+{
+    // Window
+    ID3D12CommandQueue*             CommandQueue;
+    ID3D12GraphicsCommandList*      CommandList;
+    ID3D12DescriptorHeap*           RtvDescHeap;
+    IDXGISwapChain3*                SwapChain;
+    HANDLE                          SwapChainWaitableObject;
+    UINT                            NumFramesInFlight;
+    ImGui_ImplDX12_FrameContext*    FrameCtx;
+
+    // Render buffers
+    UINT                            FrameIndex;
+    ImGui_ImplDX12_RenderBuffers*   FrameRenderBuffers;
+
+    ImGui_ImplDX12_ViewportData(UINT num_frames_in_flight)
+    {
+        CommandQueue = nullptr;
+        CommandList = nullptr;
+        RtvDescHeap = nullptr;
+        SwapChain = nullptr;
+        SwapChainWaitableObject = nullptr;
+        NumFramesInFlight = num_frames_in_flight;
+        FrameCtx = new ImGui_ImplDX12_FrameContext[NumFramesInFlight];
+        FrameIndex = 0;
+        FrameRenderBuffers = new ImGui_ImplDX12_RenderBuffers[NumFramesInFlight];
+
+        for (UINT i = 0; i < NumFramesInFlight; ++i)
+        {
+            FrameCtx[i].FenceValue = 0;
+            FrameCtx[i].CommandAllocator = nullptr;
+            FrameCtx[i].RenderTarget = nullptr;
+
+            // Create buffers with a default size (they will later be grown as needed)
+            FrameRenderBuffers[i].IndexBuffer = nullptr;
+            FrameRenderBuffers[i].VertexBuffer = nullptr;
+            FrameRenderBuffers[i].VertexBufferSize = 5000;
+            FrameRenderBuffers[i].IndexBufferSize = 10000;
+        }
+    }
+    ~ImGui_ImplDX12_ViewportData()
+    {
+        IM_ASSERT(CommandQueue == nullptr && CommandList == nullptr);
+        IM_ASSERT(RtvDescHeap == nullptr);
+        IM_ASSERT(SwapChain == nullptr);
+        IM_ASSERT(SwapChainWaitableObject == nullptr);
+
+        for (UINT i = 0; i < NumFramesInFlight; ++i)
+        {
+            IM_ASSERT(FrameCtx[i].CommandAllocator == nullptr && FrameCtx[i].RenderTarget == nullptr);
+            IM_ASSERT(FrameRenderBuffers[i].IndexBuffer == nullptr && FrameRenderBuffers[i].VertexBuffer == nullptr);
+        }
+
+        delete[] FrameCtx; FrameCtx = nullptr;
+        delete[] FrameRenderBuffers; FrameRenderBuffers = nullptr;
+    }
+};
+
 struct VERTEX_CONSTANT_BUFFER_DX12
 {
     float   mvp[4][4];
 };
 
+// Forward Declarations
+static void ImGui_ImplDX12_InitMultiViewportSupport();
+static void ImGui_ImplDX12_ShutdownMultiViewportSupport();
+
+// FIXME-WIP: Allow user to forward declare those two, for until we come up with a backend agnostic API to do this. (#9173)
+void ImGui_ImplDX12_SetupSamplerLinear(ID3D12GraphicsCommandList* command_list);
+void ImGui_ImplDX12_SetupSamplerNearest(ID3D12GraphicsCommandList* command_list);
+
 // Functions
-static void ImGui_ImplDX12_SetupSamplerLinear(ID3D12GraphicsCommandList* command_list)
+void ImGui_ImplDX12_SetupSamplerLinear(ID3D12GraphicsCommandList* command_list)
 {
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
     command_list->SetPipelineState(bd->pPipelineStateLinear);
     command_list->SetGraphicsRootSignature(bd->pRootSignatureLinear);
 }
 
-static void ImGui_ImplDX12_SetupSamplerNearest(ID3D12GraphicsCommandList* command_list)
+void ImGui_ImplDX12_SetupSamplerNearest(ID3D12GraphicsCommandList* command_list)
 {
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
     command_list->SetPipelineState(bd->pPipelineStateNearest);
@@ -199,7 +275,7 @@ static void ImGui_ImplDX12_SetupRenderState(ImDrawData* draw_data, ID3D12Graphic
     command_list->IASetVertexBuffers(0, 1, &vbv);
     D3D12_INDEX_BUFFER_VIEW ibv = {};
     ibv.BufferLocation = fr->IndexBuffer->GetGPUVirtualAddress();
-    ibv.SizeInBytes = (UINT)fr->IndexBufferSize * sizeof(ImDrawIdx);
+    ibv.SizeInBytes = fr->IndexBufferSize * sizeof(ImDrawIdx);
     ibv.Format = sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT;
     command_list->IASetIndexBuffer(&ibv);
     command_list->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
@@ -219,11 +295,6 @@ static inline void SafeRelease(T*& res)
     res = nullptr;
 }
 
-// Draw callbacks
-static void ImGui_ImplDX12_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)   {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplDX12_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)   { ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData(); ImGui_ImplDX12_SetupSamplerLinear(bd->RenderState->CommandList); }
-static void ImGui_ImplDX12_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)  { ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData(); ImGui_ImplDX12_SetupSamplerNearest(bd->RenderState->CommandList); }
-
 // Render function
 void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandList* command_list)
 {
@@ -240,8 +311,9 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
 
     // FIXME: We are assuming that this only gets called once per frame!
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
-    bd->frameIndex = bd->frameIndex + 1;
-    ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[bd->frameIndex % bd->numFramesInFlight];
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)draw_data->OwnerViewport->RendererUserData;
+    ImGui_ImplDX12_RenderBuffers* fr = &vd->FrameRenderBuffers[vd->FrameIndex % bd->numFramesInFlight];
+    vd->FrameIndex++;
 
     // Create and grow vertex/index buffers if needed
     if (fr->VertexBuffer == nullptr || fr->VertexBufferSize < draw_data->TotalVtxCount)
@@ -321,7 +393,7 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     ImGui_ImplDX12_RenderState render_state;
     render_state.Device = bd->pd3dDevice;
     render_state.CommandList = command_list;
-    platform_io.Renderer_RenderState = bd->RenderState = &render_state;
+    platform_io.Renderer_RenderState = &render_state;
 
     // Render command lists
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
@@ -338,7 +410,7 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
             {
                 // User callback, registered via ImDrawList::AddCallback()
                 // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
-                if (pcmd->UserCallback == ImGui_ImplDX12_DrawCallback_ResetRenderState)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplDX12_SetupRenderState(draw_data, command_list, fr);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -365,7 +437,7 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
         global_idx_offset += draw_list->IdxBuffer.Size;
         global_vtx_offset += draw_list->VtxBuffer.Size;
     }
-    platform_io.Renderer_RenderState = bd->RenderState = nullptr;
+    platform_io.Renderer_RenderState = nullptr;
 }
 
 static void ImGui_ImplDX12_DestroyTexture(ImTextureData* tex)
@@ -668,7 +740,7 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
         bd->pd3dDevice->CreateRootSignature(0, blob->GetBufferPointer(), blob->GetBufferSize(), IID_PPV_ARGS(&bd->pRootSignatureLinear));
         blob->Release();
 
-        // Nearest sampler
+        // Root Signature for ImDrawCallback_SetSamplerNearest
         staticSampler[0].Filter = D3D12_FILTER_MIN_MAG_MIP_POINT;
         if (D3D12SerializeRootSignatureFn(&desc, D3D_ROOT_SIGNATURE_VERSION_1, &blob, nullptr) != S_OK)
             return false;
@@ -817,6 +889,7 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
         return false;
     }
 
+    // Pipeline State for ImDrawCallback_SetSamplerNearest
     psoDesc.pRootSignature = bd->pRootSignatureNearest;
 
     result_pipeline_state = bd->pd3dDevice->CreateGraphicsPipelineState(&psoDesc, IID_PPV_ARGS(&bd->pPipelineStateNearest));
@@ -842,6 +915,13 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
     return true;
 }
 
+static void ImGui_ImplDX12_DestroyRenderBuffers(ImGui_ImplDX12_RenderBuffers* render_buffers)
+{
+    SafeRelease(render_buffers->IndexBuffer);
+    SafeRelease(render_buffers->VertexBuffer);
+    render_buffers->IndexBufferSize = render_buffers->VertexBufferSize = 0;
+}
+
 void    ImGui_ImplDX12_InvalidateDeviceObjects()
 {
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
@@ -874,13 +954,6 @@ void    ImGui_ImplDX12_InvalidateDeviceObjects()
     for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
         if (tex->RefCount == 1)
             ImGui_ImplDX12_DestroyTexture(tex);
-
-    for (UINT i = 0; i < bd->numFramesInFlight; i++)
-    {
-        ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[i];
-        SafeRelease(fr->IndexBuffer);
-        SafeRelease(fr->VertexBuffer);
-    }
 }
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
@@ -929,11 +1002,15 @@ bool ImGui_ImplDX12_Init(ImGui_ImplDX12_InitInfo* init_info)
     io.BackendRendererName = "imgui_impl_dx12";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
     io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplDX12_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplDX12_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplDX12_DrawCallback_SetSamplerNearest;
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplDX12_InitMultiViewportSupport();
+
+    // Create a dummy ImGui_ImplDX12_ViewportData holder for the main viewport,
+    // Since this is created and managed by the application, we will only use the ->Resources[] fields.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->RendererUserData = IM_NEW(ImGui_ImplDX12_ViewportData)(bd->numFramesInFlight);
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     if (init_info->SrvDescriptorAllocFn == nullptr)
@@ -941,18 +1018,6 @@ bool ImGui_ImplDX12_Init(ImGui_ImplDX12_InitInfo* init_info)
 #endif
     IM_ASSERT(init_info->SrvDescriptorAllocFn != nullptr && init_info->SrvDescriptorFreeFn != nullptr);
 
-    // Create buffers with a default size (they will later be grown as needed)
-    bd->frameIndex = UINT_MAX;
-    bd->pFrameResources = new ImGui_ImplDX12_RenderBuffers[bd->numFramesInFlight];
-    for (int i = 0; i < (int)bd->numFramesInFlight; i++)
-    {
-        ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[i];
-        fr->IndexBuffer = nullptr;
-        fr->VertexBuffer = nullptr;
-        fr->IndexBufferSize = 10000;
-        fr->VertexBufferSize = 5000;
-    }
-
     return true;
 }
 
@@ -979,7 +1044,6 @@ bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FO
     bool ret = ImGui_ImplDX12_Init(&init_info);
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
     bd->commandQueueOwned = true;
-
     ImGuiIO& io = ImGui::GetIO();
     io.BackendFlags &= ~ImGuiBackendFlags_RendererHasTextures; // Using legacy ImGui_ImplDX12_Init() call with 1 SRV descriptor we cannot support multiple textures.
 
@@ -994,12 +1058,23 @@ void ImGui_ImplDX12_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    // Manually delete main viewport render resources in-case we haven't initialized for viewports
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    if (ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)main_viewport->RendererUserData)
+    {
+        // We could just call ImGui_ImplDX12_DestroyWindow(main_viewport) as a convenience but that would be misleading since we only use data->Resources[]
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+            ImGui_ImplDX12_DestroyRenderBuffers(&vd->FrameRenderBuffers[i]);
+        IM_DELETE(vd);
+        main_viewport->RendererUserData = nullptr;
+    }
+
+    ImGui_ImplDX12_ShutdownMultiViewportSupport();
     ImGui_ImplDX12_InvalidateDeviceObjects();
-    delete[] bd->pFrameResources;
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     platform_io.ClearRendererHandlers();
     IM_DELETE(bd);
 }
@@ -1014,6 +1089,254 @@ void ImGui_ImplDX12_NewFrame()
             IM_ASSERT(0 && "ImGui_ImplDX12_CreateDeviceObjects() failed!");
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplDX12_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = IM_NEW(ImGui_ImplDX12_ViewportData)(bd->numFramesInFlight);
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+
+    // Use shared command queue from init info
+    vd->FrameIndex = 0;
+    vd->CommandQueue = bd->pCommandQueue;
+
+    // Create command allocator.
+    HRESULT res = S_OK;
+    for (UINT i = 0; i < bd->numFramesInFlight; ++i)
+    {
+        res = bd->pd3dDevice->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&vd->FrameCtx[i].CommandAllocator));
+        IM_ASSERT(res == S_OK);
+    }
+
+    // Create command list.
+    res = bd->pd3dDevice->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, vd->FrameCtx[0].CommandAllocator, nullptr, IID_PPV_ARGS(&vd->CommandList));
+    IM_ASSERT(res == S_OK);
+    vd->CommandList->Close();
+
+    // Create swap chain
+    // FIXME-VIEWPORT: May want to copy/inherit swap chain settings from the user/application.
+    DXGI_SWAP_CHAIN_DESC1 sd1;
+    ZeroMemory(&sd1, sizeof(sd1));
+    sd1.BufferCount = bd->numFramesInFlight;
+    sd1.Width = (UINT)viewport->Size.x;
+    sd1.Height = (UINT)viewport->Size.y;
+    sd1.Format = bd->RTVFormat;
+    sd1.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
+    sd1.SampleDesc.Count = 1;
+    sd1.SampleDesc.Quality = 0;
+    sd1.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
+    sd1.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED;
+    sd1.Scaling = DXGI_SCALING_NONE;
+    sd1.Stereo = FALSE;
+    sd1.Flags = DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT;
+
+    if (bd->tearingSupport)
+        sd1.Flags |= DXGI_SWAP_CHAIN_FLAG_ALLOW_TEARING;
+
+    IDXGISwapChain1* swap_chain = nullptr;
+    res = bd->pdxgiFactory->CreateSwapChainForHwnd(vd->CommandQueue, hwnd, &sd1, nullptr, nullptr, &swap_chain);
+    IM_ASSERT(res == S_OK);
+    res = bd->pdxgiFactory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_WINDOW_CHANGES); // Disable e.g. Alt+Enter
+    IM_ASSERT(res == S_OK);
+
+    // Or swapChain.As(&mSwapChain)
+    IM_ASSERT(vd->SwapChain == nullptr);
+    swap_chain->QueryInterface(IID_PPV_ARGS(&vd->SwapChain));
+    swap_chain->Release();
+
+    // Create the render targets and waitable object
+    if (vd->SwapChain)
+    {
+        D3D12_DESCRIPTOR_HEAP_DESC desc = {};
+        desc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV;
+        desc.NumDescriptors = bd->numFramesInFlight;
+        desc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
+        desc.NodeMask = 1;
+
+        HRESULT hr = bd->pd3dDevice->CreateDescriptorHeap(&desc, IID_PPV_ARGS(&vd->RtvDescHeap));
+        IM_ASSERT(hr == S_OK);
+
+        SIZE_T rtv_descriptor_size = bd->pd3dDevice->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);
+        D3D12_CPU_DESCRIPTOR_HANDLE rtv_handle = vd->RtvDescHeap->GetCPUDescriptorHandleForHeapStart();
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            vd->FrameCtx[i].RenderTargetCpuDescriptors = rtv_handle;
+            rtv_handle.ptr += rtv_descriptor_size;
+        }
+
+        ID3D12Resource* back_buffer;
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            IM_ASSERT(vd->FrameCtx[i].RenderTarget == nullptr);
+            vd->SwapChain->GetBuffer(i, IID_PPV_ARGS(&back_buffer));
+            bd->pd3dDevice->CreateRenderTargetView(back_buffer, nullptr, vd->FrameCtx[i].RenderTargetCpuDescriptors);
+            vd->FrameCtx[i].RenderTarget = back_buffer;
+        }
+
+        hr = vd->SwapChain->SetMaximumFrameLatency(bd->numFramesInFlight);
+        IM_ASSERT(hr == S_OK);
+        vd->SwapChainWaitableObject = vd->SwapChain->GetFrameLatencyWaitableObject();
+    }
+
+    for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        ImGui_ImplDX12_DestroyRenderBuffers(&vd->FrameRenderBuffers[i]);
+}
+
+static void ImGui_WaitForPendingOperations(ImGui_ImplDX12_ViewportData* vd)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    HRESULT hr = vd->CommandQueue->Signal(bd->Fence, ++bd->FenceLastSignaledValue);
+    IM_ASSERT(hr == S_OK);
+
+    hr = bd->Fence->SetEventOnCompletion(bd->FenceLastSignaledValue, bd->FenceEvent);
+    IM_ASSERT(hr == S_OK);
+    ::WaitForSingleObject(bd->FenceEvent, INFINITE);
+}
+
+static ImGui_ImplDX12_FrameContext* ImGui_WaitForNextFrameContext(ImGui_ImplDX12_ViewportData* vd)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_FrameContext* frame_context = &vd->FrameCtx[vd->FrameIndex % vd->NumFramesInFlight];
+    if (bd->Fence->GetCompletedValue() < frame_context->FenceValue)
+    {
+        HRESULT hr = bd->Fence->SetEventOnCompletion(frame_context->FenceValue, bd->FenceEvent);
+        IM_ASSERT(hr == S_OK);
+        HANDLE waitableObjects[] = { vd->SwapChainWaitableObject, bd->FenceEvent };
+        ::WaitForMultipleObjects(2, waitableObjects, TRUE, INFINITE);
+    }
+    else
+    {
+        ::WaitForSingleObject(vd->SwapChainWaitableObject, INFINITE);
+    }
+    return frame_context;
+}
+
+static void ImGui_ImplDX12_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 since we didn't create the data for it.
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    if (ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData)
+    {
+        ImGui_WaitForPendingOperations(vd);
+
+        vd->CommandQueue = nullptr;
+        ::CloseHandle(vd->SwapChainWaitableObject);
+        vd->SwapChainWaitableObject = nullptr;
+        SafeRelease(vd->CommandList);
+        SafeRelease(vd->SwapChain);
+        SafeRelease(vd->RtvDescHeap);
+
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            SafeRelease(vd->FrameCtx[i].RenderTarget);
+            SafeRelease(vd->FrameCtx[i].CommandAllocator);
+            ImGui_ImplDX12_DestroyRenderBuffers(&vd->FrameRenderBuffers[i]);
+        }
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX12_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData;
+
+    ImGui_WaitForPendingOperations(vd);
+
+    for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        SafeRelease(vd->FrameCtx[i].RenderTarget);
+
+    if (vd->SwapChain)
+    {
+        ID3D12Resource* back_buffer = nullptr;
+        DXGI_SWAP_CHAIN_DESC1 desc = {};
+        vd->SwapChain->GetDesc1(&desc);
+        vd->SwapChain->ResizeBuffers(0, (UINT)size.x, (UINT)size.y, desc.Format, desc.Flags);
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            vd->SwapChain->GetBuffer(i, IID_PPV_ARGS(&back_buffer));
+            bd->pd3dDevice->CreateRenderTargetView(back_buffer, nullptr, vd->FrameCtx[i].RenderTargetCpuDescriptors);
+            vd->FrameCtx[i].RenderTarget = back_buffer;
+        }
+    }
+}
+
+static void ImGui_ImplDX12_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData;
+
+    ImGui_ImplDX12_FrameContext* frame_context = ImGui_WaitForNextFrameContext(vd);
+    UINT back_buffer_idx = vd->SwapChain->GetCurrentBackBufferIndex();
+
+    const ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+    D3D12_RESOURCE_BARRIER barrier = {};
+    barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
+    barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
+    barrier.Transition.pResource = vd->FrameCtx[back_buffer_idx].RenderTarget;
+    barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
+    barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_PRESENT;
+    barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_RENDER_TARGET;
+
+    // Draw
+    ID3D12GraphicsCommandList* cmd_list = vd->CommandList;
+
+    frame_context->CommandAllocator->Reset();
+    cmd_list->Reset(frame_context->CommandAllocator, nullptr);
+    cmd_list->ResourceBarrier(1, &barrier);
+    cmd_list->OMSetRenderTargets(1, &vd->FrameCtx[back_buffer_idx].RenderTargetCpuDescriptors, FALSE, nullptr);
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+        cmd_list->ClearRenderTargetView(vd->FrameCtx[back_buffer_idx].RenderTargetCpuDescriptors, (const float*)&clear_color, 0, nullptr);
+    cmd_list->SetDescriptorHeaps(1, &bd->pd3dSrvDescHeap);
+
+    ImGui_ImplDX12_RenderDrawData(viewport->DrawData, cmd_list);
+
+    barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_RENDER_TARGET;
+    barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_PRESENT;
+    cmd_list->ResourceBarrier(1, &barrier);
+    cmd_list->Close();
+
+    vd->CommandQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&cmd_list);
+
+    HRESULT hr = vd->CommandQueue->Signal(bd->Fence, ++bd->FenceLastSignaledValue);
+    IM_ASSERT(hr == S_OK);
+    frame_context->FenceValue = bd->FenceLastSignaledValue;
+}
+
+static void ImGui_ImplDX12_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData;
+
+    vd->SwapChain->Present(0, bd->tearingSupport ? DXGI_PRESENT_ALLOW_TEARING : 0);
+}
+
+void ImGui_ImplDX12_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX12_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX12_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX12_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX12_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX12_SwapBuffers;
+}
+
+void ImGui_ImplDX12_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx12.h

@@ -6,6 +6,7 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // The aim of imgui_impl_dx12.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/

backends/imgui_impl_dx9.cpp

@@ -6,6 +6,7 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: IMGUI_USE_BGRA_PACKED_COLOR support, as this is the optimal color encoding for DirectX9.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -17,7 +18,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-03-19: Fixed issue in ImGui_ImplDX9_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295, #9310)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: DirectX9: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
@@ -89,6 +90,12 @@ static ImGui_ImplDX9_Data* ImGui_ImplDX9_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX9_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX9_InitMultiViewportSupport();
+static void ImGui_ImplDX9_ShutdownMultiViewportSupport();
+static void ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows();
+static void ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows();
+
 // Functions
 static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
 {
@@ -163,11 +170,6 @@ static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
     }
 }
 
-// Draw callbacks
-static void ImGui_ImplDX9_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)    {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplDX9_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)    { ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData(); bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR); bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR); }
-static void ImGui_ImplDX9_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)   { ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData(); bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_POINT); bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_POINT); }
-
 // Render function.
 void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
 {
@@ -190,14 +192,14 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     {
         if (bd->pVB) { bd->pVB->Release(); bd->pVB = nullptr; }
         bd->VertexBufferSize = draw_data->TotalVtxCount + 5000;
-        if (device->CreateVertexBuffer((UINT)bd->VertexBufferSize * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &bd->pVB, nullptr) < 0)
+        if (device->CreateVertexBuffer(bd->VertexBufferSize * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &bd->pVB, nullptr) < 0)
             return;
     }
     if (!bd->pIB || bd->IndexBufferSize < draw_data->TotalIdxCount)
     {
         if (bd->pIB) { bd->pIB->Release(); bd->pIB = nullptr; }
         bd->IndexBufferSize = draw_data->TotalIdxCount + 10000;
-        if (device->CreateIndexBuffer((UINT)bd->IndexBufferSize * sizeof(ImDrawIdx), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, sizeof(ImDrawIdx) == 2 ? D3DFMT_INDEX16 : D3DFMT_INDEX32, D3DPOOL_DEFAULT, &bd->pIB, nullptr) < 0)
+        if (device->CreateIndexBuffer(bd->IndexBufferSize * sizeof(ImDrawIdx), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, sizeof(ImDrawIdx) == 2 ? D3DFMT_INDEX16 : D3DFMT_INDEX32, D3DPOOL_DEFAULT, &bd->pIB, nullptr) < 0)
             return;
     }
 
@@ -275,7 +277,8 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
             if (pcmd->UserCallback != nullptr)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplDX9_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplDX9_SetupRenderState(draw_data);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -302,6 +305,11 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
         global_vtx_offset += draw_list->VtxBuffer.Size;
     }
 
+    // When using multi-viewports, it appears that there's an odd logic in DirectX9 which prevent subsequent windows
+    // from rendering until the first window submits at least one draw call, even once. That's our workaround. (see #2560)
+    if (global_vtx_offset == 0)
+        bd->pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 0, 0, 0);
+
     // Restore the DX9 transform
     device->SetTransform(D3DTS_WORLD, &last_world);
     device->SetTransform(D3DTS_VIEW, &last_view);
@@ -330,6 +338,50 @@ static bool ImGui_ImplDX9_CheckFormatSupport(LPDIRECT3DDEVICE9 pDevice, D3DFORMA
     return support;
 }
 
+bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplDX9_Data* bd = IM_NEW(ImGui_ImplDX9_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_dx9";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = 4096;
+
+    bd->pd3dDevice = device;
+    bd->pd3dDevice->AddRef();
+    bd->HasRgbaSupport = ImGui_ImplDX9_CheckFormatSupport(bd->pd3dDevice, D3DFMT_A8B8G8R8);
+
+    ImGui_ImplDX9_InitMultiViewportSupport();
+
+    return true;
+}
+
+void ImGui_ImplDX9_Shutdown()
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplDX9_ShutdownMultiViewportSupport();
+    ImGui_ImplDX9_InvalidateDeviceObjects();
+    if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 // Convert RGBA32 to BGRA32 (because RGBA32 is not well supported by DX9 devices)
 static void ImGui_ImplDX9_CopyTextureRegion(bool tex_use_colors, const ImU32* src, int src_pitch, ImU32* dst, int dst_pitch, int w, int h)
 {
@@ -415,6 +467,7 @@ bool ImGui_ImplDX9_CreateDeviceObjects()
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     if (!bd || !bd->pd3dDevice)
         return false;
+    ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows();
     return true;
 }
 
@@ -433,6 +486,7 @@ void ImGui_ImplDX9_InvalidateDeviceObjects()
         }
     if (bd->pVB) { bd->pVB->Release(); bd->pVB = nullptr; }
     if (bd->pIB) { bd->pIB->Release(); bd->pIB = nullptr; }
+    ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows();
 }
 
 void ImGui_ImplDX9_NewFrame()
@@ -442,48 +496,146 @@ void ImGui_ImplDX9_NewFrame()
     IM_UNUSED(bd);
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
 
-bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplDX9_ViewportData
 {
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+    IDirect3DSwapChain9*    SwapChain;
+    D3DPRESENT_PARAMETERS   d3dpp;
 
-    // Setup backend capabilities flags
-    ImGui_ImplDX9_Data* bd = IM_NEW(ImGui_ImplDX9_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_dx9";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    ImGui_ImplDX9_ViewportData()  { SwapChain = nullptr; ZeroMemory(&d3dpp, sizeof(D3DPRESENT_PARAMETERS)); }
+    ~ImGui_ImplDX9_ViewportData() { IM_ASSERT(SwapChain == nullptr); }
+};
 
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = 4096;
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplDX9_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplDX9_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplDX9_DrawCallback_SetSamplerNearest;
-
-    bd->pd3dDevice = device;
-    bd->pd3dDevice->AddRef();
-    bd->HasRgbaSupport = ImGui_ImplDX9_CheckFormatSupport(bd->pd3dDevice, D3DFMT_A8B8G8R8);
-
-    return true;
-}
-
-void ImGui_ImplDX9_Shutdown()
+static void ImGui_ImplDX9_CreateWindow(ImGuiViewport* viewport)
 {
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplDX9_ViewportData* vd = IM_NEW(ImGui_ImplDX9_ViewportData)();
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+
+    ZeroMemory(&vd->d3dpp, sizeof(D3DPRESENT_PARAMETERS));
+    vd->d3dpp.Windowed = TRUE;
+    vd->d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
+    vd->d3dpp.BackBufferWidth = (UINT)viewport->Size.x;
+    vd->d3dpp.BackBufferHeight = (UINT)viewport->Size.y;
+    vd->d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;
+    vd->d3dpp.hDeviceWindow = hwnd;
+    vd->d3dpp.EnableAutoDepthStencil = FALSE;
+    vd->d3dpp.AutoDepthStencilFormat = D3DFMT_D16;
+    vd->d3dpp.PresentationInterval = D3DPRESENT_INTERVAL_IMMEDIATE;   // Present without vsync
+
+    HRESULT hr = bd->pd3dDevice->CreateAdditionalSwapChain(&vd->d3dpp, &vd->SwapChain); IM_UNUSED(hr);
+    IM_ASSERT(hr == D3D_OK);
+    IM_ASSERT(vd->SwapChain != nullptr);
+}
+
+static void ImGui_ImplDX9_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 since we didn't create the data for it.
+    if (ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData)
+    {
+        if (vd->SwapChain)
+            vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        ZeroMemory(&vd->d3dpp, sizeof(D3DPRESENT_PARAMETERS));
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX9_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData;
+    if (vd->SwapChain)
+    {
+        vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        vd->d3dpp.BackBufferWidth = (UINT)size.x;
+        vd->d3dpp.BackBufferHeight = (UINT)size.y;
+        HRESULT hr = bd->pd3dDevice->CreateAdditionalSwapChain(&vd->d3dpp, &vd->SwapChain); IM_UNUSED(hr);
+        IM_ASSERT(hr == D3D_OK);
+    }
+}
+
+static void ImGui_ImplDX9_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData;
+    ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+
+    LPDIRECT3DSURFACE9 render_target = nullptr;
+    LPDIRECT3DSURFACE9 last_render_target = nullptr;
+    LPDIRECT3DSURFACE9 last_depth_stencil = nullptr;
+    vd->SwapChain->GetBackBuffer(0, D3DBACKBUFFER_TYPE_MONO, &render_target);
+    bd->pd3dDevice->GetRenderTarget(0, &last_render_target);
+    bd->pd3dDevice->GetDepthStencilSurface(&last_depth_stencil);
+    bd->pd3dDevice->SetRenderTarget(0, render_target);
+    bd->pd3dDevice->SetDepthStencilSurface(nullptr);
+
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+    {
+        D3DCOLOR clear_col_dx = D3DCOLOR_RGBA((int)(clear_color.x*255.0f), (int)(clear_color.y*255.0f), (int)(clear_color.z*255.0f), (int)(clear_color.w*255.0f));
+        bd->pd3dDevice->Clear(0, nullptr, D3DCLEAR_TARGET, clear_col_dx, 1.0f, 0);
+    }
+
+    ImGui_ImplDX9_RenderDrawData(viewport->DrawData);
+
+    // Restore render target
+    bd->pd3dDevice->SetRenderTarget(0, last_render_target);
+    bd->pd3dDevice->SetDepthStencilSurface(last_depth_stencil);
+    render_target->Release();
+    last_render_target->Release();
+    if (last_depth_stencil) last_depth_stencil->Release();
+}
+
+static void ImGui_ImplDX9_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData;
+    HRESULT hr = vd->SwapChain->Present(nullptr, nullptr, vd->d3dpp.hDeviceWindow, nullptr, 0);
+    // Let main application handle D3DERR_DEVICELOST by resetting the device.
+    IM_ASSERT(SUCCEEDED(hr) || hr == D3DERR_DEVICELOST);
+}
+
+static void ImGui_ImplDX9_InitMultiViewportSupport()
+{
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX9_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX9_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX9_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX9_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX9_SwapBuffers;
+}
 
-    ImGui_ImplDX9_InvalidateDeviceObjects();
-    if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
+static void ImGui_ImplDX9_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
 
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
+static void ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (!platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplDX9_CreateWindow(platform_io.Viewports[i]);
+}
+
+static void ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplDX9_DestroyWindow(platform_io.Viewports[i]);
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_dx9.h

@@ -6,6 +6,7 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: IMGUI_USE_BGRA_PACKED_COLOR support, as this is the optimal color encoding for DirectX9.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_glfw.cpp

@@ -9,10 +9,12 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy GLFW_KEY_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors) with GLFW 3.1+. Resizing cursors requires GLFW 3.4+! Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 //  [X] Multiple Dear ImGui contexts support.
 // Missing features or Issues:
 //  [ ] Platform: Touch events are only correctly identified as Touch on Windows. This create issues with some interactions. GLFW doesn't provide a way to identify touch inputs from mouse inputs, we cannot call io.AddMouseSourceEvent() to identify the source. We provide a Windows-specific workaround.
 //  [ ] Platform: Missing ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress cursors.
+//  [ ] Platform: Multi-viewport: Missing ImGuiBackendFlags_HasParentViewport support. The viewport->ParentViewportID field is ignored, and therefore io.ConfigViewportsNoDefaultParent has no effect either.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -29,19 +31,26 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-21: Added a Win32-specific implementation of ImGui_ImplGlfw_GetContentScaleXXXX functions for legacy GLFW 3.2.
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-03-25: Mouse cursor is properly restored if changed by user app/code while using glfwSetInputMode(..., GLFW_CURSOR_DISABLED) or ImGuiConfigFlags_NoMouseCursorChange. Amend change from 2025-12-10.
 //  2026-02-10: Try to set IMGUI_IMPL_GLFW_DISABLE_X11 / IMGUI_IMPL_GLFW_DISABLE_WAYLAND automatically if corresponding headers are not accessible. (#9225)
+//  2026-01-25: [Docking] Improve workarounds for cases where GLFW is unable to provide any reliable monitor info. Preserve existing monitor list when none of the new one is valid. (#9195, #7902, #5683)
+//  2026-01-18: [Docking] Dynamically load X11 functions to avoid -lx11 linking requirement introduced on 2025-09-10.
 //  2025-12-12: Added IMGUI_IMPL_GLFW_DISABLE_X11 / IMGUI_IMPL_GLFW_DISABLE_WAYLAND to forcefully disable either.
 //  2025-12-10: Avoid repeated glfwSetCursor()/glfwSetInputMode() calls when unnecessary. Lowers overhead for very high framerates (e.g. 10k+ FPS).
 //  2025-11-06: Lower minimum requirement to GLFW 3.0. Though a recent version e.g GLFW 3.4 is highly recommended.
 //  2025-09-18: Call platform_io.ClearPlatformHandlers() on shutdown.
 //  2025-09-15: Content Scales are always reported as 1.0 on Wayland. FramebufferScale are always reported as 1.0 on X11. (#8920, #8921)
+//  2025-09-10: [Docking] Improve multi-viewport behavior in tiling WMs on X11 via the ImGui_ImplGlfw_SetWindowFloating() function. Note: using GLFW backend on Linux/BSD etc. requires linking with -lX11. (#8884, #8474, #8289)
 //  2025-07-08: Made ImGui_ImplGlfw_GetContentScaleForWindow(), ImGui_ImplGlfw_GetContentScaleForMonitor() helpers return 1.0f on Emscripten and Android platforms, matching macOS logic. (#8742, #8733)
 //  2025-06-18: Added support for multiple Dear ImGui contexts. (#8676, #8239, #8069)
 //  2025-06-11: Added ImGui_ImplGlfw_GetContentScaleForWindow(GLFWwindow* window) and ImGui_ImplGlfw_GetContentScaleForMonitor(GLFWmonitor* monitor) helper to facilitate making DPI-aware apps.
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
+//  2025-04-26: [Docking] Disable multi-viewports under Wayland. (#8587)
 //  2025-03-10: Map GLFW_KEY_WORLD_1 and GLFW_KEY_WORLD_2 into ImGuiKey_Oem102.
 //  2025-03-03: Fixed clipboard handler assertion when using GLFW <= 3.2.1 compiled with asserts enabled.
+//  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
+//  2024-11-05: [Docking] Added Linux workaround for spurious mouse up events emitted while dragging and creating new viewport. (#3158, #7733, #7922)
 //  2024-08-22: Moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
 //               - io.GetClipboardTextFn    -> platform_io.Platform_GetClipboardTextFn
 //               - io.SetClipboardTextFn    -> platform_io.Platform_SetClipboardTextFn
@@ -58,6 +67,7 @@
 //  2023-03-16: Inputs: Fixed key modifiers handling on secondary viewports (docking branch). Broken on 2023/01/04. (#6248, #6034)
 //  2023-03-14: Emscripten: Avoid using glfwGetError() and glfwGetGamepadState() which are not correctly implemented in Emscripten emulation. (#6240)
 //  2023-02-03: Emscripten: Registering custom low-level mouse wheel handler to get more accurate scrolling impulses on Emscripten. (#4019, #6096)
+//  2023-01-18: Handle unsupported glfwGetVideoMode() call on e.g. Emscripten.
 //  2023-01-04: Inputs: Fixed mods state on Linux when using Alt-GR text input (e.g. German keyboard layout), could lead to broken text input. Revert a 2022/01/17 change were we resumed using mods provided by GLFW, turns out they were faulty.
 //  2022-11-22: Perform a dummy glfwGetError() read to cancel missing names with glfwGetKeyName(). (#5908)
 //  2022-10-18: Perform a dummy glfwGetError() read to cancel missing mouse cursors errors. Using GLFW_VERSION_COMBINED directly. (#5785)
@@ -110,6 +120,8 @@
 #pragma clang diagnostic ignored "-Wsign-conversion"        // warning: implicit conversion changes signedness
 #pragma clang diagnostic ignored "-Wexit-time-destructors"  // warning: declaration requires an exit-time destructor     // exit-time destruction order is undefined. if MemFree() leads to users code that has been disabled before exit it might cause problems. ImGui coding style welcomes static/globals.
 #pragma clang diagnostic ignored "-Wglobal-constructors"    // warning: declaration requires a global destructor         // similar to above, not sure what the exact difference is.
+#elif defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wfloat-equal"              // warning: comparing floating-point with '==' or '!=' is unsafe
 #endif
 
 #if defined(__has_include)
@@ -147,10 +159,13 @@
 #elif GLFW_HAS_X11
 #ifndef GLFW_EXPOSE_NATIVE_X11      // for glfwGetX11Display(), glfwGetX11Window() on Freedesktop (Linux, BSD, etc.)
 #define GLFW_EXPOSE_NATIVE_X11
+#include <X11/Xatom.h>
+#include <dlfcn.h>              // for dlopen()
 #endif
 #include <GLFW/glfw3native.h>
-#endif
 #undef Status                   // X11 headers are leaking this.
+#endif
+
 #ifndef _WIN32
 #include <unistd.h>             // for usleep()
 #endif
@@ -169,12 +184,29 @@
 // We gather version tests as define in order to easily see which features are version-dependent.
 #define GLFW_VERSION_COMBINED           (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 + GLFW_VERSION_REVISION)
 #define GLFW_HAS_CREATECURSOR           (GLFW_VERSION_COMBINED >= 3100) // 3.1+ glfwCreateCursor()
+#define GLFW_HAS_WINDOW_TOPMOST         (GLFW_VERSION_COMBINED >= 3200) // 3.2+ GLFW_FLOATING
+#define GLFW_HAS_WINDOW_HOVERED         (GLFW_VERSION_COMBINED >= 3300) // 3.3+ GLFW_HOVERED
+#define GLFW_HAS_WINDOW_ALPHA           (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwSetWindowOpacity
 #define GLFW_HAS_PER_MONITOR_DPI        (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorContentScale
+#if defined(__EMSCRIPTEN__) || defined(__SWITCH__)                      // no Vulkan support in GLFW for Emscripten or homebrew Nintendo Switch
+#define GLFW_HAS_VULKAN                 (0)
+#else
+#define GLFW_HAS_VULKAN                 (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwCreateWindowSurface
+#endif
+#define GLFW_HAS_FOCUS_WINDOW           (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwFocusWindow
+#define GLFW_HAS_FOCUS_ON_SHOW          (GLFW_VERSION_COMBINED >= 3300) // 3.3+ GLFW_FOCUS_ON_SHOW
+#define GLFW_HAS_MONITOR_WORK_AREA      (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorWorkarea
+#define GLFW_HAS_OSX_WINDOW_POS_FIX     (GLFW_VERSION_COMBINED >= 3301) // 3.3.1+ Fixed: Resizing window repositions it on MacOS #1553
 #ifdef GLFW_RESIZE_NESW_CURSOR          // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
 #define GLFW_HAS_NEW_CURSORS            (GLFW_VERSION_COMBINED >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
 #else
 #define GLFW_HAS_NEW_CURSORS            (0)
 #endif
+#ifdef GLFW_MOUSE_PASSTHROUGH           // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2020-07-17 (passthrough)
+#define GLFW_HAS_MOUSE_PASSTHROUGH      (GLFW_VERSION_COMBINED >= 3400) // 3.4+ GLFW_MOUSE_PASSTHROUGH
+#else
+#define GLFW_HAS_MOUSE_PASSTHROUGH      (0)
+#endif
 #define GLFW_HAS_GAMEPAD_API            (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetGamepadState() new api
 #define GLFW_HAS_GETKEYNAME             (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwGetKeyName()
 #define GLFW_HAS_GETERROR               (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetError()
@@ -197,6 +229,13 @@ enum GlfwClientApi
     GlfwClientApi_Unknown,  // Anything else fits here.
 };
 
+#if GLFW_HAS_X11
+typedef Atom (*PFN_XInternAtom)(Display*, const char* ,Bool);
+typedef int  (*PFN_XChangeProperty)(Display*, Window, Atom, Atom, int, int, const unsigned char*, int);
+typedef int  (*PFN_XChangeWindowAttributes)(Display*, Window, unsigned long, XSetWindowAttributes*);
+typedef int  (*PFN_XFlush)(Display*);
+#endif
+
 // GLFW data
 struct ImGui_ImplGlfw_Data
 {
@@ -209,11 +248,14 @@ struct ImGui_ImplGlfw_Data
     GLFWcursor*             MouseCursors[ImGuiMouseCursor_COUNT];
     GLFWcursor*             LastMouseCursor;
 #endif
+    bool                    MouseIgnoreButtonUpWaitForFocusLoss;
+    bool                    MouseIgnoreButtonUp;
     ImVec2                  LastValidMousePos;
+    GLFWwindow*             KeyOwnerWindows[GLFW_KEY_LAST];
     bool                    IsWayland;
     bool                    InstalledCallbacks;
     bool                    CallbacksChainForAllWindows;
-    char                    BackendPlatformName[40];
+    char                    BackendPlatformName[32];
 #ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
     const char*             CanvasSelector;
 #endif
@@ -231,6 +273,15 @@ struct ImGui_ImplGlfw_Data
     WNDPROC                 PrevWndProc;
 #endif
 
+#if GLFW_HAS_X11
+    // Module and function pointers loaded at initialization to avoid linking statically with X11.
+    void*                       X11Module;
+    PFN_XInternAtom             XInternAtom;
+    PFN_XChangeProperty         XChangeProperty;
+    PFN_XChangeWindowAttributes XChangeWindowAttributes;
+    PFN_XFlush                  XFlush;
+#endif
+
     ImGui_ImplGlfw_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
 
@@ -254,6 +305,11 @@ static ImGui_ImplGlfw_Data* ImGui_ImplGlfw_GetBackendData(GLFWwindow* window)
     return (ImGui_ImplGlfw_Data*)ImGui::GetIO(ctx).BackendPlatformUserData;
 }
 
+// Forward Declarations
+static void ImGui_ImplGlfw_UpdateMonitors();
+static void ImGui_ImplGlfw_InitMultiViewportSupport();
+static void ImGui_ImplGlfw_ShutdownMultiViewportSupport();
+
 // Functions
 static bool ImGui_ImplGlfw_IsWayland()
 {
@@ -424,6 +480,10 @@ void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int acti
     if (bd->PrevUserCallbackMousebutton != nullptr && ImGui_ImplGlfw_ShouldChainCallback(bd, window))
         bd->PrevUserCallbackMousebutton(window, button, action, mods);
 
+    // Workaround for Linux: ignore mouse up events which are following an focus loss following a viewport creation
+    if (bd->MouseIgnoreButtonUp && action == GLFW_RELEASE)
+        return;
+
     ImGuiIO& io = ImGui::GetIO(bd->Context);
     ImGui_ImplGlfw_UpdateKeyModifiers(io, window);
     if (button >= 0 && button < ImGuiMouseButton_COUNT)
@@ -491,6 +551,9 @@ void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int keycode, int scancode, i
     ImGuiIO& io = ImGui::GetIO(bd->Context);
     ImGui_ImplGlfw_UpdateKeyModifiers(io, window);
 
+    if (keycode >= 0 && keycode < IM_COUNTOF(bd->KeyOwnerWindows))
+        bd->KeyOwnerWindows[keycode] = (action == GLFW_PRESS) ? window : nullptr;
+
     keycode = ImGui_ImplGlfw_TranslateUntranslatedKey(keycode, scancode);
 
     ImGuiKey imgui_key = ImGui_ImplGlfw_KeyToImGuiKey(keycode, scancode);
@@ -504,6 +567,10 @@ void ImGui_ImplGlfw_WindowFocusCallback(GLFWwindow* window, int focused)
     if (bd->PrevUserCallbackWindowFocus != nullptr && ImGui_ImplGlfw_ShouldChainCallback(bd, window))
         bd->PrevUserCallbackWindowFocus(window, focused);
 
+    // Workaround for Linux: when losing focus with MouseIgnoreButtonUpWaitForFocusLoss set, we will temporarily ignore subsequent Mouse Up events
+    bd->MouseIgnoreButtonUp = (bd->MouseIgnoreButtonUpWaitForFocusLoss && focused == 0);
+    bd->MouseIgnoreButtonUpWaitForFocusLoss = false;
+
     ImGuiIO& io = ImGui::GetIO(bd->Context);
     io.AddFocusEvent(focused != 0);
 }
@@ -515,6 +582,13 @@ void ImGui_ImplGlfw_CursorPosCallback(GLFWwindow* window, double x, double y)
         bd->PrevUserCallbackCursorPos(window, x, y);
 
     ImGuiIO& io = ImGui::GetIO(bd->Context);
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        int window_x, window_y;
+        glfwGetWindowPos(window, &window_x, &window_y);
+        x += window_x;
+        y += window_y;
+    }
     io.AddMousePosEvent((float)x, (float)y);
     bd->LastValidMousePos = ImVec2((float)x, (float)y);
 }
@@ -553,7 +627,7 @@ void ImGui_ImplGlfw_CharCallback(GLFWwindow* window, unsigned int c)
 
 void ImGui_ImplGlfw_MonitorCallback(GLFWmonitor*, int)
 {
-    // Unused in 'master' branch but 'docking' branch will use this, so we declare it ahead of it so if you have to install callbacks you can install this one too.
+    // This function is technically part of the API even if we stopped using the callback, so leaving it around.
 }
 
 #ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
@@ -576,35 +650,7 @@ static EM_BOOL ImGui_ImplEmscripten_WheelCallback(int, const EmscriptenWheelEven
 #endif
 
 #ifdef _WIN32
-// GLFW doesn't allow to distinguish Mouse vs TouchScreen vs Pen.
-// Add support for Win32 (based on imgui_impl_win32), because we rely on _TouchScreen info to trickle inputs differently.
-static ImGuiMouseSource GetMouseSourceFromMessageExtraInfo()
-{
-    LPARAM extra_info = ::GetMessageExtraInfo();
-    if ((extra_info & 0xFFFFFF80) == 0xFF515700)
-        return ImGuiMouseSource_Pen;
-    if ((extra_info & 0xFFFFFF80) == 0xFF515780)
-        return ImGuiMouseSource_TouchScreen;
-    return ImGuiMouseSource_Mouse;
-}
-static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
-{
-    ImGui_ImplGlfw_Data* bd = (ImGui_ImplGlfw_Data*)::GetPropA(hWnd, "IMGUI_BACKEND_DATA");
-    ImGuiIO& io = ImGui::GetIO(bd->Context);
-
-    switch (msg)
-    {
-    case WM_MOUSEMOVE: case WM_NCMOUSEMOVE:
-    case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK: case WM_LBUTTONUP:
-    case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK: case WM_RBUTTONUP:
-    case WM_MBUTTONDOWN: case WM_MBUTTONDBLCLK: case WM_MBUTTONUP:
-    case WM_XBUTTONDOWN: case WM_XBUTTONDBLCLK: case WM_XBUTTONUP:
-        io.AddMouseSourceEvent(GetMouseSourceFromMessageExtraInfo());
-        break;
-    default: break;
-    }
-    return ::CallWindowProcW(bd->PrevWndProc, hWnd, msg, wParam, lParam);
-}
+static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 #endif
 
 void ImGui_ImplGlfw_InstallCallbacks(GLFWwindow* window)
@@ -676,13 +722,7 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 
     // Setup backend capabilities flags
     ImGui_ImplGlfw_Data* bd = IM_NEW(ImGui_ImplGlfw_Data)();
-    bd->Context = ImGui::GetCurrentContext();
-    bd->Window = window;
-    bd->Time = 0.0;
-    bd->IsWayland = ImGui_ImplGlfw_IsWayland();
-    ImGui_ImplGlfw_ContextMap_Add(window, bd->Context);
-
-    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_glfw (%d)%s", GLFW_VERSION_COMBINED, bd->IsWayland ? " (Wayland)" : "");
+    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_glfw (%d)", GLFW_VERSION_COMBINED);
     io.BackendPlatformUserData = (void*)bd;
     io.BackendPlatformName = bd->BackendPlatformName;
 #if GLFW_HAS_CREATECURSOR
@@ -690,6 +730,26 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 #endif
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
 
+    bool has_viewports = false;
+#ifndef __EMSCRIPTEN__
+    has_viewports = true;
+#if GLFW_HAS_GETPLATFORM
+    if (glfwGetPlatform() == GLFW_PLATFORM_WAYLAND)
+        has_viewports = false;
+#endif
+    if (has_viewports)
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
+#endif
+#if GLFW_HAS_MOUSE_PASSTHROUGH || GLFW_HAS_WINDOW_HOVERED
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can call io.AddMouseViewportEvent() with correct data (optional)
+#endif
+
+    bd->Context = ImGui::GetCurrentContext();
+    bd->Window = window;
+    bd->Time = 0.0;
+    bd->IsWayland = ImGui_ImplGlfw_IsWayland();
+    ImGui_ImplGlfw_ContextMap_Add(window, bd->Context);
+
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 #if GLFW_VERSION_COMBINED < 3300
     platform_io.Platform_SetClipboardTextFn = [](ImGuiContext*, const char* text) { glfwSetClipboardString(ImGui_ImplGlfw_GetBackendData()->Window, text); };
@@ -735,6 +795,11 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     if (install_callbacks)
         ImGui_ImplGlfw_InstallCallbacks(window);
 
+    // Update monitor a first time during init
+    // (note: monitor callback are broken in GLFW 3.2 and earlier, see github.com/glfw/glfw/issues/784)
+    ImGui_ImplGlfw_UpdateMonitors();
+    glfwSetMonitorCallback(ImGui_ImplGlfw_MonitorCallback);
+
     // Set platform dependent data in viewport
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     main_viewport->PlatformHandle = (void*)bd->Window;
@@ -745,6 +810,8 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 #else
     IM_UNUSED(main_viewport);
 #endif
+    if (has_viewports)
+        ImGui_ImplGlfw_InitMultiViewportSupport();
 
     // Windows: register a WndProc hook so we can intercept some messages.
 #ifdef _WIN32
@@ -755,6 +822,26 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     ::SetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC, (LONG_PTR)ImGui_ImplGlfw_WndProc);
 #endif
 
+#if GLFW_HAS_X11
+    if (!bd->IsWayland)
+    {
+        // Load X11 module dynamically. Copied from the way that GLFW does it in x11_init.c
+#if defined(__CYGWIN__)
+        const char* x11_module_path = "libX11-6.so";
+#elif defined(__OpenBSD__) || defined(__NetBSD__)
+        const char* x11_module_path = "libX11.so";
+#else
+        const char* x11_module_path = "libX11.so.6";
+#endif
+        bd->X11Module = dlopen(x11_module_path, RTLD_LAZY | RTLD_LOCAL);
+        bd->XInternAtom = (PFN_XInternAtom)dlsym(bd->X11Module, "XInternAtom");
+        bd->XChangeProperty = (PFN_XChangeProperty)dlsym(bd->X11Module, "XChangeProperty");
+        bd->XChangeWindowAttributes = (PFN_XChangeWindowAttributes)dlsym(bd->X11Module, "XChangeWindowAttributes");
+        bd->XFlush = (PFN_XFlush)dlsym(bd->X11Module, "XFlush");
+        IM_ASSERT(bd->XInternAtom != nullptr && bd->XChangeProperty != nullptr && bd->XChangeWindowAttributes != nullptr && bd->XFlush != nullptr);
+    }
+#endif
+
     // Emscripten: the same application can run on various platforms, so we detect the Apple platform at runtime
     // to override io.ConfigMacOSXBehaviors from its default (which is always false in Emscripten).
 #ifdef __EMSCRIPTEN__
@@ -799,6 +886,7 @@ void ImGui_ImplGlfw_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ImGui_ImplGlfw_ShutdownMultiViewportSupport();
     if (bd->InstalledCallbacks)
         ImGui_ImplGlfw_RestoreCallbacks(bd->Window);
 #ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
@@ -817,9 +905,14 @@ void ImGui_ImplGlfw_Shutdown()
     bd->PrevWndProc = nullptr;
 #endif
 
+#if GLFW_HAS_X11
+    if (bd->X11Module != nullptr)
+        dlclose(bd->X11Module);
+#endif
+
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport);
     platform_io.ClearPlatformHandlers();
     ImGui_ImplGlfw_ContextMap_Remove(bd->Window);
     IM_DELETE(bd);
@@ -829,10 +922,15 @@ static void ImGui_ImplGlfw_UpdateMouseData()
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
     ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
-    // (those braces are here to reduce diff with multi-viewports support in 'docking' branch)
+    ImGuiID mouse_viewport_id = 0;
+    const ImVec2 mouse_pos_prev = io.MousePos;
+    for (int n = 0; n < platform_io.Viewports.Size; n++)
     {
-        GLFWwindow* window = bd->Window;
+        ImGuiViewport* viewport = platform_io.Viewports[n];
+        GLFWwindow* window = (GLFWwindow*)viewport->PlatformHandle;
+
 #ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
         const bool is_window_focused = true;
 #else
@@ -841,19 +939,54 @@ static void ImGui_ImplGlfw_UpdateMouseData()
         if (is_window_focused)
         {
             // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
+            // When multi-viewports are enabled, all Dear ImGui positions are same as OS positions.
             if (io.WantSetMousePos)
-                glfwSetCursorPos(window, (double)io.MousePos.x, (double)io.MousePos.y);
+                glfwSetCursorPos(window, (double)(mouse_pos_prev.x - viewport->Pos.x), (double)(mouse_pos_prev.y - viewport->Pos.y));
 
             // (Optional) Fallback to provide mouse position when focused (ImGui_ImplGlfw_CursorPosCallback already provides this when hovered or captured)
             if (bd->MouseWindow == nullptr)
             {
                 double mouse_x, mouse_y;
                 glfwGetCursorPos(window, &mouse_x, &mouse_y);
+                if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                {
+                    // Single viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+                    // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+                    int window_x, window_y;
+                    glfwGetWindowPos(window, &window_x, &window_y);
+                    mouse_x += window_x;
+                    mouse_y += window_y;
+                }
                 bd->LastValidMousePos = ImVec2((float)mouse_x, (float)mouse_y);
                 io.AddMousePosEvent((float)mouse_x, (float)mouse_y);
             }
         }
+
+        // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+        // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+        // - [X] GLFW >= 3.3 backend ON WINDOWS ONLY does correctly ignore viewports with the _NoInputs flag (since we implement hit via our WndProc hook)
+        //       On other platforms we rely on the library fallbacking to its own search when reporting a viewport with _NoInputs flag.
+        // - [!] GLFW <= 3.2 backend CANNOT correctly ignore viewports with the _NoInputs flag, and CANNOT reported Hovered Viewport because of mouse capture.
+        //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+        //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+        //       by the backend, and use its flawed heuristic to guess the viewport behind.
+        // - [X] GLFW backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+        // FIXME: This is currently only correct on Win32. See what we do below with the WM_NCHITTEST, missing an equivalent for other systems.
+        // See https://github.com/glfw/glfw/issues/1236 if you want to help in making this a GLFW feature.
+#if GLFW_HAS_MOUSE_PASSTHROUGH
+        const bool window_no_input = (viewport->Flags & ImGuiViewportFlags_NoInputs) != 0;
+        glfwSetWindowAttrib(window, GLFW_MOUSE_PASSTHROUGH, window_no_input);
+#endif
+#if GLFW_HAS_MOUSE_PASSTHROUGH || GLFW_HAS_WINDOW_HOVERED
+        if (glfwGetWindowAttrib(window, GLFW_HOVERED))
+            mouse_viewport_id = viewport->ID;
+#else
+        // We cannot use bd->MouseWindow maintained from CursorEnter/Leave callbacks, because it is locked to the window capturing mouse.
+#endif
     }
+
+    if (io.BackendFlags & ImGuiBackendFlags_HasMouseHoveredViewport)
+        io.AddMouseViewportEvent(mouse_viewport_id);
 }
 
 static void ImGui_ImplGlfw_UpdateMouseCursor()
@@ -867,9 +1000,10 @@ static void ImGui_ImplGlfw_UpdateMouseCursor()
     }
 
     ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
-    // (those braces are here to reduce diff with multi-viewports support in 'docking' branch)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int n = 0; n < platform_io.Viewports.Size; n++)
     {
-        GLFWwindow* window = bd->Window;
+        GLFWwindow* window = (GLFWwindow*)platform_io.Viewports[n]->PlatformHandle;
         if (imgui_cursor == ImGuiMouseCursor_None || io.MouseDrawCursor)
         {
             if (bd->LastMouseCursor != nullptr)
@@ -949,15 +1083,48 @@ static void ImGui_ImplGlfw_UpdateGamepads()
     #undef MAP_ANALOG
 }
 
-// For GFLW 3.2 + Windows: include a simplified non-monitor aware version of ImGui_ImplWin32_GetDpiScaleForMonitor().
-// This is merely a band-aid to make using GLFW 3.2 a little bit nicer, but prefer to use GLFW 3.3+ or the full correct functions from the Win32 backend.
-#if !GLFW_HAS_PER_MONITOR_DPI && defined(_WIN32) && !defined(NOGDI)
-static float   ImGui_ImplWin32_GetLegacyDpiScale()   { const HDC dc = ::GetDC(nullptr); UINT xdpi = ::GetDeviceCaps(dc, LOGPIXELSX); ::ReleaseDC(nullptr, dc); return (float)xdpi / 96.0f; }
-static void    glfwGetWindowContentScale(GLFWwindow*, float* x_scale, float* y_scale)   { *x_scale = *y_scale = ImGui_ImplWin32_GetLegacyDpiScale(); }
-static void    glfwGetMonitorContentScale(GLFWmonitor*, float* x_scale, float* y_scale) { *x_scale = *y_scale = ImGui_ImplWin32_GetLegacyDpiScale(); }
-#undef GLFW_HAS_PER_MONITOR_DPI
-#define GLFW_HAS_PER_MONITOR_DPI 1
+static void ImGui_ImplGlfw_UpdateMonitors()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    int monitors_count = 0;
+    GLFWmonitor** glfw_monitors = glfwGetMonitors(&monitors_count);
+
+    bool updated_monitors = false;
+    for (int n = 0; n < monitors_count; n++)
+    {
+        ImGuiPlatformMonitor monitor;
+        int x, y;
+        glfwGetMonitorPos(glfw_monitors[n], &x, &y);
+        const GLFWvidmode* vid_mode = glfwGetVideoMode(glfw_monitors[n]);
+        if (vid_mode == nullptr)
+            continue; // Failed to get Video mode (e.g. Emscripten does not support this function)
+        if (vid_mode->width <= 0 || vid_mode->height <= 0)
+            continue; // Failed to query suitable monitor info (#9195)
+        monitor.MainPos = monitor.WorkPos = ImVec2((float)x, (float)y);
+        monitor.MainSize = monitor.WorkSize = ImVec2((float)vid_mode->width, (float)vid_mode->height);
+#if GLFW_HAS_MONITOR_WORK_AREA
+        int w, h;
+        glfwGetMonitorWorkarea(glfw_monitors[n], &x, &y, &w, &h);
+        if (w > 0 && h > 0) // Workaround a small GLFW issue reporting zero on monitor changes: https://github.com/glfw/glfw/pull/1761
+        {
+            monitor.WorkPos = ImVec2((float)x, (float)y);
+            monitor.WorkSize = ImVec2((float)w, (float)h);
+        }
 #endif
+        float scale = ImGui_ImplGlfw_GetContentScaleForMonitor(glfw_monitors[n]);
+        if (scale == 0.0f)
+            continue; // Some accessibility applications are declaring virtual monitors with a DPI of 0 (#7902)
+        monitor.DpiScale = scale;
+        monitor.PlatformHandle = (void*)glfw_monitors[n]; // [...] GLFW doc states: "guaranteed to be valid only until the monitor configuration changes"
+
+        // Preserve existing monitor list until a valid one is added.
+        // Happens on macOS sleeping (#5683) and seemingly occasionally on Windows (#9195)
+        if (!updated_monitors)
+            platform_io.Monitors.resize(0);
+        updated_monitors = true;
+        platform_io.Monitors.push_back(monitor);
+    }
+}
 
 // - On Windows the process needs to be marked DPI-aware!! SDL2 doesn't do it by default. You can call ::SetProcessDPIAware() or call ImGui_ImplWin32_EnableDpiAwareness() from Win32 backend.
 // - Apple platforms use FramebufferScale so we always return 1.0f.
@@ -1022,15 +1189,17 @@ void ImGui_ImplGlfw_NewFrame()
 
     // Setup main viewport size (every frame to accommodate for window resizing)
     ImGui_ImplGlfw_GetWindowSizeAndFramebufferScale(bd->Window, &io.DisplaySize, &io.DisplayFramebufferScale);
+    ImGui_ImplGlfw_UpdateMonitors();
 
     // Setup time step
     // (Accept glfwGetTime() not returning a monotonically increasing value. Seems to happens on disconnecting peripherals and probably on VMs and Emscripten, see #6491, #6189, #6114, #3644)
     double current_time = glfwGetTime();
     if (current_time <= bd->Time)
-        current_time = bd->Time + 0.00001;
+        current_time = bd->Time + 0.00001f;
     io.DeltaTime = bd->Time > 0.0 ? (float)(current_time - bd->Time) : (float)(1.0f / 60.0f);
     bd->Time = current_time;
 
+    bd->MouseIgnoreButtonUp = false;
     ImGui_ImplGlfw_UpdateMouseData();
     ImGui_ImplGlfw_UpdateMouseCursor();
 
@@ -1100,6 +1269,444 @@ void ImGui_ImplGlfw_InstallEmscriptenCallbacks(GLFWwindow* window, const char* c
 }
 #endif // #ifdef EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3
 
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplGlfw_ViewportData
+{
+    GLFWwindow* Window;             // Stored in ImGuiViewport::PlatformHandle
+    bool        WindowOwned;
+    int         IgnoreWindowPosEventFrame;
+    int         IgnoreWindowSizeEventFrame;
+#ifdef _WIN32
+    WNDPROC     PrevWndProc;
+#endif
+
+    ImGui_ImplGlfw_ViewportData()  { memset((void*)this, 0, sizeof(*this)); IgnoreWindowSizeEventFrame = IgnoreWindowPosEventFrame = -1; }
+    ~ImGui_ImplGlfw_ViewportData() { IM_ASSERT(Window == nullptr); }
+};
+
+static void ImGui_ImplGlfw_WindowCloseCallback(GLFWwindow* window)
+{
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle(window))
+        viewport->PlatformRequestClose = true;
+}
+
+// GLFW may dispatch window pos/size events after calling glfwSetWindowPos()/glfwSetWindowSize().
+// However: depending on the platform the callback may be invoked at different time:
+// - on Windows it appears to be called within the glfwSetWindowPos()/glfwSetWindowSize() call
+// - on Linux it is queued and invoked during glfwPollEvents()
+// Because the event doesn't always fire on glfwSetWindowXXX() we use a frame counter tag to only
+// ignore recent glfwSetWindowXXX() calls.
+static void ImGui_ImplGlfw_WindowPosCallback(GLFWwindow* window, int, int)
+{
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle(window))
+    {
+        if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+        {
+            bool ignore_event = (ImGui::GetFrameCount() <= vd->IgnoreWindowPosEventFrame + 1);
+            //data->IgnoreWindowPosEventFrame = -1;
+            if (ignore_event)
+                return;
+        }
+        viewport->PlatformRequestMove = true;
+    }
+}
+
+static void ImGui_ImplGlfw_WindowSizeCallback(GLFWwindow* window, int, int)
+{
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle(window))
+    {
+        if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+        {
+            bool ignore_event = (ImGui::GetFrameCount() <= vd->IgnoreWindowSizeEventFrame + 1);
+            //data->IgnoreWindowSizeEventFrame = -1;
+            if (ignore_event)
+                return;
+        }
+        viewport->PlatformRequestResize = true;
+    }
+}
+
+#if !defined(__APPLE__) && !defined(_WIN32) && !defined(__EMSCRIPTEN__) && GLFW_HAS_GETPLATFORM
+#define IMGUI_GLFW_HAS_SETWINDOWFLOATING
+static void ImGui_ImplGlfw_SetWindowFloating(ImGui_ImplGlfw_Data* bd, GLFWwindow* window)
+{
+#ifdef GLFW_EXPOSE_NATIVE_X11
+    if (glfwGetPlatform() == GLFW_PLATFORM_X11)
+    {
+        Display* display = glfwGetX11Display();
+        Window xwindow = glfwGetX11Window(window);
+        Atom wm_type = bd->XInternAtom(display, "_NET_WM_WINDOW_TYPE", False);
+        Atom wm_type_dialog = bd->XInternAtom(display, "_NET_WM_WINDOW_TYPE_DIALOG", False);
+        bd->XChangeProperty(display, xwindow, wm_type, XA_ATOM, 32, PropModeReplace, (unsigned char*)&wm_type_dialog, 1);
+        XSetWindowAttributes attrs;
+        attrs.override_redirect = False;
+        bd->XChangeWindowAttributes(display, xwindow, CWOverrideRedirect, &attrs);
+        bd->XFlush(display);
+    }
+#endif // GLFW_EXPOSE_NATIVE_X11
+#ifdef GLFW_EXPOSE_NATIVE_WAYLAND
+    // FIXME: Help needed, see #8884, #8474 for discussions about this.
+#endif // GLFW_EXPOSE_NATIVE_X11
+}
+#endif // IMGUI_GLFW_HAS_SETWINDOWFLOATING
+
+static void ImGui_ImplGlfw_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = IM_NEW(ImGui_ImplGlfw_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    // Workaround for Linux: ignore mouse up events corresponding to losing focus of the previously focused window (#7733, #3158, #7922)
+#ifdef __linux__
+    bd->MouseIgnoreButtonUpWaitForFocusLoss = true;
+#endif
+
+    // GLFW 3.2 unfortunately always set focus on glfwCreateWindow() if GLFW_VISIBLE is set, regardless of GLFW_FOCUSED
+    // With GLFW 3.3, the hint GLFW_FOCUS_ON_SHOW fixes this problem
+    glfwWindowHint(GLFW_VISIBLE, false);
+    glfwWindowHint(GLFW_FOCUSED, false);
+#if GLFW_HAS_FOCUS_ON_SHOW
+    glfwWindowHint(GLFW_FOCUS_ON_SHOW, false);
+#endif
+    glfwWindowHint(GLFW_DECORATED, (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? false : true);
+#if GLFW_HAS_WINDOW_TOPMOST
+    glfwWindowHint(GLFW_FLOATING, (viewport->Flags & ImGuiViewportFlags_TopMost) ? true : false);
+#endif
+    GLFWwindow* share_window = (bd->ClientApi == GlfwClientApi_OpenGL) ? bd->Window : nullptr;
+    vd->Window = glfwCreateWindow((int)viewport->Size.x, (int)viewport->Size.y, "No Title Yet", nullptr, share_window);
+    vd->WindowOwned = true;
+    ImGui_ImplGlfw_ContextMap_Add(vd->Window, bd->Context);
+    viewport->PlatformHandle = (void*)vd->Window;
+#ifdef IMGUI_GLFW_HAS_SETWINDOWFLOATING
+    ImGui_ImplGlfw_SetWindowFloating(bd, vd->Window);
+#endif
+#ifdef _WIN32
+    viewport->PlatformHandleRaw = glfwGetWin32Window(vd->Window);
+    ::SetPropA((HWND)viewport->PlatformHandleRaw, "IMGUI_BACKEND_DATA", bd);
+#elif defined(__APPLE__)
+    viewport->PlatformHandleRaw = (void*)glfwGetCocoaWindow(vd->Window);
+#endif
+    glfwSetWindowPos(vd->Window, (int)viewport->Pos.x, (int)viewport->Pos.y);
+
+    // Install GLFW callbacks for secondary viewports
+    glfwSetWindowFocusCallback(vd->Window, ImGui_ImplGlfw_WindowFocusCallback);
+    glfwSetCursorEnterCallback(vd->Window, ImGui_ImplGlfw_CursorEnterCallback);
+    glfwSetCursorPosCallback(vd->Window, ImGui_ImplGlfw_CursorPosCallback);
+    glfwSetMouseButtonCallback(vd->Window, ImGui_ImplGlfw_MouseButtonCallback);
+    glfwSetScrollCallback(vd->Window, ImGui_ImplGlfw_ScrollCallback);
+    glfwSetKeyCallback(vd->Window, ImGui_ImplGlfw_KeyCallback);
+    glfwSetCharCallback(vd->Window, ImGui_ImplGlfw_CharCallback);
+    glfwSetWindowCloseCallback(vd->Window, ImGui_ImplGlfw_WindowCloseCallback);
+    glfwSetWindowPosCallback(vd->Window, ImGui_ImplGlfw_WindowPosCallback);
+    glfwSetWindowSizeCallback(vd->Window, ImGui_ImplGlfw_WindowSizeCallback);
+    if (bd->ClientApi == GlfwClientApi_OpenGL)
+    {
+        glfwMakeContextCurrent(vd->Window);
+        glfwSwapInterval(0);
+    }
+}
+
+static void ImGui_ImplGlfw_DestroyWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+    {
+        if (vd->WindowOwned)
+        {
+#if !GLFW_HAS_MOUSE_PASSTHROUGH && GLFW_HAS_WINDOW_HOVERED && defined(_WIN32)
+            HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+            ::RemovePropA(hwnd, "IMGUI_VIEWPORT");
+#endif
+
+            // Release any keys that were pressed in the window being destroyed and are still held down,
+            // because we will not receive any release events after window is destroyed.
+            for (int i = 0; i < IM_COUNTOF(bd->KeyOwnerWindows); i++)
+                if (bd->KeyOwnerWindows[i] == vd->Window)
+                    ImGui_ImplGlfw_KeyCallback(vd->Window, i, 0, GLFW_RELEASE, 0); // Later params are only used for main viewport, on which this function is never called.
+
+            ImGui_ImplGlfw_ContextMap_Remove(vd->Window);
+            glfwDestroyWindow(vd->Window);
+        }
+        vd->Window = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplGlfw_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+
+#if defined(_WIN32)
+    // GLFW hack: Hide icon from task bar
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+    if (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon)
+    {
+        LONG ex_style = ::GetWindowLong(hwnd, GWL_EXSTYLE);
+        ex_style &= ~WS_EX_APPWINDOW;
+        ex_style |= WS_EX_TOOLWINDOW;
+        ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
+    }
+
+    // GLFW hack: install WndProc for mouse source event and WM_NCHITTEST message handler.
+    ::SetPropA(hwnd, "IMGUI_VIEWPORT", viewport);
+    vd->PrevWndProc = (WNDPROC)::GetWindowLongPtrW(hwnd, GWLP_WNDPROC);
+    ::SetWindowLongPtrW(hwnd, GWLP_WNDPROC, (LONG_PTR)ImGui_ImplGlfw_WndProc);
+
+#if !GLFW_HAS_FOCUS_ON_SHOW
+    // GLFW hack: GLFW 3.2 has a bug where glfwShowWindow() also activates/focus the window.
+    // The fix was pushed to GLFW repository on 2018/01/09 and should be included in GLFW 3.3 via a GLFW_FOCUS_ON_SHOW window attribute.
+    // See https://github.com/glfw/glfw/issues/1189
+    // FIXME-VIEWPORT: Implement same work-around for Linux/OSX in the meanwhile.
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+    {
+        ::ShowWindow(hwnd, SW_SHOWNA);
+        return;
+    }
+#endif
+#endif
+
+    glfwShowWindow(vd->Window);
+}
+
+static ImVec2 ImGui_ImplGlfw_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    int x = 0, y = 0;
+    glfwGetWindowPos(vd->Window, &x, &y);
+    return ImVec2((float)x, (float)y);
+}
+
+static void ImGui_ImplGlfw_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    vd->IgnoreWindowPosEventFrame = ImGui::GetFrameCount();
+    glfwSetWindowPos(vd->Window, (int)pos.x, (int)pos.y);
+}
+
+static ImVec2 ImGui_ImplGlfw_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    int w = 0, h = 0;
+    glfwGetWindowSize(vd->Window, &w, &h);
+    return ImVec2((float)w, (float)h);
+}
+
+static void ImGui_ImplGlfw_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+#if defined(__APPLE__) && !GLFW_HAS_OSX_WINDOW_POS_FIX
+    // Native OS windows are positioned from the bottom-left corner on macOS, whereas on other platforms they are
+    // positioned from the upper-left corner. GLFW makes an effort to convert macOS style coordinates, however it
+    // doesn't handle it when changing size. We are manually moving the window in order for changes of size to be based
+    // on the upper-left corner.
+    int x, y, width, height;
+    glfwGetWindowPos(vd->Window, &x, &y);
+    glfwGetWindowSize(vd->Window, &width, &height);
+    glfwSetWindowPos(vd->Window, x, y - height + size.y);
+#endif
+    vd->IgnoreWindowSizeEventFrame = ImGui::GetFrameCount();
+    glfwSetWindowSize(vd->Window, (int)size.x, (int)size.y);
+}
+
+static ImVec2 ImGui_ImplGlfw_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    ImVec2 framebuffer_scale;
+    ImGui_ImplGlfw_GetWindowSizeAndFramebufferScale(vd->Window, nullptr, &framebuffer_scale);
+    return framebuffer_scale;
+}
+
+static void ImGui_ImplGlfw_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    glfwSetWindowTitle(vd->Window, title);
+}
+
+static void ImGui_ImplGlfw_SetWindowFocus(ImGuiViewport* viewport)
+{
+#if GLFW_HAS_FOCUS_WINDOW
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    glfwFocusWindow(vd->Window);
+#else
+    // FIXME: What are the effect of not having this function? At the moment imgui doesn't actually call SetWindowFocus - we set that up ahead, will answer that question later.
+    (void)viewport;
+#endif
+}
+
+static bool ImGui_ImplGlfw_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    return glfwGetWindowAttrib(vd->Window, GLFW_FOCUSED) != 0;
+}
+
+static bool ImGui_ImplGlfw_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    return glfwGetWindowAttrib(vd->Window, GLFW_ICONIFIED) != 0;
+}
+
+#if GLFW_HAS_WINDOW_ALPHA
+static void ImGui_ImplGlfw_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    glfwSetWindowOpacity(vd->Window, alpha);
+}
+#endif
+
+static void ImGui_ImplGlfw_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    if (bd->ClientApi == GlfwClientApi_OpenGL)
+        glfwMakeContextCurrent(vd->Window);
+}
+
+static void ImGui_ImplGlfw_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    if (bd->ClientApi == GlfwClientApi_OpenGL)
+    {
+        glfwMakeContextCurrent(vd->Window);
+        glfwSwapBuffers(vd->Window);
+    }
+}
+
+//--------------------------------------------------------------------------------------------------------
+// Vulkan support (the Vulkan renderer needs to call a platform-side support function to create the surface)
+//--------------------------------------------------------------------------------------------------------
+
+// Avoid including <vulkan.h> so we can build without it
+#if GLFW_HAS_VULKAN
+#ifndef VULKAN_H_
+#define VK_DEFINE_HANDLE(object) typedef struct object##_T* object;
+#if defined(__LP64__) || defined(_WIN64) || defined(__x86_64__) || defined(_M_X64) || defined(__ia64) || defined (_M_IA64) || defined(__aarch64__) || defined(__powerpc64__)
+#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef struct object##_T *object;
+#else
+#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef uint64_t object;
+#endif
+VK_DEFINE_HANDLE(VkInstance)
+VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSurfaceKHR)
+struct VkAllocationCallbacks;
+enum VkResult { VK_RESULT_MAX_ENUM = 0x7FFFFFFF };
+#endif // VULKAN_H_
+extern "C" { extern GLFWAPI VkResult glfwCreateWindowSurface(VkInstance instance, GLFWwindow* window, const VkAllocationCallbacks* allocator, VkSurfaceKHR* surface); }
+static int ImGui_ImplGlfw_CreateVkSurface(ImGuiViewport* viewport, ImU64 vk_instance, const void* vk_allocator, ImU64* out_vk_surface)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    IM_UNUSED(bd);
+    IM_ASSERT(bd->ClientApi == GlfwClientApi_Vulkan);
+    VkResult err = glfwCreateWindowSurface((VkInstance)vk_instance, vd->Window, (const VkAllocationCallbacks*)vk_allocator, (VkSurfaceKHR*)out_vk_surface);
+    return (int)err;
+}
+#endif // GLFW_HAS_VULKAN
+
+static void ImGui_ImplGlfw_InitMultiViewportSupport()
+{
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplGlfw_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplGlfw_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplGlfw_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplGlfw_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplGlfw_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplGlfw_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplGlfw_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplGlfw_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplGlfw_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplGlfw_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplGlfw_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplGlfw_SetWindowTitle;
+    platform_io.Platform_RenderWindow = ImGui_ImplGlfw_RenderWindow;
+    platform_io.Platform_SwapBuffers = ImGui_ImplGlfw_SwapBuffers;
+#if GLFW_HAS_WINDOW_ALPHA
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplGlfw_SetWindowAlpha;
+#endif
+#if GLFW_HAS_VULKAN
+    platform_io.Platform_CreateVkSurface = ImGui_ImplGlfw_CreateVkSurface;
+#endif
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplGlfw_ViewportData* vd = IM_NEW(ImGui_ImplGlfw_ViewportData)();
+    vd->Window = bd->Window;
+    vd->WindowOwned = false;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (void*)bd->Window;
+}
+
+static void ImGui_ImplGlfw_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
+//-----------------------------------------------------------------------------
+
+// WndProc hook (declared here because we will need access to ImGui_ImplGlfw_ViewportData)
+#ifdef _WIN32
+static ImGuiMouseSource GetMouseSourceFromMessageExtraInfo()
+{
+    LPARAM extra_info = ::GetMessageExtraInfo();
+    if ((extra_info & 0xFFFFFF80) == 0xFF515700)
+        return ImGuiMouseSource_Pen;
+    if ((extra_info & 0xFFFFFF80) == 0xFF515780)
+        return ImGuiMouseSource_TouchScreen;
+    return ImGuiMouseSource_Mouse;
+}
+static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+    ImGui_ImplGlfw_Data* bd = (ImGui_ImplGlfw_Data*)::GetPropA(hWnd, "IMGUI_BACKEND_DATA");
+    ImGuiIO& io = ImGui::GetIO(bd->Context);
+
+    WNDPROC prev_wndproc = bd->PrevWndProc;
+    ImGuiViewport* viewport = (ImGuiViewport*)::GetPropA(hWnd, "IMGUI_VIEWPORT");
+    if (viewport != NULL)
+        if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+            prev_wndproc = vd->PrevWndProc;
+
+    switch (msg)
+    {
+        // GLFW doesn't allow to distinguish Mouse vs TouchScreen vs Pen.
+        // Add support for Win32 (based on imgui_impl_win32), because we rely on _TouchScreen info to trickle inputs differently.
+    case WM_MOUSEMOVE: case WM_NCMOUSEMOVE:
+    case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK: case WM_LBUTTONUP:
+    case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK: case WM_RBUTTONUP:
+    case WM_MBUTTONDOWN: case WM_MBUTTONDBLCLK: case WM_MBUTTONUP:
+    case WM_XBUTTONDOWN: case WM_XBUTTONDBLCLK: case WM_XBUTTONUP:
+        io.AddMouseSourceEvent(GetMouseSourceFromMessageExtraInfo());
+        break;
+
+        // We have submitted https://github.com/glfw/glfw/pull/1568 to allow GLFW to support "transparent inputs".
+        // In the meanwhile we implement custom per-platform workarounds here (FIXME-VIEWPORT: Implement same work-around for Linux/OSX!)
+#if !GLFW_HAS_MOUSE_PASSTHROUGH && GLFW_HAS_WINDOW_HOVERED
+    case WM_NCHITTEST:
+    {
+        // Let mouse pass-through the window. This will allow the backend to call io.AddMouseViewportEvent() properly (which is OPTIONAL).
+        // The ImGuiViewportFlags_NoInputs flag is set while dragging a viewport, as want to detect the window behind the one we are dragging.
+        // If you cannot easily access those viewport flags from your windowing/event code: you may manually synchronize its state e.g. in
+        // your main loop after calling UpdatePlatformWindows(). Iterate all viewports/platform windows and pass the flag to your windowing system.
+        if (viewport && (viewport->Flags & ImGuiViewportFlags_NoInputs))
+            return HTTRANSPARENT;
+        break;
+    }
+#endif
+    default: break;
+    }
+    return ::CallWindowProcW(prev_wndproc, hWnd, msg, wParam, lParam);
+}
+#endif // #ifdef _WIN32
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_glfw.h

@@ -9,10 +9,12 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy GLFW_KEY_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors) with GLFW 3.1+. Resizing cursors requires GLFW 3.4+! Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 //  [X] Multiple Dear ImGui contexts support.
 // Missing features or Issues:
 //  [ ] Platform: Touch events are only correctly identified as Touch on Windows. This create issues with some interactions. GLFW doesn't provide a way to identify touch inputs from mouse inputs, we cannot call io.AddMouseSourceEvent() to identify the source. We provide a Windows-specific workaround.
 //  [ ] Platform: Missing ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress cursors.
+//  [ ] Platform: Multi-viewport: Missing ImGuiBackendFlags_HasParentViewport support. The viewport->ParentViewportID field is ignored, and therefore io.ConfigViewportsNoDefaultParent has no effect either.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_glut.cpp

@@ -13,6 +13,7 @@
 //  [ ] Platform: Missing mouse cursor shape/visibility support.
 //  [ ] Platform: Missing clipboard support (not supported by Glut).
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Platform: Missing multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_glut.h

@@ -13,6 +13,7 @@
 //  [ ] Platform: Missing mouse cursor shape/visibility support.
 //  [ ] Platform: Missing clipboard support (not supported by Glut).
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Platform: Missing multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_metal.h

@@ -5,6 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'MTLTexture' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_metal.mm

@@ -5,6 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'MTLTexture' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -16,10 +17,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-28: Added support for standard draw callbacks (in platform_io): DrawCallback_SetSamplerLinear and DrawCallback_SetSamplerNearest. (#9378, #9381)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState (others are not yet supported). (#9378)
-//  2026-04-14: Metal: use a dedicated bufferCacheLock to avoid crashing when bufferCache is replaced by a new object while being used for @synchronize(). (#9367)
-//  2026-04-03: Metal: avoid redundant vertex buffer bind in SetupRenderState. (#9343)
+//  2026-XX-XX: Metal: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-03-19: Fixed issue in ImGui_ImplMetal_RenderDrawData() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295, #9310)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplMetal_CreateFontsTexture() and ImGui_ImplMetal_DestroyFontsTexture().
@@ -48,6 +46,12 @@
 #import <time.h>
 #import <Metal/Metal.h>
 
+// Forward Declarations
+static void ImGui_ImplMetal_InitMultiViewportSupport();
+static void ImGui_ImplMetal_ShutdownMultiViewportSupport();
+static void ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows();
+static void ImGui_ImplMetal_InvalidateDeviceObjectsForPlatformWindows();
+
 #pragma mark - Support classes
 
 // A wrapper around a MTLBuffer object that knows the last time it was reused
@@ -78,12 +82,9 @@
 @interface MetalContext : NSObject
 @property (nonatomic, strong) id<MTLDevice>                 device;
 @property (nonatomic, strong) id<MTLDepthStencilState>      depthStencilState;
-@property (nonatomic, strong) id<MTLSamplerState>           samplerStateLinear;
-@property (nonatomic, strong) id<MTLSamplerState>           samplerStateNearest;
 @property (nonatomic, strong) FramebufferDescriptor*        framebufferDescriptor; // framebuffer descriptor for current frame; transient
 @property (nonatomic, strong) NSMutableDictionary*          renderPipelineStateCache; // pipeline cache; keyed on framebuffer descriptors
 @property (nonatomic, strong) NSMutableArray<MetalBuffer*>* bufferCache;
-@property (nonatomic, strong) NSObject*                     bufferCacheLock;
 @property (nonatomic, assign) double                        lastBufferCachePurge;
 - (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device;
 - (id<MTLRenderPipelineState>)renderPipelineStateForFramebufferDescriptor:(FramebufferDescriptor*)descriptor device:(id<MTLDevice>)device;
@@ -92,7 +93,6 @@
 struct ImGui_ImplMetal_Data
 {
     MetalContext*               SharedMetalContext;
-    id<MTLRenderCommandEncoder> RenderCommandEncoder;
 
     ImGui_ImplMetal_Data()      { memset((void*)this, 0, sizeof(*this)); }
 };
@@ -123,6 +123,7 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data,
     ImGui_ImplMetal_RenderDrawData(draw_data,
                                    (__bridge id<MTLCommandBuffer>)(commandBuffer),
                                    (__bridge id<MTLRenderCommandEncoder>)(commandEncoder));
+
 }
 
 bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)
@@ -134,6 +135,45 @@ bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)
 
 #pragma mark - Dear ImGui Metal Backend API
 
+bool ImGui_ImplMetal_Init(id<MTLDevice> device)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    ImGui_ImplMetal_Data* bd = IM_NEW(ImGui_ImplMetal_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_metal";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+
+    bd->SharedMetalContext = [[MetalContext alloc] init];
+    bd->SharedMetalContext.device = device;
+
+    ImGui_ImplMetal_InitMultiViewportSupport();
+
+    return true;
+}
+
+void ImGui_ImplMetal_Shutdown()
+{
+    ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
+    IM_UNUSED(bd);
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplMetal_ShutdownMultiViewportSupport();
+    ImGui_ImplMetal_DestroyDeviceObjects();
+    ImGui_ImplMetal_DestroyBackendData();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
+    platform_io.ClearRendererHandlers();
+}
+
 void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor)
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
@@ -186,16 +226,11 @@ static void ImGui_ImplMetal_SetupRenderState(ImDrawData* draw_data, id<MTLComman
     [commandEncoder setVertexBytes:&ortho_projection length:sizeof(ortho_projection) atIndex:1];
 
     [commandEncoder setRenderPipelineState:renderPipelineState];
-    [commandEncoder setFragmentSamplerState:bd->SharedMetalContext.samplerStateLinear atIndex:0];
 
-    [commandEncoder setVertexBuffer:vertexBuffer.buffer offset:vertexBufferOffset atIndex:0];
+    [commandEncoder setVertexBuffer:vertexBuffer.buffer offset:0 atIndex:0];
+    [commandEncoder setVertexBufferOffset:vertexBufferOffset atIndex:0];
 }
 
-// Draw callbacks
-static void ImGui_ImplMetal_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)  {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplMetal_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)  { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); [bd->RenderCommandEncoder setFragmentSamplerState:bd->SharedMetalContext.samplerStateLinear atIndex:0]; }
-static void ImGui_ImplMetal_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*) { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); [bd->RenderCommandEncoder setFragmentSamplerState:bd->SharedMetalContext.samplerStateNearest atIndex:0]; }
-
 // Metal Render function.
 void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer> commandBuffer, id<MTLRenderCommandEncoder> commandEncoder)
 {
@@ -232,7 +267,6 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer>
     MetalBuffer* vertexBuffer = [ctx dequeueReusableBufferOfLength:vertexBufferLength device:commandBuffer.device];
     MetalBuffer* indexBuffer = [ctx dequeueReusableBufferOfLength:indexBufferLength device:commandBuffer.device];
 
-    bd->RenderCommandEncoder = commandEncoder;
     ImGui_ImplMetal_SetupRenderState(draw_data, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, 0);
 
     // Will project scissor/clipping rectangles into framebuffer space
@@ -253,7 +287,8 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer>
             if (pcmd->UserCallback)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplMetal_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplMetal_SetupRenderState(draw_data, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, vertexBufferOffset);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -267,8 +302,8 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer>
                 // Clamp to viewport as setScissorRect() won't accept values that are off bounds
                 if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
                 if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
-                if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; }
-                if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; }
+                if (clip_max.x > fb_width) { clip_max.x = (float)fb_width; }
+                if (clip_max.y > fb_height) { clip_max.y = (float)fb_height; }
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
                 if (pcmd->ElemCount == 0) // drawIndexedPrimitives() validation doesn't accept this
@@ -305,13 +340,14 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer>
     MetalContext* sharedMetalContext = bd->SharedMetalContext;
     [commandBuffer addCompletedHandler:^(id<MTLCommandBuffer>)
     {
-        @synchronized(sharedMetalContext.bufferCacheLock)
-        {
-            [sharedMetalContext.bufferCache addObject:vertexBuffer];
-            [sharedMetalContext.bufferCache addObject:indexBuffer];
-        }
+        dispatch_async(dispatch_get_main_queue(), ^{
+            @synchronized(sharedMetalContext.bufferCache)
+            {
+                [sharedMetalContext.bufferCache addObject:vertexBuffer];
+                [sharedMetalContext.bufferCache addObject:indexBuffer];
+            }
+        });
     }];
-    bd->RenderCommandEncoder = nil;
 }
 
 static void ImGui_ImplMetal_DestroyTexture(ImTextureData* tex)
@@ -388,17 +424,8 @@ bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device)
     depthStencilDescriptor.depthWriteEnabled = NO;
     depthStencilDescriptor.depthCompareFunction = MTLCompareFunctionAlways;
     bd->SharedMetalContext.depthStencilState = [device newDepthStencilStateWithDescriptor:depthStencilDescriptor];
-    MTLSamplerDescriptor* samplerDescriptor = [[MTLSamplerDescriptor alloc] init];
-    samplerDescriptor.minFilter = MTLSamplerMinMagFilterLinear;
-    samplerDescriptor.magFilter = MTLSamplerMinMagFilterLinear;
-    samplerDescriptor.mipFilter = MTLSamplerMipFilterLinear;
-    bd->SharedMetalContext.samplerStateLinear = [device newSamplerStateWithDescriptor:samplerDescriptor];
-    samplerDescriptor.minFilter = MTLSamplerMinMagFilterNearest;
-    samplerDescriptor.magFilter = MTLSamplerMinMagFilterNearest;
-    samplerDescriptor.mipFilter = MTLSamplerMipFilterNearest;
-    bd->SharedMetalContext.samplerStateNearest = [device newSamplerStateWithDescriptor:samplerDescriptor];
+    ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows();
 #ifdef IMGUI_IMPL_METAL_CPP
-    [samplerDescriptor release];
     [depthStencilDescriptor release];
 #endif
 
@@ -414,49 +441,152 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
         if (tex->RefCount == 1)
             ImGui_ImplMetal_DestroyTexture(tex);
 
+    ImGui_ImplMetal_InvalidateDeviceObjectsForPlatformWindows();
     [bd->SharedMetalContext.renderPipelineStateCache removeAllObjects];
-    bd->SharedMetalContext.samplerStateLinear = nil;
-    bd->SharedMetalContext.samplerStateNearest = nil;
 }
 
-bool ImGui_ImplMetal_Init(id<MTLDevice> device)
+#pragma mark - Multi-viewport support
+
+#import <QuartzCore/CAMetalLayer.h>
+
+#if TARGET_OS_OSX
+#import <Cocoa/Cocoa.h>
+#endif
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the back-end to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+struct ImGuiViewportDataMetal
 {
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+    CAMetalLayer*               MetalLayer;
+    id<MTLCommandQueue>         CommandQueue;
+    MTLRenderPassDescriptor*    RenderPassDescriptor;
+    void*                       Handle = nullptr;
+    bool                        FirstFrame = true;
+};
 
-    ImGui_ImplMetal_Data* bd = IM_NEW(ImGui_ImplMetal_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_metal";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplMetal_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplMetal_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplMetal_DrawCallback_SetSamplerNearest;
-
-    bd->SharedMetalContext = [[MetalContext alloc] init];
-    bd->SharedMetalContext.device = device;
-
-    return true;
-}
-
-void ImGui_ImplMetal_Shutdown()
+static void ImGui_ImplMetal_CreateWindow(ImGuiViewport* viewport)
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-    IM_UNUSED(bd);
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
+    ImGuiViewportDataMetal* data = IM_NEW(ImGuiViewportDataMetal)();
+    viewport->RendererUserData = data;
+
+    // PlatformHandleRaw should always be a NSWindow*, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL_Window*).
+    // Some back-ends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the NSWindow*.
+    void* handle = viewport->PlatformHandleRaw ? viewport->PlatformHandleRaw : viewport->PlatformHandle;
+    IM_ASSERT(handle != nullptr);
+
+    id<MTLDevice> device = bd->SharedMetalContext.device;
+    CAMetalLayer* layer = [CAMetalLayer layer];
+    layer.device = device;
+    layer.framebufferOnly = YES;
+    layer.pixelFormat = bd->SharedMetalContext.framebufferDescriptor.colorPixelFormat;
+#if TARGET_OS_OSX
+    NSWindow* window = (__bridge NSWindow*)handle;
+    NSView* view = window.contentView;
+    view.layer = layer;
+    view.wantsLayer = YES;
+#endif
+    data->MetalLayer = layer;
+    data->CommandQueue = [device newCommandQueue];
+    data->RenderPassDescriptor = [[MTLRenderPassDescriptor alloc] init];
+    data->Handle = handle;
+}
+
+static void ImGui_ImplMetal_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 since we didn't create the data for it.
+    if (ImGuiViewportDataMetal* data = (ImGuiViewportDataMetal*)viewport->RendererUserData)
+        IM_DELETE(data);
+    viewport->RendererUserData = nullptr;
+}
+
+inline static CGSize MakeScaledSize(CGSize size, CGFloat scale)
+{
+    return CGSizeMake(size.width * scale, size.height * scale);
+}
+
+static void ImGui_ImplMetal_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGuiViewportDataMetal* data = (ImGuiViewportDataMetal*)viewport->RendererUserData;
+    data->MetalLayer.drawableSize = MakeScaledSize(CGSizeMake(size.x, size.y), viewport->DpiScale);
+}
+
+static void ImGui_ImplMetal_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGuiViewportDataMetal* data = (ImGuiViewportDataMetal*)viewport->RendererUserData;
+
+#if TARGET_OS_OSX
+    void* handle = viewport->PlatformHandleRaw ? viewport->PlatformHandleRaw : viewport->PlatformHandle;
+    NSWindow* window = (__bridge NSWindow*)handle;
+
+    // Always render the first frame, regardless of occlusionState, to avoid an initial flicker
+    if ((window.occlusionState & NSWindowOcclusionStateVisible) == 0 && !data->FirstFrame)
+    {
+        // Do not render windows which are completely occluded. Calling -[CAMetalLayer nextDrawable] will hang for
+        // approximately 1 second if the Metal layer is completely occluded.
+        return;
+    }
+    data->FirstFrame = false;
+
+    float fb_scale = (float)window.backingScaleFactor;
+    if (data->MetalLayer.contentsScale != fb_scale)
+    {
+        data->MetalLayer.contentsScale = fb_scale;
+        data->MetalLayer.drawableSize = MakeScaledSize(window.frame.size, fb_scale);
+    }
+#endif
+
+    id <CAMetalDrawable> drawable = [data->MetalLayer nextDrawable];
+    if (drawable == nil)
+        return;
+
+    MTLRenderPassDescriptor* renderPassDescriptor = data->RenderPassDescriptor;
+    renderPassDescriptor.colorAttachments[0].texture = drawable.texture;
+    renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(0, 0, 0, 0);
+    if ((viewport->Flags & ImGuiViewportFlags_NoRendererClear) == 0)
+        renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
+
+    id <MTLCommandBuffer> commandBuffer = [data->CommandQueue commandBuffer];
+    id <MTLRenderCommandEncoder> renderEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
+    ImGui_ImplMetal_RenderDrawData(viewport->DrawData, commandBuffer, renderEncoder);
+    [renderEncoder endEncoding];
+
+    [commandBuffer presentDrawable:drawable];
+    [commandBuffer commit];
+}
+
+static void ImGui_ImplMetal_InitMultiViewportSupport()
+{
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplMetal_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplMetal_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplMetal_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplMetal_RenderWindow;
+}
 
-    ImGui_ImplMetal_DestroyDeviceObjects();
-    ImGui_ImplMetal_DestroyBackendData();
+static void ImGui_ImplMetal_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
 
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
+static void ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (!platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplMetal_CreateWindow(platform_io.Viewports[i]);
+}
+
+static void ImGui_ImplMetal_InvalidateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplMetal_DestroyWindow(platform_io.Viewports[i]);
 }
 
 #pragma mark - MetalBuffer implementation
@@ -542,7 +672,6 @@ void ImGui_ImplMetal_Shutdown()
     {
         self.renderPipelineStateCache = [NSMutableDictionary dictionary];
         self.bufferCache = [NSMutableArray array];
-        self.bufferCacheLock = [[NSObject alloc] init];
         _lastBufferCachePurge = GetMachAbsoluteTimeInSeconds();
     }
     return self;
@@ -550,9 +679,9 @@ void ImGui_ImplMetal_Shutdown()
 
 - (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device
 {
-    double now = GetMachAbsoluteTimeInSeconds();
+    uint64_t now = GetMachAbsoluteTimeInSeconds();
 
-    @synchronized(self.bufferCacheLock)
+    @synchronized(self.bufferCache)
     {
         // Purge old buffers that haven't been useful for a while
         if (now - self.lastBufferCachePurge > 1.0)
@@ -619,9 +748,9 @@ void ImGui_ImplMetal_Shutdown()
     "}\n"
     "\n"
     "fragment half4 fragment_main(VertexOut in [[stage_in]],\n"
-    "                             texture2d<half, access::sample> texture [[texture(0)]],\n"
-    "                             sampler textureSampler [[sampler(0)]]) {\n"
-    "    half4 texColor = texture.sample(textureSampler, in.texCoords);\n"
+    "                             texture2d<half, access::sample> texture [[texture(0)]]) {\n"
+    "    constexpr sampler linearSampler(coord::normalized, min_filter::linear, mag_filter::linear, mip_filter::linear);\n"
+    "    half4 texColor = texture.sample(linearSampler, in.texCoords);\n"
     "    return half4(in.color) * texColor;\n"
     "}\n";
 

backends/imgui_impl_metal4.h

@@ -1,89 +0,0 @@
-// dear imgui: Renderer Backend for Metal 4
-// This needs to be used along with a Platform Backend (e.g. OSX)
-// Metal 4 requires Apple Silicon and macOS 26+.
-
-// Implemented features:
-//  [X] Renderer: User texture binding. Use 'MTLTexture.gpuResourceID' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
-//  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
-//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
-// Missing features or Issues:
-//  [ ] Texture view pool support? Reevaluate which type to use for ImtextureID.
-
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
-// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
-// Learn about Dear ImGui:
-// - FAQ                  https://dearimgui.com/faq
-// - Getting Started      https://dearimgui.com/getting-started
-// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
-// - Introduction, links and more at the top of imgui.cpp
-
-#pragma once
-#include "imgui.h"      // IMGUI_IMPL_API
-#ifndef IMGUI_DISABLE
-
-//-----------------------------------------------------------------------------
-// ObjC API
-//-----------------------------------------------------------------------------
-
-#ifdef __OBJC__
-
-@class MTL4RenderPassDescriptor;
-@protocol MTLDevice, MTL4CommandBuffer, MTL4RenderCommandEncoder, MTL4CommandQueue;
-
-// framesInFlight must match the number of frames your application keeps in flight (e.g. the size of your own
-// command buffer/allocator ring). The backend uses it to size its own per-frame-in-flight resources (constant
-// buffer, vertex/index buffer cache) so the CPU never overwrites a slot the GPU may still be reading.
-// Follow "Getting Started" link and check examples/ folder to learn about using backends!
-IMGUI_IMPL_API bool ImGui_ImplMetal4_Init(id<MTLDevice> device, id<MTL4CommandQueue> commandQueue, int framesInFlight);
-IMGUI_IMPL_API void ImGui_ImplMetal4_Shutdown();
-// frameInFlightIndex must match the slot you use to index your own per-frame-in-flight resources
-// (e.g. the same index used to pick your command buffer/allocator), and must be < framesInFlight passed to Init().
-IMGUI_IMPL_API void ImGui_ImplMetal4_NewFrame(MTL4RenderPassDescriptor* renderPassDescriptor, int frameInFlightIndex);
-IMGUI_IMPL_API void ImGui_ImplMetal4_RenderDrawData(ImDrawData* drawData,
-                                                   id<MTL4CommandBuffer> commandBuffer,
-                                                   id<MTL4RenderCommandEncoder> commandEncoder);
-
-// Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool ImGui_ImplMetal4_CreateDeviceObjects(id<MTLDevice> device);
-IMGUI_IMPL_API void ImGui_ImplMetal4_DestroyDeviceObjects();
-
-// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = nullptr to handle this manually.
-IMGUI_IMPL_API void ImGui_ImplMetal4_UpdateTexture(ImTextureData* tex);
-
-#endif
-
-//-----------------------------------------------------------------------------
-// C++ API
-//-----------------------------------------------------------------------------
-
-// Enable Metal C++ binding support with '#define IMGUI_IMPL_METAL_CPP' in your imconfig.h file
-// More info about using Metal from C++: https://developer.apple.com/metal/cpp/
-
-#ifdef IMGUI_IMPL_METAL_CPP
-#ifndef __OBJC__
-
-// Forward declare relevant classes from the MTL and MTL4 namespace
-namespace MTL { class Device; }
-namespace MTL4 { class CommandQueue; class CommandBuffer; class RenderPassDescriptor; class RenderCommandEncoder; }
-
-// Follow "Getting Started" link and check examples/ folder to learn about using backends!
-IMGUI_IMPL_API bool ImGui_ImplMetal4_Init(MTL::Device* device, MTL4::CommandQueue* commandQueue, int framesInFlight);
-IMGUI_IMPL_API void ImGui_ImplMetal4_Shutdown();
-IMGUI_IMPL_API void ImGui_ImplMetal4_NewFrame(MTL4::RenderPassDescriptor* renderPassDescriptor, int frameInFlightIndex);
-IMGUI_IMPL_API void ImGui_ImplMetal4_RenderDrawData(ImDrawData* draw_data,
-                                                   MTL4::CommandBuffer* commandBuffer,
-                                                   MTL4::RenderCommandEncoder* commandEncoder);
-
-// Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool ImGui_ImplMetal4_CreateDeviceObjects(MTL::Device* device);
-IMGUI_IMPL_API void ImGui_ImplMetal4_DestroyDeviceObjects();
-
-// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = nullptr to handle this manually.
-IMGUI_IMPL_API void ImGui_ImplMetal4_UpdateTexture(ImTextureData* tex);
-
-#endif
-#endif
-
-//-----------------------------------------------------------------------------
-
-#endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_metal4.mm

@@ -1,743 +0,0 @@
-// dear imgui: Renderer Backend for Metal 4
-// This needs to be used along with a Platform Backend (e.g. OSX)
-// Metal 4 requires Apple Silicon and macOS 26+.
-
-// Implemented features:
-//  [X] Renderer: User texture binding. Use 'MTLTexture' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
-//  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
-//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
-// Missing features or Issues:
-//  [ ] Texture view pool support? Reevaluate which type to use for ImtextureID.
-
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
-// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
-// Learn about Dear ImGui:
-// - FAQ                  https://dearimgui.com/faq
-// - Getting Started      https://dearimgui.com/getting-started
-// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
-// - Introduction, links and more at the top of imgui.cpp
-
-// CHANGELOG
-// (minor and older changes stripped away, please see git history for details)
-//  2026-07-07: Metal 4: Added metal-cpp support. (#9461)
-//  2026-07-02: Metal 4: Added new Metal 4 backend implementation. (#9458)
-
-#include "imgui.h"
-#ifndef IMGUI_DISABLE
-#include "imgui_impl_metal4.h"
-#import <time.h>
-#import <Metal/Metal.h>
-
-#ifdef IMGUI_IMPL_METAL_CPP
-#include <Metal/Metal.hpp>
-#endif
-
-#pragma mark - Support classes and structs
-
-struct ImGui_Metal4_ConstantData
-{
-    float ModelViewProjectionMatrix[4][4];
-};
-
-@interface MetalBuffer : NSObject
-@property (nonatomic, strong) id<MTLBuffer> buffer;
-@property (nonatomic, assign) double        lastReuseTime;
-- (instancetype)initWithBuffer:(id<MTLBuffer>)buffer;
-@end
-
-// An object that encapsulates the data necessary to uniquely identify a
-// render pipeline state. These are used as cache keys.
-@interface FramebufferDescriptor : NSObject<NSCopying>
-@property (nonatomic, assign) unsigned long  sampleCount;
-@property (nonatomic, assign) MTLPixelFormat colorPixelFormat;
-@property (nonatomic, assign) MTLPixelFormat depthPixelFormat;
-@property (nonatomic, assign) MTLPixelFormat stencilPixelFormat;
-- (instancetype)initWithRenderPassDescriptor:(MTL4RenderPassDescriptor*)renderPassDescriptor;
-@end
-
-@interface MetalTexture : NSObject
-@property (nonatomic, strong) id<MTLTexture> metalTexture;
-- (instancetype)initWithTexture:(id<MTLTexture>)metalTexture;
-@end
-
-// A singleton that stores long-lived objects that are needed by the Metal
-// renderer backend. Stores the render pipeline state cache and the default
-// font texture, and manages the reusable buffer cache.
-@interface MetalContext : NSObject
-@property (nonatomic, strong) id<MTLDevice>                 device;
-@property (nonatomic, strong) id<MTL4CommandQueue>          commandQueue;
-@property (nonatomic, strong) id<MTLDepthStencilState>      depthStencilState;
-@property (nonatomic, strong) id<MTL4ArgumentTable>         argumentTable;
-@property (nonatomic, strong) id<MTLSamplerState>           samplerStateLinear;
-@property (nonatomic, strong) id<MTLSamplerState>           samplerStateNearest;
-@property (nonatomic, strong) id<MTLResidencySet>           residencySet;
-@property (nonatomic, strong) FramebufferDescriptor*        framebufferDescriptor;
-@property (nonatomic, strong) NSMutableDictionary*          renderPipelineStateCache;
-@property (nonatomic, assign) NSUInteger                    framesInFlight;
-@property (nonatomic, assign) NSUInteger                    currentFrameSlot;
-@property (nonatomic, strong) NSArray<id<MTLBuffer>>*       constantBuffers;
-@property (nonatomic, assign) ImGui_Metal4_ConstantData**   constantBufferContentsArray;
-@property (nonatomic, strong) NSMutableArray<NSMutableArray<MetalBuffer*>*>* bufferCaches;
-@property (nonatomic, strong) NSObject*                     bufferCacheLock;
-@property (nonatomic, assign) double                        lastBufferCachePurge;
-- (id<MTLBuffer>)currentConstantBuffer;
-- (ImGui_Metal4_ConstantData*)currentConstantBufferContents;
-- (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device;
-- (id<MTLRenderPipelineState>)renderPipelineStateForFramebufferDescriptor:(FramebufferDescriptor*)descriptor device:(id<MTLDevice>)device;
-@end
-
-struct ImGui_ImplMetal4_Data
-{
-    MetalContext*                SharedMetalContext;
-    id<MTL4RenderCommandEncoder> RenderCommandEncoder;
-
-    ImGui_ImplMetal4_Data()       { memset((void*)this, 0, sizeof(*this)); }
-};
-
-static ImGui_ImplMetal4_Data*    ImGui_ImplMetal4_GetBackendData()    { return ImGui::GetCurrentContext() ? (ImGui_ImplMetal4_Data*)ImGui::GetIO().BackendRendererUserData : nullptr; }
-static void                      ImGui_ImplMetal4_DestroyBackendData(){ IM_DELETE(ImGui_ImplMetal4_GetBackendData()); }
-
-static inline CFTimeInterval    GetMachAbsoluteTimeInSeconds()      { return (CFTimeInterval)(double)(clock_gettime_nsec_np(CLOCK_UPTIME_RAW) / 1e9); }
-
-#ifdef IMGUI_IMPL_METAL_CPP
-
-#pragma mark - Dear ImGui Metal C++ Backend API
-
-bool ImGui_ImplMetal4_Init(MTL::Device* device, MTL4::CommandQueue* commandQueue, int framesInFlight)
-{
-    return ImGui_ImplMetal4_Init((__bridge id<MTLDevice>)(device),(__bridge id<MTL4CommandQueue>)(commandQueue), framesInFlight);
-}
-
-void ImGui_ImplMetal4_NewFrame(MTL4::RenderPassDescriptor* renderPassDescriptor, int frameInFlightIndex)
-{
-    ImGui_ImplMetal4_NewFrame((__bridge MTL4RenderPassDescriptor*)(renderPassDescriptor), frameInFlightIndex);
-}
-
-void ImGui_ImplMetal4_RenderDrawData(ImDrawData* draw_data,
-                                    MTL4::CommandBuffer* commandBuffer,
-                                    MTL4::RenderCommandEncoder* commandEncoder)
-{
-    ImGui_ImplMetal4_RenderDrawData(draw_data,
-                                   (__bridge id<MTL4CommandBuffer>)(commandBuffer),
-                                   (__bridge id<MTL4RenderCommandEncoder>)(commandEncoder));
-}
-
-bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)
-{
-    return ImGui_ImplMetal4_CreateDeviceObjects((__bridge id<MTLDevice>)(device));
-}
-
-#endif // #ifdef IMGUI_IMPL_METAL_CPP
-
-#pragma mark - Dear ImGui Metal Backend API
-
-void ImGui_ImplMetal4_NewFrame(MTL4RenderPassDescriptor* renderPassDescriptor, int frameInFlightIndex)
-{
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-    IM_ASSERT(bd != nil && "Context or backend not initialized! Did you call ImGui_ImplMetal4_Init()?");
-    IM_ASSERT(frameInFlightIndex < bd->SharedMetalContext.framesInFlight && "frameInFlightIndex out of range! See framesInFlight passed to ImGui_ImplMetal4_Init().");
-#ifdef IMGUI_IMPL_METAL_CPP
-    bd->SharedMetalContext.framebufferDescriptor = [[[FramebufferDescriptor alloc] initWithRenderPassDescriptor:renderPassDescriptor]autorelease];
-#else
-    bd->SharedMetalContext.framebufferDescriptor = [[FramebufferDescriptor alloc] initWithRenderPassDescriptor:renderPassDescriptor];
-#endif
-    bd->SharedMetalContext.currentFrameSlot = (NSUInteger)frameInFlightIndex;
-    if (bd->SharedMetalContext.depthStencilState == nil)
-        ImGui_ImplMetal4_CreateDeviceObjects(bd->SharedMetalContext.device);
-}
-
-static void ImGui_ImplMetal4_SetupRenderState(ImDrawData* draw_data, id<MTL4CommandBuffer> commandBuffer,
-    id<MTL4RenderCommandEncoder> commandEncoder, id<MTLRenderPipelineState> renderPipelineState,
-    MetalBuffer* vertexBuffer, size_t vertexBufferOffset)
-{
-    IM_UNUSED(commandBuffer);
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-    [commandEncoder setCullMode:MTLCullModeNone];
-    [commandEncoder setDepthStencilState:bd->SharedMetalContext.depthStencilState];
-
-    // Setup viewport, orthographic projection matrix
-    // Our visible imgui space lies from draw_data->DisplayPos (top left) to
-    // draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
-    MTLViewport viewport =
-    {
-        .originX = 0.0,
-        .originY = 0.0,
-        .width = (double)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x),
-        .height = (double)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y),
-        .znear = 0.0,
-        .zfar = 1.0
-    };
-    [commandEncoder setViewport:viewport];
-
-    float L = draw_data->DisplayPos.x;
-    float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
-    float T = draw_data->DisplayPos.y;
-    float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
-    float N = (float)viewport.znear;
-    float F = (float)viewport.zfar;
-    const float ortho_projection[4][4] =
-    {
-        { 2.0f/(R-L),   0.0f,           0.0f,   0.0f },
-        { 0.0f,         2.0f/(T-B),     0.0f,   0.0f },
-        { 0.0f,         0.0f,        1/(F-N),   0.0f },
-        { (R+L)/(L-R),  (T+B)/(B-T), N/(F-N),   1.0f },
-    };
-    ImGui_Metal4_ConstantData* constantBufferContents = [bd->SharedMetalContext currentConstantBufferContents];
-    memcpy(constantBufferContents->ModelViewProjectionMatrix, ortho_projection, sizeof(ortho_projection));
-
-    id<MTL4ArgumentTable> argumentTable = bd->SharedMetalContext.argumentTable;
-    [argumentTable setAddress:[bd->SharedMetalContext currentConstantBuffer].gpuAddress atIndex:1];
-    [argumentTable setAddress:(vertexBuffer.buffer.gpuAddress + vertexBufferOffset) attributeStride:sizeof(ImDrawVert) atIndex:0];
-    [argumentTable setSamplerState:bd->SharedMetalContext.samplerStateLinear.gpuResourceID atIndex:0];
-    [commandEncoder setArgumentTable:argumentTable atStages:MTLRenderStageVertex | MTLRenderStageFragment];
-    [commandEncoder setRenderPipelineState:renderPipelineState];
-}
-
-static void ImGui_ImplMetal4_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)  {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplMetal4_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)  { ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData(); [bd->SharedMetalContext.argumentTable setSamplerState:bd->SharedMetalContext.samplerStateLinear.gpuResourceID atIndex:0]; }
-static void ImGui_ImplMetal4_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*) { ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData(); [bd->SharedMetalContext.argumentTable setSamplerState:bd->SharedMetalContext.samplerStateNearest.gpuResourceID atIndex:0]; }
-
-void ImGui_ImplMetal4_RenderDrawData(ImDrawData* draw_data, id<MTL4CommandBuffer> commandBuffer, id<MTL4RenderCommandEncoder> commandEncoder)
-{
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-    MetalContext* ctx = bd->SharedMetalContext;
-
-    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
-    int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
-    int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
-    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdLists.Size == 0)
-        return;
-
-    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
-    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
-    if (draw_data->Textures != nullptr)
-        for (ImTextureData* tex : *draw_data->Textures)
-            if (tex->Status != ImTextureStatus_OK)
-                ImGui_ImplMetal4_UpdateTexture(tex);
-
-    // Try to retrieve a render pipeline state that is compatible with the framebuffer config for this frame
-    // The hit rate for this cache should be very near 100%.
-    id<MTLRenderPipelineState> renderPipelineState = ctx.renderPipelineStateCache[ctx.framebufferDescriptor];
-    if (renderPipelineState == nil)
-    {
-        // No luck; make a new render pipeline state
-        renderPipelineState = [ctx renderPipelineStateForFramebufferDescriptor:ctx.framebufferDescriptor device:commandBuffer.device];
-
-        // Cache render pipeline state for later reuse
-        ctx.renderPipelineStateCache[ctx.framebufferDescriptor] = renderPipelineState;
-    }
-
-    size_t vertexBufferLength = (size_t)draw_data->TotalVtxCount * sizeof(ImDrawVert);
-    size_t indexBufferLength = (size_t)draw_data->TotalIdxCount * sizeof(ImDrawIdx);
-    MetalBuffer* vertexBuffer = [ctx dequeueReusableBufferOfLength:vertexBufferLength device:commandBuffer.device];
-    MetalBuffer* indexBuffer = [ctx dequeueReusableBufferOfLength:indexBufferLength device:commandBuffer.device];
-
-    bd->RenderCommandEncoder = commandEncoder;
-    ImGui_ImplMetal4_SetupRenderState(draw_data, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, 0);
-
-    // Will project scissor/clipping rectangles into framebuffer space
-    ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
-    ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
-
-    // Render command lists
-    size_t vertexBufferOffset = 0;
-    size_t indexBufferOffset = 0;
-    for (const ImDrawList* draw_list : draw_data->CmdLists)
-    {
-        memcpy((char*)vertexBuffer.buffer.contents + vertexBufferOffset, draw_list->VtxBuffer.Data, (size_t)draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
-        memcpy((char*)indexBuffer.buffer.contents + indexBufferOffset, draw_list->IdxBuffer.Data, (size_t)draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
-
-        for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
-        {
-            const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
-            if (pcmd->UserCallback)
-            {
-                // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplMetal4_DrawCallback_ResetRenderState)
-                    ImGui_ImplMetal4_SetupRenderState(draw_data, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, vertexBufferOffset);
-                else
-                    pcmd->UserCallback(draw_list, pcmd);
-            }
-            else
-            {
-                // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
-                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
-
-                // Clamp to viewport as setScissorRect() won't accept values that are off bounds
-                if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
-                if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
-                if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; }
-                if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; }
-                if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
-                    continue;
-                if (pcmd->ElemCount == 0) // drawIndexedPrimitives() validation doesn't accept this
-                    continue;
-
-                // Apply scissor/clipping rectangle
-                MTLScissorRect scissorRect =
-                {
-                    .x = NSUInteger(clip_min.x),
-                    .y = NSUInteger(clip_min.y),
-                    .width = NSUInteger(clip_max.x - clip_min.x),
-                    .height = NSUInteger(clip_max.y - clip_min.y)
-                };
-                [commandEncoder setScissorRect:scissorRect];
-
-                // Bind texture, Draw
-                ImTextureID tex_id = pcmd->GetTexID();
-                if (tex_id != ImTextureID_Invalid)
-                {
-                    id<MTLTexture> texture = (__bridge id<MTLTexture>)(void*)(intptr_t)tex_id;
-                    [bd->SharedMetalContext.residencySet addAllocation:texture];
-                    [bd->SharedMetalContext.argumentTable setTexture:texture.gpuResourceID atIndex:0];
-                }
-
-                [bd->SharedMetalContext.argumentTable setAddress:(vertexBuffer.buffer.gpuAddress + vertexBufferOffset + (pcmd->VtxOffset * sizeof(ImDrawVert))) attributeStride:sizeof(ImDrawVert) atIndex:0];
-
-                size_t indexBufferCmdOffset = indexBufferOffset + (pcmd->IdxOffset * sizeof(ImDrawIdx));
-                [commandEncoder drawIndexedPrimitives:MTLPrimitiveTypeTriangle
-                                   indexCount:pcmd->ElemCount
-                                    indexType:sizeof(ImDrawIdx) == 2 ? MTLIndexTypeUInt16 : MTLIndexTypeUInt32
-                                  indexBuffer:indexBuffer.buffer.gpuAddress + indexBufferCmdOffset
-                            indexBufferLength:indexBuffer.buffer.length - indexBufferCmdOffset];
-            }
-        }
-
-        vertexBufferOffset += (size_t)draw_list->VtxBuffer.Size * sizeof(ImDrawVert);
-        indexBufferOffset += (size_t)draw_list->IdxBuffer.Size * sizeof(ImDrawIdx);
-    }
-
-    MetalContext* sharedMetalContext = bd->SharedMetalContext;
-    @synchronized(sharedMetalContext.bufferCacheLock)
-    {
-        NSMutableArray<MetalBuffer*>* slotCache = sharedMetalContext.bufferCaches[sharedMetalContext.currentFrameSlot];
-        [slotCache addObject:vertexBuffer];
-        [slotCache addObject:indexBuffer];
-    }
-    
-    // Commit residency set
-    [bd->SharedMetalContext.residencySet commit];
-    bd->RenderCommandEncoder = nil;
-}
-
-static void ImGui_ImplMetal4_DestroyTexture(ImTextureData* tex)
-{
-    if (MetalTexture* backend_tex = (__bridge_transfer MetalTexture*)(tex->BackendUserData))
-    {
-        IM_ASSERT(backend_tex.metalTexture == (__bridge id<MTLTexture>)(void*)(intptr_t)tex->TexID);
-        backend_tex.metalTexture = nil;
-
-        // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
-        tex->SetTexID(ImTextureID_Invalid);
-        tex->BackendUserData = nullptr;
-    }
-    tex->SetStatus(ImTextureStatus_Destroyed);
-}
-
-void ImGui_ImplMetal4_UpdateTexture(ImTextureData* tex)
-{
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-    if (tex->Status == ImTextureStatus_WantCreate)
-    {
-        // Create and upload new texture to graphics system
-        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
-        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
-        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
-
-        // We are retrieving and uploading the font atlas as a 4-channels RGBA texture here.
-        // In theory we could call GetTexDataAsAlpha8() and upload a 1-channel texture to save on memory access bandwidth.
-        // However, using a shader designed for 1-channel texture would make it less obvious to use the ImTextureID facility to render users own textures.
-        // You can make that change in your implementation.
-        MTLTextureDescriptor* textureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm
-                                                                                                     width:(NSUInteger)tex->Width
-                                                                                                    height:(NSUInteger)tex->Height
-                                                                                                 mipmapped:NO];
-        textureDescriptor.usage = MTLTextureUsageShaderRead;
-        textureDescriptor.storageMode = MTLStorageModeShared;
-
-        id <MTLTexture> texture = [bd->SharedMetalContext.device newTextureWithDescriptor:textureDescriptor];
-        [bd->SharedMetalContext.residencySet addAllocation:texture];
-        [texture replaceRegion:MTLRegionMake2D(0, 0, (NSUInteger)tex->Width, (NSUInteger)tex->Height) mipmapLevel:0 withBytes:tex->Pixels bytesPerRow:(NSUInteger)tex->Width * 4];
-        MetalTexture* backend_tex = [[MetalTexture alloc] initWithTexture:texture];
-
-        // Store identifiers
-        tex->SetTexID((ImTextureID)(intptr_t)texture);
-        tex->SetStatus(ImTextureStatus_OK);
-        tex->BackendUserData = (__bridge_retained void*)(backend_tex);
-    }
-    else if (tex->Status == ImTextureStatus_WantUpdates)
-    {
-        // Update selected blocks. We only ever write to textures regions which have never been used before!
-        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
-        MetalTexture* backend_tex = (__bridge MetalTexture*)(tex->BackendUserData);
-        for (ImTextureRect& r : tex->Updates)
-        {
-            [backend_tex.metalTexture replaceRegion:MTLRegionMake2D((NSUInteger)r.x, (NSUInteger)r.y, (NSUInteger)r.w, (NSUInteger)r.h)
-                                        mipmapLevel:0
-                                          withBytes:tex->GetPixelsAt(r.x, r.y)
-                                        bytesPerRow:(NSUInteger)tex->Width * 4];
-        }
-        tex->SetStatus(ImTextureStatus_OK);
-    }
-    else if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
-    {
-        ImGui_ImplMetal4_DestroyTexture(tex);
-    }
-}
-
-bool ImGui_ImplMetal4_CreateDeviceObjects(id<MTLDevice> device)
-{
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-
-    MTLResidencySetDescriptor* residencySetDescriptor = [[MTLResidencySetDescriptor alloc] init];
-    residencySetDescriptor.initialCapacity = 1000;
-
-    NSError* error = nil;
-    bd->SharedMetalContext.residencySet = [device newResidencySetWithDescriptor:residencySetDescriptor error:&error];
-    IM_ASSERT(bd->SharedMetalContext.residencySet != nil && error == nil);
-
-    [bd->SharedMetalContext.commandQueue addResidencySet:bd->SharedMetalContext.residencySet];
-
-    MTLDepthStencilDescriptor* depthStencilDescriptor = [[MTLDepthStencilDescriptor alloc] init];
-    depthStencilDescriptor.depthWriteEnabled = NO;
-    depthStencilDescriptor.depthCompareFunction = MTLCompareFunctionAlways;
-    bd->SharedMetalContext.depthStencilState = [device newDepthStencilStateWithDescriptor:depthStencilDescriptor];
-    MTLSamplerDescriptor* samplerDescriptor = [[MTLSamplerDescriptor alloc] init];
-    samplerDescriptor.supportArgumentBuffers = YES;
-    samplerDescriptor.minFilter = MTLSamplerMinMagFilterLinear;
-    samplerDescriptor.magFilter = MTLSamplerMinMagFilterLinear;
-    samplerDescriptor.mipFilter = MTLSamplerMipFilterLinear;
-    bd->SharedMetalContext.samplerStateLinear = [device newSamplerStateWithDescriptor:samplerDescriptor];
-    samplerDescriptor.minFilter = MTLSamplerMinMagFilterNearest;
-    samplerDescriptor.magFilter = MTLSamplerMinMagFilterNearest;
-    samplerDescriptor.mipFilter = MTLSamplerMipFilterNearest;
-    bd->SharedMetalContext.samplerStateNearest = [device newSamplerStateWithDescriptor:samplerDescriptor];
-
-    NSMutableArray<id<MTLBuffer>>* constantBuffers = [NSMutableArray array];
-    ImGui_Metal4_ConstantData** constantBufferContentsArray = (ImGui_Metal4_ConstantData**)malloc(sizeof(ImGui_Metal4_ConstantData*) * bd->SharedMetalContext.framesInFlight);
-    for (NSUInteger i = 0; i < bd->SharedMetalContext.framesInFlight; i++)
-    {
-        id<MTLBuffer> constantBuffer = [device newBufferWithLength:sizeof(ImGui_Metal4_ConstantData) options:MTLResourceStorageModeShared];
-        [constantBuffers addObject:constantBuffer];
-        constantBufferContentsArray[i] = (ImGui_Metal4_ConstantData*)constantBuffer.contents;
-        [bd->SharedMetalContext.residencySet addAllocation:constantBuffer];
-    }
-    bd->SharedMetalContext.constantBuffers = constantBuffers;
-    bd->SharedMetalContext.constantBufferContentsArray = constantBufferContentsArray;
-
-    MTL4ArgumentTableDescriptor* argumentTableDescriptor = [[MTL4ArgumentTableDescriptor alloc] init];
-    argumentTableDescriptor.maxBufferBindCount = 8;
-    argumentTableDescriptor.maxTextureBindCount = 8;
-    argumentTableDescriptor.maxSamplerStateBindCount = 8;
-    argumentTableDescriptor.supportAttributeStrides = YES; // required: vertex buffer is bound via setAddress:stride:atIndex: for stage_in fetch
-
-    bd->SharedMetalContext.argumentTable = [device newArgumentTableWithDescriptor:argumentTableDescriptor error:&error];
-    IM_ASSERT(bd->SharedMetalContext.argumentTable != nil && error == nil);
-
-    return true;
-}
-
-void ImGui_ImplMetal4_DestroyDeviceObjects()
-{
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-
-    // Destroy all textures
-    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
-        if (tex->RefCount == 1)
-            ImGui_ImplMetal4_DestroyTexture(tex);
-
-    [bd->SharedMetalContext.renderPipelineStateCache removeAllObjects];
-    bd->SharedMetalContext.samplerStateLinear = nil;
-    bd->SharedMetalContext.samplerStateNearest = nil;
-}
-
-bool ImGui_ImplMetal4_Init(id<MTLDevice> device, id<MTL4CommandQueue> commandQueue, int framesInFlight)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-    IM_ASSERT(framesInFlight > 0 && "framesInFlight must be at least 1!");
-
-    ImGui_ImplMetal4_Data* bd = IM_NEW(ImGui_ImplMetal4_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_metal4";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplMetal4_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplMetal4_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplMetal4_DrawCallback_SetSamplerNearest;
-
-    bd->SharedMetalContext = [[MetalContext alloc] init];
-    bd->SharedMetalContext.device = device;
-    bd->SharedMetalContext.commandQueue = commandQueue;
-    bd->SharedMetalContext.framesInFlight = (NSUInteger)framesInFlight;
-    NSMutableArray<NSMutableArray<MetalBuffer*>*>* bufferCaches = [NSMutableArray array];
-    for (NSUInteger i = 0; i < framesInFlight; i++)
-        [bufferCaches addObject:[NSMutableArray array]];
-    bd->SharedMetalContext.bufferCaches = bufferCaches;
-    return true;
-}
-
-void ImGui_ImplMetal4_Shutdown()
-{
-    ImGui_ImplMetal4_Data* bd = ImGui_ImplMetal4_GetBackendData();
-    IM_UNUSED(bd);
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplMetal4_DestroyDeviceObjects();
-    ImGui_ImplMetal4_DestroyBackendData();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-}
-
-@implementation MetalBuffer
-- (instancetype)initWithBuffer:(id<MTLBuffer>)buffer
-{
-    if ((self = [super init]))
-    {
-        _buffer = buffer;
-        _lastReuseTime = GetMachAbsoluteTimeInSeconds();
-    }
-    return self;
-}
-@end
-
-#pragma mark - FramebufferDescriptor implementation
-
-@implementation FramebufferDescriptor
-- (instancetype)initWithRenderPassDescriptor:(MTL4RenderPassDescriptor*)renderPassDescriptor
-{
-    if ((self = [super init]))
-    {
-        _sampleCount = renderPassDescriptor.colorAttachments[0].texture.sampleCount;
-        _colorPixelFormat = renderPassDescriptor.colorAttachments[0].texture.pixelFormat;
-        _depthPixelFormat = renderPassDescriptor.depthAttachment.texture.pixelFormat;
-        _stencilPixelFormat = renderPassDescriptor.stencilAttachment.texture.pixelFormat;
-    }
-    return self;
-}
-
-- (nonnull id)copyWithZone:(nullable NSZone*)zone
-{
-    FramebufferDescriptor* copy = [[FramebufferDescriptor allocWithZone:zone] init];
-    copy.sampleCount = self.sampleCount;
-    copy.colorPixelFormat = self.colorPixelFormat;
-    copy.depthPixelFormat = self.depthPixelFormat;
-    copy.stencilPixelFormat = self.stencilPixelFormat;
-    return copy;
-}
-
-- (NSUInteger)hash
-{
-    NSUInteger sc = _sampleCount & 0x3;
-    NSUInteger cf = _colorPixelFormat & 0x3FF;
-    NSUInteger df = _depthPixelFormat & 0x3FF;
-    NSUInteger sf = _stencilPixelFormat & 0x3FF;
-    NSUInteger hash = (sf << 22) | (df << 12) | (cf << 2) | sc;
-    return hash;
-}
-
-- (BOOL)isEqual:(id)object
-{
-    FramebufferDescriptor* other = object;
-    if (![other isKindOfClass:[FramebufferDescriptor class]])
-        return NO;
-    return other.sampleCount == self.sampleCount      &&
-    other.colorPixelFormat   == self.colorPixelFormat &&
-    other.depthPixelFormat   == self.depthPixelFormat &&
-    other.stencilPixelFormat == self.stencilPixelFormat;
-}
-
-@end
-
-#pragma mark - MetalTexture implementation
-
-@implementation MetalTexture
-- (instancetype)initWithTexture:(id<MTLTexture>)metalTexture
-{
-    if ((self = [super init]))
-        self.metalTexture = metalTexture;
-    return self;
-}
-
-@end
-
-#pragma mark - MetalContext implementation
-
-@implementation MetalContext
-- (instancetype)init
-{
-    if ((self = [super init]))
-    {
-        self.renderPipelineStateCache = [NSMutableDictionary dictionary];
-        self.bufferCacheLock = [[NSObject alloc] init];
-        _lastBufferCachePurge = GetMachAbsoluteTimeInSeconds();
-    }
-    return self;
-}
-
-- (void)dealloc
-{
-    free(_constantBufferContentsArray);
-}
-
-- (id<MTLBuffer>)currentConstantBuffer
-{
-    return self.constantBuffers[self.currentFrameSlot];
-}
-
-- (ImGui_Metal4_ConstantData*)currentConstantBufferContents
-{
-    return self.constantBufferContentsArray[self.currentFrameSlot];
-}
-
-- (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device
-{
-    double now = GetMachAbsoluteTimeInSeconds();
-    NSMutableArray<MetalBuffer*>* slotCache = self.bufferCaches[self.currentFrameSlot];
-
-    @synchronized(self.bufferCacheLock)
-    {
-        // Purge old buffers that haven't been useful for a while
-        if (now - self.lastBufferCachePurge > 1.0)
-        {
-            for (NSMutableArray<MetalBuffer*>* cache in self.bufferCaches)
-            {
-                NSMutableArray* survivors = [NSMutableArray array];
-                for (MetalBuffer* candidate in cache)
-                    if (candidate.lastReuseTime > self.lastBufferCachePurge)
-                        [survivors addObject:candidate];
-                [cache setArray:survivors];
-            }
-            self.lastBufferCachePurge = now;
-        }
-
-        // See if we have a buffer we can reuse, from this frame-in-flight slot's own cache
-        MetalBuffer* bestCandidate = nil;
-        for (MetalBuffer* candidate in slotCache)
-            if (candidate.buffer.length >= length && (bestCandidate == nil || bestCandidate.lastReuseTime > candidate.lastReuseTime))
-                bestCandidate = candidate;
-
-        if (bestCandidate != nil)
-        {
-            [slotCache removeObject:bestCandidate];
-            bestCandidate.lastReuseTime = now;
-            return bestCandidate;
-        }
-    }
-
-    // No luck; make a new buffer
-    id<MTLBuffer> backing = [device newBufferWithLength:length options:MTLResourceStorageModeShared];
-    [self.residencySet addAllocation:backing];
-    return [[MetalBuffer alloc] initWithBuffer:backing];
-}
-
-const char* shaderCode = R"(
-#include <metal_stdlib>
-using namespace metal;
-
-struct Uniforms {
-    float4x4 projectionMatrix;
-};
-
-struct VertexIn {
-    float2 position  [[attribute(0)]];
-    float2 texCoords [[attribute(1)]];
-    uchar4 color     [[attribute(2)]];
-};
-
-struct VertexOut {
-    float4 position [[position]];
-    float2 texCoords;
-    float4 color;
-};
-
-vertex VertexOut vertex_main(VertexIn in                 [[stage_in]],
-                             constant Uniforms &uniforms [[buffer(1)]])
-{
-    VertexOut out;
-    out.position = uniforms.projectionMatrix * float4(in.position, 0, 1);
-    out.texCoords = in.texCoords;
-    out.color = float4(in.color) / float4(255.0);
-    return out;
-}
-
-fragment half4 fragment_main(VertexOut in [[stage_in]],
-                             texture2d<half, access::sample> texture [[texture(0)]],
-                             sampler textureSampler [[sampler(0)]])
-{
-    half4 texColor = texture.sample(textureSampler, in.texCoords);
-    return half4(in.color) * texColor;
-}
-)";
-
-- (id<MTLRenderPipelineState>)renderPipelineStateForFramebufferDescriptor:(FramebufferDescriptor*)descriptor device:(id<MTLDevice>)device
-{
-    NSError* error = nil;
-
-    id<MTLLibrary> library = [device newLibraryWithSource:[NSString stringWithUTF8String:shaderCode] options:nil error:&error];
-    if (library == nil)
-    {
-        NSLog(@"Error: failed to create Metal library: %@", error);
-        return nil;
-    }
-
-    id<MTLFunction> vertexFunction = [library newFunctionWithName:@"vertex_main"];
-    id<MTLFunction> fragmentFunction = [library newFunctionWithName:@"fragment_main"];
-
-    if (vertexFunction == nil || fragmentFunction == nil)
-    {
-        NSLog(@"Error: failed to find Metal shader functions in library: %@", error);
-        return nil;
-    }
-
-    MTLVertexDescriptor* vertexDescriptor = [MTLVertexDescriptor vertexDescriptor];
-    vertexDescriptor.attributes[0].offset = offsetof(ImDrawVert, pos);
-    vertexDescriptor.attributes[0].format = MTLVertexFormatFloat2; // position
-    vertexDescriptor.attributes[0].bufferIndex = 0;
-    vertexDescriptor.attributes[1].offset = offsetof(ImDrawVert, uv);
-    vertexDescriptor.attributes[1].format = MTLVertexFormatFloat2; // texCoords
-    vertexDescriptor.attributes[1].bufferIndex = 0;
-    vertexDescriptor.attributes[2].offset = offsetof(ImDrawVert, col);
-    vertexDescriptor.attributes[2].format = MTLVertexFormatUChar4; // color
-    vertexDescriptor.attributes[2].bufferIndex = 0;
-    vertexDescriptor.layouts[0].stepRate = 1;
-    vertexDescriptor.layouts[0].stepFunction = MTLVertexStepFunctionPerVertex;
-    vertexDescriptor.layouts[0].stride = sizeof(ImDrawVert);
-
-    MTLRenderPipelineDescriptor* pipelineDescriptor = [[MTLRenderPipelineDescriptor alloc] init];
-    pipelineDescriptor.vertexFunction = vertexFunction;
-    pipelineDescriptor.fragmentFunction = fragmentFunction;
-    pipelineDescriptor.vertexDescriptor = vertexDescriptor;
-    pipelineDescriptor.rasterSampleCount = self.framebufferDescriptor.sampleCount;
-    pipelineDescriptor.colorAttachments[0].pixelFormat = self.framebufferDescriptor.colorPixelFormat;
-    pipelineDescriptor.colorAttachments[0].blendingEnabled = YES;
-    pipelineDescriptor.colorAttachments[0].rgbBlendOperation = MTLBlendOperationAdd;
-    pipelineDescriptor.colorAttachments[0].sourceRGBBlendFactor = MTLBlendFactorSourceAlpha;
-    pipelineDescriptor.colorAttachments[0].destinationRGBBlendFactor = MTLBlendFactorOneMinusSourceAlpha;
-    pipelineDescriptor.colorAttachments[0].alphaBlendOperation = MTLBlendOperationAdd;
-    pipelineDescriptor.colorAttachments[0].sourceAlphaBlendFactor = MTLBlendFactorOne;
-    pipelineDescriptor.colorAttachments[0].destinationAlphaBlendFactor = MTLBlendFactorOneMinusSourceAlpha;
-    pipelineDescriptor.depthAttachmentPixelFormat = self.framebufferDescriptor.depthPixelFormat;
-    pipelineDescriptor.stencilAttachmentPixelFormat = self.framebufferDescriptor.stencilPixelFormat;
-
-    id<MTLRenderPipelineState> renderPipelineState = [device newRenderPipelineStateWithDescriptor:pipelineDescriptor error:&error];
-    if (error != nil)
-        NSLog(@"Error: failed to create Metal pipeline state: %@", error);
-
-    return renderPipelineState;
-}
-
-@end
-
-//-----------------------------------------------------------------------------
-
-#endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_opengl2.cpp

@@ -4,9 +4,9 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 // Missing features or Issues:
 //  [ ] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
-//  [ ] Renderer: Use of DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest is emulated by poking to glTexParameter(), as legacy OpenGL doesn't have glBindSampler().
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -26,7 +26,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: OpenGL: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-03-12: OpenGL: Fixed invalid assert in ImGui_ImplOpenGL3_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-07-15: OpenGL: Set GL_UNPACK_ALIGNMENT to 1 before updating textures. (#8802)
@@ -88,9 +88,6 @@
 // OpenGL data
 struct ImGui_ImplOpenGL2_Data
 {
-    bool        UseTexParameterToSetSampler;
-    GLuint      NextSampler;
-
     ImGui_ImplOpenGL2_Data() { memset((void*)this, 0, sizeof(*this)); }
 };
 
@@ -101,7 +98,46 @@ static ImGui_ImplOpenGL2_Data* ImGui_ImplOpenGL2_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL2_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplOpenGL2_InitMultiViewportSupport();
+static void ImGui_ImplOpenGL2_ShutdownMultiViewportSupport();
+
 // Functions
+bool    ImGui_ImplOpenGL2_Init()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplOpenGL2_Data* bd = IM_NEW(ImGui_ImplOpenGL2_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_opengl2";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;      // We can create multi-viewports on the Renderer side (optional)
+
+    ImGui_ImplOpenGL2_InitMultiViewportSupport();
+
+    return true;
+}
+
+void    ImGui_ImplOpenGL2_Shutdown()
+{
+    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplOpenGL2_ShutdownMultiViewportSupport();
+    ImGui_ImplOpenGL2_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 void    ImGui_ImplOpenGL2_NewFrame()
 {
     ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
@@ -112,7 +148,6 @@ void    ImGui_ImplOpenGL2_NewFrame()
 static void ImGui_ImplOpenGL2_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height)
 {
     // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers, polygon fill.
-    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     //glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA); // In order to composite our output buffer we need to preserve alpha
@@ -130,7 +165,6 @@ static void ImGui_ImplOpenGL2_SetupRenderState(ImDrawData* draw_data, int fb_wid
     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
     glShadeModel(GL_SMOOTH);
     glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
-    bd->NextSampler = GL_LINEAR;
 
     // If you are using this code with non-legacy OpenGL header/contexts (which you should not, prefer using imgui_impl_opengl3.cpp!!),
     // you may need to backup/reset/restore other state, e.g. for current shader using the commented lines below.
@@ -155,18 +189,12 @@ static void ImGui_ImplOpenGL2_SetupRenderState(ImDrawData* draw_data, int fb_wid
     glLoadIdentity();
 }
 
-// Draw callbacks
-static void ImGui_ImplOpenGL2_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)    {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplOpenGL2_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)    { ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData(); bd->UseTexParameterToSetSampler = true; bd->NextSampler = GL_LINEAR; }
-static void ImGui_ImplOpenGL2_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)   { ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData(); bd->UseTexParameterToSetSampler = true; bd->NextSampler = GL_NEAREST; }
-
 // OpenGL2 Render function.
 // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly.
 // This is in order to be able to run within an OpenGL engine that doesn't do so.
 void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
 {
     // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
-    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
     int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
     int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
     if (fb_width == 0 || fb_height == 0)
@@ -210,7 +238,8 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
             if (pcmd->UserCallback)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplOpenGL2_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplOpenGL2_SetupRenderState(draw_data, fb_width, fb_height);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -227,17 +256,7 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
                 glScissor((int)clip_min.x, (int)((float)fb_height - clip_max.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y));
 
                 // Bind texture, Draw
-                GLuint pcmd_texture = (GLuint)(intptr_t)pcmd->GetTexID();
-                glBindTexture(GL_TEXTURE_2D, pcmd_texture);
-
-                // Emulate sampler change (even though it is technically part of texture data)
-                // As a sort of hack/workaround, we only start writing using glTextParameter() if sampler is ever changed explicitly.
-                if (bd->UseTexParameterToSetSampler)
-                {
-                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, bd->NextSampler);
-                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, bd->NextSampler);
-                }
-
+                glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->GetTexID());
                 glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer + pcmd->IdxOffset);
             }
         }
@@ -335,40 +354,33 @@ void    ImGui_ImplOpenGL2_DestroyDeviceObjects()
         }
 }
 
-bool    ImGui_ImplOpenGL2_Init()
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplOpenGL2_RenderWindow(ImGuiViewport* viewport, void*)
 {
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplOpenGL2_Data* bd = IM_NEW(ImGui_ImplOpenGL2_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_opengl2";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplOpenGL2_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplOpenGL2_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplOpenGL2_DrawCallback_SetSamplerNearest;
-
-    return true;
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+    {
+        ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
+    }
+    ImGui_ImplOpenGL2_RenderDrawData(viewport->DrawData);
 }
 
-void    ImGui_ImplOpenGL2_Shutdown()
+static void ImGui_ImplOpenGL2_InitMultiViewportSupport()
 {
-    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplOpenGL2_RenderWindow;
+}
 
-    ImGui_ImplOpenGL2_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
+static void ImGui_ImplOpenGL2_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_opengl2.h

@@ -4,9 +4,9 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 // Missing features or Issues:
 //  [ ] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
-//  [ ] Renderer: Use of DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest is emulated by poking to glTexParameter(), as legacy OpenGL doesn't have glBindSampler().
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_opengl3.cpp

@@ -7,6 +7,7 @@
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [x] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset) [Desktop OpenGL only!]
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // About WebGL/ES:
 // - You need to '#define IMGUI_IMPL_OPENGL_ES2' or '#define IMGUI_IMPL_OPENGL_ES3' to use WebGL or OpenGL ES.
@@ -23,10 +24,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-06-17: OpenGL: Expose selected render state in ImGui_ImplOpenGL3_RenderState, Allowing to dynamically select between use of glBindSampler() and glTexParameter(). You can access in 'void* platform_io.Renderer_RenderState' during rendering.
-//  2026-06-03: OpenGL: GLSL version detection assume GLSL 410 when GL context is 4.1. Fixes an issue running on macOS with Wine. (#9427, #6577)
-//  2026-04-23: OpenGL: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
-//                      (Breaking): this change prioritize using glBindSampler() when available, which would override glTexParameter() settings you may have set on custom textures.
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-03-12: OpenGL: Fixed invalid assert in ImGui_ImplOpenGL3_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-12-11: OpenGL: Fixed embedded loader multiple init/shutdown cycles broken on some platforms. (#8792, #9112)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
@@ -256,10 +254,6 @@ struct ImGui_ImplOpenGL3_Data
     bool            HasBindSampler;
     bool            HasClipOrigin;
     bool            UseBufferSubData;
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    GLuint          TexSamplers[2];         // Used if HasBindSimpler. (0=linear, 1=nearest)
-#endif
-
     ImVector<char>  TempBuffer;
 
     ImGui_ImplOpenGL3_Data() { memset((void*)this, 0, sizeof(*this)); }
@@ -272,6 +266,10 @@ static ImGui_ImplOpenGL3_Data* ImGui_ImplOpenGL3_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplOpenGL3_InitMultiViewportSupport();
+static void ImGui_ImplOpenGL3_ShutdownMultiViewportSupport();
+
 // OpenGL vertex attribute state (for ES 1.0 and ES 2.0 only)
 #ifndef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
 struct ImGui_ImplOpenGL3_VtxAttribState
@@ -320,6 +318,143 @@ static void ImGui_ImplOpenGL3_ShutdownLoader()
 }
 
 // Functions
+bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    // Initialize loader
+    if (!ImGui_ImplOpenGL3_InitLoader())
+        return false;
+
+    // Setup backend capabilities flags
+    ImGui_ImplOpenGL3_Data* bd = IM_NEW(ImGui_ImplOpenGL3_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_opengl3";
+
+    // Query for GL version (e.g. 320 for GL 3.2)
+    const char* gl_version_str = (const char*)glGetString(GL_VERSION);
+#if defined(IMGUI_IMPL_OPENGL_ES2)
+    // GLES 2
+    bd->GlVersion = 200;
+    bd->GlProfileIsES2 = true;
+    IM_UNUSED(gl_version_str);
+#else
+    // Desktop or GLES 3
+    GLint major = 0;
+    GLint minor = 0;
+    glGetIntegerv(GL_MAJOR_VERSION, &major);
+    glGetIntegerv(GL_MINOR_VERSION, &minor);
+    if (major == 0 && minor == 0)
+        sscanf(gl_version_str, "%d.%d", &major, &minor); // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
+    bd->GlVersion = (GLuint)(major * 100 + minor * 10);
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &bd->MaxTextureSize);
+
+#if defined(IMGUI_IMPL_OPENGL_ES3)
+    bd->GlProfileIsES3 = true;
+#else
+    if (strncmp(gl_version_str, "OpenGL ES 3", 11) == 0)
+        bd->GlProfileIsES3 = true;
+#endif
+
+#if defined(GL_CONTEXT_PROFILE_MASK)
+    if (!bd->GlProfileIsES3 && bd->GlVersion >= 320)
+        glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &bd->GlProfileMask);
+    bd->GlProfileIsCompat = (bd->GlProfileMask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT) != 0;
+#endif
+
+    bd->UseBufferSubData = false;
+    /*
+    // Query vendor to enable glBufferSubData kludge
+#ifdef _WIN32
+    if (const char* vendor = (const char*)glGetString(GL_VENDOR))
+        if (strncmp(vendor, "Intel", 5) == 0)
+            bd->UseBufferSubData = true;
+#endif
+    */
+#endif
+
+#ifdef IMGUI_IMPL_OPENGL_DEBUG
+    printf("GlVersion = %d, \"%s\"\nGlProfileIsCompat = %d\nGlProfileMask = 0x%X\nGlProfileIsES2/IsEs3 = %d/%d\nGL_VENDOR = '%s'\nGL_RENDERER = '%s'\n", bd->GlVersion, gl_version_str, bd->GlProfileIsCompat, bd->GlProfileMask, bd->GlProfileIsES2, bd->GlProfileIsES3, (const char*)glGetString(GL_VENDOR), (const char*)glGetString(GL_RENDERER)); // [DEBUG]
+#endif
+
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
+    if (bd->GlVersion >= 320)
+        io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+#endif
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;      // We can create multi-viewports on the Renderer side (optional)
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = (int)bd->MaxTextureSize;
+
+    // Store GLSL version string so we can refer to it later in case we recreate shaders.
+    // Note: GLSL version is NOT the same as GL version. Leave this to nullptr if unsure.
+    if (glsl_version == nullptr)
+    {
+#if defined(IMGUI_IMPL_OPENGL_ES2)
+        glsl_version = "#version 100";
+#elif defined(IMGUI_IMPL_OPENGL_ES3)
+        glsl_version = "#version 300 es";
+#elif defined(__APPLE__)
+        glsl_version = "#version 150";
+#else
+        glsl_version = "#version 130";
+#endif
+    }
+    IM_ASSERT((int)strlen(glsl_version) + 2 < IM_COUNTOF(bd->GlslVersionString));
+    strcpy(bd->GlslVersionString, glsl_version);
+    strcat(bd->GlslVersionString, "\n");
+
+    // Make an arbitrary GL call (we don't actually need the result)
+    // IF YOU GET A CRASH HERE: it probably means the OpenGL function loader didn't do its job. Let us know!
+    GLint current_texture;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
+
+    // Detect extensions we support
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
+    bd->HasPolygonMode = (!bd->GlProfileIsES2 && !bd->GlProfileIsES3);
+#endif
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
+    bd->HasBindSampler = (bd->GlVersion >= 330 || bd->GlProfileIsES3);
+#endif
+    bd->HasClipOrigin = (bd->GlVersion >= 450);
+#ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
+    GLint num_extensions = 0;
+    glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
+    for (GLint i = 0; i < num_extensions; i++)
+    {
+        const char* extension = (const char*)glGetStringi(GL_EXTENSIONS, i);
+        if (extension != nullptr && strcmp(extension, "GL_ARB_clip_control") == 0)
+            bd->HasClipOrigin = true;
+    }
+#endif
+
+    ImGui_ImplOpenGL3_InitMultiViewportSupport();
+
+    return true;
+}
+
+void    ImGui_ImplOpenGL3_Shutdown()
+{
+    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplOpenGL3_ShutdownMultiViewportSupport();
+    ImGui_ImplOpenGL3_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+
+    ImGui_ImplOpenGL3_ShutdownLoader();
+}
+
 void    ImGui_ImplOpenGL3_NewFrame()
 {
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
@@ -331,7 +466,7 @@ void    ImGui_ImplOpenGL3_NewFrame()
             IM_ASSERT(0 && "ImGui_ImplOpenGL3_CreateDeviceObjects() failed!");
 }
 
-static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, ImGui_ImplOpenGL3_RenderState* render_state, int fb_width, int fb_height, GLuint vertex_array_object)
+static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
 {
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
 
@@ -385,11 +520,8 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, ImGui_Impl
     glUniformMatrix4fv(bd->AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
 
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    if (render_state->UseBindSampler)
-    {
-        render_state->CurrentSampler = bd->TexSamplers[0];
-        glBindSampler(0, render_state->CurrentSampler); // We use combined texture/sampler state. Applications using GL 3.3 and GL ES 3.0 may set that otherwise.
-    }
+    if (bd->HasBindSampler)
+        glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 and GL ES 3.0 may set that otherwise.
 #endif
 
     (void)vertex_array_object;
@@ -408,45 +540,6 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, ImGui_Impl
     GL_CALL(glVertexAttribPointer(bd->AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)offsetof(ImDrawVert, col)));
 }
 
-// Draw callbacks
-static void ImGui_ImplOpenGL3_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)    {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplOpenGL3_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)
-{
-    ImGui_ImplOpenGL3_RenderState* render_state = ImGui_ImplOpenGL3_GetRenderState();
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-    if (bd->HasBindSampler)
-    {
-        render_state->CurrentSampler = bd->TexSamplers[0];
-        render_state->UseTexParameterFilter = false;
-        glBindSampler(0, render_state->CurrentSampler);
-    }
-    else
-#endif
-    {
-        render_state->UseTexParameterFilter = true;
-        render_state->CurrentTexParameterFilter = GL_LINEAR;
-    }
-}
-static void ImGui_ImplOpenGL3_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)
-{
-    ImGui_ImplOpenGL3_RenderState* render_state = ImGui_ImplOpenGL3_GetRenderState();
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-    if (bd->HasBindSampler)
-    {
-        render_state->CurrentSampler = bd->TexSamplers[1];
-        render_state->UseTexParameterFilter = false;
-        glBindSampler(0, render_state->CurrentSampler);
-    }
-    else
-#endif
-    {
-        render_state->UseTexParameterFilter = true;
-        render_state->CurrentTexParameterFilter = GL_NEAREST;
-    }
-}
-
 // OpenGL3 Render function.
 // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly.
 // This is in order to be able to run within an OpenGL engine that doesn't do so.
@@ -515,17 +608,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
     GL_CALL(glGenVertexArrays(1, &vertex_array_object));
 #endif
-
-    // Setup render state structure (for callbacks and custom texture bindings)
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    ImGui_ImplOpenGL3_RenderState render_state;
-    render_state.UseBindSampler = bd->HasBindSampler;
-    render_state.UseTexParameterFilter = false;
-    render_state.CurrentSampler = 0;
-    render_state.CurrentTexParameterFilter = 0;
-    platform_io.Renderer_RenderState = &render_state;
-
-    ImGui_ImplOpenGL3_SetupRenderState(draw_data, &render_state, fb_width, fb_height, vertex_array_object);
+    ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
 
     // Will project scissor/clipping rectangles into framebuffer space
     ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
@@ -571,8 +654,9 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
             if (pcmd->UserCallback != nullptr)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplOpenGL3_DrawCallback_ResetRenderState)
-                    ImGui_ImplOpenGL3_SetupRenderState(draw_data, &render_state, fb_width, fb_height, vertex_array_object);
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
             }
@@ -589,15 +673,6 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
 
                 // Bind texture, Draw
                 GL_CALL(glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->GetTexID()));
-
-                // Emulate sampler change (even though it is technically part of texture data)
-                // As a sort of hack/workaround, we only start writing using glTexParameter() if sampler is ever changed explicitly.
-                if (render_state.UseTexParameterFilter)
-                {
-                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, render_state.CurrentTexParameterFilter);
-                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, render_state.CurrentTexParameterFilter);
-                }
-
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
                 if (bd->GlVersion >= 320)
                     GL_CALL(glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)), (GLint)pcmd->VtxOffset));
@@ -607,7 +682,6 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
             }
         }
     }
-    platform_io.Renderer_RenderState = nullptr;
 
     // Destroy the temporary VAO
 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
@@ -964,20 +1038,6 @@ bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
     glGenBuffers(1, &bd->VboHandle);
     glGenBuffers(1, &bd->ElementsHandle);
 
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    if (bd->HasBindSampler)
-    {
-        glGenSamplers(2, &bd->TexSamplers[0]);
-        for (int sampler_n = 0; sampler_n < 2; sampler_n++)
-        {
-            GL_CALL(glSamplerParameteri(bd->TexSamplers[sampler_n], GL_TEXTURE_MIN_FILTER, (sampler_n == 0) ? GL_LINEAR : GL_NEAREST));
-            GL_CALL(glSamplerParameteri(bd->TexSamplers[sampler_n], GL_TEXTURE_MAG_FILTER, (sampler_n == 0) ? GL_LINEAR : GL_NEAREST));
-            GL_CALL(glSamplerParameteri(bd->TexSamplers[sampler_n], GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
-            GL_CALL(glSamplerParameteri(bd->TexSamplers[sampler_n], GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
-        }
-    }
-#endif
-
     // Restore modified GL state
     glBindTexture(GL_TEXTURE_2D, last_texture);
     glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
@@ -995,9 +1055,6 @@ void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
 {
     ImGui_ImplOpenGL3_InitLoader();
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    if (bd->TexSamplers[0]) { glDeleteSamplers(2, &bd->TexSamplers[0]); bd->TexSamplers[0] = bd->TexSamplers[1] = 0; }
-#endif
     if (bd->VboHandle)      { glDeleteBuffers(1, &bd->VboHandle); bd->VboHandle = 0; }
     if (bd->ElementsHandle) { glDeleteBuffers(1, &bd->ElementsHandle); bd->ElementsHandle = 0; }
     if (bd->ShaderHandle)   { glDeleteProgram(bd->ShaderHandle); bd->ShaderHandle = 0; }
@@ -1008,143 +1065,32 @@ void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
             ImGui_ImplOpenGL3_DestroyTexture(tex);
 }
 
-bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplOpenGL3_RenderWindow(ImGuiViewport* viewport, void*)
 {
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    // Initialize loader
-    if (!ImGui_ImplOpenGL3_InitLoader())
-        return false;
-
-    // Setup backend capabilities flags
-    ImGui_ImplOpenGL3_Data* bd = IM_NEW(ImGui_ImplOpenGL3_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_opengl3";
-
-    // Query for GL version (e.g. 320 for GL 3.2)
-    const char* gl_version_str = (const char*)glGetString(GL_VERSION);
-#if defined(IMGUI_IMPL_OPENGL_ES2)
-    // GLES 2
-    bd->GlVersion = 200;
-    bd->GlProfileIsES2 = true;
-    IM_UNUSED(gl_version_str);
-#else
-    // Desktop or GLES 3
-    GLint major = 0;
-    GLint minor = 0;
-    glGetIntegerv(GL_MAJOR_VERSION, &major);
-    glGetIntegerv(GL_MINOR_VERSION, &minor);
-    if (major == 0 && minor == 0)
-        sscanf(gl_version_str, "%d.%d", &major, &minor); // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
-    bd->GlVersion = (GLuint)(major * 100 + minor * 10);
-    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &bd->MaxTextureSize);
-
-#if defined(IMGUI_IMPL_OPENGL_ES3)
-    bd->GlProfileIsES3 = true;
-#else
-    if (strncmp(gl_version_str, "OpenGL ES 3", 11) == 0)
-        bd->GlProfileIsES3 = true;
-#endif
-
-#if defined(GL_CONTEXT_PROFILE_MASK)
-    if (!bd->GlProfileIsES3 && bd->GlVersion >= 320)
-        glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &bd->GlProfileMask);
-    bd->GlProfileIsCompat = (bd->GlProfileMask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT) != 0;
-#endif
-
-    bd->UseBufferSubData = false;
-    /*
-    // Query vendor to enable glBufferSubData kludge
-#ifdef _WIN32
-    if (const char* vendor = (const char*)glGetString(GL_VENDOR))
-        if (strncmp(vendor, "Intel", 5) == 0)
-            bd->UseBufferSubData = true;
-#endif
-    */
-#endif
-
-#ifdef IMGUI_IMPL_OPENGL_DEBUG
-    printf("GlVersion = %d, \"%s\"\nGlProfileIsCompat = %d\nGlProfileMask = 0x%X\nGlProfileIsES2/IsEs3 = %d/%d\nGL_VENDOR = '%s'\nGL_RENDERER = '%s'\n", bd->GlVersion, gl_version_str, bd->GlProfileIsCompat, bd->GlProfileMask, bd->GlProfileIsES2, bd->GlProfileIsES3, (const char*)glGetString(GL_VENDOR), (const char*)glGetString(GL_RENDERER)); // [DEBUG]
-#endif
-
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
-    if (bd->GlVersion >= 320)
-        io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-#endif
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = (int)bd->MaxTextureSize;
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplOpenGL3_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplOpenGL3_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplOpenGL3_DrawCallback_SetSamplerNearest;
-
-    // Store GLSL version string so we can refer to it later in case we recreate shaders.
-    // Note: GLSL version is NOT the same as GL version. Leave this to nullptr if unsure.
-    if (glsl_version == nullptr)
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
     {
-#if defined(IMGUI_IMPL_OPENGL_ES2)
-        glsl_version = "#version 100";
-#elif defined(IMGUI_IMPL_OPENGL_ES3)
-        glsl_version = "#version 300 es";
-#elif defined(__APPLE__)
-        glsl_version = "#version 150";
-#else
-        if (bd->GlVersion >= 410)
-            glsl_version = "#version 410";
-        else
-            glsl_version = "#version 130";
-#endif
+        ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
     }
-    IM_ASSERT((int)strlen(glsl_version) + 2 < IM_COUNTOF(bd->GlslVersionString));
-    strcpy(bd->GlslVersionString, glsl_version);
-    strcat(bd->GlslVersionString, "\n");
-
-    // Make an arbitrary GL call (we don't actually need the result)
-    // IF YOU GET A CRASH HERE: it probably means the OpenGL function loader didn't do its job. Let us know!
-    GLint current_texture;
-    glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
-
-    // Detect extensions we support
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
-    bd->HasPolygonMode = (!bd->GlProfileIsES2 && !bd->GlProfileIsES3);
-#endif
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    bd->HasBindSampler = (bd->GlVersion >= 330 || bd->GlProfileIsES3);
-#endif
-    bd->HasClipOrigin = (bd->GlVersion >= 450);
-#ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
-    GLint num_extensions = 0;
-    glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
-    for (GLint i = 0; i < num_extensions; i++)
-    {
-        const char* extension = (const char*)glGetStringi(GL_EXTENSIONS, i);
-        if (extension != nullptr && strcmp(extension, "GL_ARB_clip_control") == 0)
-            bd->HasClipOrigin = true;
-    }
-#endif
-
-    return true;
+    ImGui_ImplOpenGL3_RenderDrawData(viewport->DrawData);
 }
 
-void    ImGui_ImplOpenGL3_Shutdown()
+static void ImGui_ImplOpenGL3_InitMultiViewportSupport()
 {
-    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplOpenGL3_RenderWindow;
+}
 
-    ImGui_ImplOpenGL3_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-
-    ImGui_ImplOpenGL3_ShutdownLoader();
+static void ImGui_ImplOpenGL3_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_opengl3.h

@@ -7,6 +7,7 @@
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [x] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset) [Desktop OpenGL only!]
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // About WebGL/ES:
 // - You need to '#define IMGUI_IMPL_OPENGL_ES2' or '#define IMGUI_IMPL_OPENGL_ES3' to use WebGL or OpenGL ES.
@@ -65,17 +66,4 @@ IMGUI_IMPL_API void     ImGui_ImplOpenGL3_UpdateTexture(ImTextureData* tex);
 
 #endif
 
-// [BETA] Selected render state data shared with callbacks.
-// This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplOpenGL3_RenderDrawData() call.
-// (Please open an issue if you feel you need access to more data)
-struct ImGui_ImplOpenGL3_RenderState
-{
-    bool            UseBindSampler;
-    bool            UseTexParameterFilter;
-    unsigned int    CurrentSampler;                 // (GLuint) Used if UseBindSampler == true, otherwise always 0
-    unsigned int    CurrentTexParameterFilter;      // (GLuint) Used if UseTexParameterToSetSampler == true
-};
-
-static inline ImGui_ImplOpenGL3_RenderState* ImGui_ImplOpenGL3_GetRenderState() { return (ImGui_ImplOpenGL3_RenderState*)ImGui::GetPlatformIO().Renderer_RenderState; }
-
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_osx.h

@@ -10,6 +10,10 @@
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport / platform windows.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Window size not correctly reported when enabling io.ConfigViewportsNoDecoration
+//  [ ] Platform: Multi-viewport: Missing ImGuiBackendFlags_HasParentViewport support. The viewport->ParentViewportID field is ignored, and therefore io.ConfigViewportsNoDefaultParent has no effect either.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_osx.mm

@@ -10,6 +10,10 @@
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport / platform windows.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Window size not correctly reported when enabling io.ConfigViewportsNoDecoration
+//  [ ] Platform: Multi-viewport: Missing ImGuiBackendFlags_HasParentViewport support. The viewport->ParentViewportID field is ignored, and therefore io.ConfigViewportsNoDefaultParent has no effect either.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -29,9 +33,12 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2026-XX-XX: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2025-09-18: Call platform_io.ClearPlatformHandlers() on shutdown.
+//  2025-07-08: [Docking] Fixed multi-viewport handling broken on 2025-06-02. (#8644, #8777)
 //  2025-06-27: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-06-12: ImGui_ImplOSX_HandleEvent() only process event for window containing our view. (#8644)
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
 //  2025-03-21: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad regardless of ImGuiConfigFlags_NavEnableGamepad being set.
 //  2025-01-20: Removed notification observer when shutting down. (#8331)
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
@@ -101,6 +108,9 @@ static void                     ImGui_ImplOSX_DestroyBackendData()  { IM_DELETE(
 static inline CFTimeInterval    GetMachAbsoluteTimeInSeconds()      { return (CFTimeInterval)(double)(clock_gettime_nsec_np(CLOCK_UPTIME_RAW) / 1e9); }
 
 // Forward Declarations
+static void ImGui_ImplOSX_InitMultiViewportSupport();
+static void ImGui_ImplOSX_ShutdownMultiViewportSupport();
+static void ImGui_ImplOSX_UpdateMonitors();
 static void ImGui_ImplOSX_AddTrackingArea(NSView* _Nonnull view);
 static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
@@ -148,6 +158,20 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
     NSWindow* window = view.window;
     if (!window)
         return;
+
+    ImGuiIO& io = ImGui::GetIO();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        NSRect frame = window.frame;
+        NSRect contentRect = window.contentLayoutRect;
+        if (window.styleMask & NSWindowStyleMaskFullSizeContentView) // No title bar windows should be considered.
+            contentRect = frame;
+
+        NSRect firstScreenFrame = NSScreen.screens[0].frame;
+        _imeRect = NSMakeRect(_posX, _posY, 0, 0);
+        _imeRect.origin.y = firstScreenFrame.size.height - _imeRect.size.height - _imeRect.origin.y; // Opposite of ConvertNSRect()
+    }
+    else
     {
         NSRect contentRect = [window contentRectForFrameRect:window.frame];
         NSRect rect = NSMakeRect(_posX, contentRect.size.height - _posY, 0, 0);
@@ -247,6 +271,7 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
 - (void)onApplicationBecomeActive:(NSNotification*)aNotification;
 - (void)onApplicationBecomeInactive:(NSNotification*)aNotification;
+- (void)displaysDidChange:(NSNotification*)aNotification;
 
 @end
 
@@ -264,6 +289,11 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
     io.AddFocusEvent(false);
 }
 
+- (void)displaysDidChange:(NSNotification*)aNotification
+{
+    ImGui_ImplOSX_UpdateMonitors();
+}
+
 @end
 
 // Functions
@@ -418,11 +448,15 @@ bool ImGui_ImplOSX_Init(NSView* view)
     io.BackendPlatformName = "imgui_impl_osx";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
     //io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
+    io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;      // We can create multi-viewports on the Platform side (optional)
+    //io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can call io.AddMouseViewportEvent() with correct data (optional)
 
     bd->Observer = [ImGuiObserver new];
     bd->Window = view.window ?: NSApp.orderedWindows.firstObject;
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     main_viewport->PlatformHandle = main_viewport->PlatformHandleRaw = (__bridge_retained void*)bd->Window;
+    ImGui_ImplOSX_UpdateMonitors();
+    ImGui_ImplOSX_InitMultiViewportSupport();
 
     // Load cursors. Some of them are undocumented.
     bd->MouseCursorHidden = false;
@@ -514,14 +548,14 @@ void ImGui_ImplOSX_Shutdown()
         bd->Monitor = nullptr;
     }
 
+    ImGui_ImplOSX_ShutdownMultiViewportSupport();
     ImGui_ImplOSX_DestroyBackendData();
-
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports);
     platform_io.ClearPlatformHandlers();
 }
 
@@ -672,10 +706,10 @@ static ImGuiMouseSource GetMouseSource(NSEvent* event)
 static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view)
 {
     // Only process events from the window containing ImGui view
-    if (event.window != view.window)
+    if (!ImGui::FindViewportByPlatformHandle((__bridge void*)event.window))
         return false;
-    ImGuiIO& io = ImGui::GetIO();
 
+    ImGuiIO& io = ImGui::GetIO();
     if (event.type == NSEventTypeLeftMouseDown || event.type == NSEventTypeRightMouseDown || event.type == NSEventTypeOtherMouseDown)
     {
         int button = (int)[event buttonNumber];
@@ -700,14 +734,23 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view)
 
     if (event.type == NSEventTypeMouseMoved || event.type == NSEventTypeLeftMouseDragged || event.type == NSEventTypeRightMouseDragged || event.type == NSEventTypeOtherMouseDragged)
     {
-        NSPoint mousePoint = event.locationInWindow;
-        if (event.window == nil)
-            mousePoint = [[view window] convertPointFromScreen:mousePoint];
-        mousePoint = [view convertPoint:mousePoint fromView:nil];
-        if ([view isFlipped])
-            mousePoint = NSMakePoint(mousePoint.x, mousePoint.y);
+        NSPoint mousePoint;
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            mousePoint = NSEvent.mouseLocation;
+            mousePoint.y = CGDisplayPixelsHigh(kCGDirectMainDisplay) - mousePoint.y; // Normalize y coordinate to top-left of main display.
+        }
         else
-            mousePoint = NSMakePoint(mousePoint.x, view.bounds.size.height - mousePoint.y);
+        {
+            mousePoint = event.locationInWindow;
+            if (event.window == nil)
+                mousePoint = [[view window] convertPointFromScreen:mousePoint];
+            mousePoint = [view convertPoint:mousePoint fromView:nil]; // Convert to local coordinates of view
+            if ([view isFlipped])
+                mousePoint = NSMakePoint(mousePoint.x, mousePoint.y);
+            else
+                mousePoint = NSMakePoint(mousePoint.x, view.bounds.size.height - mousePoint.y);
+        }
         io.AddMouseSourceEvent(GetMouseSource(event));
         io.AddMousePosEvent((float)mousePoint.x, (float)mousePoint.y);
         return io.WantCaptureMouse;
@@ -833,6 +876,300 @@ static void ImGui_ImplOSX_AddTrackingArea(NSView* _Nonnull view)
     }];
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the back-end to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+struct ImGui_ImplOSX_ViewportData
+{
+    NSWindow*        Window;
+    bool             WindowOwned;
+
+    ImGui_ImplOSX_ViewportData()  { WindowOwned = false; }
+    ~ImGui_ImplOSX_ViewportData() { IM_ASSERT(Window == nil); }
+};
+
+@interface ImGui_ImplOSX_Window: NSWindow
+@end
+
+@implementation ImGui_ImplOSX_Window
+
+- (BOOL)canBecomeKeyWindow
+{
+    return YES;
+}
+
+@end
+
+static void ConvertNSRect(NSRect* r)
+{
+    NSRect firstScreenFrame = NSScreen.screens[0].frame;
+    IM_ASSERT(firstScreenFrame.origin.x == 0 && firstScreenFrame.origin.y == 0);
+    r->origin.y = firstScreenFrame.size.height - r->origin.y - r->size.height;
+}
+
+static void ImGui_ImplOSX_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    ImGui_ImplOSX_ViewportData* vd = IM_NEW(ImGui_ImplOSX_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    NSScreen* screen = bd->Window.screen;
+    NSRect rect = NSMakeRect(viewport->Pos.x, viewport->Pos.y, viewport->Size.x, viewport->Size.y);
+    ConvertNSRect(&rect);
+
+    NSWindowStyleMask styleMask = 0;
+    if (viewport->Flags & ImGuiViewportFlags_NoDecoration)
+        styleMask |= NSWindowStyleMaskBorderless;
+    else
+        styleMask |= NSWindowStyleMaskTitled | NSWindowStyleMaskResizable | NSWindowStyleMaskClosable | NSWindowStyleMaskMiniaturizable;
+
+    NSWindow* window = [[ImGui_ImplOSX_Window alloc] initWithContentRect:rect
+                                                               styleMask:styleMask
+                                                                 backing:NSBackingStoreBuffered
+                                                                   defer:YES
+                                                                  screen:screen];
+    if (viewport->Flags & ImGuiViewportFlags_TopMost)
+        [window setLevel:NSFloatingWindowLevel];
+
+    window.title = @"Untitled";
+    window.opaque = YES;
+
+    KeyEventResponder* view = [[KeyEventResponder alloc] initWithFrame:rect];
+    if (floor(NSAppKitVersionNumber) > NSAppKitVersionNumber10_6 && ceil(NSAppKitVersionNumber) < NSAppKitVersionNumber10_15)
+        [view setWantsBestResolutionOpenGLSurface:YES];
+
+    window.contentView = view;
+
+    vd->Window = window;
+    vd->WindowOwned = true;
+    viewport->PlatformRequestResize = false;
+    viewport->PlatformHandle = viewport->PlatformHandleRaw = (__bridge_retained void*)window;
+}
+
+static void ImGui_ImplOSX_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData)
+    {
+        NSWindow* window = vd->Window;
+        if (window != nil && vd->WindowOwned)
+        {
+            window.contentView = nil;
+            window.contentViewController = nil;
+            [window orderOut:nil];
+        }
+        vd->Window = nil;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = viewport->PlatformHandleRaw = nullptr;
+}
+
+static void ImGui_ImplOSX_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+        [vd->Window orderFront:nil];
+    else
+        [vd->Window makeKeyAndOrderFront:nil];
+
+    [vd->Window setIsVisible:YES];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSRect frame = window.frame;
+    NSRect contentRect = window.contentLayoutRect;
+    if (window.styleMask & NSWindowStyleMaskFullSizeContentView) // No title bar windows should be considered.
+        contentRect = frame;
+
+    NSRect firstScreenFrame = NSScreen.screens[0].frame;
+    return ImVec2(frame.origin.x, firstScreenFrame.size.height - frame.origin.y - contentRect.size.height);
+}
+
+static void ImGui_ImplOSX_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSSize size = window.frame.size;
+
+    NSRect r = NSMakeRect(pos.x, pos.y, size.width, size.height);
+    ConvertNSRect(&r);
+    [window setFrameOrigin:r.origin];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSSize size = window.contentLayoutRect.size;
+    return ImVec2(size.width, size.height);
+}
+
+static void ImGui_ImplOSX_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSRect rect = window.frame;
+    rect.origin.y -= (size.y - rect.size.height);
+    rect.size.width = size.x;
+    rect.size.height = size.y;
+    [window setFrame:rect display:YES];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    NSWindow* window = vd->Window;
+    const float fb_scale = (float)[window backingScaleFactor];
+    return ImVec2(fb_scale, fb_scale);
+}
+
+static void ImGui_ImplOSX_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+    [vd->Window makeKeyAndOrderFront:bd->Window];
+}
+
+static bool ImGui_ImplOSX_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    return vd->Window.isKeyWindow;
+}
+
+static bool ImGui_ImplOSX_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    return vd->Window.isMiniaturized;
+}
+
+static void ImGui_ImplOSX_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    vd->Window.title = [NSString stringWithUTF8String:title];
+}
+
+static void ImGui_ImplOSX_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+    IM_ASSERT(alpha >= 0.0f && alpha <= 1.0f);
+
+    vd->Window.alphaValue = alpha;
+}
+
+static float ImGui_ImplOSX_GetWindowDpiScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    return vd->Window.backingScaleFactor;
+}
+
+static void ImGui_ImplOSX_UpdateMonitors()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
+
+    NSRect firstScreenFrame = NSScreen.screens[0].frame;
+    IM_ASSERT(firstScreenFrame.origin.x == 0 && firstScreenFrame.origin.y == 0);
+
+    for (NSScreen* screen in NSScreen.screens)
+    {
+        NSRect frame = screen.frame;
+        NSRect visibleFrame = screen.visibleFrame;
+        ConvertNSRect(&frame);
+        ConvertNSRect(&visibleFrame);
+
+        ImGuiPlatformMonitor imgui_monitor;
+        imgui_monitor.MainPos = ImVec2(frame.origin.x, frame.origin.y);
+        imgui_monitor.MainSize = ImVec2(frame.size.width, frame.size.height);
+        imgui_monitor.WorkPos = ImVec2(visibleFrame.origin.x, visibleFrame.origin.y);
+        imgui_monitor.WorkSize = ImVec2(visibleFrame.size.width, visibleFrame.size.height);
+        imgui_monitor.DpiScale = screen.backingScaleFactor;
+        imgui_monitor.PlatformHandle = (__bridge_retained void*)screen;
+
+        platform_io.Monitors.push_back(imgui_monitor);
+    }
+}
+
+static void ImGui_ImplOSX_InitMultiViewportSupport()
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplOSX_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplOSX_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplOSX_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplOSX_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplOSX_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplOSX_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplOSX_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplOSX_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplOSX_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplOSX_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplOSX_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplOSX_SetWindowTitle;
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplOSX_SetWindowAlpha;
+    platform_io.Platform_GetWindowDpiScale = ImGui_ImplOSX_GetWindowDpiScale; // FIXME-DPI
+
+    // Register main window handle (which is owned by the main application, not by us)
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplOSX_ViewportData* vd = IM_NEW(ImGui_ImplOSX_ViewportData)();
+    vd->Window = bd->Window;
+    vd->WindowOwned = false;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (__bridge void*)bd->Window;
+
+    [NSNotificationCenter.defaultCenter addObserver:bd->Observer
+                                           selector:@selector(displaysDidChange:)
+                                               name:NSApplicationDidChangeScreenParametersNotification
+                                             object:nil];
+}
+
+static void ImGui_ImplOSX_ShutdownMultiViewportSupport()
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    [NSNotificationCenter.defaultCenter removeObserver:bd->Observer
+                                                  name:NSApplicationDidChangeScreenParametersNotification
+                                                object:nil];
+    bd->Observer = nullptr;
+    bd->Window = nullptr;
+    if (bd->Monitor != nullptr)
+    {
+        [NSEvent removeMonitor:bd->Monitor];
+        bd->Monitor = nullptr;
+    }
+
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)main_viewport->PlatformUserData;
+    IM_DELETE(vd);
+    main_viewport->PlatformUserData = nullptr;
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdl2.cpp

@@ -10,6 +10,10 @@
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: Basic IME support. App needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [ ] Platform: Multi-viewport: Missing ImGuiBackendFlags_HasParentViewport support. The viewport->ParentViewportID field is ignored, and therefore io.ConfigViewportsNoDefaultParent has no effect either.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -21,7 +25,8 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-16: Made ImGui_ImplSDL2_GetContentScaleForWindow(), ImGui_ImplSDL2_GetContentScaleForDisplay() helpers return a minimum of 1.0f, as some Linux setup seems to report <1.0f value and this breaks scaling border size. (#9369)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2026-03-09: [Docking] Fixed an issue dated 2025/04/09 (1.92 WIP) where a refactor+merge caused ImGuiBackendFlags_HasMouseHoveredViewport to never be set, causing foreign windows to be ignored when deciding of hovered viewport. (#9284)
 //  2026-02-13: Inputs: systems other than X11 are back to starting mouse capture on mouse down (reverts 2025-02-26 change). Only X11 requires waiting for a drag by default (not ideal, but a better default for X11 users). Added ImGui_ImplSDL2_SetMouseCaptureMode() for X11 debugger users. (#3650, #6410, #9235)
 //  2026-01-15: Changed GetClipboardText() handler to return nullptr on error aka clipboard contents is not text. Consistent with other backends. (#9168)
 //  2025-09-24: Skip using the SDL_GetGlobalMouseState() state when one of our window is hovered, as the SDL_MOUSEMOTION data is reliable. Fix macOS notch mouse coordinates issue in fullscreen mode + better perf on X11. (#7919, #7786)
@@ -29,11 +34,15 @@
 //  2025-09-15: Content Scales are always reported as 1.0 on Wayland. (#8921)
 //  2025-07-08: Made ImGui_ImplSDL2_GetContentScaleForWindow(), ImGui_ImplSDL2_GetContentScaleForDisplay() helpers return 1.0f on Emscripten and Android platforms, matching macOS logic. (#8742, #8733)
 //  2025-06-11: Added ImGui_ImplSDL2_GetContentScaleForWindow(SDL_Window* window) and ImGui_ImplSDL2_GetContentScaleForDisplay(int display_index) helper to facilitate making DPI-aware apps.
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
+//  2025-04-09: [Docking] Revert update monitors and work areas information every frame. Only do it on Windows. (#8415, #8558)
 //  2025-04-09: Don't attempt to call SDL_CaptureMouse() on drivers where we don't call SDL_GetGlobalMouseState(). (#8561)
 //  2025-03-21: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad regardless of ImGuiConfigFlags_NavEnableGamepad being set.
 //  2025-03-10: When dealing with OEM keys, use scancodes instead of translated keycodes to choose ImGuiKey values. (#7136, #7201, #7206, #7306, #7670, #7672, #8468)
 //  2025-02-26: Only start SDL_CaptureMouse() when mouse is being dragged, to mitigate issues with e.g. Linux debuggers not claiming capture back. (#6410, #3650)
+//  2025-02-25: [Docking] Revert to use SDL_GetDisplayBounds() for WorkPos/WorkRect if SDL_GetDisplayUsableBounds() failed.
 //  2025-02-24: Avoid calling SDL_GetGlobalMouseState() when mouse is in relative mode.
+//  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
 //  2025-01-20: Made ImGui_ImplSDL2_SetGamepadMode(ImGui_ImplSDL2_GamepadMode_Manual) accept an empty array.
@@ -74,7 +83,7 @@
 //  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModsEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-08-17: Calling io.AddFocusEvent() on SDL_WINDOWEVENT_FOCUS_GAINED/SDL_WINDOWEVENT_FOCUS_LOST.
 //  2021-07-29: Inputs: MousePos is correctly reported when the host platform window is hovered but not focused (using SDL_GetMouseFocus() + SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, requires SDL 2.0.5+)
-//  2021-06-29: *BREAKING CHANGE* Removed 'SDL_Window* window' parameter to ImGui_ImplSDL2_NewFrame() which was unnecessary.
+//  2021-06:29: *BREAKING CHANGE* Removed 'SDL_Window* window' parameter to ImGui_ImplSDL2_NewFrame() which was unnecessary.
 //  2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
 //  2021-03-22: Rework global mouse pos availability check listing supported platforms explicitly, effectively fixing mouse access on Raspberry Pi. (#2837, #3950)
 //  2020-05-25: Misc: Report a zero display-size when window is minimized, to be consistent with other backends.
@@ -116,6 +125,7 @@
 #endif
 
 // SDL
+// (the multi-viewports feature requires SDL features supported from SDL 2.0.4+. SDL 2.0.5+ is highly recommended)
 #include <SDL.h>
 #include <SDL_syswm.h>
 #include <stdio.h>              // for snprintf()
@@ -132,11 +142,18 @@
 #else
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    0
 #endif
+#define SDL_HAS_WINDOW_ALPHA                SDL_VERSION_ATLEAST(2,0,5)
+#define SDL_HAS_ALWAYS_ON_TOP               SDL_VERSION_ATLEAST(2,0,5)
+#define SDL_HAS_USABLE_DISPLAY_BOUNDS       SDL_VERSION_ATLEAST(2,0,5)
 #define SDL_HAS_PER_MONITOR_DPI             SDL_VERSION_ATLEAST(2,0,4)
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
+#define SDL_HAS_DISPLAY_EVENT               SDL_VERSION_ATLEAST(2,0,9)
 #define SDL_HAS_OPEN_URL                    SDL_VERSION_ATLEAST(2,0,14)
+#define SDL_HAS_SHOW_WINDOW_ACTIVATION_HINT SDL_VERSION_ATLEAST(2,0,18)
 #if SDL_HAS_VULKAN
 #include <SDL_vulkan.h>
+#else
+static const Uint32 SDL_WINDOW_VULKAN = 0x10000000;
 #endif
 
 // SDL Data
@@ -147,8 +164,9 @@ struct ImGui_ImplSDL2_Data
     SDL_Renderer*           Renderer;
     Uint64                  Time;
     char*                   ClipboardTextData;
-    char                    BackendPlatformName[64];
-    bool                    IsWayland;
+    char                    BackendPlatformName[48];
+    bool                    UseVulkan;
+    bool                    WantUpdateMonitors;
 
     // Mouse handling
     Uint32                  MouseWindowID;
@@ -157,6 +175,7 @@ struct ImGui_ImplSDL2_Data
     SDL_Cursor*             MouseLastCursor;
     int                     MouseLastLeaveFrame;
     bool                    MouseCanUseGlobalState;
+    bool                    MouseCanReportHoveredViewport;  // This is hard to use/unreliable on SDL so we'll set ImGuiBackendFlags_HasMouseHoveredViewport dynamically based on state.
     ImGui_ImplSDL2_MouseCaptureMode MouseCaptureMode;
 
     // Gamepad handling
@@ -176,6 +195,11 @@ static ImGui_ImplSDL2_Data* ImGui_ImplSDL2_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplSDL2_Data*)ImGui::GetIO().BackendPlatformUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplSDL2_UpdateMonitors();
+static void ImGui_ImplSDL2_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context);
+static void ImGui_ImplSDL2_ShutdownMultiViewportSupport();
+
 // Functions
 static const char* ImGui_ImplSDL2_GetClipboardText(ImGuiContext*)
 {
@@ -195,13 +219,13 @@ static void ImGui_ImplSDL2_SetClipboardText(ImGuiContext*, const char* text)
 }
 
 // Note: native IME will only display if user calls SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1") _before_ SDL_CreateWindow().
-static void ImGui_ImplSDL2_PlatformSetImeData(ImGuiContext*, ImGuiViewport*, ImGuiPlatformImeData* data)
+static void ImGui_ImplSDL2_PlatformSetImeData(ImGuiContext*, ImGuiViewport* viewport, ImGuiPlatformImeData* data)
 {
     if (data->WantVisible)
     {
         SDL_Rect r;
-        r.x = (int)data->InputPos.x;
-        r.y = (int)data->InputPos.y;
+        r.x = (int)(data->InputPos.x - viewport->Pos.x);
+        r.y = (int)(data->InputPos.y - viewport->Pos.y);
         r.w = 1;
         r.h = (int)data->InputLineHeight;
         SDL_SetTextInputRect(&r);
@@ -367,8 +391,7 @@ static void ImGui_ImplSDL2_UpdateKeyModifiers(SDL_Keymod sdl_key_mods)
 
 static ImGuiViewport* ImGui_ImplSDL2_GetViewportForWindowID(Uint32 window_id)
 {
-    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
-    return (window_id == bd->WindowID) ? ImGui::GetMainViewport() : nullptr;
+    return ImGui::FindViewportByPlatformHandle((void*)(intptr_t)window_id);
 }
 
 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
@@ -388,6 +411,13 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             if (ImGui_ImplSDL2_GetViewportForWindowID(event->motion.windowID) == nullptr)
                 return false;
             ImVec2 mouse_pos((float)event->motion.x, (float)event->motion.y);
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                int window_x, window_y;
+                SDL_GetWindowPosition(SDL_GetWindowFromID(event->motion.windowID), &window_x, &window_y);
+                mouse_pos.x += window_x;
+                mouse_pos.y += window_y;
+            }
             io.AddMouseSourceEvent(event->motion.which == SDL_TOUCH_MOUSEID ? ImGuiMouseSource_TouchScreen : ImGuiMouseSource_Mouse);
             io.AddMousePosEvent(mouse_pos.x, mouse_pos.y);
             return true;
@@ -439,20 +469,32 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
         case SDL_KEYDOWN:
         case SDL_KEYUP:
         {
-            if (ImGui_ImplSDL2_GetViewportForWindowID(event->key.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL2_GetViewportForWindowID(event->key.windowID);
+            if (viewport == nullptr)
                 return false;
+            //IMGUI_DEBUG_LOG("SDL_KEY%s : key=0x%08X ('%s'), scancode=%d ('%s'), mod=%X, windowID=%d, viewport=%08X\n",
+            //    (event->type == SDL_KEYDOWN) ? "DOWN" : "UP  ", event->key.keysym.sym, SDL_GetKeyName(event->key.keysym.sym), event->key.keysym.scancode, SDL_GetScancodeName(event->key.keysym.scancode), event->key.keysym.mod, event->key.windowID, viewport ? viewport->ID : 0);
             ImGui_ImplSDL2_UpdateKeyModifiers((SDL_Keymod)event->key.keysym.mod);
-            //IMGUI_DEBUG_LOG("SDL_KEY_%s : key=%d ('%s'), scancode=%d ('%s'), mod=%X\n",
-            //    (event->type == SDL_KEYDOWN) ? "DOWN" : "UP  ", event->key.keysym.sym, SDL_GetKeyName(event->key.keysym.sym), event->key.keysym.scancode, SDL_GetScancodeName(event->key.keysym.scancode), event->key.keysym.mod);
             ImGuiKey key = ImGui_ImplSDL2_KeyEventToImGuiKey(event->key.keysym.sym, event->key.keysym.scancode);
             io.AddKeyEvent(key, (event->type == SDL_KEYDOWN));
             io.SetKeyEventNativeData(key, (int)event->key.keysym.sym, (int)event->key.keysym.scancode, (int)event->key.keysym.scancode); // To support legacy indexing (<1.87 user code). Legacy backend uses SDLK_*** as indices to IsKeyXXX() functions.
             return true;
         }
+#if SDL_HAS_DISPLAY_EVENT
+        case SDL_DISPLAYEVENT:
+        {
+            // 2.0.26 has SDL_DISPLAYEVENT_CONNECTED/SDL_DISPLAYEVENT_DISCONNECTED/SDL_DISPLAYEVENT_ORIENTATION,
+            // so change of DPI/Scaling are not reflected in this event. (SDL3 has it)
+            bd->WantUpdateMonitors = true;
+            return true;
+        }
+#endif
         case SDL_WINDOWEVENT:
         {
-            if (ImGui_ImplSDL2_GetViewportForWindowID(event->window.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL2_GetViewportForWindowID(event->window.windowID);
+            if (viewport == NULL)
                 return false;
+
             // - When capturing mouse, SDL will send a bunch of conflicting LEAVE/ENTER event on every mouse move, but the final ENTER tends to be right.
             // - However we won't get a correct LEAVE event for a captured window.
             // - In some cases, when detaching a window from main viewport SDL may send SDL_WINDOWEVENT_ENTER one frame too late,
@@ -466,10 +508,18 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             }
             if (window_event == SDL_WINDOWEVENT_LEAVE)
                 bd->MouseLastLeaveFrame = ImGui::GetFrameCount() + 1;
+            //if (window_event == SDL_WINDOWEVENT_FOCUS_GAINED) { IMGUI_DEBUG_LOG("SDL_WINDOWEVENT_FOCUS_GAINED: windowId %d, viewport: %08X\n", event->window.windowID, viewport ? viewport->ID : 0); }
+            //if (window_event == SDL_WINDOWEVENT_FOCUS_LOST) { IMGUI_DEBUG_LOG("SDL_WINDOWEVENT_FOCUS_LOST: windowId %d, viewport: %08X\n", event->window.windowID, viewport ? viewport->ID : 0); }
             if (window_event == SDL_WINDOWEVENT_FOCUS_GAINED)
                 io.AddFocusEvent(true);
             if (window_event == SDL_WINDOWEVENT_FOCUS_LOST)
                 io.AddFocusEvent(false);
+            if (window_event == SDL_WINDOWEVENT_CLOSE)
+                viewport->PlatformRequestClose = true;
+            if (window_event == SDL_WINDOWEVENT_MOVED)
+                viewport->PlatformRequestMove = true;
+            if (window_event == SDL_WINDOWEVENT_RESIZED)
+                viewport->PlatformRequestResize = true;
             return true;
         }
         case SDL_CONTROLLERDEVICEADDED:
@@ -500,35 +550,45 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void
     SDL_version ver_runtime;
     SDL_VERSION(&ver_compiled);
     SDL_GetVersion(&ver_runtime);
-    const char* sdl_video_driver = SDL_GetCurrentVideoDriver();
 
     // Setup backend capabilities flags
     ImGui_ImplSDL2_Data* bd = IM_NEW(ImGui_ImplSDL2_Data)();
-    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_sdl2 (%u.%u.%u, %u.%u.%u) (%s)",
-        ver_compiled.major, ver_compiled.minor, ver_compiled.patch, ver_runtime.major, ver_runtime.minor, ver_runtime.patch, sdl_video_driver);
+    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_sdl2 (%u.%u.%u, %u.%u.%u)",
+        ver_compiled.major, ver_compiled.minor, ver_compiled.patch, ver_runtime.major, ver_runtime.minor, ver_runtime.patch);
     io.BackendPlatformUserData = (void*)bd;
     io.BackendPlatformName = bd->BackendPlatformName;
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;            // We can honor io.WantSetMousePos requests (optional, rarely used)
+    // (ImGuiBackendFlags_PlatformHasViewports may be set just below)
 
     bd->Window = window;
     bd->WindowID = SDL_GetWindowID(window);
     bd->Renderer = renderer;
-    bd->IsWayland = strcmp(sdl_video_driver, "Wayland") == 0;
 
     // Check and store if we are on a SDL backend that supports SDL_GetGlobalMouseState() and SDL_CaptureMouse()
     // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
     bd->MouseCanUseGlobalState = false;
     bd->MouseCaptureMode = ImGui_ImplSDL2_MouseCaptureMode_Disabled;
 #if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+    const char* sdl_backend = SDL_GetCurrentVideoDriver();
     const char* capture_and_global_state_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
     for (const char* item : capture_and_global_state_whitelist)
-        if (strncmp(sdl_video_driver, item, strlen(item)) == 0)
+        if (strncmp(sdl_backend, item, strlen(item)) == 0)
         {
             bd->MouseCanUseGlobalState = true;
             bd->MouseCaptureMode = (strcmp(item, "x11") == 0) ? ImGui_ImplSDL2_MouseCaptureMode_EnabledAfterDrag : ImGui_ImplSDL2_MouseCaptureMode_Enabled;
         }
 #endif
+    if (bd->MouseCanUseGlobalState)
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
+
+    // SDL on Linux/OSX doesn't report events for unfocused windows (see https://github.com/ocornut/imgui/issues/4960)
+    // We will use 'MouseCanReportHoveredViewport' to set 'ImGuiBackendFlags_HasMouseHoveredViewport' dynamically each frame.
+#ifndef __APPLE__
+    bd->MouseCanReportHoveredViewport = bd->MouseCanUseGlobalState;
+#else
+    bd->MouseCanReportHoveredViewport = false;
+#endif
 
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Platform_SetClipboardTextFn = ImGui_ImplSDL2_SetClipboardText;
@@ -541,6 +601,9 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void
     platform_io.Platform_OpenInShellFn = [](ImGuiContext*, const char* url) { return SDL_OpenURL(url) == 0; };
 #endif
 
+    // Update monitor a first time during init
+    ImGui_ImplSDL2_UpdateMonitors();
+
     // Gamepad handling
     bd->GamepadMode = ImGui_ImplSDL2_GamepadMode_AutoFirst;
     bd->WantUpdateGamepadsList = true;
@@ -595,7 +658,11 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
 #endif
 
-    (void)sdl_gl_context; // Unused in 'master' branch.
+    // We need SDL_CaptureMouse(), SDL_GetGlobalMouseState() from SDL 2.0.4+ to support multiple viewports.
+    // We left the call to ImGui_ImplSDL2_InitMultiViewportSupport() outside of #ifdef to avoid unused-function warnings.
+    if (io.BackendFlags & ImGuiBackendFlags_PlatformHasViewports)
+        ImGui_ImplSDL2_InitMultiViewportSupport(window, sdl_gl_context);
+
     return true;
 }
 
@@ -609,7 +676,11 @@ bool ImGui_ImplSDL2_InitForVulkan(SDL_Window* window)
 #if !SDL_HAS_VULKAN
     IM_ASSERT(0 && "Unsupported");
 #endif
-    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
+    if (!ImGui_ImplSDL2_Init(window, nullptr, nullptr))
+        return false;
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    bd->UseVulkan = true;
+    return true;
 }
 
 bool ImGui_ImplSDL2_InitForD3D(SDL_Window* window)
@@ -644,6 +715,7 @@ void ImGui_ImplSDL2_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ImGui_ImplSDL2_ShutdownMultiViewportSupport();
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -652,7 +724,7 @@ void ImGui_ImplSDL2_Shutdown()
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport);
     platform_io.ClearPlatformHandlers();
     IM_DELETE(bd);
 }
@@ -665,6 +737,7 @@ void ImGui_ImplSDL2_SetMouseCaptureMode(ImGui_ImplSDL2_MouseCaptureMode mode)
     bd->MouseCaptureMode = mode;
 }
 
+// This code is rather messy because some of the functions we need for full viewport support are not available in SDL < 2.0.4.
 static void ImGui_ImplSDL2_UpdateMouseData()
 {
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
@@ -688,16 +761,24 @@ static void ImGui_ImplSDL2_UpdateMouseData()
     }
 
     SDL_Window* focused_window = SDL_GetKeyboardFocus();
-    const bool is_app_focused = (bd->Window == focused_window);
+    const bool is_app_focused = (focused_window && (bd->Window == focused_window || ImGui_ImplSDL2_GetViewportForWindowID(SDL_GetWindowID(focused_window)) != NULL));
 #else
     SDL_Window* focused_window = bd->Window;
     const bool is_app_focused = (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0; // SDL 2.0.3 and non-windowed systems: single-viewport only
 #endif
+
     if (is_app_focused)
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
         if (io.WantSetMousePos)
-            SDL_WarpMouseInWindow(bd->Window, (int)io.MousePos.x, (int)io.MousePos.y);
+        {
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                SDL_WarpMouseGlobal((int)io.MousePos.x, (int)io.MousePos.y);
+            else
+#endif
+                SDL_WarpMouseInWindow(bd->Window, (int)io.MousePos.x, (int)io.MousePos.y);
+        }
 
         // (Optional) Fallback to provide unclamped mouse position when focused but not hovered (SDL_MOUSEMOTION already provides this when hovered or captured)
         // Note that SDL_GetGlobalMouseState() is in theory slow on X11, but this only runs on rather specific cases. If a problem we may provide a way to opt-out this feature.
@@ -706,15 +787,34 @@ static void ImGui_ImplSDL2_UpdateMouseData()
         if (hovered_window == nullptr && bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0 && !is_relative_mouse_mode)
         {
             // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
             int mouse_x, mouse_y;
             int window_x, window_y;
             SDL_GetGlobalMouseState(&mouse_x, &mouse_y);
-            SDL_GetWindowPosition(focused_window, &window_x, &window_y);
-            mouse_x -= window_x;
-            mouse_y -= window_y;
+            if (!(io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable))
+            {
+                SDL_GetWindowPosition(focused_window, &window_x, &window_y);
+                mouse_x -= window_x;
+                mouse_y -= window_y;
+            }
             io.AddMousePosEvent((float)mouse_x, (float)mouse_y);
         }
     }
+
+    // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+    // - [!] SDL backend does NOT correctly ignore viewports with the _NoInputs flag.
+    //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+    //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+    //       by the backend, and use its flawed heuristic to guess the viewport behind.
+    // - [X] SDL backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+    if (io.BackendFlags & ImGuiBackendFlags_HasMouseHoveredViewport)
+    {
+        ImGuiID mouse_viewport_id = 0;
+        if (ImGuiViewport* mouse_viewport = ImGui_ImplSDL2_GetViewportForWindowID(bd->MouseWindowID))
+            mouse_viewport_id = mouse_viewport->ID;
+        io.AddMouseViewportEvent(mouse_viewport_id);
+    }
 }
 
 static void ImGui_ImplSDL2_UpdateMouseCursor()
@@ -751,7 +851,6 @@ float ImGui_ImplSDL2_GetContentScaleForWindow(SDL_Window* window)
     return ImGui_ImplSDL2_GetContentScaleForDisplay(SDL_GetWindowDisplayIndex(window));
 }
 
-// SDL_GetDisplayDPI() seems rather unreliable on Linux.
 float ImGui_ImplSDL2_GetContentScaleForDisplay(int display_index)
 {
     const char* sdl_driver = SDL_GetCurrentVideoDriver();
@@ -761,11 +860,7 @@ float ImGui_ImplSDL2_GetContentScaleForDisplay(int display_index)
 #if !defined(__APPLE__) && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__)
     float dpi = 0.0f;
     if (SDL_GetDisplayDPI(display_index, &dpi, nullptr, nullptr) == 0)
-    {
-        if (dpi < 96.0f)
-            dpi = 96.0f;
         return dpi / 96.0f;
-    }
 #endif
 #endif
     IM_UNUSED(display_index);
@@ -874,6 +969,38 @@ static void ImGui_ImplSDL2_UpdateGamepads()
     ImGui_ImplSDL2_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickDown,  SDL_CONTROLLER_AXIS_RIGHTY, +thumb_dead_zone, +32767);
 }
 
+// FIXME: Note that doesn't update with DPI/Scaling change only as SDL2 doesn't have an event for it (SDL3 has).
+static void ImGui_ImplSDL2_UpdateMonitors()
+{
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
+    bd->WantUpdateMonitors = false;
+    int display_count = SDL_GetNumVideoDisplays();
+    for (int n = 0; n < display_count; n++)
+    {
+        // Warning: the validity of monitor DPI information on Windows depends on the application DPI awareness settings, which generally needs to be set in the manifest or at runtime.
+        ImGuiPlatformMonitor monitor;
+        SDL_Rect r;
+        SDL_GetDisplayBounds(n, &r);
+        monitor.MainPos = monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+        monitor.MainSize = monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+#if SDL_HAS_USABLE_DISPLAY_BOUNDS
+        if (SDL_GetDisplayUsableBounds(n, &r) == 0 && r.w > 0 && r.h > 0)
+        {
+            monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+            monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        }
+#endif
+        float dpi_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(n);
+        if (dpi_scale <= 0.0f)
+            continue; // Some accessibility applications are declaring virtual monitors with a DPI of 0, see #7902.
+        monitor.DpiScale = dpi_scale;
+        monitor.PlatformHandle = (void*)(intptr_t)n;
+        platform_io.Monitors.push_back(monitor);
+    }
+}
+
 static void ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(SDL_Window* window, SDL_Renderer* renderer, ImVec2* out_size, ImVec2* out_framebuffer_scale)
 {
     int w, h;
@@ -892,7 +1019,7 @@ static void ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(SDL_Window* window,
     if (out_size != nullptr)
         *out_size = ImVec2((float)w, (float)h);
     if (out_framebuffer_scale != nullptr)
-        *out_framebuffer_scale = (w > 0 && h > 0) ? ImVec2((float)display_w / (float)w, (float)display_h / (float)h) : ImVec2(1.0f, 1.0f);
+        *out_framebuffer_scale = (w > 0 && h > 0) ? ImVec2((float)display_w / w, (float)display_h / h) : ImVec2(1.0f, 1.0f);
 }
 
 void ImGui_ImplSDL2_NewFrame()
@@ -904,13 +1031,20 @@ void ImGui_ImplSDL2_NewFrame()
     // Setup main viewport size (every frame to accommodate for window resizing)
     ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(bd->Window, bd->Renderer, &io.DisplaySize, &io.DisplayFramebufferScale);
 
+    // Update monitors
+#ifdef WIN32
+    bd->WantUpdateMonitors = true; // Keep polling under Windows to handle changes of work area when resizing task-bar (#8415)
+#endif
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplSDL2_UpdateMonitors();
+
     // Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
     // (Accept SDL_GetPerformanceCounter() not returning a monotonically increasing value. Happens in VMs and Emscripten, see #6189, #6114, #3644)
     static Uint64 frequency = SDL_GetPerformanceFrequency();
     Uint64 current_time = SDL_GetPerformanceCounter();
     if (current_time <= bd->Time)
         current_time = bd->Time + 1;
-    io.DeltaTime = bd->Time > 0 ? (float)((double)(current_time - bd->Time) / (double)frequency) : (float)(1.0f / 60.0f);
+    io.DeltaTime = bd->Time > 0 ? (float)((double)(current_time - bd->Time) / frequency) : (float)(1.0f / 60.0f);
     bd->Time = current_time;
 
     if (bd->MouseLastLeaveFrame && bd->MouseLastLeaveFrame >= ImGui::GetFrameCount() && bd->MouseButtonsDown == 0)
@@ -920,6 +1054,13 @@ void ImGui_ImplSDL2_NewFrame()
         io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
     }
 
+    // Our io.AddMouseViewportEvent() calls will only be valid when not capturing.
+    // Technically speaking testing for 'bd->MouseButtonsDown == 0' would be more rigorous, but testing for payload reduces noise and potential side-effects.
+    if (bd->MouseCanReportHoveredViewport && ImGui::GetDragDropPayload() == nullptr)
+        io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport;
+    else
+        io.BackendFlags &= ~ImGuiBackendFlags_HasMouseHoveredViewport;
+
     ImGui_ImplSDL2_UpdateMouseData();
     ImGui_ImplSDL2_UpdateMouseCursor();
 
@@ -927,6 +1068,266 @@ void ImGui_ImplSDL2_NewFrame()
     ImGui_ImplSDL2_UpdateGamepads();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplSDL2_ViewportData
+{
+    SDL_Window*     Window;
+    Uint32          WindowID;       // Stored in ImGuiViewport::PlatformHandle. Use SDL_GetWindowFromID() to get SDL_Window* from Uint32 WindowID.
+    bool            WindowOwned;
+    SDL_GLContext   GLContext;
+
+    ImGui_ImplSDL2_ViewportData()   { Window = nullptr; WindowID = 0; WindowOwned = false; GLContext = nullptr; }
+    ~ImGui_ImplSDL2_ViewportData()  { IM_ASSERT(Window == nullptr && GLContext == nullptr); }
+};
+
+static void ImGui_ImplSDL2_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    ImGui_ImplSDL2_ViewportData* vd = IM_NEW(ImGui_ImplSDL2_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL2_ViewportData* main_viewport_data = (ImGui_ImplSDL2_ViewportData*)main_viewport->PlatformUserData;
+
+    // Share GL resources with main context
+    bool use_opengl = (main_viewport_data->GLContext != nullptr);
+    SDL_GLContext backup_context = nullptr;
+    if (use_opengl)
+    {
+        backup_context = SDL_GL_GetCurrentContext();
+        SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
+        SDL_GL_MakeCurrent(main_viewport_data->Window, main_viewport_data->GLContext);
+    }
+
+    Uint32 sdl_flags = 0;
+    sdl_flags |= use_opengl ? SDL_WINDOW_OPENGL : (bd->UseVulkan ? SDL_WINDOW_VULKAN : 0);
+    sdl_flags |= SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_ALLOW_HIGHDPI;
+    sdl_flags |= SDL_WINDOW_HIDDEN;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? SDL_WINDOW_BORDERLESS : 0;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? 0 : SDL_WINDOW_RESIZABLE;
+#if !defined(_WIN32)
+    // See SDL hack in ImGui_ImplSDL2_ShowWindow().
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) ? SDL_WINDOW_SKIP_TASKBAR : 0;
+#endif
+#if SDL_HAS_ALWAYS_ON_TOP
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_TopMost) ? SDL_WINDOW_ALWAYS_ON_TOP : 0;
+#endif
+    vd->Window = SDL_CreateWindow("No Title Yet", (int)viewport->Pos.x, (int)viewport->Pos.y, (int)viewport->Size.x, (int)viewport->Size.y, sdl_flags);
+    vd->WindowOwned = true;
+    if (use_opengl)
+    {
+        vd->GLContext = SDL_GL_CreateContext(vd->Window);
+        SDL_GL_SetSwapInterval(0);
+    }
+    if (use_opengl && backup_context)
+        SDL_GL_MakeCurrent(vd->Window, backup_context);
+
+    viewport->PlatformHandle = (void*)(intptr_t)SDL_GetWindowID(vd->Window);
+    viewport->PlatformHandleRaw = nullptr;
+    SDL_SysWMinfo info;
+    SDL_VERSION(&info.version);
+    if (SDL_GetWindowWMInfo(vd->Window, &info))
+    {
+#if defined(SDL_VIDEO_DRIVER_WINDOWS)
+        viewport->PlatformHandleRaw = info.info.win.window;
+#elif defined(__APPLE__) && defined(SDL_VIDEO_DRIVER_COCOA)
+        viewport->PlatformHandleRaw = (void*)info.info.cocoa.window;
+#endif
+    }
+}
+
+static void ImGui_ImplSDL2_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData)
+    {
+        if (vd->GLContext && vd->WindowOwned)
+            SDL_GL_DeleteContext(vd->GLContext);
+        if (vd->Window && vd->WindowOwned)
+            SDL_DestroyWindow(vd->Window);
+        vd->GLContext = nullptr;
+        vd->Window = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplSDL2_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+#if defined(_WIN32) && !(defined(WINAPI_FAMILY) && ((defined(WINAPI_FAMILY_APP) && WINAPI_FAMILY == WINAPI_FAMILY_APP) || (defined(WINAPI_FAMILY_GAMES) && WINAPI_FAMILY == WINAPI_FAMILY_GAMES)))
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+
+    // SDL hack: Hide icon from task bar
+    // Note: SDL 2.0.6+ has a SDL_WINDOW_SKIP_TASKBAR flag which is supported under Windows but the way it create the window breaks our seamless transition.
+    if (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon)
+    {
+        LONG ex_style = ::GetWindowLong(hwnd, GWL_EXSTYLE);
+        ex_style &= ~WS_EX_APPWINDOW;
+        ex_style |= WS_EX_TOOLWINDOW;
+        ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
+    }
+#endif
+
+#if SDL_HAS_SHOW_WINDOW_ACTIVATION_HINT
+    SDL_SetHint(SDL_HINT_WINDOW_NO_ACTIVATION_WHEN_SHOWN, (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing) ? "1" : "0");
+#elif defined(_WIN32)
+    // SDL hack: SDL always activate/focus windows :/
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+    {
+        ::ShowWindow(hwnd, SW_SHOWNA);
+        return;
+    }
+#endif
+    SDL_ShowWindow(vd->Window);
+}
+
+static ImVec2 ImGui_ImplSDL2_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    int x = 0, y = 0;
+    SDL_GetWindowPosition(vd->Window, &x, &y);
+    return ImVec2((float)x, (float)y);
+}
+
+static void ImGui_ImplSDL2_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowPosition(vd->Window, (int)pos.x, (int)pos.y);
+}
+
+static ImVec2 ImGui_ImplSDL2_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    int w = 0, h = 0;
+    SDL_GetWindowSize(vd->Window, &w, &h);
+    return ImVec2((float)w, (float)h);
+}
+
+static void ImGui_ImplSDL2_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowSize(vd->Window, (int)size.x, (int)size.y);
+}
+
+static ImVec2 ImGui_ImplSDL2_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    // FIXME: SDL_Renderer does not support multi-viewport.
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    ImVec2 framebuffer_scale;
+    ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(vd->Window, nullptr, nullptr, &framebuffer_scale);
+    return framebuffer_scale;
+}
+
+static void ImGui_ImplSDL2_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowTitle(vd->Window, title);
+}
+
+#if SDL_HAS_WINDOW_ALPHA
+static void ImGui_ImplSDL2_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowOpacity(vd->Window, alpha);
+}
+#endif
+
+static void ImGui_ImplSDL2_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_RaiseWindow(vd->Window);
+}
+
+static bool ImGui_ImplSDL2_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0;
+}
+
+static bool ImGui_ImplSDL2_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_MINIMIZED) != 0;
+}
+
+static void ImGui_ImplSDL2_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+}
+
+static void ImGui_ImplSDL2_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+    {
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+        SDL_GL_SwapWindow(vd->Window);
+    }
+}
+
+// Vulkan support (the Vulkan renderer needs to call a platform-side support function to create the surface)
+// SDL is graceful enough to _not_ need <vulkan/vulkan.h> so we can safely include this.
+#if SDL_HAS_VULKAN
+#include <SDL_vulkan.h>
+static int ImGui_ImplSDL2_CreateVkSurface(ImGuiViewport* viewport, ImU64 vk_instance, const void* vk_allocator, ImU64* out_vk_surface)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    (void)vk_allocator;
+    SDL_bool ret = SDL_Vulkan_CreateSurface(vd->Window, (VkInstance)vk_instance, (VkSurfaceKHR*)out_vk_surface);
+    return ret ? 0 : 1; // ret ? VK_SUCCESS : VK_NOT_READY
+}
+#endif // SDL_HAS_VULKAN
+
+static void ImGui_ImplSDL2_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context)
+{
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplSDL2_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplSDL2_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplSDL2_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplSDL2_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplSDL2_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplSDL2_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplSDL2_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplSDL2_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplSDL2_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplSDL2_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplSDL2_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplSDL2_SetWindowTitle;
+    platform_io.Platform_RenderWindow = ImGui_ImplSDL2_RenderWindow;
+    platform_io.Platform_SwapBuffers = ImGui_ImplSDL2_SwapBuffers;
+#if SDL_HAS_WINDOW_ALPHA
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplSDL2_SetWindowAlpha;
+#endif
+#if SDL_HAS_VULKAN
+    platform_io.Platform_CreateVkSurface = ImGui_ImplSDL2_CreateVkSurface;
+#endif
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL2_ViewportData* vd = IM_NEW(ImGui_ImplSDL2_ViewportData)();
+    vd->Window = window;
+    vd->WindowID = SDL_GetWindowID(window);
+    vd->WindowOwned = false;
+    vd->GLContext = sdl_gl_context;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (void*)(intptr_t)vd->WindowID;
+}
+
+static void ImGui_ImplSDL2_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdl2.h

@@ -9,6 +9,10 @@
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: Basic IME support. App needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [ ] Platform: Multi-viewport: Missing ImGuiBackendFlags_HasParentViewport support. The viewport->ParentViewportID field is ignored, and therefore io.ConfigViewportsNoDefaultParent has no effect either.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_sdl3.cpp

@@ -8,7 +8,10 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-//  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [x] Platform: IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -20,6 +23,9 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2026-03-25: [Docking] Use SDL_HAS_EVENT_DISPLAY_USABLE_BOUNDS_CHANGED (SDL 3.4.0+) when available to avoid refreshing monitor work area every frame on Windows. (#8415)
+//  2026-03-09: [Docking] Fixed an issue dated 2025/04/09 (1.92 WIP) where a refactor+merge caused ImGuiBackendFlags_HasMouseHoveredViewport to never be set, causing foreign windows to be ignored when deciding of hovered viewport. (#9284)
 //  2026-02-13: Inputs: systems other than X11 are back to starting mouse capture on mouse down (reverts 2025-02-26 change). Only X11 requires waiting for a drag by default (not ideal, but a better default for X11 users). Added ImGui_ImplSDL3_SetMouseCaptureMode() for X11 debugger users. (#3650, #6410, #9235)
 //  2026-01-15: Changed GetClipboardText() handler to return nullptr on error aka clipboard contents is not text. Consistent with other backends. (#9168)
 //  2025-11-05: Fixed an issue with missing characters events when an already active text field changes viewports. (#9054)
@@ -28,17 +34,23 @@
 //  2025-09-18: Call platform_io.ClearPlatformHandlers() on shutdown.
 //  2025-09-15: Use SDL_GetWindowDisplayScale() on Mac to output DisplayFrameBufferScale. The function is more reliable during resolution changes e.g. going fullscreen. (#8703, #4414)
 //  2025-06-27: IME: avoid calling SDL_StartTextInput() again if already active. (#8727)
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
+//  2025-05-06: [Docking] macOS: fixed secondary viewports not appearing on other monitors before of parenting.
+//  2025-04-09: [Docking] Revert update monitors and work areas information every frame. Only do it on Windows. (#8415, #8558)
 //  2025-04-22: IME: honor ImGuiPlatformImeData->WantTextInput as an alternative way to call SDL_StartTextInput(), without IME being necessarily visible.
 //  2025-04-09: Don't attempt to call SDL_CaptureMouse() on drivers where we don't call SDL_GetGlobalMouseState(). (#8561)
 //  2025-03-30: Update for SDL3 api changes: Revert SDL_GetClipboardText() memory ownership change. (#8530, #7801)
 //  2025-03-21: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad regardless of ImGuiConfigFlags_NavEnableGamepad being set.
 //  2025-03-10: When dealing with OEM keys, use scancodes instead of translated keycodes to choose ImGuiKey values. (#7136, #7201, #7206, #7306, #7670, #7672, #8468)
 //  2025-02-26: Only start SDL_CaptureMouse() when mouse is being dragged, to mitigate issues with e.g. Linux debuggers not claiming capture back. (#6410, #3650)
+//  2025-02-25: [Docking] Revert to use SDL_GetDisplayBounds() for WorkPos/WorkRect if SDL_GetDisplayUsableBounds() failed.
 //  2025-02-24: Avoid calling SDL_GetGlobalMouseState() when mouse is in relative mode.
+//  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
 //  2025-01-20: Made ImGui_ImplSDL3_SetGamepadMode(ImGui_ImplSDL3_GamepadMode_Manual) accept an empty array.
 //  2024-10-24: Emscripten: SDL_EVENT_MOUSE_WHEEL event doesn't require dividing by 100.0f on Emscripten.
+//  2024-09-11: (Docking) Added support for viewport->ParentViewportId field to support parenting at OS level. (#7973)
 //  2024-09-03: Update for SDL3 api changes: SDL_GetGamepads() memory ownership revert. (#7918, #7898, #7807)
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
 //               - io.GetClipboardTextFn    -> platform_io.Platform_GetClipboardTextFn
@@ -94,6 +106,7 @@
 #else
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    0
 #endif
+#define SDL_HAS_EVENT_DISPLAY_USABLE_BOUNDS_CHANGED     SDL_VERSION_ATLEAST(3,4,0)
 
 // FIXME-LEGACY: remove when SDL 3.1.3 preview is released.
 #ifndef SDLK_APOSTROPHE
@@ -111,8 +124,9 @@ struct ImGui_ImplSDL3_Data
     SDL_Renderer*           Renderer;
     Uint64                  Time;
     char*                   ClipboardTextData;
-    char                    BackendPlatformName[64];
-    bool                    IsWayland;
+    char                    BackendPlatformName[48];
+    bool                    UseVulkan;
+    bool                    WantUpdateMonitors;
 
     // IME handling
     SDL_Window*             ImeWindow;
@@ -126,12 +140,13 @@ struct ImGui_ImplSDL3_Data
     SDL_Cursor*             MouseLastCursor;
     int                     MousePendingLeaveFrame;
     bool                    MouseCanUseGlobalState;
+    bool                    MouseCanReportHoveredViewport;  // This is hard to use/unreliable on SDL so we'll set ImGuiBackendFlags_HasMouseHoveredViewport dynamically based on state.
     ImGui_ImplSDL3_MouseCaptureMode MouseCaptureMode;
 
     // Gamepad handling
-    ImVector<SDL_Gamepad*>      Gamepads;
+    ImVector<SDL_Gamepad*>  Gamepads;
     ImGui_ImplSDL3_GamepadMode  GamepadMode;
-    bool                        WantUpdateGamepadsList;
+    bool                    WantUpdateGamepadsList;
 
     ImGui_ImplSDL3_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
@@ -147,6 +162,9 @@ static ImGui_ImplSDL3_Data* ImGui_ImplSDL3_GetBackendData()
 
 // Forward Declarations
 static void ImGui_ImplSDL3_UpdateIme();
+static void ImGui_ImplSDL3_UpdateMonitors();
+static void ImGui_ImplSDL3_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context);
+static void ImGui_ImplSDL3_ShutdownMultiViewportSupport();
 
 // Functions
 static const char* ImGui_ImplSDL3_GetClipboardText(ImGuiContext*)
@@ -168,8 +186,7 @@ static void ImGui_ImplSDL3_SetClipboardText(ImGuiContext*, const char* text)
 
 static ImGuiViewport* ImGui_ImplSDL3_GetViewportForWindowID(SDL_WindowID window_id)
 {
-    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
-    return (window_id == bd->WindowID) ? ImGui::GetMainViewport() : nullptr;
+    return ImGui::FindViewportByPlatformHandle((void*)(intptr_t)window_id);
 }
 
 static void ImGui_ImplSDL3_PlatformSetImeData(ImGuiContext*, ImGuiViewport*, ImGuiPlatformImeData* data)
@@ -200,9 +217,12 @@ static void ImGui_ImplSDL3_UpdateIme()
     bd->ImeDirty = false;
     if (data->WantVisible)
     {
+        ImVec2 viewport_pos;
+        if (ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(SDL_GetWindowID(window)))
+            viewport_pos = viewport->Pos;
         SDL_Rect r;
-        r.x = (int)data->InputPos.x;
-        r.y = (int)data->InputPos.y;
+        r.x = (int)(data->InputPos.x - viewport_pos.x);
+        r.y = (int)(data->InputPos.y - viewport_pos.y);
         r.w = 1;
         r.h = (int)data->InputLineHeight;
         SDL_SetTextInputArea(window, &r, 0);
@@ -391,6 +411,13 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
             if (ImGui_ImplSDL3_GetViewportForWindowID(event->motion.windowID) == nullptr)
                 return false;
             ImVec2 mouse_pos((float)event->motion.x, (float)event->motion.y);
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                int window_x, window_y;
+                SDL_GetWindowPosition(SDL_GetWindowFromID(event->motion.windowID), &window_x, &window_y);
+                mouse_pos.x += window_x;
+                mouse_pos.y += window_y;
+            }
             io.AddMouseSourceEvent(event->motion.which == SDL_TOUCH_MOUSEID ? ImGuiMouseSource_TouchScreen : ImGuiMouseSource_Mouse);
             io.AddMousePosEvent(mouse_pos.x, mouse_pos.y);
             return true;
@@ -434,16 +461,29 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
         case SDL_EVENT_KEY_DOWN:
         case SDL_EVENT_KEY_UP:
         {
-            if (ImGui_ImplSDL3_GetViewportForWindowID(event->key.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(event->key.windowID);
+            if (viewport == nullptr)
                 return false;
+            //IMGUI_DEBUG_LOG("SDL_EVENT_KEY_%s : key=0x%08X ('%s'), scancode=%d ('%s'), mod=%X, windowID=%d, viewport=%08X\n",
+            //    (event->type == SDL_EVENT_KEY_DOWN) ? "DOWN" : "UP  ", event->key.key, SDL_GetKeyName(event->key.key), event->key.scancode, SDL_GetScancodeName(event->key.scancode), event->key.mod, event->key.windowID, viewport ? viewport->ID : 0);
             ImGui_ImplSDL3_UpdateKeyModifiers((SDL_Keymod)event->key.mod);
-            //IMGUI_DEBUG_LOG("SDL_EVENT_KEY_%s : key=%d ('%s'), scancode=%d ('%s'), mod=%X\n",
-            //    (event->type == SDL_EVENT_KEY_DOWN) ? "DOWN" : "UP  ", event->key.key, SDL_GetKeyName(event->key.key), event->key.scancode, SDL_GetScancodeName(event->key.scancode), event->key.mod);
             ImGuiKey key = ImGui_ImplSDL3_KeyEventToImGuiKey(event->key.key, event->key.scancode);
             io.AddKeyEvent(key, (event->type == SDL_EVENT_KEY_DOWN));
             io.SetKeyEventNativeData(key, (int)event->key.key, (int)event->key.scancode, (int)event->key.scancode); // To support legacy indexing (<1.87 user code). Legacy backend uses SDLK_*** as indices to IsKeyXXX() functions.
             return true;
         }
+        case SDL_EVENT_DISPLAY_ORIENTATION:
+        case SDL_EVENT_DISPLAY_ADDED:
+        case SDL_EVENT_DISPLAY_REMOVED:
+        case SDL_EVENT_DISPLAY_MOVED:
+        case SDL_EVENT_DISPLAY_CONTENT_SCALE_CHANGED:
+#if SDL_HAS_EVENT_DISPLAY_USABLE_BOUNDS_CHANGED
+        case SDL_EVENT_DISPLAY_USABLE_BOUNDS_CHANGED:
+#endif
+        {
+            bd->WantUpdateMonitors = true;
+            return true;
+        }
         case SDL_EVENT_WINDOW_MOUSE_ENTER:
         {
             if (ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID) == nullptr)
@@ -466,11 +506,28 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
         case SDL_EVENT_WINDOW_FOCUS_GAINED:
         case SDL_EVENT_WINDOW_FOCUS_LOST:
         {
-            if (ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID);
+            if (viewport == nullptr)
                 return false;
+            //IMGUI_DEBUG_LOG("%s: windowId %d, viewport: %08X\n", (event->type == SDL_EVENT_WINDOW_FOCUS_GAINED) ? "SDL_EVENT_WINDOW_FOCUS_GAINED" : "SDL_WINDOWEVENT_FOCUS_LOST", event->window.windowID, viewport ? viewport->ID : 0);
             io.AddFocusEvent(event->type == SDL_EVENT_WINDOW_FOCUS_GAINED);
             return true;
         }
+        case SDL_EVENT_WINDOW_CLOSE_REQUESTED:
+        case SDL_EVENT_WINDOW_MOVED:
+        case SDL_EVENT_WINDOW_RESIZED:
+        {
+            ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID);
+            if (viewport == NULL)
+                return false;
+            if (event->type == SDL_EVENT_WINDOW_CLOSE_REQUESTED)
+                viewport->PlatformRequestClose = true;
+            if (event->type == SDL_EVENT_WINDOW_MOVED)
+                viewport->PlatformRequestMove = true;
+            if (event->type == SDL_EVENT_WINDOW_RESIZED)
+                viewport->PlatformRequestResize = true;
+            return true;
+        }
         case SDL_EVENT_GAMEPAD_ADDED:
         case SDL_EVENT_GAMEPAD_REMOVED:
         {
@@ -503,36 +560,49 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     //SDL_SetHint(SDL_HINT_EVENT_LOGGING, "2");
 
     const int ver_linked = SDL_GetVersion();
-    const char* sdl_video_driver = SDL_GetCurrentVideoDriver();
 
     // Setup backend capabilities flags
     ImGui_ImplSDL3_Data* bd = IM_NEW(ImGui_ImplSDL3_Data)();
-    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_sdl3 (%d.%d.%d; %d.%d.%d) (%s)",
-        SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_MICRO_VERSION, SDL_VERSIONNUM_MAJOR(ver_linked), SDL_VERSIONNUM_MINOR(ver_linked), SDL_VERSIONNUM_MICRO(ver_linked),
-        sdl_video_driver);
+    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_sdl3 (%d.%d.%d; %d.%d.%d)",
+        SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_MICRO_VERSION, SDL_VERSIONNUM_MAJOR(ver_linked), SDL_VERSIONNUM_MINOR(ver_linked), SDL_VERSIONNUM_MICRO(ver_linked));
     io.BackendPlatformUserData = (void*)bd;
     io.BackendPlatformName = bd->BackendPlatformName;
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;            // We can honor io.WantSetMousePos requests (optional, rarely used)
+    // (ImGuiBackendFlags_PlatformHasViewports and ImGuiBackendFlags_HasParentViewport may be set just below)
+    // (ImGuiBackendFlags_HasMouseHoveredViewport is set dynamically in our _NewFrame function)
 
     bd->Window = window;
     bd->WindowID = SDL_GetWindowID(window);
     bd->Renderer = renderer;
-    bd->IsWayland = strcmp(sdl_video_driver, "wayland") == 0;
 
     // Check and store if we are on a SDL backend that supports SDL_GetGlobalMouseState() and SDL_CaptureMouse()
     // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
     bd->MouseCanUseGlobalState = false;
     bd->MouseCaptureMode = ImGui_ImplSDL3_MouseCaptureMode_Disabled;
 #if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+    const char* sdl_backend = SDL_GetCurrentVideoDriver();
     const char* capture_and_global_state_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
     for (const char* item : capture_and_global_state_whitelist)
-        if (strncmp(sdl_video_driver, item, strlen(item)) == 0)
+        if (strncmp(sdl_backend, item, strlen(item)) == 0)
         {
             bd->MouseCanUseGlobalState = true;
             bd->MouseCaptureMode = (strcmp(item, "x11") == 0) ? ImGui_ImplSDL3_MouseCaptureMode_EnabledAfterDrag : ImGui_ImplSDL3_MouseCaptureMode_Enabled;
         }
 #endif
+    if (bd->MouseCanUseGlobalState)
+    {
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
+        io.BackendFlags |= ImGuiBackendFlags_HasParentViewport;     // We can honor viewport->ParentViewportId by applying the corresponding parent/child relationship at platform level (optional)
+    }
+
+    // SDL on Linux/OSX doesn't report events for unfocused windows (see https://github.com/ocornut/imgui/issues/4960)
+    // We will use 'MouseCanReportHoveredViewport' to set 'ImGuiBackendFlags_HasMouseHoveredViewport' dynamically each frame.
+#ifndef __APPLE__
+    bd->MouseCanReportHoveredViewport = bd->MouseCanUseGlobalState;
+#else
+    bd->MouseCanReportHoveredViewport = false;
+#endif
 
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Platform_SetClipboardTextFn = ImGui_ImplSDL3_SetClipboardText;
@@ -540,6 +610,9 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     platform_io.Platform_SetImeDataFn = ImGui_ImplSDL3_PlatformSetImeData;
     platform_io.Platform_OpenInShellFn = [](ImGuiContext*, const char* url) { return SDL_OpenURL(url); };
 
+    // Update monitor a first time during init
+    ImGui_ImplSDL3_UpdateMonitors();
+
     // Gamepad handling
     bd->GamepadMode = ImGui_ImplSDL3_GamepadMode_AutoFirst;
     bd->WantUpdateGamepadsList = true;
@@ -572,6 +645,14 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     // From 2.0.22: Disable auto-capture, this is preventing drag and drop across multiple windows (see #5710)
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
 
+    // SDL 3.x : see https://github.com/libsdl-org/SDL/issues/6659
+    SDL_SetHint("SDL_BORDERLESS_WINDOWED_STYLE", "0");
+
+    // We need SDL_CaptureMouse(), SDL_GetGlobalMouseState() from SDL 2.0.4+ to support multiple viewports.
+    // We left the call to ImGui_ImplSDL3_InitPlatformInterface() outside of #ifdef to avoid unused-function warnings.
+    if (io.BackendFlags & ImGuiBackendFlags_PlatformHasViewports)
+        ImGui_ImplSDL3_InitMultiViewportSupport(window, sdl_gl_context);
+
     return true;
 }
 
@@ -583,7 +664,11 @@ bool ImGui_ImplSDL3_InitForOpenGL(SDL_Window* window, void* sdl_gl_context)
 
 bool ImGui_ImplSDL3_InitForVulkan(SDL_Window* window)
 {
-    return ImGui_ImplSDL3_Init(window, nullptr, nullptr);
+    if (!ImGui_ImplSDL3_Init(window, nullptr, nullptr))
+        return false;
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
+    bd->UseVulkan = true;
+    return true;
 }
 
 bool ImGui_ImplSDL3_InitForD3D(SDL_Window* window)
@@ -623,6 +708,7 @@ void ImGui_ImplSDL3_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ImGui_ImplSDL3_ShutdownMultiViewportSupport();
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -631,7 +717,7 @@ void ImGui_ImplSDL3_Shutdown()
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport | ImGuiBackendFlags_HasParentViewport);
     platform_io.ClearPlatformHandlers();
     IM_DELETE(bd);
 }
@@ -667,7 +753,7 @@ static void ImGui_ImplSDL3_UpdateMouseData()
     }
 
     SDL_Window* focused_window = SDL_GetKeyboardFocus();
-    const bool is_app_focused = (bd->Window == focused_window);
+    const bool is_app_focused = (focused_window && (bd->Window == focused_window || ImGui_ImplSDL3_GetViewportForWindowID(SDL_GetWindowID(focused_window)) != NULL));
 #else
     SDL_Window* focused_window = bd->Window;
     const bool is_app_focused = (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0; // SDL 2.0.3 and non-windowed systems: single-viewport only
@@ -676,7 +762,14 @@ static void ImGui_ImplSDL3_UpdateMouseData()
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
         if (io.WantSetMousePos)
-            SDL_WarpMouseInWindow(bd->Window, io.MousePos.x, io.MousePos.y);
+        {
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                SDL_WarpMouseGlobal(io.MousePos.x, io.MousePos.y);
+            else
+#endif
+                SDL_WarpMouseInWindow(bd->Window, io.MousePos.x, io.MousePos.y);
+        }
 
         // (Optional) Fallback to provide unclamped mouse position when focused but not hovered (SDL_EVENT_MOUSE_MOTION already provides this when hovered or captured)
         // Note that SDL_GetGlobalMouseState() is in theory slow on X11, but this only runs on rather specific cases. If a problem we may provide a way to opt-out this feature.
@@ -685,15 +778,34 @@ static void ImGui_ImplSDL3_UpdateMouseData()
         if (hovered_window == nullptr && bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0 && !is_relative_mouse_mode)
         {
             // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
             float mouse_x, mouse_y;
             int window_x, window_y;
             SDL_GetGlobalMouseState(&mouse_x, &mouse_y);
-            SDL_GetWindowPosition(focused_window, &window_x, &window_y);
-            mouse_x -= (float)window_x;
-            mouse_y -= (float)window_y;
+            if (!(io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable))
+            {
+                SDL_GetWindowPosition(focused_window, &window_x, &window_y);
+                mouse_x -= window_x;
+                mouse_y -= window_y;
+            }
             io.AddMousePosEvent(mouse_x, mouse_y);
         }
     }
+
+    // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+    // - [!] SDL backend does NOT correctly ignore viewports with the _NoInputs flag.
+    //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+    //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+    //       by the backend, and use its flawed heuristic to guess the viewport behind.
+    // - [X] SDL backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+    if (io.BackendFlags & ImGuiBackendFlags_HasMouseHoveredViewport)
+    {
+        ImGuiID mouse_viewport_id = 0;
+        if (ImGuiViewport* mouse_viewport = ImGui_ImplSDL3_GetViewportForWindowID(bd->MouseWindowID))
+            mouse_viewport_id = mouse_viewport->ID;
+        io.AddMouseViewportEvent(mouse_viewport_id);
+    }
 }
 
 static void ImGui_ImplSDL3_UpdateMouseCursor()
@@ -825,6 +937,38 @@ static void ImGui_ImplSDL3_UpdateGamepads()
     ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickDown,  SDL_GAMEPAD_AXIS_RIGHTY, +thumb_dead_zone, +32767);
 }
 
+static void ImGui_ImplSDL3_UpdateMonitors()
+{
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
+    bd->WantUpdateMonitors = false;
+
+    int display_count;
+    SDL_DisplayID* displays = SDL_GetDisplays(&display_count);
+    for (int n = 0; n < display_count; n++)
+    {
+        // Warning: the validity of monitor DPI information on Windows depends on the application DPI awareness settings, which generally needs to be set in the manifest or at runtime.
+        SDL_DisplayID display_id = displays[n];
+        ImGuiPlatformMonitor monitor;
+        SDL_Rect r;
+        SDL_GetDisplayBounds(display_id, &r);
+        monitor.MainPos = monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+        monitor.MainSize = monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        if (SDL_GetDisplayUsableBounds(display_id, &r) && r.w > 0 && r.h > 0)
+        {
+            monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+            monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        }
+        monitor.DpiScale = SDL_GetDisplayContentScale(display_id); // See https://wiki.libsdl.org/SDL3/README-highdpi for details.
+        monitor.PlatformHandle = (void*)(intptr_t)n;
+        if (monitor.DpiScale <= 0.0f)
+            continue; // Some accessibility applications are declaring virtual monitors with a DPI of 0, see #7902.
+        platform_io.Monitors.push_back(monitor);
+    }
+    SDL_free(displays);
+}
+
 static void ImGui_ImplSDL3_GetWindowSizeAndFramebufferScale(SDL_Window* window, ImVec2* out_size, ImVec2* out_framebuffer_scale)
 {
     int w, h;
@@ -857,13 +1001,20 @@ void ImGui_ImplSDL3_NewFrame()
     // Setup main viewport size (every frame to accommodate for window resizing)
     ImGui_ImplSDL3_GetWindowSizeAndFramebufferScale(bd->Window, &io.DisplaySize, &io.DisplayFramebufferScale);
 
+    // Update monitors
+#if defined(WIN32) && !SDL_HAS_EVENT_DISPLAY_USABLE_BOUNDS_CHANGED
+    bd->WantUpdateMonitors = true; // Keep polling under Windows to handle changes of work area when resizing task-bar (#8415)
+#endif
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplSDL3_UpdateMonitors();
+
     // Setup time step (we could also use SDL_GetTicksNS() available since SDL3)
     // (Accept SDL_GetPerformanceCounter() not returning a monotonically increasing value. Happens in VMs and Emscripten, see #6189, #6114, #3644)
     static Uint64 frequency = SDL_GetPerformanceFrequency();
     Uint64 current_time = SDL_GetPerformanceCounter();
     if (current_time <= bd->Time)
         current_time = bd->Time + 1;
-    io.DeltaTime = bd->Time > 0 ? (float)((double)(current_time - bd->Time) / (double)frequency) : (float)(1.0f / 60.0f);
+    io.DeltaTime = bd->Time > 0 ? (float)((double)(current_time - bd->Time) / frequency) : (float)(1.0f / 60.0f);
     bd->Time = current_time;
 
     if (bd->MousePendingLeaveFrame && bd->MousePendingLeaveFrame >= ImGui::GetFrameCount() && bd->MouseButtonsDown == 0)
@@ -873,6 +1024,13 @@ void ImGui_ImplSDL3_NewFrame()
         io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
     }
 
+    // Our io.AddMouseViewportEvent() calls will only be valid when not capturing.
+    // Technically speaking testing for 'bd->MouseButtonsDown == 0' would be more rigorous, but testing for payload reduces noise and potential side-effects.
+    if (bd->MouseCanReportHoveredViewport && ImGui::GetDragDropPayload() == nullptr)
+        io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport;
+    else
+        io.BackendFlags &= ~ImGuiBackendFlags_HasMouseHoveredViewport;
+
     ImGui_ImplSDL3_UpdateMouseData();
     ImGui_ImplSDL3_UpdateMouseCursor();
     ImGui_ImplSDL3_UpdateIme();
@@ -881,6 +1039,272 @@ void ImGui_ImplSDL3_NewFrame()
     ImGui_ImplSDL3_UpdateGamepads();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplSDL3_ViewportData
+{
+    SDL_Window*     Window;
+    SDL_Window*     ParentWindow;
+    Uint32          WindowID;       // Stored in ImGuiViewport::PlatformHandle. Use SDL_GetWindowFromID() to get SDL_Window* from Uint32 WindowID.
+    bool            WindowOwned;
+    SDL_GLContext   GLContext;
+
+    ImGui_ImplSDL3_ViewportData()   { Window = ParentWindow = nullptr; WindowID = 0; WindowOwned = false; GLContext = nullptr; }
+    ~ImGui_ImplSDL3_ViewportData()  { IM_ASSERT(Window == nullptr && GLContext == nullptr); }
+};
+
+static SDL_Window* ImGui_ImplSDL3_GetSDLWindowFromViewport(ImGuiViewport* viewport)
+{
+    if (viewport != nullptr)
+    {
+        SDL_WindowID window_id = (SDL_WindowID)(intptr_t)viewport->PlatformHandle;
+        return SDL_GetWindowFromID(window_id);
+    }
+    return nullptr;
+}
+
+static void ImGui_ImplSDL3_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
+    ImGui_ImplSDL3_ViewportData* vd = IM_NEW(ImGui_ImplSDL3_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    vd->ParentWindow = ImGui_ImplSDL3_GetSDLWindowFromViewport(viewport->ParentViewport);
+
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL3_ViewportData* main_viewport_data = (ImGui_ImplSDL3_ViewportData*)main_viewport->PlatformUserData;
+
+    // Share GL resources with main context
+    bool use_opengl = (main_viewport_data->GLContext != nullptr);
+    SDL_GLContext backup_context = nullptr;
+    if (use_opengl)
+    {
+        backup_context = SDL_GL_GetCurrentContext();
+        SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
+        SDL_GL_MakeCurrent(main_viewport_data->Window, main_viewport_data->GLContext);
+    }
+
+    SDL_WindowFlags sdl_flags = 0;
+    sdl_flags |= SDL_WINDOW_HIDDEN;
+    sdl_flags |= use_opengl ? SDL_WINDOW_OPENGL : (bd->UseVulkan ? SDL_WINDOW_VULKAN : 0);
+    sdl_flags |= SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? SDL_WINDOW_BORDERLESS : 0;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? 0 : SDL_WINDOW_RESIZABLE;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) ? SDL_WINDOW_UTILITY : 0;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_TopMost) ? SDL_WINDOW_ALWAYS_ON_TOP : 0;
+    vd->Window = SDL_CreateWindow("No Title Yet", (int)viewport->Size.x, (int)viewport->Size.y, sdl_flags);
+#ifndef __APPLE__ // On Mac, SDL3 Parenting appears to prevent viewport from appearing in another monitor
+    SDL_SetWindowParent(vd->Window, vd->ParentWindow);
+#endif
+    SDL_SetWindowPosition(vd->Window, (int)viewport->Pos.x, (int)viewport->Pos.y);
+    vd->WindowOwned = true;
+    if (use_opengl)
+    {
+        vd->GLContext = SDL_GL_CreateContext(vd->Window);
+        SDL_GL_SetSwapInterval(0);
+    }
+    if (use_opengl && backup_context)
+        SDL_GL_MakeCurrent(vd->Window, backup_context);
+
+    ImGui_ImplSDL3_SetupPlatformHandles(viewport, vd->Window);
+}
+
+static void ImGui_ImplSDL3_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData)
+    {
+        if (vd->GLContext && vd->WindowOwned)
+            SDL_GL_DestroyContext(vd->GLContext);
+        if (vd->Window && vd->WindowOwned)
+            SDL_DestroyWindow(vd->Window);
+        vd->GLContext = nullptr;
+        vd->Window = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplSDL3_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+#if defined(_WIN32) && !(defined(WINAPI_FAMILY) && ((defined(WINAPI_FAMILY_APP) && WINAPI_FAMILY == WINAPI_FAMILY_APP) || (defined(WINAPI_FAMILY_GAMES) && WINAPI_FAMILY == WINAPI_FAMILY_GAMES)))
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+
+    // SDL hack: Show icon in task bar (#7989)
+    // Note: SDL_WINDOW_UTILITY can be used to control task bar visibility, but on Windows, it does not affect child windows.
+    if (!(viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon))
+    {
+        LONG ex_style = ::GetWindowLong(hwnd, GWL_EXSTYLE);
+        ex_style |= WS_EX_APPWINDOW;
+        ex_style &= ~WS_EX_TOOLWINDOW;
+        ::ShowWindow(hwnd, SW_HIDE);
+        ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
+    }
+#endif
+
+#ifdef __APPLE__
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, "1"); // Otherwise new window appear under
+#else
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing) ? "0" : "1");
+#endif
+    SDL_ShowWindow(vd->Window);
+}
+
+static void ImGui_ImplSDL3_UpdateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    IM_UNUSED(vd);
+
+#ifndef __APPLE__ // On Mac, SDL3 Parenting appears to prevent viewport from appearing in another monitor
+    // Update SDL3 parent if it changed _after_ creation.
+    // This is for advanced apps that are manipulating ParentViewportID manually.
+    SDL_Window* new_parent = ImGui_ImplSDL3_GetSDLWindowFromViewport(viewport->ParentViewport);
+    if (new_parent != vd->ParentWindow)
+    {
+        vd->ParentWindow = new_parent;
+        SDL_SetWindowParent(vd->Window, vd->ParentWindow);
+    }
+#endif
+}
+
+static ImVec2 ImGui_ImplSDL3_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    int x = 0, y = 0;
+    SDL_GetWindowPosition(vd->Window, &x, &y);
+    return ImVec2((float)x, (float)y);
+}
+
+static void ImGui_ImplSDL3_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowPosition(vd->Window, (int)pos.x, (int)pos.y);
+}
+
+static ImVec2 ImGui_ImplSDL3_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    int w = 0, h = 0;
+    SDL_GetWindowSize(vd->Window, &w, &h);
+    return ImVec2((float)w, (float)h);
+}
+
+static void ImGui_ImplSDL3_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowSize(vd->Window, (int)size.x, (int)size.y);
+}
+
+static ImVec2 ImGui_ImplSDL3_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    ImVec2 framebuffer_scale;
+    ImGui_ImplSDL3_GetWindowSizeAndFramebufferScale(vd->Window, nullptr, &framebuffer_scale);
+    return framebuffer_scale;
+}
+
+static void ImGui_ImplSDL3_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowTitle(vd->Window, title);
+}
+
+static void ImGui_ImplSDL3_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowOpacity(vd->Window, alpha);
+}
+
+static void ImGui_ImplSDL3_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_RaiseWindow(vd->Window);
+}
+
+static bool ImGui_ImplSDL3_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0;
+}
+
+static bool ImGui_ImplSDL3_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_MINIMIZED) != 0;
+}
+
+static void ImGui_ImplSDL3_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+}
+
+static void ImGui_ImplSDL3_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+    {
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+        SDL_GL_SwapWindow(vd->Window);
+    }
+}
+
+// Vulkan support (the Vulkan renderer needs to call a platform-side support function to create the surface)
+// SDL is graceful enough to _not_ need <vulkan/vulkan.h> so we can safely include this.
+#include <SDL3/SDL_vulkan.h>
+static int ImGui_ImplSDL3_CreateVkSurface(ImGuiViewport* viewport, ImU64 vk_instance, const void* vk_allocator, ImU64* out_vk_surface)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    (void)vk_allocator;
+    bool ret = SDL_Vulkan_CreateSurface(vd->Window, (VkInstance)vk_instance, (const VkAllocationCallbacks*)vk_allocator, (VkSurfaceKHR*)out_vk_surface);
+    return ret ? 0 : 1; // ret ? VK_SUCCESS : VK_NOT_READY
+}
+
+static void ImGui_ImplSDL3_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context)
+{
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplSDL3_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplSDL3_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplSDL3_ShowWindow;
+    platform_io.Platform_UpdateWindow = ImGui_ImplSDL3_UpdateWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplSDL3_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplSDL3_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplSDL3_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplSDL3_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplSDL3_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplSDL3_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplSDL3_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplSDL3_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplSDL3_SetWindowTitle;
+    platform_io.Platform_RenderWindow = ImGui_ImplSDL3_RenderWindow;
+    platform_io.Platform_SwapBuffers = ImGui_ImplSDL3_SwapBuffers;
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplSDL3_SetWindowAlpha;
+    platform_io.Platform_CreateVkSurface = ImGui_ImplSDL3_CreateVkSurface;
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL3_ViewportData* vd = IM_NEW(ImGui_ImplSDL3_ViewportData)();
+    vd->Window = window;
+    vd->WindowID = SDL_GetWindowID(window);
+    vd->WindowOwned = false;
+    vd->GLContext = (SDL_GLContext)sdl_gl_context;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (void*)(intptr_t)vd->WindowID;
+}
+
+static void ImGui_ImplSDL3_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdl3.h

@@ -8,7 +8,10 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-//  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [x] Platform: IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_sdlgpu3.cpp

@@ -5,6 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'SDL_GPUTexture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef! **IMPORTANT** Before 2025/08/08, ImTextureID was a reference to a SDL_GPUTextureSamplerBinding struct.
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // The aim of imgui_impl_sdlgpu3.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -22,7 +23,7 @@
 //   Calling the function is MANDATORY, otherwise the ImGui will not upload neither the vertex nor the index buffer for the GPU. See imgui_impl_sdlgpu3.cpp for more info.
 
 // CHANGELOG
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. Obsoleting samplers from ImGui_ImplSDLGPU3_RenderState. (#9378)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2026-03-19: Fixed issue in ImGui_ImplSDLGPU3_DestroyTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295, #9310)
 //  2026-02-25: Removed unnecessary call to SDL_WaitForGPUIdle when releasing vertex/index buffers. (#9262)
 //  2025-11-26: macOS version can use MSL shaders in order to support macOS 10.14+ (vs Metallib shaders requiring macOS 14+). Requires calling SDL_CreateGPUDevice() with SDL_GPU_SHADERFORMAT_MSL.
@@ -60,10 +61,6 @@ struct ImGui_ImplSDLGPU3_Data
 {
     ImGui_ImplSDLGPU3_InitInfo   InitInfo;
 
-    // Render state
-    ImGui_ImplSDLGPU3_RenderState*  RenderState         = nullptr; // == ImGui::GetPlatformIO().Renderer_RenderState during rendering.
-    SDL_GPUSampler*                 CurrentSampler      = nullptr;
-
     // Graphics pipeline & shaders
     SDL_GPUShader*               VertexShader           = nullptr;
     SDL_GPUShader*               FragmentShader         = nullptr;
@@ -92,10 +89,10 @@ static ImGui_ImplSDLGPU3_Data* ImGui_ImplSDLGPU3_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplSDLGPU3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
-static void ImGui_ImplSDLGPU3_SetupRenderState(ImDrawData* draw_data, SDL_GPUGraphicsPipeline* pipeline, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass* render_pass, ImGui_ImplSDLGPU3_FrameData* fd, uint32_t fb_width, uint32_t fb_height)
+static void ImGui_ImplSDLGPU3_SetupRenderState(ImDrawData* draw_data, ImGui_ImplSDLGPU3_RenderState* render_state, SDL_GPUGraphicsPipeline* pipeline, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass* render_pass, ImGui_ImplSDLGPU3_FrameData* fd, uint32_t fb_width, uint32_t fb_height)
 {
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
-    bd->CurrentSampler = bd->TexSamplerLinear;
+    render_state->SamplerCurrent = bd->TexSamplerLinear;
 
     // Bind graphics pipeline
     SDL_BindGPUGraphicsPipeline(render_pass, pipeline);
@@ -179,8 +176,8 @@ void ImGui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuff
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
     ImGui_ImplSDLGPU3_FrameData* fd = &bd->MainWindowFrameData;
 
-    uint32_t vertex_size = (uint32_t)draw_data->TotalVtxCount * sizeof(ImDrawVert);
-    uint32_t index_size  = (uint32_t)draw_data->TotalIdxCount * sizeof(ImDrawIdx);
+    uint32_t vertex_size = draw_data->TotalVtxCount * sizeof(ImDrawVert);
+    uint32_t index_size  = draw_data->TotalIdxCount * sizeof(ImDrawIdx);
     if (fd->VertexBuffer == nullptr || fd->VertexBufferSize < vertex_size)
         CreateOrResizeBuffers(&fd->VertexBuffer, &fd->VertexTransferBuffer, &fd->VertexBufferSize, vertex_size, SDL_GPU_BUFFERUSAGE_VERTEX);
     if (fd->IndexBuffer == nullptr || fd->IndexBufferSize < index_size)
@@ -221,11 +218,6 @@ void ImGui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuff
     SDL_EndGPUCopyPass(copy_pass);
 }
 
-// Draw callbacks
-static void ImGui_ImplSDLGPU3_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)    {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplSDLGPU3_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)    { ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData(); bd->CurrentSampler = bd->TexSamplerLinear; }
-static void ImGui_ImplSDLGPU3_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)   { ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData(); bd->CurrentSampler = bd->TexSamplerNearest; }
-
 void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass* render_pass, SDL_GPUGraphicsPipeline* pipeline)
 {
     // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
@@ -248,9 +240,11 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     ImGui_ImplSDLGPU3_RenderState render_state;
     render_state.Device = bd->InitInfo.Device;
-    platform_io.Renderer_RenderState = bd->RenderState = &render_state;
+    render_state.SamplerLinear = render_state.SamplerCurrent = bd->TexSamplerLinear;
+    render_state.SamplerNearest = bd->TexSamplerNearest;
+    platform_io.Renderer_RenderState = &render_state;
 
-    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
+    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, &render_state, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
 
     // Render command lists
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
@@ -264,8 +258,9 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
             if (pcmd->UserCallback != nullptr)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplSDLGPU3_DrawCallback_ResetRenderState)
-                    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, &render_state, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
             }
@@ -278,8 +273,8 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
                 // Clamp to viewport as SDL_SetGPUScissor() won't accept values that are off bounds
                 if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
                 if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
-                if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; }
-                if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; }
+                if (clip_max.x > fb_width) { clip_max.x = (float)fb_width; }
+                if (clip_max.y > fb_height) { clip_max.y = (float)fb_height; }
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 
@@ -294,7 +289,7 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
                 // Bind DescriptorSet with font or user texture
                 SDL_GPUTextureSamplerBinding texture_sampler_binding;
                 texture_sampler_binding.texture = (SDL_GPUTexture*)(intptr_t)pcmd->GetTexID();
-                texture_sampler_binding.sampler = bd->CurrentSampler;
+                texture_sampler_binding.sampler = render_state.SamplerCurrent;
                 SDL_BindGPUFragmentSamplers(render_pass, 0, &texture_sampler_binding, 1);
 
                 // Draw
@@ -313,8 +308,6 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
     // We perform a call to SDL_SetGPUScissor() to set back a full viewport which is likely to fix things for 99% users but technically this is not perfect. (See github #4644)
     SDL_Rect scissor_rect { 0, 0, fb_width, fb_height };
     SDL_SetGPUScissor(render_pass, &scissor_rect);
-
-    platform_io.Renderer_RenderState = bd->RenderState = nullptr;
 }
 
 static void ImGui_ImplSDLGPU3_DestroyTexture(ImTextureData* tex)
@@ -652,6 +645,9 @@ void ImGui_ImplSDLGPU3_DestroyDeviceObjects()
     if (bd->Pipeline)           { SDL_ReleaseGPUGraphicsPipeline(v->Device, bd->Pipeline); bd->Pipeline = nullptr; }
 }
 
+static void ImGui_ImplSDLGPU3_InitMultiViewportSupport();
+static void ImGui_ImplSDLGPU3_ShutdownMultiViewportSupport();
+
 bool ImGui_ImplSDLGPU3_Init(ImGui_ImplSDLGPU3_InitInfo* info)
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -664,17 +660,15 @@ bool ImGui_ImplSDLGPU3_Init(ImGui_ImplSDLGPU3_InitInfo* info)
     io.BackendRendererName = "imgui_impl_sdlgpu3";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
     io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplSDLGPU3_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplSDLGPU3_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplSDLGPU3_DrawCallback_SetSamplerNearest;
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     IM_ASSERT(info->Device != nullptr);
     IM_ASSERT(info->ColorTargetFormat != SDL_GPU_TEXTUREFORMAT_INVALID);
 
     bd->InitInfo = *info;
 
+    ImGui_ImplSDLGPU3_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -685,11 +679,12 @@ void ImGui_ImplSDLGPU3_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ImGui_ImplSDLGPU3_ShutdownMultiViewportSupport();
     ImGui_ImplSDLGPU3_DestroyDeviceObjects();
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     platform_io.ClearRendererHandlers();
     IM_DELETE(bd);
 }
@@ -703,4 +698,76 @@ void ImGui_ImplSDLGPU3_NewFrame()
         ImGui_ImplSDLGPU3_CreateDeviceObjects();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplSDLGPU3_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDLGPU3_Data* data = ImGui_ImplSDLGPU3_GetBackendData();
+    SDL_Window* window = SDL_GetWindowFromID((SDL_WindowID)(intptr_t)viewport->PlatformHandle);
+    SDL_ClaimWindowForGPUDevice(data->InitInfo.Device, window);
+    SDL_SetGPUSwapchainParameters(data->InitInfo.Device, window, data->InitInfo.SwapchainComposition, data->InitInfo.PresentMode);
+    viewport->RendererUserData = (void*)1;
+}
+
+static void ImGui_ImplSDLGPU3_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDLGPU3_Data* data = ImGui_ImplSDLGPU3_GetBackendData();
+    SDL_Window* window = SDL_GetWindowFromID((SDL_WindowID)(intptr_t)viewport->PlatformHandle);
+
+    ImDrawData* draw_data = viewport->DrawData;
+
+    SDL_GPUCommandBuffer* command_buffer = SDL_AcquireGPUCommandBuffer(data->InitInfo.Device);
+
+    SDL_GPUTexture* swapchain_texture;
+    SDL_AcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, nullptr, nullptr);
+
+    if (swapchain_texture != nullptr)
+    {
+        ImGui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer); // FIXME-OPT: Not optimal, may this be done earlier?
+        SDL_GPUColorTargetInfo target_info = {};
+        target_info.texture = swapchain_texture;
+        target_info.clear_color = SDL_FColor{ 0.0f,0.0f,0.0f,1.0f };
+        target_info.load_op = SDL_GPU_LOADOP_CLEAR;
+        target_info.store_op = SDL_GPU_STOREOP_STORE;
+        target_info.mip_level = 0;
+        target_info.layer_or_depth_plane = 0;
+        target_info.cycle = false;
+        SDL_GPURenderPass* render_pass = SDL_BeginGPURenderPass(command_buffer, &target_info, 1, nullptr);
+        ImGui_ImplSDLGPU3_RenderDrawData(draw_data, command_buffer, render_pass);
+        SDL_EndGPURenderPass(render_pass);
+    }
+
+    SDL_SubmitGPUCommandBuffer(command_buffer);
+}
+
+static void ImGui_ImplSDLGPU3_DestroyWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDLGPU3_Data* data = ImGui_ImplSDLGPU3_GetBackendData();
+    if (viewport->RendererUserData)
+    {
+        SDL_Window* window = SDL_GetWindowFromID((SDL_WindowID)(intptr_t)viewport->PlatformHandle);
+        SDL_ReleaseWindowFromGPUDevice(data->InitInfo.Device, window);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplSDLGPU3_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplSDLGPU3_RenderWindow;
+    platform_io.Renderer_CreateWindow = ImGui_ImplSDLGPU3_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplSDLGPU3_DestroyWindow;
+}
+
+static void ImGui_ImplSDLGPU3_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
+//-----------------------------------------------------------------------------
+
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdlgpu3.h

@@ -5,6 +5,7 @@
 //  [X] Renderer: User texture binding. Use 'SDL_GPUTexture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef! **IMPORTANT** Before 2025/08/08, ImTextureID was a reference to a SDL_GPUTextureSamplerBinding struct.
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // The aim of imgui_impl_sdlgpu3.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -57,6 +58,9 @@ IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_UpdateTexture(ImTextureData* tex);
 struct ImGui_ImplSDLGPU3_RenderState
 {
     SDL_GPUDevice*      Device;
+    SDL_GPUSampler*     SamplerLinear;      // Bilinear filtering sampler
+    SDL_GPUSampler*     SamplerNearest;     // Nearest/point filtering sampler
+    SDL_GPUSampler*     SamplerCurrent;     // Current sampler (may be changed by callback)
 };
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdlrenderer2.cpp

@@ -14,10 +14,10 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
-// Missing features or Issues:
-//  [ ] Renderer: Missing support for DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest callbacks: SDLRenderer2 does not support changing SDL_SCALE_MODE while rendering.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
 // Learn about Dear ImGui:
 // - FAQ                  https://dearimgui.com/faq
@@ -26,8 +26,6 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
-// (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState (others cannot be supported). (#9378)
 //  2026-03-12: Fixed invalid assert in ImGui_ImplSDLRenderer2_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLRenderer2_CreateFontsTexture() and ImGui_ImplSDLRenderer2_DestroyFontsTexture().
@@ -76,6 +74,41 @@ static ImGui_ImplSDLRenderer2_Data* ImGui_ImplSDLRenderer2_GetBackendData()
 }
 
 // Functions
+bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplSDLRenderer2_Data* bd = IM_NEW(ImGui_ImplSDLRenderer2_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_sdlrenderer2";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    bd->Renderer = renderer;
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer2_Shutdown()
+{
+    ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplSDLRenderer2_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 static void ImGui_ImplSDLRenderer2_SetupRenderState(SDL_Renderer* renderer)
 {
     // Clear out any viewports and cliprect set by the user
@@ -91,9 +124,6 @@ void ImGui_ImplSDLRenderer2_NewFrame()
     IM_UNUSED(bd);
 }
 
-// Draw callbacks
-static void ImGui_ImplSDLRenderer2_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*) {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-
 void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
 {
     // If there's a scale factor set by the user, use that instead
@@ -156,7 +186,8 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
             if (pcmd->UserCallback)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplSDLRenderer2_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplSDLRenderer2_SetupRenderState(renderer);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -264,44 +295,6 @@ void ImGui_ImplSDLRenderer2_DestroyDeviceObjects()
         }
 }
 
-bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplSDLRenderer2_Data* bd = IM_NEW(ImGui_ImplSDLRenderer2_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_sdlrenderer2";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplSDLRenderer2_DrawCallback_ResetRenderState;
-
-    bd->Renderer = renderer;
-
-    return true;
-}
-
-void ImGui_ImplSDLRenderer2_Shutdown()
-{
-    ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplSDLRenderer2_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-}
-
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdlrenderer2.h

@@ -14,8 +14,8 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
-// Missing features or Issues:
-//  [ ] Renderer: Missing support for DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest callbacks: SDLRenderer2 does not support changing SDL_SCALE_MODE while rendering.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_sdlrenderer3.cpp

@@ -14,8 +14,10 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
 // Learn about Dear ImGui:
 // - FAQ                  https://dearimgui.com/faq
@@ -24,8 +26,6 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
-// (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
 //  2026-03-12: Fixed invalid assert in ImGui_ImplSDLRenderer3_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLRenderer3_CreateFontsTexture() and ImGui_ImplSDLRenderer3_DestroyFontsTexture().
@@ -61,9 +61,6 @@ struct ImGui_ImplSDLRenderer3_Data
     SDL_Renderer*           Renderer;       // Main viewport's renderer
     ImVector<SDL_FColor>    ColorBuffer;
 
-    // Render State
-    SDL_ScaleMode           CurrentScaleMode;
-
     ImGui_ImplSDLRenderer3_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
 
@@ -75,6 +72,41 @@ static ImGui_ImplSDLRenderer3_Data* ImGui_ImplSDLRenderer3_GetBackendData()
 }
 
 // Functions
+bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_sdlrenderer3";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    bd->Renderer = renderer;
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer3_Shutdown()
+{
+    ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplSDLRenderer3_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 static void ImGui_ImplSDLRenderer3_SetupRenderState(SDL_Renderer* renderer)
 {
     // Clear out any viewports and cliprect set by the user
@@ -108,11 +140,6 @@ static int SDL_RenderGeometryRaw8BitColor(SDL_Renderer* renderer, ImVector<SDL_F
     return SDL_RenderGeometryRaw(renderer, texture, xy, xy_stride, color3, sizeof(*color3), uv, uv_stride, num_vertices, indices, num_indices, size_indices);
 }
 
-// Draw callbacks
-static void ImGui_ImplSDLRenderer3_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)   {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplSDLRenderer3_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)   { ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData(); bd->CurrentScaleMode = SDL_SCALEMODE_LINEAR; }
-static void ImGui_ImplSDLRenderer3_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)  { ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData(); bd->CurrentScaleMode = SDL_SCALEMODE_NEAREST; }
-
 void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
 {
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
@@ -179,7 +206,8 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
             if (pcmd->UserCallback)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplSDLRenderer3_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplSDLRenderer3_SetupRenderState(renderer);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -205,7 +233,6 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
 
                 // Bind texture, Draw
                 SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
-                SDL_SetTextureScaleMode(tex, bd->CurrentScaleMode);
                 SDL_RenderGeometryRaw8BitColor(renderer, bd->ColorBuffer, tex,
                     xy, (int)sizeof(ImDrawVert),
                     color, (int)sizeof(ImDrawVert),
@@ -284,46 +311,6 @@ void ImGui_ImplSDLRenderer3_DestroyDeviceObjects()
         }
 }
 
-bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_sdlrenderer3";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplSDLRenderer3_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplSDLRenderer3_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplSDLRenderer3_DrawCallback_SetSamplerNearest;
-
-    bd->Renderer = renderer;
-
-    return true;
-}
-
-void ImGui_ImplSDLRenderer3_Shutdown()
-{
-    ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplSDLRenderer3_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-}
-
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdlrenderer3.h

@@ -14,8 +14,10 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
-// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
 // Learn about Dear ImGui:
 // - FAQ                  https://dearimgui.com/faq

backends/imgui_impl_vulkan.h

@@ -2,10 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [!] Renderer: User texture binding. Use a VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE 'VkDescriptorSet' as texture identifier. Call ImGui_ImplVulkan_AddTexture() to register one. Read the FAQ about ImTextureID/ImTextureRef + https://github.com/ocornut/imgui/pull/914 for discussions.
+//  [!] Renderer: User texture binding. Use 'VkDescriptorSet' as texture identifier. Call ImGui_ImplVulkan_AddTexture() to register one. Read the FAQ about ImTextureID/ImTextureRef + https://github.com/ocornut/imgui/pull/914 for discussions.
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [x] Renderer: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
 
 // The aim of imgui_impl_vulkan.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -78,19 +79,24 @@
 #endif
 
 // Backend uses a small number of descriptors per font atlas + as many as additional calls done to ImGui_ImplVulkan_AddTexture().
-#define IMGUI_IMPL_VULKAN_MINIMUM_SAMPLED_IMAGE_POOL_SIZE   (8)     // Minimum per atlas
-#define IMGUI_IMPL_VULKAN_MINIMUM_SAMPLER_POOL_SIZE         (2)     // Minimum for linear + nearest
+#define IMGUI_IMPL_VULKAN_MINIMUM_IMAGE_SAMPLER_POOL_SIZE   (8)     // Minimum per atlas
 
 // Specify settings to create pipeline and swapchain
 struct ImGui_ImplVulkan_PipelineInfo
 {
+    // For Main viewport only
     VkRenderPass                    RenderPass;                     // Ignored if using dynamic rendering
+
+    // For Main and Secondary viewports
     uint32_t                        Subpass;                        //
     VkSampleCountFlagBits           MSAASamples = {};               // 0 defaults to VK_SAMPLE_COUNT_1_BIT
     ImVector<VkDynamicState>        ExtraDynamicStates;             // Optional, allows to insert more dynamic states into our VkPipeline
 #ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
     VkPipelineRenderingCreateInfoKHR PipelineRenderingCreateInfo;   // Optional, valid if .sType == VK_STRUCTURE_TYPE_PIPELINE_RENDERING_CREATE_INFO_KHR
 #endif
+
+    // For Secondary viewports only (created/managed by backend)
+    VkImageUsageFlags               SwapChainImageUsage;            // Extra flags for vkCreateSwapchainKHR() calls for secondary viewports. We automatically add VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT. You can add e.g. VK_IMAGE_USAGE_TRANSFER_SRC_BIT if you need to capture from viewports.
 };
 
 // Initialization data, for ImGui_ImplVulkan_Init()
@@ -110,20 +116,21 @@ struct ImGui_ImplVulkan_InitInfo
     uint32_t                        QueueFamily;
     VkQueue                         Queue;
     VkDescriptorPool                DescriptorPool;             // See requirements in note above; ignored if using DescriptorPoolSize > 0
-    uint32_t                        DescriptorPoolSize;         // Optional: set to create internal ImageView descriptor pool automatically instead of using DescriptorPool.
+    uint32_t                        DescriptorPoolSize;         // Optional: set to create internal descriptor pool automatically instead of using DescriptorPool.
     uint32_t                        MinImageCount;              // >= 2
     uint32_t                        ImageCount;                 // >= MinImageCount
     VkPipelineCache                 PipelineCache;              // Optional
 
     // Pipeline
     ImGui_ImplVulkan_PipelineInfo   PipelineInfoMain;           // Infos for Main Viewport (created by app/user)
+    ImGui_ImplVulkan_PipelineInfo   PipelineInfoForViewports;   // Infos for Secondary Viewports (created by backend)
     //VkRenderPass                  RenderPass;                 // --> Since 2025/09/26: set 'PipelineInfoMain.RenderPass' instead
     //uint32_t                      Subpass;                    // --> Since 2025/09/26: set 'PipelineInfoMain.Subpass' instead
     //VkSampleCountFlagBits         MSAASamples;                // --> Since 2025/09/26: set 'PipelineInfoMain.MSAASamples' instead
     //VkPipelineRenderingCreateInfoKHR PipelineRenderingCreateInfo; // Since 2025/09/26: set 'PipelineInfoMain.PipelineRenderingCreateInfo' instead
 
     // (Optional) Dynamic Rendering
-    // Need to explicitly enable VK_KHR_dynamic_rendering extension to use this, even for Vulkan 1.3 + setup PipelineInfoMain.PipelineRenderingCreateInfo.
+    // Need to explicitly enable VK_KHR_dynamic_rendering extension to use this, even for Vulkan 1.3 + setup PipelineInfoMain.PipelineRenderingCreateInfo and PipelineInfoViewports.PipelineRenderingCreateInfo.
     bool                            UseDynamicRendering;
 
     // (Optional) Allocation, Debugging
@@ -153,21 +160,18 @@ IMGUI_IMPL_API void             ImGui_ImplVulkan_CreateMainPipeline(const ImGui_
 // (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = nullptr to handle this manually.
 IMGUI_IMPL_API void             ImGui_ImplVulkan_UpdateTexture(ImTextureData* tex);
 
-// Register a texture (VkDescriptorSet for a VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE == ImTextureID)
-IMGUI_IMPL_API VkDescriptorSet  ImGui_ImplVulkan_AddTexture(VkImageView image_view, VkImageLayout image_layout);
+// Register a texture (VkDescriptorSet == ImTextureID)
+// FIXME: This is experimental in the sense that we are unsure how to best design/tackle this problem
+// Please post to https://github.com/ocornut/imgui/pull/914 if you have suggestions.
+IMGUI_IMPL_API VkDescriptorSet  ImGui_ImplVulkan_AddTexture(VkSampler sampler, VkImageView image_view, VkImageLayout image_layout);
 IMGUI_IMPL_API void             ImGui_ImplVulkan_RemoveTexture(VkDescriptorSet descriptor_set);
 
-#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
-IMGUI_IMPL_API VkDescriptorSet  ImGui_ImplVulkan_AddTexture(VkSampler sampler, VkImageView image_view, VkImageLayout image_layout); // Ignore VkSampler
-#endif
-
 // Optional: load Vulkan functions with a custom function loader
 // This is only useful with IMGUI_IMPL_VULKAN_NO_PROTOTYPES / VK_NO_PROTOTYPES
 IMGUI_IMPL_API bool             ImGui_ImplVulkan_LoadFunctions(uint32_t api_version, PFN_vkVoidFunction(*loader_func)(const char* function_name, void* user_data), void* user_data = nullptr);
 
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplVulkan_RenderDrawData() call.
-//      ImGui_ImplVulkan_RenderState* render_state = (ImGui_ImplVulkan_RenderState*)ImGui::GetPlatformIO().Renderer_RenderState;
 // (Please open an issue if you feel you need access to more data)
 struct ImGui_ImplVulkan_RenderState
 {
@@ -208,6 +212,7 @@ IMGUI_IMPL_API VkPresentModeKHR     ImGui_ImplVulkanH_SelectPresentMode(VkPhysic
 IMGUI_IMPL_API VkPhysicalDevice     ImGui_ImplVulkanH_SelectPhysicalDevice(VkInstance instance);
 IMGUI_IMPL_API uint32_t             ImGui_ImplVulkanH_SelectQueueFamilyIndex(VkPhysicalDevice physical_device);
 IMGUI_IMPL_API int                  ImGui_ImplVulkanH_GetMinImageCountFromPresentMode(VkPresentModeKHR present_mode);
+IMGUI_IMPL_API ImGui_ImplVulkanH_Window* ImGui_ImplVulkanH_GetWindowDataFromViewport(ImGuiViewport* viewport); // Access to Vulkan objects associated with a viewport (e.g to export a screenshot)
 
 // Helper structure to hold the data needed by one rendering frame
 // (Used by example's main.cpp. Used by multi-viewport features. Probably NOT used by your own engine/app.)
@@ -245,7 +250,6 @@ struct ImGui_ImplVulkanH_Window
     int                     Height;
     VkSwapchainKHR          Swapchain;
     VkRenderPass            RenderPass;
-    VkPipeline              Pipeline;           // The window pipeline may uses a different VkRenderPass than the one passed in ImGui_ImplVulkan_InitInfo
     uint32_t                FrameIndex;         // Current frame being rendered to (0 <= FrameIndex < FrameInFlightCount)
     uint32_t                ImageCount;         // Number of simultaneous in-flight frames (returned by vkGetSwapchainImagesKHR, usually derived from min_image_count)
     uint32_t                SemaphoreCount;     // Number of simultaneous in-flight frames + 1, to be able to use it in vkAcquireNextImageKHR
@@ -258,7 +262,7 @@ struct ImGui_ImplVulkanH_Window
         memset((void*)this, 0, sizeof(*this));
 
         // Parameters to create SwapChain
-        PresentMode = VK_PRESENT_MODE_MAX_ENUM_KHR;     // Ensure we get an error if user doesn't set this.
+        PresentMode = (VkPresentModeKHR)~0;             // Ensure we get an error if user doesn't set this.
 
         // Parameters to create RenderPass
         AttachmentDesc.format = VK_FORMAT_UNDEFINED;    // Will automatically use wd->SurfaceFormat.format.

backends/imgui_impl_wgpu.cpp

@@ -7,6 +7,8 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
 //  [X] Renderer: Texture updates support for dynamic font system (ImGuiBackendFlags_RendererHasTextures).
+// Missing features or Issues:
+//  [ ] Renderer: Multi-viewport support (multiple windows), useful for desktop.
 
 // Read imgui_impl_wgpu.h about how to use the IMGUI_IMPL_WEBGPU_BACKEND_WGPU or IMGUI_IMPL_WEBGPU_BACKEND_DAWN flags.
 
@@ -20,7 +22,6 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
 //  2026-03-25: Added support for WGVK native backend via IMGUI_IMPL_WEBGPU_BACKEND_WGVK define, with SPIRV shaders if WGSL is not available. (#9316, #9246, #9257)
 //  2026-03-09: Removed support for Emscripten < 4.0.10. (#9281)
 //  2025-10-16: Update to compile with Dawn and Emscripten's 4.0.10+ '--use-port=emdawnwebgpu' ports. (#8381, #8898)
@@ -84,13 +85,11 @@ struct ImGui_ImplWGPU_Texture
 
 struct RenderResources
 {
-    WGPUSampler         SamplerLinear = nullptr;            // Bilinear sampler
-    WGPUSampler         SamplerNearest = nullptr;           // Nearest/point sampler
-    WGPUBuffer          Uniforms = nullptr;                 // Shader uniforms
-    WGPUBindGroup       CommonBindGroupLinear = nullptr;    // Common bind-group bound to group 0 (uniforms + SamplerLinear)
-    WGPUBindGroup       CommonBindGroupNearest = nullptr;   // Common bind-group bound to group 0 (uniforms + SamplerNearest)
-    ImGuiStorage        ImageBindGroups;                    // Resources bind-group to bind the font/image resources to pipeline (this is a key->value map)
-    WGPUBindGroupLayout ImageBindGroupLayout = nullptr;     // Cache layout used for the image bind group. Avoids allocating unnecessary JS objects when working with WebASM
+    WGPUSampler         Sampler = nullptr;              // Sampler for textures
+    WGPUBuffer          Uniforms = nullptr;             // Shader uniforms
+    WGPUBindGroup       CommonBindGroup = nullptr;      // Resources bind-group to bind the common resources to pipeline
+    ImGuiStorage        ImageBindGroups;                // Resources bind-group to bind the font/image resources to pipeline (this is a key->value map)
+    WGPUBindGroupLayout ImageBindGroupLayout = nullptr; // Cache layout used for the image bind group. Avoids allocating unnecessary JS objects when working with WebASM
 };
 
 struct FrameResources
@@ -117,7 +116,6 @@ struct ImGui_ImplWGPU_Data
     WGPUTextureFormat       renderTargetFormat = WGPUTextureFormat_Undefined;
     WGPUTextureFormat       depthStencilFormat = WGPUTextureFormat_Undefined;
     WGPURenderPipeline      pipelineState = nullptr;
-    ImGui_ImplWGPU_RenderState* RenderState = nullptr;  // == ImGui::GetPlatformIO().Renderer_RenderState during rendering.
 
     RenderResources         renderResources;
     FrameResources*         pFrameResources = nullptr;
@@ -300,11 +298,9 @@ static void SafeRelease(WGPUShaderModule& res)
 }
 static void SafeRelease(RenderResources& res)
 {
-    SafeRelease(res.SamplerLinear);
-    SafeRelease(res.SamplerNearest);
+    SafeRelease(res.Sampler);
     SafeRelease(res.Uniforms);
-    SafeRelease(res.CommonBindGroupLinear);
-    SafeRelease(res.CommonBindGroupNearest);
+    SafeRelease(res.CommonBindGroup);
     SafeRelease(res.ImageBindGroupLayout);
 };
 
@@ -319,7 +315,6 @@ static void SafeRelease(FrameResources& res)
 static WGPUProgrammableStageDescriptor ImGui_ImplWGPU_CreateShaderModuleWGSL(const char* wgsl_source)
 {
     ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData();
-    IM_UNUSED(bd);
 
     WGPUShaderSourceWGSL wgsl_desc = {};
     wgsl_desc.chain.sType = WGPUSType_ShaderSourceWGSL;
@@ -328,31 +323,10 @@ static WGPUProgrammableStageDescriptor ImGui_ImplWGPU_CreateShaderModuleWGSL(con
     WGPUShaderModuleDescriptor desc = {};
     desc.nextInChain = (WGPUChainedStruct*)&wgsl_desc;
 
-    // Detect shader compilation errors by using an error scope.
-    // Flag to be passed into the validation callback `userdata1` pointer.
-    int validation_error = 0;
-    wgpuDevicePushErrorScope(bd->wgpuDevice, WGPUErrorFilter_Validation);
-    WGPUShaderModule module = wgpuDeviceCreateShaderModule(bd->wgpuDevice, &desc);
-    WGPUPopErrorScopeCallbackInfo pop_cb = {};
-    pop_cb.mode = WGPUCallbackMode_AllowSpontaneous;
-    pop_cb.callback = [](WGPUPopErrorScopeStatus, WGPUErrorType type, WGPUStringView, void* userdata1, void*)
-    {
-        if (type == WGPUErrorType_Validation)
-            *static_cast<int*>(userdata1) = 1;
-    };
-    pop_cb.userdata1 = &validation_error;
-    wgpuDevicePopErrorScope(bd->wgpuDevice, pop_cb);
-
     WGPUProgrammableStageDescriptor stage_desc = {};
-    if (module && !validation_error)
-    {
-        stage_desc.module = module;
-        stage_desc.entryPoint = { "main", WGPU_STRLEN };
-    }
-    else if (module)
-    {
-        wgpuShaderModuleRelease(module);
-    }
+    stage_desc.module = wgpuDeviceCreateShaderModule(bd->wgpuDevice, &desc);
+
+    stage_desc.entryPoint = { "main", WGPU_STRLEN };
     return stage_desc;
 }
 
@@ -446,19 +420,15 @@ static void ImGui_ImplWGPU_SetupRenderState(ImDrawData* draw_data, WGPURenderPas
     wgpuRenderPassEncoderSetVertexBuffer(ctx, 0, fr->VertexBuffer, 0, fr->VertexBufferSize * sizeof(ImDrawVert));
     wgpuRenderPassEncoderSetIndexBuffer(ctx, fr->IndexBuffer, sizeof(ImDrawIdx) == 2 ? WGPUIndexFormat_Uint16 : WGPUIndexFormat_Uint32, 0, fr->IndexBufferSize * sizeof(ImDrawIdx));
     wgpuRenderPassEncoderSetPipeline(ctx, bd->pipelineState);
-    wgpuRenderPassEncoderSetBindGroup(ctx, 0, bd->renderResources.CommonBindGroupLinear, 0, nullptr);
+    wgpuRenderPassEncoderSetBindGroup(ctx, 0, bd->renderResources.CommonBindGroup, 0, nullptr);
 
     // Setup blend factor
     WGPUColor blend_color = { 0.f, 0.f, 0.f, 0.f };
     wgpuRenderPassEncoderSetBlendConstant(ctx, &blend_color);
 }
 
-// Draw callbacks
-static void ImGui_ImplWGPU_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)   {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplWGPU_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)   { ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData(); wgpuRenderPassEncoderSetBindGroup(bd->RenderState->RenderPassEncoder, 0, bd->renderResources.CommonBindGroupLinear, 0, nullptr); }
-static void ImGui_ImplWGPU_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)  { ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData(); wgpuRenderPassEncoderSetBindGroup(bd->RenderState->RenderPassEncoder, 0, bd->renderResources.CommonBindGroupNearest, 0, nullptr); }
-
 // Render function
+// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder pass_encoder)
 {
     // Avoid rendering when minimized
@@ -553,7 +523,7 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     ImGui_ImplWGPU_RenderState render_state;
     render_state.Device = bd->wgpuDevice;
     render_state.RenderPassEncoder = pass_encoder;
-    platform_io.Renderer_RenderState = bd->RenderState = &render_state;
+    platform_io.Renderer_RenderState = &render_state;
 
     // Render command lists
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
@@ -569,7 +539,8 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
             if (pcmd->UserCallback != nullptr)
             {
                 // User callback, registered via ImDrawList::AddCallback()
-                if (pcmd->UserCallback == ImGui_ImplWGPU_DrawCallback_ResetRenderState)
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplWGPU_SetupRenderState(draw_data, pass_encoder, fr);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
@@ -580,11 +551,12 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
                 ImTextureID tex_id = pcmd->GetTexID();
                 ImGuiID tex_id_hash = ImHashData(&tex_id, sizeof(tex_id), 0);
                 WGPUBindGroup bind_group = (WGPUBindGroup)bd->renderResources.ImageBindGroups.GetVoidPtr(tex_id_hash);
-                if (!bind_group && tex_id != 0)
-                    if ((bind_group = ImGui_ImplWGPU_CreateImageBindGroup(bd->renderResources.ImageBindGroupLayout, (WGPUTextureView)tex_id)) != 0)
-                        bd->renderResources.ImageBindGroups.SetVoidPtr(tex_id_hash, bind_group);
-                if (bind_group)
-                    wgpuRenderPassEncoderSetBindGroup(pass_encoder, 1, (WGPUBindGroup)bind_group, 0, nullptr);
+                if (!bind_group)
+                {
+                    bind_group = ImGui_ImplWGPU_CreateImageBindGroup(bd->renderResources.ImageBindGroupLayout, (WGPUTextureView)tex_id);
+                    bd->renderResources.ImageBindGroups.SetVoidPtr(tex_id_hash, bind_group);
+                }
+                wgpuRenderPassEncoderSetBindGroup(pass_encoder, 1, (WGPUBindGroup)bind_group, 0, nullptr);
 
                 // Project scissor/clipping rectangles into framebuffer space
                 ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
@@ -593,8 +565,8 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
                 // Clamp to viewport as wgpuRenderPassEncoderSetScissorRect() won't accept values that are off bounds
                 if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
                 if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
-                if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; }
-                if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; }
+                if (clip_max.x > fb_width) { clip_max.x = (float)fb_width; }
+                if (clip_max.y > fb_height) { clip_max.y = (float)fb_height; }
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 
@@ -616,7 +588,7 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     }
     image_bind_groups.Data.resize(0);
 
-    platform_io.Renderer_RenderState = bd->RenderState = nullptr;
+    platform_io.Renderer_RenderState = nullptr;
 }
 
 static void ImGui_ImplWGPU_DestroyTexture(ImTextureData* tex)
@@ -844,35 +816,29 @@ bool ImGui_ImplWGPU_CreateDeviceObjects()
 
     ImGui_ImplWGPU_CreateUniformBuffer();
 
-    // Create samplers (Linear/Nearest)
+    // Create sampler
     // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
     WGPUSamplerDescriptor sampler_desc = {};
+    sampler_desc.minFilter = WGPUFilterMode_Linear;
+    sampler_desc.magFilter = WGPUFilterMode_Linear;
+    sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
     sampler_desc.addressModeU = WGPUAddressMode_ClampToEdge;
     sampler_desc.addressModeV = WGPUAddressMode_ClampToEdge;
     sampler_desc.addressModeW = WGPUAddressMode_ClampToEdge;
     sampler_desc.maxAnisotropy = 1;
-    sampler_desc.minFilter = WGPUFilterMode_Linear;
-    sampler_desc.magFilter = WGPUFilterMode_Linear;
-    sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
-    bd->renderResources.SamplerLinear = wgpuDeviceCreateSampler(bd->wgpuDevice, &sampler_desc);
-    sampler_desc.minFilter = WGPUFilterMode_Nearest;
-    sampler_desc.magFilter = WGPUFilterMode_Nearest;
-    sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Nearest;
-    bd->renderResources.SamplerNearest = wgpuDeviceCreateSampler(bd->wgpuDevice, &sampler_desc);
+    bd->renderResources.Sampler = wgpuDeviceCreateSampler(bd->wgpuDevice, &sampler_desc);
 
-    // Create resource bind groups (one per sampler, otherwise identical)
+    // Create resource bind group
     WGPUBindGroupEntry common_bg_entries[] =
     {
         { nullptr, 0, bd->renderResources.Uniforms, 0, MEMALIGN(sizeof(Uniforms), 16), 0, 0 },
-        { nullptr, 1, 0, 0, 0, bd->renderResources.SamplerLinear, 0 },
+        { nullptr, 1, 0, 0, 0, bd->renderResources.Sampler, 0 },
     };
     WGPUBindGroupDescriptor common_bg_descriptor = {};
     common_bg_descriptor.layout = bg_layouts[0];
     common_bg_descriptor.entryCount = sizeof(common_bg_entries) / sizeof(WGPUBindGroupEntry);
     common_bg_descriptor.entries = common_bg_entries;
-    bd->renderResources.CommonBindGroupLinear = wgpuDeviceCreateBindGroup(bd->wgpuDevice, &common_bg_descriptor);
-    common_bg_entries[1].sampler = bd->renderResources.SamplerNearest;
-    bd->renderResources.CommonBindGroupNearest = wgpuDeviceCreateBindGroup(bd->wgpuDevice, &common_bg_descriptor);
+    bd->renderResources.CommonBindGroup = wgpuDeviceCreateBindGroup(bd->wgpuDevice, &common_bg_descriptor);
     bd->renderResources.ImageBindGroupLayout = bg_layouts[1];
 
     SafeRelease(vertex_shader_desc.module);
@@ -924,11 +890,6 @@ bool ImGui_ImplWGPU_Init(ImGui_ImplWGPU_InitInfo* init_info)
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
     io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
 
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.DrawCallback_ResetRenderState = ImGui_ImplWGPU_DrawCallback_ResetRenderState;
-    platform_io.DrawCallback_SetSamplerLinear = ImGui_ImplWGPU_DrawCallback_SetSamplerLinear;
-    platform_io.DrawCallback_SetSamplerNearest = ImGui_ImplWGPU_DrawCallback_SetSamplerNearest;
-
     bd->initInfo = *init_info;
     bd->wgpuDevice = init_info->Device;
     bd->defaultQueue = wgpuDeviceGetQueue(bd->wgpuDevice);
@@ -937,7 +898,11 @@ bool ImGui_ImplWGPU_Init(ImGui_ImplWGPU_InitInfo* init_info)
     bd->numFramesInFlight = init_info->NumFramesInFlight;
     bd->frameIndex = UINT_MAX;
 
+    bd->renderResources.Sampler = nullptr;
+    bd->renderResources.Uniforms = nullptr;
+    bd->renderResources.CommonBindGroup = nullptr;
     bd->renderResources.ImageBindGroups.Data.reserve(100);
+    bd->renderResources.ImageBindGroupLayout = nullptr;
 
     // Create buffers with a default size (they will later be grown as needed)
     bd->pFrameResources = new FrameResources[bd->numFramesInFlight];

backends/imgui_impl_wgpu.h

@@ -19,6 +19,8 @@
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
 //  [X] Renderer: Texture updates support for dynamic font system (ImGuiBackendFlags_RendererHasTextures).
+// Missing features or Issues:
+//  [ ] Renderer: Multi-viewport support (multiple windows), useful for desktop.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_win32.cpp

@@ -7,6 +7,7 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy VK_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -21,15 +22,23 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2026-05-19: DPI: ImGui_ImplWin32_EnableDpiAwareness() helper uses SetProcessDpiAwarenessContext() instead of SetThreadDpiAwarenessContext(), fixes DPI scaling issues with e.g. OpenGL. (#9403)
+//  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2026-03-31: [Viewports] Fixed setting/getting size when viewports have OS decorations (e.g. io.ConfigViewportsNoDecoration = false) and process is running in Per-Monitor V2 DPI mode. (#8897)
 //  2026-01-28: Inputs: Minor optimization not submitting gamepad input if packet number has not changed (reworked from 2025-09-23 attempt). (#9202, #8556)
+//  2026-01-26: [Viewports] Fixed an issue from 1.90.5 where newly appearing windows that are not parented to the main viewport don't have task bar icon appear before the windows was explicited refocused. (#7354, #8669)
 //  2025-12-03: Inputs: handle WM_IME_CHAR/WM_IME_COMPOSITION messages to support Unicode inputs on MBCS (non-Unicode) Windows. (#9099, #3653, #5961)
 //  2025-10-19: Inputs: Revert previous change to allow for io.ClearInputKeys() on focus-out not losing gamepad state.
 //  2025-09-23: Inputs: Minor optimization not submitting gamepad input if packet number has not changed.
 //  2025-09-18: Call platform_io.ClearPlatformHandlers() on shutdown.
+//  2025-06-02: [Viewports] WM_DPICHANGED also apply io.ConfigDpiScaleViewports for main viewport instead of letting it be done by application code.
 //  2025-04-30: Inputs: Fixed an issue where externally losing mouse capture (due to e.g. focus loss) would fail to claim it again the next subsequent click. (#8594)
+//  2025-03-26: [Viewports] Viewports: fixed an issue when closing a window from the OS close button (with io.ConfigViewportsNoDecoration = false) while user code was discarding the 'bool* p_open = false' output from Begin(). Because we allowed the Win32 window to close early, Windows destroyed it and our imgui window became not visible even though user code was still submitting it.
 //  2025-03-10: When dealing with OEM keys, use scancodes instead of translated keycodes to choose ImGuiKey values. (#7136, #7201, #7206, #7306, #7670, #7672, #8468)
+//  2025-02-21: [Viewports] WM_SETTINGCHANGE's SPI_SETWORKAREA message also triggers a refresh of monitor list. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
+//  2024-11-21: [Viewports] Fixed a crash when multiple processes are running with multi-viewports, caused by misusage of GetProp(). (#8162, #8069)
+//  2024-10-28: [Viewports] Rely on property stored inside HWND to retrieve context/viewport, should facilitate attempt to use this for parallel contexts. (#8069)
+//  2024-09-16: [Viewports] Inputs: fixed an issue where a viewport destroyed while clicking would hog mouse tracking and temporary lead to incorrect update of HoveredWindow. (#7971)
 //  2024-07-08: Inputs: Fixed ImGuiMod_Super being mapped to VK_APPS instead of VK_LWIN||VK_RWIN. (#7768)
 //  2023-10-05: Inputs: Added support for extra ImGuiKey values: F13 to F24 function keys, app back/forward keys.
 //  2023-09-25: Inputs: Synthesize key-down event on key-up for VK_SNAPSHOT / ImGuiKey_PrintScreen as Windows doesn't emit it (same behavior as GLFW/SDL).
@@ -100,6 +109,7 @@
 typedef DWORD(WINAPI* PFN_XInputGetCapabilities)(DWORD, DWORD, XINPUT_CAPABILITIES*);
 typedef DWORD(WINAPI* PFN_XInputGetState)(DWORD, XINPUT_STATE*);
 #endif
+typedef BOOL(WINAPI* PFN_AdjustWindowRectExForDpi)(LPRECT, DWORD, BOOL, DWORD, UINT);
 
 // Clang/GCC warnings with -Weverything
 #if defined(__clang__)
@@ -112,6 +122,12 @@ typedef DWORD(WINAPI* PFN_XInputGetState)(DWORD, XINPUT_STATE*);
 #pragma GCC diagnostic ignored "-Wcast-function-type"       // warning: cast between incompatible function types (for loader)
 #endif
 
+// Forward Declarations
+static void ImGui_ImplWin32_InitMultiViewportSupport(bool platform_has_own_dc);
+static void ImGui_ImplWin32_ShutdownMultiViewportSupport();
+static void ImGui_ImplWin32_UpdateMonitors();
+static bool ImGui_ImplWin32_IsDpiAwarenessPerMonitorAwareV2();
+
 struct ImGui_ImplWin32_Data
 {
     HWND                        hWnd;
@@ -122,6 +138,9 @@ struct ImGui_ImplWin32_Data
     INT64                       TicksPerSecond;
     ImGuiMouseCursor            LastMouseCursor;
     UINT32                      KeyboardCodePage;
+    bool                        WantUpdateMonitors;
+    bool                        IsPerMonitorDpiAwareV2;
+    PFN_AdjustWindowRectExForDpi AdjustWindowRectExForDpi;
 
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     bool                        HasGamepad;
@@ -177,6 +196,9 @@ static bool ImGui_ImplWin32_InitEx(void* hwnd, bool platform_has_own_dc)
     io.BackendPlatformName = "imgui_impl_win32";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
+    io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;    // We can create multi-viewports on the Platform side (optional)
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can call io.AddMouseViewportEvent() with correct data (optional)
+    io.BackendFlags |= ImGuiBackendFlags_HasParentViewport;       // We can honor viewport->ParentViewportId by applying the corresponding parent/child relationship at platform levle (optional)
 
     bd->hWnd = (HWND)hwnd;
     bd->TicksPerSecond = perf_frequency;
@@ -184,10 +206,21 @@ static bool ImGui_ImplWin32_InitEx(void* hwnd, bool platform_has_own_dc)
     bd->LastMouseCursor = ImGuiMouseCursor_COUNT;
     ImGui_ImplWin32_UpdateKeyboardCodePage(io);
 
+    // Update monitor a first time during init
+    ImGui_ImplWin32_UpdateMonitors();
+
     // Our mouse update function expect PlatformHandle to be filled for the main viewport
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     main_viewport->PlatformHandle = main_viewport->PlatformHandleRaw = (void*)bd->hWnd;
-    IM_UNUSED(platform_has_own_dc); // Used in 'docking' branch
+
+    // Be aware that GetPropA()/SetPropA() may be accessed from other processes.
+    // So as we store a pointer in IMGUI_CONTEXT we need to make sure we only call GetPropA() on windows owned by our process.
+    ::SetPropA(bd->hWnd, "IMGUI_CONTEXT", ImGui::GetCurrentContext());
+    ImGui_ImplWin32_InitMultiViewportSupport(platform_has_own_dc);
+
+    if (HINSTANCE user32_dll = ::GetModuleHandleA("user32.dll"))
+        bd->AdjustWindowRectExForDpi = (PFN_AdjustWindowRectExForDpi)::GetProcAddress(user32_dll, "AdjustWindowRectExForDpi");
+    bd->IsPerMonitorDpiAwareV2 = ImGui_ImplWin32_IsDpiAwarenessPerMonitorAwareV2();
 
     // Dynamically load XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
@@ -231,6 +264,9 @@ void    ImGui_ImplWin32_Shutdown()
     ImGuiIO& io = ImGui::GetIO();
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
+    ::SetPropA(bd->hWnd, "IMGUI_CONTEXT", nullptr);
+    ImGui_ImplWin32_ShutdownMultiViewportSupport();
+
     // Unload XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     if (bd->XInputDLL)
@@ -239,7 +275,7 @@ void    ImGui_ImplWin32_Shutdown()
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport | ImGuiBackendFlags_HasParentViewport);
     platform_io.ClearPlatformHandlers();
     IM_DELETE(bd);
 }
@@ -312,32 +348,69 @@ static void ImGui_ImplWin32_UpdateKeyModifiers(ImGuiIO& io)
     io.AddKeyEvent(ImGuiMod_Super, IsVkDown(VK_LWIN) || IsVkDown(VK_RWIN));
 }
 
-static void ImGui_ImplWin32_UpdateMouseData(ImGuiIO& io)
+static ImGuiViewport* ImGui_ImplWin32_FindViewportByPlatformHandle(ImGuiPlatformIO& platform_io, HWND hwnd)
+{
+    // We cannot use ImGui::FindViewportByPlatformHandle() because it doesn't take a context.
+    // When called from ImGui_ImplWin32_WndProcHandler_PlatformWindow() we don't assume that context is bound.
+    //return ImGui::FindViewportByPlatformHandle((void*)hwnd);
+    for (ImGuiViewport* viewport : platform_io.Viewports)
+        if (viewport->PlatformHandle == hwnd)
+            return viewport;
+    return nullptr;
+}
+
+// This code supports multi-viewports (multiple OS Windows mapped into different Dear ImGui viewports)
+// Because of that, it is a little more complicated than your typical single-viewport binding code!
+static void ImGui_ImplWin32_UpdateMouseData(ImGuiIO& io, ImGuiPlatformIO& platform_io)
 {
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData(io);
     IM_ASSERT(bd->hWnd != 0);
 
+    POINT mouse_screen_pos;
+    bool has_mouse_screen_pos = ::GetCursorPos(&mouse_screen_pos) != 0;
+
     HWND focused_window = ::GetForegroundWindow();
-    const bool is_app_focused = (focused_window == bd->hWnd);
+    const bool is_app_focused = (focused_window && (focused_window == bd->hWnd || ::IsChild(focused_window, bd->hWnd) || ImGui_ImplWin32_FindViewportByPlatformHandle(platform_io, focused_window)));
     if (is_app_focused)
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
+        // When multi-viewports are enabled, all Dear ImGui positions are same as OS positions.
         if (io.WantSetMousePos)
         {
             POINT pos = { (int)io.MousePos.x, (int)io.MousePos.y };
-            if (::ClientToScreen(bd->hWnd, &pos))
-                ::SetCursorPos(pos.x, pos.y);
+            if ((io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) == 0)
+                ::ClientToScreen(focused_window, &pos);
+            ::SetCursorPos(pos.x, pos.y);
         }
 
         // (Optional) Fallback to provide mouse position when focused (WM_MOUSEMOVE already provides this when hovered or captured)
         // This also fills a short gap when clicking non-client area: WM_NCMOUSELEAVE -> modal OS move -> gap -> WM_NCMOUSEMOVE
-        if (!io.WantSetMousePos && bd->MouseTrackedArea == 0)
+        if (!io.WantSetMousePos && bd->MouseTrackedArea == 0 && has_mouse_screen_pos)
         {
-            POINT pos;
-            if (::GetCursorPos(&pos) && ::ScreenToClient(bd->hWnd, &pos))
-                io.AddMousePosEvent((float)pos.x, (float)pos.y);
+            // Single viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+            // (This is the position you can get with ::GetCursorPos() + ::ScreenToClient() or WM_MOUSEMOVE.)
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+            // (This is the position you can get with ::GetCursorPos() or WM_MOUSEMOVE + ::ClientToScreen(). In theory adding viewport->Pos to a client position would also be the same.)
+            POINT mouse_pos = mouse_screen_pos;
+            if (!(io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable))
+                ::ScreenToClient(bd->hWnd, &mouse_pos);
+            io.AddMousePosEvent((float)mouse_pos.x, (float)mouse_pos.y);
         }
     }
+
+    // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+    // - [X] Win32 backend correctly ignore viewports with the _NoInputs flag (here using ::WindowFromPoint with WM_NCHITTEST + HTTRANSPARENT in WndProc does that)
+    //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+    //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+    //       by the backend, and use its flawed heuristic to guess the viewport behind.
+    // - [X] Win32 backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+    ImGuiID mouse_viewport_id = 0;
+    if (has_mouse_screen_pos)
+        if (HWND hovered_hwnd = ::WindowFromPoint(mouse_screen_pos))
+            if (ImGuiViewport* viewport = ImGui_ImplWin32_FindViewportByPlatformHandle(platform_io, hovered_hwnd))
+                mouse_viewport_id = viewport->ID;
+    io.AddMouseViewportEvent(mouse_viewport_id);
 }
 
 // Gamepad navigation mapping
@@ -399,25 +472,59 @@ static void ImGui_ImplWin32_UpdateGamepads(ImGuiIO& io)
 #endif
 }
 
+static BOOL CALLBACK ImGui_ImplWin32_UpdateMonitors_EnumFunc(HMONITOR monitor, HDC, LPRECT, LPARAM)
+{
+    MONITORINFO info = {};
+    info.cbSize = sizeof(MONITORINFO);
+    if (!::GetMonitorInfo(monitor, &info))
+        return TRUE;
+    ImGuiPlatformMonitor imgui_monitor;
+    imgui_monitor.MainPos = ImVec2((float)info.rcMonitor.left, (float)info.rcMonitor.top);
+    imgui_monitor.MainSize = ImVec2((float)(info.rcMonitor.right - info.rcMonitor.left), (float)(info.rcMonitor.bottom - info.rcMonitor.top));
+    imgui_monitor.WorkPos = ImVec2((float)info.rcWork.left, (float)info.rcWork.top);
+    imgui_monitor.WorkSize = ImVec2((float)(info.rcWork.right - info.rcWork.left), (float)(info.rcWork.bottom - info.rcWork.top));
+    imgui_monitor.DpiScale = ImGui_ImplWin32_GetDpiScaleForMonitor(monitor);
+    imgui_monitor.PlatformHandle = (void*)monitor;
+    if (imgui_monitor.DpiScale <= 0.0f)
+        return TRUE; // Some accessibility applications are declaring virtual monitors with a DPI of 0, see #7902.
+    ImGuiPlatformIO& io = ImGui::GetPlatformIO();
+    if (info.dwFlags & MONITORINFOF_PRIMARY)
+        io.Monitors.push_front(imgui_monitor);
+    else
+        io.Monitors.push_back(imgui_monitor);
+    return TRUE;
+}
+
+static void ImGui_ImplWin32_UpdateMonitors()
+{
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    ImGui::GetPlatformIO().Monitors.resize(0);
+    ::EnumDisplayMonitors(nullptr, nullptr, ImGui_ImplWin32_UpdateMonitors_EnumFunc, 0);
+    bd->WantUpdateMonitors = false;
+}
+
 void    ImGui_ImplWin32_NewFrame()
 {
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized? Did you call ImGui_ImplWin32_Init()?");
     ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
     // Setup display size (every frame to accommodate for window resizing)
     RECT rect = { 0, 0, 0, 0 };
     ::GetClientRect(bd->hWnd, &rect);
     io.DisplaySize = ImVec2((float)(rect.right - rect.left), (float)(rect.bottom - rect.top));
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplWin32_UpdateMonitors();
 
     // Setup time step
     INT64 current_time = 0;
     ::QueryPerformanceCounter((LARGE_INTEGER*)&current_time);
-    io.DeltaTime = (float)((double)(current_time - bd->Time) / (double)bd->TicksPerSecond);
+    io.DeltaTime = (float)(current_time - bd->Time) / bd->TicksPerSecond;
     bd->Time = current_time;
 
     // Update OS mouse position
-    ImGui_ImplWin32_UpdateMouseData(io);
+    ImGui_ImplWin32_UpdateMouseData(io, platform_io);
 
     // Process workarounds for known Windows key handling issues
     ImGui_ImplWin32_ProcessKeyEventsWorkarounds(io);
@@ -622,6 +729,10 @@ static ImGuiMouseSource ImGui_ImplWin32_GetMouseSourceFromMessageExtraInfo()
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);                // Use ImGui::GetCurrentContext()
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam, ImGuiIO& io); // Doesn't use ImGui::GetCurrentContext()
 
+#ifndef WM_DPICHANGED
+#define WM_DPICHANGED 0x02E0 // From Windows SDK 8.1+ headers
+#endif
+
 IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     // Most backends don't have silent checks like this one, but we need it because WndProc are called early in CreateWindow().
@@ -656,8 +767,11 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hwnd, UINT msg, WPA
             bd->MouseTrackedArea = area;
         }
         POINT mouse_pos = { (LONG)GET_X_LPARAM(lParam), (LONG)GET_Y_LPARAM(lParam) };
-        if (msg == WM_NCMOUSEMOVE) // WM_NCMOUSEMOVE are absolute coordinates.
-             ::ScreenToClient(hwnd, &mouse_pos);
+        bool want_absolute_pos = (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) != 0;
+        if (msg == WM_MOUSEMOVE && want_absolute_pos)    // WM_MOUSEMOVE are client-relative coordinates.
+            ::ClientToScreen(hwnd, &mouse_pos);
+        if (msg == WM_NCMOUSEMOVE && !want_absolute_pos) // WM_NCMOUSEMOVE are absolute coordinates.
+            ::ScreenToClient(hwnd, &mouse_pos);
         io.AddMouseSourceEvent(mouse_source);
         io.AddMousePosEvent((float)mouse_pos.x, (float)mouse_pos.y);
         return 0;
@@ -827,6 +941,21 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hwnd, UINT msg, WPA
             bd->WantUpdateHasGamepad = true;
 #endif
         return 0;
+    case WM_DISPLAYCHANGE:
+        bd->WantUpdateMonitors = true;
+        return 0;
+    case WM_SETTINGCHANGE:
+        if (wParam == SPI_SETWORKAREA)
+            bd->WantUpdateMonitors = true;
+        return 0;
+    case WM_DPICHANGED:
+    {
+        // FIXME-DPI: see SDL3's WM_GETDPISCALEDSIZE handler.
+        const RECT* suggested_rect = (RECT*)lParam;
+        if (io.ConfigDpiScaleViewports)
+            ::SetWindowPos(hwnd, nullptr, suggested_rect->left, suggested_rect->top, suggested_rect->right - suggested_rect->left, suggested_rect->bottom - suggested_rect->top, SWP_NOZORDER | SWP_NOACTIVATE);
+        return 0;
+    }
     }
     return 0;
 }
@@ -884,23 +1013,23 @@ DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
 #ifndef DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2
 #define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 (DPI_AWARENESS_CONTEXT)-4
 #endif
-typedef HRESULT(WINAPI* PFN_SetProcessDpiAwareness)(PROCESS_DPI_AWARENESS);                     // Shcore.lib + dll, Windows 8.1+
-typedef HRESULT(WINAPI* PFN_GetDpiForMonitor)(HMONITOR, MONITOR_DPI_TYPE, UINT*, UINT*);        // Shcore.lib + dll, Windows 8.1+
-typedef DPI_AWARENESS_CONTEXT(WINAPI* PFN_SetThreadDpiAwarenessContext)(DPI_AWARENESS_CONTEXT); // User32.lib + dll, Windows 10 v1607+ (Creators Update)
-typedef BOOL(WINAPI* PFN_SetProcessDpiAwarenessContext)(DPI_AWARENESS_CONTEXT);                 // User32.lib + dll, Windows 10 v1703+ (Creators Update)
+typedef HRESULT(WINAPI* PFN_SetProcessDpiAwareness)(PROCESS_DPI_AWARENESS);                             // Shcore.lib + dll, Windows 8.1+
+typedef HRESULT(WINAPI* PFN_GetDpiForMonitor)(HMONITOR, MONITOR_DPI_TYPE, UINT*, UINT*);                // Shcore.lib + dll, Windows 8.1+
+typedef DPI_AWARENESS_CONTEXT(WINAPI* PFN_SetThreadDpiAwarenessContext)(DPI_AWARENESS_CONTEXT);         // User32.lib + dll, Windows 10 v1607+ (Creators Update)
+typedef DPI_AWARENESS_CONTEXT(WINAPI* PFN_GetThreadDpiAwarenessContext)();                              // "
+typedef BOOL(WINAPI* PFN_AreDpiAwarenessContextsEqual)(DPI_AWARENESS_CONTEXT, DPI_AWARENESS_CONTEXT);   // "
 
 // Helper function to enable DPI awareness without setting up a manifest
 void ImGui_ImplWin32_EnableDpiAwareness()
 {
+    // Make sure monitors will be updated with latest correct scaling
+    if (ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData())
+        bd->WantUpdateMonitors = true;
+
     if (_IsWindows10OrGreater())
     {
         static HINSTANCE user32_dll = ::LoadLibraryA("user32.dll"); // Reference counted per-process
-        if (PFN_SetProcessDpiAwarenessContext SetProcessDpiAwarenessContextFn = (PFN_SetProcessDpiAwarenessContext)::GetProcAddress(user32_dll, "SetProcessDpiAwarenessContext")) // Windows 10 v1703+
-        {
-            SetProcessDpiAwarenessContextFn(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
-            return;
-        }
-        if (PFN_SetThreadDpiAwarenessContext SetThreadDpiAwarenessContextFn = (PFN_SetThreadDpiAwarenessContext)::GetProcAddress(user32_dll, "SetThreadDpiAwarenessContext")) // Windows 10 v1607+
+        if (PFN_SetThreadDpiAwarenessContext SetThreadDpiAwarenessContextFn = (PFN_SetThreadDpiAwarenessContext)::GetProcAddress(user32_dll, "SetThreadDpiAwarenessContext"))
         {
             SetThreadDpiAwarenessContextFn(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
             return;
@@ -920,6 +1049,18 @@ void ImGui_ImplWin32_EnableDpiAwareness()
 #endif
 }
 
+static bool ImGui_ImplWin32_IsDpiAwarenessPerMonitorAwareV2()
+{
+    if (!_IsWindows10OrGreater())
+        return false;
+    static HINSTANCE user32_dll = ::GetModuleHandleA("user32.dll");
+    PFN_GetThreadDpiAwarenessContext GetThreadDpiAwarenessContextFn = (PFN_GetThreadDpiAwarenessContext)::GetProcAddress(user32_dll, "GetThreadDpiAwarenessContext");
+    PFN_AreDpiAwarenessContextsEqual AreDpiAwarenessContextsEqualFn = (PFN_AreDpiAwarenessContextsEqual)::GetProcAddress(user32_dll, "AreDpiAwarenessContextsEqual");
+    if (GetThreadDpiAwarenessContextFn && AreDpiAwarenessContextsEqualFn)
+        return AreDpiAwarenessContextsEqualFn(GetThreadDpiAwarenessContextFn(), DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2) != 0;
+    return false;
+}
+
 #if defined(_MSC_VER) && !defined(NOGDI)
 #pragma comment(lib, "gdi32")   // Link with gdi32.lib for GetDeviceCaps(). MinGW will require linking with '-lgdi32'
 #endif
@@ -937,7 +1078,7 @@ float ImGui_ImplWin32_GetDpiScaleForMonitor(void* monitor)
         {
             GetDpiForMonitorFn((HMONITOR)monitor, MDT_EFFECTIVE_DPI, &xdpi, &ydpi);
             IM_ASSERT(xdpi == ydpi); // Please contact me if you hit this assert!
-            return (float)xdpi / 96.0f;
+            return xdpi / 96.0f;
         }
     }
 #ifndef NOGDI
@@ -947,7 +1088,7 @@ float ImGui_ImplWin32_GetDpiScaleForMonitor(void* monitor)
     IM_ASSERT(xdpi == ydpi); // Please contact me if you hit this assert!
     ::ReleaseDC(nullptr, dc);
 #endif
-    return (float)xdpi / 96.0f;
+    return xdpi / 96.0f;
 }
 
 float ImGui_ImplWin32_GetDpiScaleForHwnd(void* hwnd)
@@ -996,6 +1137,398 @@ void ImGui_ImplWin32_EnableAlphaCompositing(void* hwnd)
     }
 }
 
+//---------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplWin32_ViewportData
+{
+    HWND    Hwnd;               // Stored in ImGuiViewport::PlatformHandle + PlatformHandleRaw
+    HWND    HwndParent;
+    bool    HwndOwned;
+    DWORD   DwStyle;
+    DWORD   DwExStyle;
+
+    ImGui_ImplWin32_ViewportData() { Hwnd = HwndParent = nullptr; HwndOwned = false;  DwStyle = DwExStyle = 0; }
+    ~ImGui_ImplWin32_ViewportData() { IM_ASSERT(Hwnd == nullptr); }
+};
+
+static void ImGui_ImplWin32_GetWin32StyleFromViewportFlags(ImGuiViewportFlags flags, DWORD* out_style, DWORD* out_ex_style)
+{
+    if (flags & ImGuiViewportFlags_NoDecoration)
+        *out_style = WS_POPUP;
+    else
+        *out_style = WS_OVERLAPPEDWINDOW;
+
+    if (flags & ImGuiViewportFlags_NoTaskBarIcon)
+        *out_ex_style = WS_EX_TOOLWINDOW;
+    else
+        *out_ex_style = WS_EX_APPWINDOW;
+
+    if (flags & ImGuiViewportFlags_TopMost)
+        *out_ex_style |= WS_EX_TOPMOST;
+}
+
+static HWND ImGui_ImplWin32_GetHwndFromViewport(ImGuiViewport* viewport)
+{
+    if (viewport != nullptr)
+        return (HWND)viewport->PlatformHandle;
+    return nullptr;
+}
+
+static void ImGui_ImplWin32_AdjustWindowRect(ImGuiViewport* viewport, RECT* rect, DWORD style, DWORD ex_style)
+{
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    if (bd->AdjustWindowRectExForDpi && bd->IsPerMonitorDpiAwareV2)
+    {
+        UINT dpi = (UINT)(viewport->DpiScale * 96.0f + 0.5f);
+        if (dpi != 0 && bd->AdjustWindowRectExForDpi(rect, style, FALSE, ex_style, dpi))
+            return;
+    }
+    ::AdjustWindowRectEx(rect, style, FALSE, ex_style);
+}
+
+static void ImGui_ImplWin32_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = IM_NEW(ImGui_ImplWin32_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    // Select style and parent window
+    ImGui_ImplWin32_GetWin32StyleFromViewportFlags(viewport->Flags, &vd->DwStyle, &vd->DwExStyle);
+    vd->HwndParent = ImGui_ImplWin32_GetHwndFromViewport(viewport->ParentViewport);
+
+    // Create window
+    RECT rect = { (LONG)viewport->Pos.x, (LONG)viewport->Pos.y, (LONG)(viewport->Pos.x + viewport->Size.x), (LONG)(viewport->Pos.y + viewport->Size.y) };
+    ImGui_ImplWin32_AdjustWindowRect(viewport, &rect, vd->DwStyle, vd->DwExStyle);
+    vd->Hwnd = ::CreateWindowExW(
+        vd->DwExStyle, L"ImGui Platform", L"Untitled", vd->DwStyle,       // Style, class name, window name
+        rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,    // Window area
+        vd->HwndParent, nullptr, ::GetModuleHandle(nullptr), nullptr);          // Owner window, Menu, Instance, Param
+    vd->HwndOwned = true;
+    viewport->PlatformRequestResize = false;
+    viewport->PlatformHandle = viewport->PlatformHandleRaw = vd->Hwnd;
+
+    // Secondary viewports store their imgui context
+    ::SetPropA(vd->Hwnd, "IMGUI_CONTEXT", ImGui::GetCurrentContext());
+}
+
+static void ImGui_ImplWin32_DestroyWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    if (ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData)
+    {
+        if (::GetCapture() == vd->Hwnd)
+        {
+            // Transfer capture so if we started dragging from a window that later disappears, we'll still receive the MOUSEUP event.
+            ::ReleaseCapture();
+            ::SetCapture(bd->hWnd);
+        }
+        if (vd->Hwnd && vd->HwndOwned)
+            ::DestroyWindow(vd->Hwnd);
+        vd->Hwnd = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplWin32_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+
+    // ShowParent() even with SW_SHOWNA also brings parent to front, which is not always desirable,
+    // so we temporarily disable parenting. (#7354, #8669)
+    bool avoid_bringing_parent_to_front = vd->HwndParent != NULL && (viewport->Flags & (ImGuiViewportFlags_NoFocusOnAppearing | ImGuiViewportFlags_NoTaskBarIcon)) != 0;
+    if (avoid_bringing_parent_to_front)
+        ::SetWindowLongPtr(vd->Hwnd, GWLP_HWNDPARENT, (LONG_PTR)nullptr);
+
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+        ::ShowWindow(vd->Hwnd, SW_SHOWNA);
+    else
+        ::ShowWindow(vd->Hwnd, SW_SHOW);
+
+    // Restore
+    if (avoid_bringing_parent_to_front)
+        ::SetWindowLongPtr(vd->Hwnd, GWLP_HWNDPARENT, (LONG_PTR)vd->HwndParent);
+}
+
+static void ImGui_ImplWin32_UpdateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+
+    // Update Win32 parent if it changed _after_ creation
+    // Unlike style settings derived from configuration flags, this is more likely to change for advanced apps that are manipulating ParentViewportID manually.
+    HWND new_parent = ImGui_ImplWin32_GetHwndFromViewport(viewport->ParentViewport);
+    if (new_parent != vd->HwndParent)
+    {
+        // Win32 windows can either have a "Parent" (for WS_CHILD window) or an "Owner" (which among other thing keeps window above its owner).
+        // Our Dear Imgui-side concept of parenting only mostly care about what Win32 call "Owner".
+        // The parent parameter of CreateWindowEx() sets up Parent OR Owner depending on WS_CHILD flag. In our case an Owner as we never use WS_CHILD.
+        // Calling ::SetParent() here would be incorrect: it will create a full child relation, alter coordinate system and clipping.
+        // Calling ::SetWindowLongPtr() with GWLP_HWNDPARENT seems correct although poorly documented.
+        // https://devblogs.microsoft.com/oldnewthing/20100315-00/?p=14613
+        vd->HwndParent = new_parent;
+        ::SetWindowLongPtr(vd->Hwnd, GWLP_HWNDPARENT, (LONG_PTR)vd->HwndParent);
+    }
+
+    // (Optional) Update Win32 style if it changed _after_ creation.
+    // Generally they won't change unless configuration flags are changed, but advanced uses (such as manually rewriting viewport flags) make this useful.
+    DWORD new_style;
+    DWORD new_ex_style;
+    ImGui_ImplWin32_GetWin32StyleFromViewportFlags(viewport->Flags, &new_style, &new_ex_style);
+
+    // Only reapply the flags that have been changed from our point of view (as other flags are being modified by Windows)
+    if (vd->DwStyle != new_style || vd->DwExStyle != new_ex_style)
+    {
+        // (Optional) Update TopMost state if it changed _after_ creation
+        bool top_most_changed = (vd->DwExStyle & WS_EX_TOPMOST) != (new_ex_style & WS_EX_TOPMOST);
+        HWND insert_after = top_most_changed ? ((viewport->Flags & ImGuiViewportFlags_TopMost) ? HWND_TOPMOST : HWND_NOTOPMOST) : 0;
+        UINT swp_flag = top_most_changed ? 0 : SWP_NOZORDER;
+
+        // Apply flags and position (since it is affected by flags)
+        vd->DwStyle = new_style;
+        vd->DwExStyle = new_ex_style;
+        ::SetWindowLong(vd->Hwnd, GWL_STYLE, vd->DwStyle);
+        ::SetWindowLong(vd->Hwnd, GWL_EXSTYLE, vd->DwExStyle);
+        RECT rect = { (LONG)viewport->Pos.x, (LONG)viewport->Pos.y, (LONG)(viewport->Pos.x + viewport->Size.x), (LONG)(viewport->Pos.y + viewport->Size.y) };
+        ImGui_ImplWin32_AdjustWindowRect(viewport, &rect, vd->DwStyle, vd->DwExStyle); // Client to Screen
+        ::SetWindowPos(vd->Hwnd, insert_after, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, swp_flag | SWP_NOACTIVATE | SWP_FRAMECHANGED);
+        ::ShowWindow(vd->Hwnd, SW_SHOWNA); // This is necessary when we alter the style
+        viewport->PlatformRequestMove = viewport->PlatformRequestResize = true;
+    }
+}
+
+static ImVec2 ImGui_ImplWin32_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    POINT pos = { 0, 0 };
+    ::ClientToScreen(vd->Hwnd, &pos);
+    return ImVec2((float)pos.x, (float)pos.y);
+}
+
+static void ImGui_ImplWin32_UpdateWin32StyleFromWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    vd->DwStyle = ::GetWindowLongW(vd->Hwnd, GWL_STYLE);
+    vd->DwExStyle = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE);
+}
+
+static void ImGui_ImplWin32_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    RECT rect = { (LONG)pos.x, (LONG)pos.y, (LONG)pos.x, (LONG)pos.y };
+    if (viewport->Flags & ImGuiViewportFlags_OwnedByApp)
+        ImGui_ImplWin32_UpdateWin32StyleFromWindow(viewport); // Not our window, poll style before using
+    ImGui_ImplWin32_AdjustWindowRect(viewport, &rect, vd->DwStyle, vd->DwExStyle);
+    ::SetWindowPos(vd->Hwnd, nullptr, rect.left, rect.top, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_NOACTIVATE);
+}
+
+static ImVec2 ImGui_ImplWin32_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    RECT rect;
+    ::GetClientRect(vd->Hwnd, &rect);
+    return ImVec2(float(rect.right - rect.left), float(rect.bottom - rect.top));
+}
+
+static void ImGui_ImplWin32_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    RECT rect = { 0, 0, (LONG)size.x, (LONG)size.y };
+    if (viewport->Flags & ImGuiViewportFlags_OwnedByApp)
+        ImGui_ImplWin32_UpdateWin32StyleFromWindow(viewport); // Not our window, poll style before using
+    ImGui_ImplWin32_AdjustWindowRect(viewport, &rect, vd->DwStyle, vd->DwExStyle); // Client to Screen
+    ::SetWindowPos(vd->Hwnd, nullptr, 0, 0, rect.right - rect.left, rect.bottom - rect.top, SWP_NOZORDER | SWP_NOMOVE | SWP_NOACTIVATE);
+}
+
+static void ImGui_ImplWin32_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    ::BringWindowToTop(vd->Hwnd);
+    ::SetForegroundWindow(vd->Hwnd);
+    ::SetFocus(vd->Hwnd);
+}
+
+static bool ImGui_ImplWin32_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    return ::GetForegroundWindow() == vd->Hwnd;
+}
+
+static bool ImGui_ImplWin32_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    return ::IsIconic(vd->Hwnd) != 0;
+}
+
+static void ImGui_ImplWin32_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    // ::SetWindowTextA() doesn't properly handle UTF-8 so we explicitely convert our string.
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    int n = ::MultiByteToWideChar(CP_UTF8, 0, title, -1, nullptr, 0);
+    ImVector<wchar_t> title_w;
+    title_w.resize(n);
+    ::MultiByteToWideChar(CP_UTF8, 0, title, -1, title_w.Data, n);
+
+    // Calling SetWindowTextW() in a project where UNICODE is not set doesn't work but there's a trick
+    // which is to pass it directly to the DefWindowProcW() handler.
+    // See: https://stackoverflow.com/questions/9410681/setwindowtextw-in-an-ansi-project
+    //::SetWindowTextW(vd->Hwnd, title_w.Data);
+    ::DefWindowProcW(vd->Hwnd, WM_SETTEXT, 0, (LPARAM)title_w.Data);
+}
+
+static void ImGui_ImplWin32_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    IM_ASSERT(alpha >= 0.0f && alpha <= 1.0f);
+    if (alpha < 1.0f)
+    {
+        DWORD ex_style = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE) | WS_EX_LAYERED;
+        ::SetWindowLongW(vd->Hwnd, GWL_EXSTYLE, ex_style);
+        ::SetLayeredWindowAttributes(vd->Hwnd, 0, (BYTE)(255 * alpha), LWA_ALPHA);
+    }
+    else
+    {
+        DWORD ex_style = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE) & ~WS_EX_LAYERED;
+        ::SetWindowLongW(vd->Hwnd, GWL_EXSTYLE, ex_style);
+    }
+}
+
+static float ImGui_ImplWin32_GetWindowDpiScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    return ImGui_ImplWin32_GetDpiScaleForHwnd(vd->Hwnd);
+}
+
+// FIXME-DPI: Testing DPI related ideas
+static void ImGui_ImplWin32_OnChangedViewport(ImGuiViewport* viewport)
+{
+    (void)viewport;
+#if 0
+    ImGuiStyle default_style;
+    //default_style.WindowPadding = ImVec2(0, 0);
+    //default_style.WindowBorderSize = 0.0f;
+    //default_style.ItemSpacing.y = 3.0f;
+    //default_style.FramePadding = ImVec2(0, 0);
+    default_style.ScaleAllSizes(viewport->DpiScale);
+    ImGuiStyle& style = ImGui::GetStyle();
+    style = default_style;
+#endif
+}
+
+namespace ImGui { extern ImGuiIO& GetIO(ImGuiContext*); extern ImGuiPlatformIO& GetPlatformIO(ImGuiContext*); }
+
+static LRESULT CALLBACK ImGui_ImplWin32_WndProcHandler_PlatformWindow(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+    // Allow secondary viewport WndProc to be called regardless of current context
+    ImGuiContext* ctx = (ImGuiContext*)::GetPropA(hWnd, "IMGUI_CONTEXT");
+    if (ctx == NULL)
+        return ::DefWindowProcW(hWnd, msg, wParam, lParam); // unlike ImGui_ImplWin32_WndProcHandler() we are called directly by Windows, we can't just return 0.
+
+    ImGuiIO& io = ImGui::GetIO(ctx);
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO(ctx);
+    LRESULT result = 0;
+    if (ImGui_ImplWin32_WndProcHandlerEx(hWnd, msg, wParam, lParam, io))
+        result = 1;
+    else if (ImGuiViewport* viewport = ImGui_ImplWin32_FindViewportByPlatformHandle(platform_io, hWnd))
+    {
+        switch (msg)
+        {
+        case WM_CLOSE:
+            viewport->PlatformRequestClose = true;
+            return 0; // 0 = Operating system will ignore the message and not destroy the window. We close ourselves.
+        case WM_MOVE:
+            viewport->PlatformRequestMove = true;
+            break;
+        case WM_SIZE:
+            viewport->PlatformRequestResize = true;
+            break;
+        case WM_MOUSEACTIVATE:
+            if (viewport->Flags & ImGuiViewportFlags_NoFocusOnClick)
+                result = MA_NOACTIVATE;
+            break;
+        case WM_NCHITTEST:
+            // Let mouse pass-through the window. This will allow the backend to call io.AddMouseViewportEvent() correctly. (which is optional).
+            // The ImGuiViewportFlags_NoInputs flag is set while dragging a viewport, as want to detect the window behind the one we are dragging.
+            // If you cannot easily access those viewport flags from your windowing/event code: you may manually synchronize its state e.g. in
+            // your main loop after calling UpdatePlatformWindows(). Iterate all viewports/platform windows and pass the flag to your windowing system.
+            if (viewport->Flags & ImGuiViewportFlags_NoInputs)
+                result = HTTRANSPARENT;
+            break;
+        }
+    }
+    if (result == 0)
+        result = ::DefWindowProcW(hWnd, msg, wParam, lParam);
+    return result;
+}
+
+static void ImGui_ImplWin32_InitMultiViewportSupport(bool platform_has_own_dc)
+{
+    WNDCLASSEXW wcex;
+    wcex.cbSize = sizeof(WNDCLASSEXW);
+    wcex.style = CS_HREDRAW | CS_VREDRAW | (platform_has_own_dc ? CS_OWNDC : 0);
+    wcex.lpfnWndProc = ImGui_ImplWin32_WndProcHandler_PlatformWindow;
+    wcex.cbClsExtra = 0;
+    wcex.cbWndExtra = 0;
+    wcex.hInstance = ::GetModuleHandle(nullptr);
+    wcex.hIcon = nullptr;
+    wcex.hCursor = nullptr;
+    wcex.hbrBackground = (HBRUSH)(COLOR_BACKGROUND + 1);
+    wcex.lpszMenuName = nullptr;
+    wcex.lpszClassName = L"ImGui Platform";
+    wcex.hIconSm = nullptr;
+    ::RegisterClassExW(&wcex);
+
+    ImGui_ImplWin32_UpdateMonitors();
+
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplWin32_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplWin32_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplWin32_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplWin32_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplWin32_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplWin32_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplWin32_GetWindowSize;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplWin32_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplWin32_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplWin32_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplWin32_SetWindowTitle;
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplWin32_SetWindowAlpha;
+    platform_io.Platform_UpdateWindow = ImGui_ImplWin32_UpdateWindow;
+    platform_io.Platform_GetWindowDpiScale = ImGui_ImplWin32_GetWindowDpiScale; // FIXME-DPI
+    platform_io.Platform_OnChangedViewport = ImGui_ImplWin32_OnChangedViewport; // FIXME-DPI
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    ImGui_ImplWin32_ViewportData* vd = IM_NEW(ImGui_ImplWin32_ViewportData)();
+    vd->Hwnd = bd->hWnd;
+    vd->HwndOwned = false;
+    main_viewport->PlatformUserData = vd;
+}
+
+static void ImGui_ImplWin32_ShutdownMultiViewportSupport()
+{
+    ::UnregisterClassW(L"ImGui Platform", ::GetModuleHandle(nullptr));
+    ImGui::DestroyPlatformWindows();
+}
+
 //---------------------------------------------------------------------------------------------------------
 
 #if defined(__GNUC__)

backends/imgui_impl_win32.h

@@ -7,6 +7,7 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy VK_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/vulkan/glsl_shader.frag

@@ -1,8 +1,7 @@
 #version 450 core
 layout(location = 0) out vec4 fColor;
 
-layout(set=0, binding=0) uniform texture2D _Texture;
-layout(set=1, binding=0) uniform sampler _Sampler;
+layout(set=0, binding=0) uniform sampler2D sTexture;
 
 layout(location = 0) in struct {
     vec4 Color;
@@ -11,5 +10,5 @@ layout(location = 0) in struct {
 
 void main()
 {
-    fColor = In.Color * texture(sampler2D(_Texture, _Sampler), In.UV.st);
+    fColor = In.Color * texture(sTexture, In.UV.st);
 }

docs/BACKENDS.md

@@ -89,7 +89,6 @@ List of Renderer Backends:
     imgui_impl_dx11.cpp         ; DirectX11
     imgui_impl_dx12.cpp         ; DirectX12
     imgui_impl_metal.mm         ; Metal (ObjC or C++)
-    imgui_impl_metal4.mm        ; Metal 4 (ObjC or C++)
     imgui_impl_opengl2.cpp      ; OpenGL 2 (legacy fixed pipeline. Don't use with modern OpenGL code!)
     imgui_impl_opengl3.cpp      ; OpenGL 3/4, OpenGL ES 2/3, WebGL
     imgui_impl_sdlgpu3.cpp      ; SDL_GPU (portable 3D graphics API of SDL3)
@@ -184,6 +183,7 @@ The Platform backends in impl_impl_XXX.cpp files contain many implementations.
   - `ImGuiBackendFlags_HasSetMousePos`: supports io.WantSetMousePos requests to reposition the OS mouse position (only used if io.ConfigNavMoveSetMousePos is set).
   - `ImGuiBackendFlags_PlatformHasViewports` supports multiple viewports. (multi-viewports only)
   - `ImGuiBackendFlags_HasMouseHoveredViewport` supports calling io.AddMouseViewportEvent() with the viewport under the mouse. IF POSSIBLE, ignore viewports with the ImGuiViewportFlags_NoInputs flag. If this cannot be done, Dear ImGui needs to use a flawed heuristic to find the viewport under mouse position, as it doesn't know about foreign windows. (multi-viewports only)
+  - `ImGuiBackendFlags_HasParentViewport` supports honoring viewport->ParentViewportId value, by applying the corresponding parent/child relation at the Platform level.
 
 **In your `ImGui_ImplXXX_NewFrame()` function:**
 - Set `io.DeltaTime` to the time elapsed (in seconds) since last frame.
@@ -256,8 +256,8 @@ void MyImGuiBackend_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
-                if (pcmd->UserCallback == platform_io.DrawCallback_ResetRenderState)
-                    MyEngineSetupSenderState();
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    MyEngineSetupenderState();
                 else
                     pcmd->UserCallback(cmd_list, pcmd);
             }

docs/EXAMPLES.md

@@ -164,10 +164,6 @@ SDL3 + DirectX11 examples, Windows only. <BR>
 SDL3 + Metal example, Mac only. <BR>
 = main.cpp + imgui_impl_sdl3.cpp + imgui_impl_metal.mm <BR>
 
-[example_sdl3_metal4/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl3_metal/) <BR>
-SDL3 + Metal4 example, Mac only. <BR>
-= main.cpp + imgui_impl_sdl3.cpp + imgui_impl_metal4.mm <BR>
-
 [example_sdl3_opengl3/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl3_opengl3/) <BR>
 SDL3 (Win32, Mac, Linux, etc.) + OpenGL3+/ES2/ES3 example. <BR>
 = main.cpp + imgui_impl_sdl3.cpp + imgui_impl_opengl3.cpp <BR>

docs/FONTS.md

@@ -77,17 +77,6 @@ Some solutions:
   You can use the `ImFontGlyphRangesBuilder` for this purpose and rebuilding your atlas between frames when new characters are needed. This will be the biggest win!
 - Set `io.Fonts.Flags |= ImFontAtlasFlags_NoPowerOfTwoHeight;` to disable rounding the texture height to the next power of two.
 
-### (5) Reduce texture resizes/copy on startup
-
-🆕 Since 1.92, the ImFontAtlas is initially created using a 512x128 texture, then grows as glyphs and fonts are used. Atlas growth leads to alloc+copy, and both the old and new sized textures are present in memory for a short time (typically one frame). If you use known fonts and want to reduce initial growth, you may set `TexMinWidth` and `TexMinHeight` during initializaton.
-
-```cpp
-ImFontAtlas* atlas = io.Fonts;
-atlas->TexMinWidth = 1024;
-atlas->TexMinHeight = 1024;
-atlas->AddFont(...);
-```
-
 ##### [Return to Index](#index)
 
 ---------------------------------------

docs/README.md

@@ -43,7 +43,7 @@ Dear ImGui is particularly suited to integration in game engines (for tooling),
 
 **Backends for a variety of graphics API and rendering platforms** are provided in the [backends/](https://github.com/ocornut/imgui/tree/master/backends) folder, along with example applications in the [examples/](https://github.com/ocornut/imgui/tree/master/examples) folder. You may also create your own backend. Anywhere where you can render textured triangles, you can render Dear ImGui.
 
-C++20 users wishing to use a module may use the [stripe2933/imgui-module](https://github.com/stripe2933/imgui-module) third-party extension.
+C++20 users wishing to use a module may the use [stripe2933/imgui-module](https://github.com/stripe2933/imgui-module) third-party extension.
 
 See the [Getting Started & Integration](#getting-started--integration) section of this document for more details.
 
@@ -141,7 +141,7 @@ Integrating Dear ImGui within your custom engine is a matter of mainly 1) wiring
 - Generally, **make sure to spend time reading the [FAQ](https://www.dearimgui.com/faq), comments, and the examples applications!**
 
 Officially maintained backends (in repository):
-- Renderers: DirectX9, DirectX10, DirectX11, DirectX12, Metal 3/4, OpenGL/ES/ES2, SDL_GPU, SDL_Renderer2/3, Vulkan, WebGPU.
+- Renderers: DirectX9, DirectX10, DirectX11, DirectX12, Metal, OpenGL/ES/ES2, SDL_GPU, SDL_Renderer2/3, Vulkan, WebGPU.
 - Platforms: GLFW, SDL2/SDL3, Win32, Glut, OSX, Android.
 - Frameworks: Allegro5, Emscripten.
 

docs/SECURITY.md

@@ -1,17 +0,0 @@
-# Security Policy
-
-Dear ImGui is primarily designed for developer tools and technical applications running trusted code and trusted data. 
-
-Given that the library was not designed as a hardened security boundary against hostile or intentionally malformed inputs: 
-consider not using it in a context where a crash (through e.g. intentionally malformed inputs) could lead to privilege elevation. 
-E.g. running in a privileged process and interacting with non-privileged clients feeding code or data to Dear ImGui.
-
-Dear ImGui development efforts are focused on improving developer experience, usability, correctness, and robustness in real-world applications. 
-We will do our best to reduce e.g. crashes caused by common programmer mistakes.
-
-However, the project does not specifically focus on adversarial fuzzing scenarios, allocation-failure hardening, or highly artificial edge cases that are unlikely to occur in normal usage.
-
-## Reporting a Vulnerability
-
-Considering the above policy, most things may be reported in GitHub Issues.
-If you have a reason to disclose privately, please reach out to the contact address listed in README.

docs/TODO.txt

@@ -2,14 +2,12 @@ dear imgui
 ISSUES & TODO LIST
 
 Issue numbers (#) refer to GitHub issues listed at https://github.com/ocornut/imgui/issues/XXXX
-
 THIS LIST IS NOT WELL MAINTAINED. MOST OF THE WORK HAPPENS ON GITHUB NOWADAYS.
-
 The list below consist mostly of ideas noted down before they are requested/discussed by users (at which point they usually exist on the github issue tracker).
 It's mostly a bunch of personal notes, probably incomplete. Feel free to query if you have any questions.
 
- - doc: checklist app to verify backends/integration of imgui (test inputs, rendering, callback, etc.).
  - doc: add a proper documentation system (maybe relying on automation? #435)
+ - doc: checklist app to verify backends/integration of imgui (test inputs, rendering, callback, etc.).
  - doc/tips: tips of the day: website? applet in imgui_club?
 
  - window: preserve/restore relative focus ordering (persistent or not), and e.g. of multiple reappearing windows (#2304) -> also see docking reference to same #.
@@ -31,9 +29,9 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - window/clipping: some form of clipping when DisplaySize (or corresponding viewport) is zero.
  - window/tabbing: add a way to signify that a window or docked window requires attention (e.g. blinking title bar, trying to click behind a modal).
  - window/id_stack: add e.g. window->GetIDFromPath() with support for leading / and ../ (#1390, #331) -> model from test engine.
-
- ! scrolling: exposing horizontal scrolling with Shift+Wheel even when scrollbar is disabled expose various issues (#2424, #1463)
+ ! scrolling: exposing horizontal scrolling with Shift+Wheel even when scrollbar is disabled expose lots of issues (#2424, #1463)
  - scrolling: while holding down a scrollbar, try to keep the same contents visible (at least while not moving mouse)
+ - scrolling: allow immediately effective change of scroll after Begin() if we haven't appended items yet.
  - scrolling: forward mouse wheel scrolling to parent window when at the edge of scrolling limits? (useful for listbox,tables?)
  - scrolling/style: shadows on scrollable areas to denote that there is more contents (see e.g. DaVinci Resolve ui)
 
@@ -53,32 +51,38 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - widgets: display mode: widget-label, label-widget (aligned on column or using fixed size), label-newline-tab-widget etc. (#395)
  - widgets: clean up widgets internal toward exposing everything and stabilizing imgui_internals.h.
  - widgets: add always-allow-overlap mode. This should perhaps be the default? one problem is that highlight after mouse-wheel scrolling gets deferred, makes scrolling more flickery.
+ - widgets: start exposing PushItemFlag() and ImGuiItemFlags
  - widgets: alignment options in style (e.g. center Selectable, Right-Align within Button, etc.) #1260
  - widgets: activate by identifier (trigger button, focus given id)
  - widgets: custom glyph/shapes replacements for stock shapes. (also #6090 #2431 #2235 #6517)
  - widgets: coloredit: keep reporting as active when picker is on?
- - widgets: group/ScalarN functions: expose more per-component information. e.g. store NextItemData.ComponentIdx set by scalarn function, groups can expose them back somehow.
+ - widgets: group/scalarn functions: expose more per-component information. e.g. store NextItemData.ComponentIdx set by scalarn function, groups can expose them back somehow.
  - selectable: using (size.x == 0.0f) and (SelectableTextAlign.x > 0.0f) followed by SameLine() is currently not supported.
  - selectable: generic BeginSelectable()/EndSelectable() mechanism. (work out alongside range-select branch)
  - selectable: a way to visualize partial/mixed selection (e.g. parent tree node has children with mixed selection)
 
- - input text: flag to disable live update of the user buffer (also applies to float/int text input) (#701)
  - input text: preserve scrolling when unfocused?
  - input text: reorganize event handling, allow CharFilter to modify buffers, allow multiple events? (#541)
+ - input text: expose CursorPos in char filter event (#816)
+ - input text: try usage idiom of using InputText with data only exposed through get/set accessors, without extraneous copy/alloc. (#3009)
+ - input text: access public fields via a non-callback API e.g. InputTextGetState("xxx") that may return nullptr if not active (available in internals)
+ - input text: flag to disable live update of the user buffer (also applies to float/int text input) (#701)
  - input text: hover tooltip could show unclamped text
  - input text: support for INSERT key to toggle overwrite mode. currently disabled because stb_textedit behavior is unsatisfactory on multi-line. (#2863)
  - input text: option to Tab after an Enter validation.
  - input text: add ImGuiInputTextFlags_EnterToApply? (off #218)
  - input text: easier ways to update buffer (from source char*) while owned. preserve some sort of cursor position for multi-line text.
  - input text: add discard flag (e.g. ImGuiInputTextFlags_DiscardActiveBuffer) or make it easier to clear active focus for text replacement during edition (#725)
+ - input text: display bug when clicking a drag/slider after an input text in a different window has all-selected text (order dependent). actually a very old bug but no one appears to have noticed it.
  - input text: allow centering/positioning text so that ctrl+clicking Drag or Slider keeps the textual value at the same pixel position.
  - input text: decorrelate display layout from inputs with custom template - e.g. what's the easiest way to implement a nice IP/Mac address input editor?
- - input text: callback system (global) so user can plug in an expression evaluator easily. (#1691)
+ - input text: global callback system so user can plug in an expression evaluator easily. (#1691)
  - input text: force scroll to end or scroll to a given line/contents (so user can implement a log or a search feature)
  - input text: a way to preview completion (e.g. disabled text completing from the cursor)
  - input text: a side bar that could e.g. preview where errors are. probably left to the user to draw but we'd need to give them the info there.
  - input text: a way for the user to provide syntax coloring.
  - input text: Shift+TAB with ImGuiInputTextFlags_AllowTabInput could eat preceding blanks, up to tab_count.
+ - input text multi-line: don't directly call AddText() which does an unnecessary vertex reserve for character count prior to clipping. and/or more line-based clipping to AddText(). and/or reorganize TextUnformatted/RenderText for more efficiency for large text (e.g TextUnformatted could clip and log separately, etc).
  - input text multi-line: support for copy/cut without selection (copy/cut current line?)
  - input text multi-line: line numbers? status bar? (follow up on #200)
  - input text multi-line: behave better when user changes input buffer while editing is active (even though it is illegal behavior). namely, the change of buffer can create a scrollbar glitch (#725)
@@ -107,7 +111,11 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
 !- color: the color conversion helpers/types are a mess and needs sorting out.
  - color: (api breaking) ImGui::ColorConvertXXX functions should be loose ImColorConvertXX to match imgui_internals.h
 
+ - plot: full featured plot/graph api w/ scrolling, zooming etc. --> promote using ImPlot
+ - (plot: deleted all other todo lines on 2023-06-28)
+
  - clipper: ability to disable the clipping through a simple flag/bool.
+ - clipper: ability to run without knowing full count in advance.
  - clipper: horizontal clipping support. (#2580)
 
  - separator: expose flags (#759)
@@ -115,7 +123,35 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - separator: width, thickness, centering (#1643, #2657)
  - splitter: formalize the splitter idiom into an official api (we want to handle n-way split) (#319)
 
- - docking: merge docking branch (#2109)
+ - docking: B: ordering currently held in tab bar should be implicitly held by windows themselves (also see #2304)
+ - docking: B- tab bar: the order/focus restoring code could be part of TabBar and not DockNode? (#8)
+ - docking: B~ rework code to be able to lazily create tab bar instance in a single place. The _Unsorted tab flag could be replacing a trailing-counter in DockNode?
+ - docking: B~ fully track windows/settings reference in dock nodes. perhaps find a representation that allows facilitate use of dock builder functions.
+ - docking: B~ Unreal style document system (requires low-level controls of dockspace serialization fork/copy/delete). this is mostly working but the DockBuilderXXX api are not exposed/finished.
+ - docking: B: when docking outer, perform size locking on neighbors nodes the same way we do it with splitters, so other nodes are not resized.
+ - docking: B~ central node resizing behavior incorrect.
+ - docking: B: changing title font/style per-window is not supported as dock nodes are created in NewFrame.
+ - docking: B- dock node inside its own viewports creates 1 temporary viewport per window on startup before ditching them (doesn't affect the user nor request platform windows to be created, but unnecessary)
+ - docking: B- resize sibling locking behavior may be less desirable if we merged same-axis sibling in a same node level?
+ - docking: B- single visible node part of a hidden split hierarchy (OnlyNodeWithWindows != NULL) should show a normal title bar (not a tab bar)
+ - docking: B~ SetNextWindowDock() calls (with conditional) -> defer everything to DockContextUpdate (repro: Documents->[X]Windows->Dock 1 elsewhere->Click Redock All
+ - docking: B~ tidy up tab list popup buttons features (available with manual tab-bar, see ImGuiTabBarFlags_NoTabListPopupButton code, not used by docking nodes)
+ - docking: B- SetNextWindowDockId(0) with a second Begin() in the frame will asserts
+ - docking: B: resize grip drawn in host window typically appears under scrollbar.
+ - docking: B: resize grip auto-resize on multiple node hierarchy doesn't make much sense or should be improved?
+ - docking: B- SetNextWindowFocus() doesn't seem to apply if the window is hidden this frame, need repro (#4)
+ - docking: B- resizing a dock tree small currently has glitches (overlapping collapse and close button, etc.)
+ - docking: B- dpi: look at interaction with the hi-dpi and multi-dpi stuff.
+ - docking: B- tab bar: appearing on first frame with a dumb layout would do less harm that not appearing? (when behind dynamic branch) or store titles + render in EndTabBar()
+ - docking: B- tab bar: make selected tab always shows its full title?
+ - docking: B- hide close button on single tab bar?
+ - docking: B- nav: design interactions so nav controls can dock/undock
+ - docking: B- dockspace: flag to lock the dock tree and/or sizes (ImGuiDockNodeFlags_Locked?)
+ - docking: B- reintroduce collapsing a floating dock node. also collapsing a docked dock node!
+ - docking: B- allow dragging a non-floating dock node by clicking on the title-bar-looking section (not just the collapse/menu button)
+ - docking: B- option to remember undocked window size? (instead of keeping their docked size) (relate to #2104)
+ - docking: C- nav: CTRL+TAB highlighting tabs shows the mismatch between focus-stack and tab-order (not visible in VS because it doesn't highlight the tabs)
+ - docking: C- after a dock/undock, the Scrollbar Status update in Begin() should use an updated e.g. size_y_for_scrollbars to avoid a 1 frame scrollbar flicker.
 
  - tabs: "there is currently a problem because TabItem() will try to submit their own tooltip after 0.50 second, and this will have the effect of making your tooltip flicker once." -> tooltip priority work (WIP branch)
  - tabs: make EndTabBar fail if users doesn't respect BeginTabBar return value, for consistency/future-proofing.
@@ -133,19 +169,22 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - knob: rotating knob widget (#942)
  - drag float: support for reversed drags (min > max) (removed is_locked, also see fdc526e)
  - drag float: up/down axis
+ - drag float: power != 0.0f with current value being outside the range keeps the value stuck.
  - drag float: added leeway on edge (e.g. a few invisible steps past the clamp limits)
 
  - combo: a way/helper to customize the combo preview (#1658) -> experimental BeginComboPreview()
  - combo/listbox: keyboard control. need InputText-like non-active focus + key handling. considering keyboard for custom listbox (pr #203)
+ - listbox: multiple selection (WIP range-select branch)
  - listbox: unselect option (#1208)
+ - listbox: make it easier/more natural to implement range-select (need some sort of info/ref about the last clicked/focused item that user can translate to an index?) (WIP range-select branch)
  - listbox: user may want to initial scroll to focus on the one selected value?
  - listbox: disable capturing mouse wheel if the listbox has no scrolling. (#1681)
  - listbox: scrolling should track modified selection.
  - listbox: future api should allow to enable horizontal scrolling (#2510)
 
 !- popups/menus: clarify usage of popups id, how MenuItem/Selectable closing parent popups affects the ID, etc. this is quite fishy needs improvement! (#331, #402)
- - modals: make modal title bar blink when trying to click outside the modal.
- - modals: technically speaking, we could make Begin() with ImGuiWindowFlags_Modal work without involving popup. May help untangle a few things, as modals are more like regular windows than popups. (#402)
+ - modals: make modal title bar blink when trying to click outside the modal
+ - modals: technically speaking, we could make Begin() with ImGuiWindowFlags_Modal work without involving popup. May help untangle a few things, as modals are more like regular windows than popups.
  - popups: if the popup functions took explicit ImGuiID it would allow the user to manage the scope of those ID. (#331)
  - popups: clicking outside (to close popup) and holding shouldn't drag window below.
  - popups: add variant using global identifier similar to Begin/End (#402)
@@ -187,7 +226,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - style: FramePadding could be different for up vs down (#584)
  - style: WindowPadding needs to be EVEN as the 0.5 multiplier used on this value probably have a subtle effect on clip rectangle
  - style: have a more global HSV setter (e.g. alter hue on all elements). consider replacing active/hovered by offset in HSV space? (#438, #707, #1223)
- - style: gradients fill (#4722, #1223) ~ 2 bg colors for each fill? tricky with rounded shapes and using textures for corners.
+ - style: gradients fill (#1223) ~ 2 bg colors for each fill? tricky with rounded shapes and using textures for corners.
  - style editor: color child window height expressed in multiple of line height.
 
  - log: improve logging of ArrowButton, ListBox, TabItem
@@ -203,6 +242,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - filters: fuzzy matches (may use code at blog.forrestthewoods.com/4cffeed33fdb)
 
  - drag and drop: focus drag target window on hold (even without open)
+ - drag and drop: releasing a drop shows the "..." tooltip for one frame - since e13e598 (#1725)
  - drag and drop: drag source on a group object (would need e.g. an invisible button covering group in EndGroup) https://twitter.com/paniq/status/1121446364909535233
  - drag and drop: have some way to know when a drag begin from BeginDragDropSource() pov. (see 2018/01/11 post in #143)
  - drag and drop: allow preview tooltip to be submitted from a different place than the drag source. (#1725)
@@ -235,6 +275,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - font: make it easier to submit own bitmap font (same texture, another texture?). (#2127, #2575)
  - font: MemoryTTF taking ownership confusing/not obvious, maybe default should be opposite?
  - font: storing MinAdvanceX per font would allow us to skip calculating line width (under a threshold of character count) in loops looking for block width
+ - font/demo: demonstrate use of ImFontGlyphRangesBuilder.
  - font/draw: vertical and/or rotated text renderer (#705) - vertical is easier clipping wise
  - font/draw: need to be able to specify wrap start position.
  - font/draw: better reserve policy for large horizontal block of text (shouldn't reserve for all clipped lines). also see #3349.
@@ -260,11 +301,12 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - nav: NavFlattened: ESC on a flattened child should select something.
  - nav: NavFlattened: broken: in typical usage scenario, the items of a fully clipped child are currently not considered to enter into a NavFlattened child.
  - nav: NavFlattened: cannot access menu-bar of a flattened child window with Alt/menu key (not a very common use case..).
+ - nav: simulate right-click or context activation? (SHIFT+F10, keyboard Menu key?)
  - nav/popup: esc/enter default behavior for popups, e.g. be able to mark an "ok" or "cancel" button that would get triggered by those keys, default validation button, etc.
  - nav/treenode: left within a tree node block as a fallback (ImGuiTreeNodeFlags_NavLeftJumpsBackHere by default?)
  - nav/menus: pressing left-right on a vertically clipped menu bar tends to jump to the collapse/close buttons.
  - nav/menus: allow pressing Menu to leave a sub-menu.
- ! nav/menus: a way to access the main menu bar with Alt? (currently needs CTRL+TAB) or last focused window menu bar?
+ - nav/menus: a way to access the main menu bar with Alt? (currently needs CTRL+TAB) or last focused window menu bar?
  - nav/menus: when using the main menu bar, even though we restore focus after, the underlying window loses its title bar highlight during menu manipulation. could we prevent it?
  - nav/menus: main menu bar currently cannot restore a nullptr focus. Could save NavWindow at the time of being focused, similarly to what popup do?
  - nav/menus: Alt,Up could open the first menu (e.g. "File") currently it tends to nav into the window/collapse menu. Do do that we would need custom transition?
@@ -272,6 +314,21 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - nav/windowing: Resizing window will currently fail with certain types of resizing constraints/callback applied
  - focus: preserve ActiveId/focus stack state, e.g. when opening a menu and close it, previously selected InputText() focus gets restored (#622)
 
+ - viewport: make it possible to have no main/hosting viewport (see #8268)
+ - viewport: We set ImGuiViewportFlags_NoFocusOnAppearing in a way that is required for GLFW/SDL binding, but could be handled better without
+   on a custom e.g. Win32 bindings. It prevents newly dragged-out viewports from taking the focus, which makes ALT+F4 more ambiguous.
+ - viewport: not focusing newly undocked viewport means clicking back on previous one doesn't bring OS window to front.
+ - viewport: with platform decoration enabled, platform may force constraint (e.g. minimum size)
+ - viewport: use getfocus/setfocus api to synchronize imgui<>platform focus better (e.g imgui-side ctrl-tab can focus os window, OS initial setup and alt-tab can focus imgui window etc.)
+ - viewport: store per-viewport/monitor DPI in .ini file so an application reload or main window changing DPI on reload can be properly patched for.
+ - viewport: implicit/fallback Debug window can hog a zombie viewport (harmless, noisy?) > could at least clear out the reference on a per session basis?
+ - viewport: need to clarify how to use GetMousePos() from a user point of view.
+ - viewport: could apply monitor boundaries to cliprect to coarse clip things out of monitor? (#8698)
+ - platform: glfw: no support for ImGuiBackendFlags_HasMouseHoveredViewport.
+ - platform: sdl: no support for ImGuiBackendFlags_HasMouseHoveredViewport. maybe we could use SDL_GetMouseFocus() / SDL_WINDOW_MOUSE_FOCUS if imgui could fallback on its heuristic when NoInputs is set
+ - platform: sdl: no refresh of monitor/display (SDL doesn't seem to have an event for it).
+ - platform: sdl: multi-viewport + minimized window seems to break mouse wheel events (at least under Win32).
+
  - inputs: support track pad style scrolling & slider edit.
  - inputs/io: backspace and arrows in the context of a text input could use system repeat rate.
  - inputs/io: clarify/standardize/expose repeat rate and repeat delays (#1808)
@@ -283,6 +340,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - misc: no way to run a root-most GetID() with ImGui:: api since there's always a Debug window in the stack. (mentioned in #2960)
  - misc: make the ImGuiCond values linear (non-power-of-two). internal storage for ImGuiWindow can use integers to combine into flags (Why?)
  - misc: PushItemFlag(): add a flag to disable keyboard capture when used with mouse? (#1682)
+ - misc: use more size_t in public api?
  - misc: support for string view/range instead of char* would e.g. facilitate usage with Rust (#683, #3038, WIP string_view branch)
 
  - demo: demonstrate using PushStyleVar() in more details.
@@ -300,7 +358,8 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - backends: opengl: could use a single vertex buffer and glBufferSubData for uploads?
  - backends: opengl: explicitly disable GL_STENCIL_TEST in bindings.
  - backends: vulkan: viewport: support for synchronized swapping of multiple swap chains.
- - backends: emscripten: dedicated backend? (#8178, #9120, eg. https://github.com/floooh/sokol-samples/blob/master/html5/imgui-emsc.cc#L42)
+ - backends: bgfx: https://gist.github.com/RichardGale/6e2b74bc42b3005e08397236e4be0fd0
+ - backends: emscripten: with refactored examples, we could provide a direct imgui_impl_emscripten platform layer (see eg. https://github.com/floooh/sokol-samples/blob/master/html5/imgui-emsc.cc#L42)
 
  - bindings: ways to use clang ast dump to generate bindings or helpers for bindings? (e.g. clang++ -Xclang -ast-dump=json imgui.h) (--> use https://github.com/dearimgui/dear_bindings)
 

examples/example_allegro5/example_allegro5.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_allegro5/main.cpp

@@ -40,6 +40,7 @@ int main(int, char**)
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;      // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();

examples/example_android_opengl3/android/app/build.gradle

@@ -1,5 +1,6 @@
 plugins {
     alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
 }
 
 android {
@@ -24,6 +25,9 @@ android {
         sourceCompatibility JavaVersion.VERSION_11
         targetCompatibility JavaVersion.VERSION_11
     }
+    kotlinOptions {
+        jvmTarget = '11'
+    }
     externalNativeBuild {
         cmake {
             path file('../../CMakeLists.txt')

examples/example_android_opengl3/android/gradle/libs.versions.toml

@@ -1,6 +1,6 @@
 [versions]
-agp = "9.2.0"
-kotlin = "2.3.21"
+agp = "8.12.0"
+kotlin = "2.0.21"
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }

examples/example_apple_metal/example_apple_metal.xcodeproj/project.pbxproj

@@ -7,7 +7,10 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		050450AB2768052600AB6805 /* imgui_tables.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5079822D257677DB0038A28D /* imgui_tables.cpp */; };
+		050450AD276863B000AB6805 /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 050450AC276863B000AB6805 /* QuartzCore.framework */; };
 		05318E0F274C397200A8DE2E /* GameController.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 05318E0E274C397200A8DE2E /* GameController.framework */; };
+		05A275442773BEA20084EF39 /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 05A275432773BEA20084EF39 /* QuartzCore.framework */; };
 		07A82ED82139413D0078D120 /* imgui_widgets.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 07A82ED72139413C0078D120 /* imgui_widgets.cpp */; };
 		07A82ED92139418F0078D120 /* imgui_widgets.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 07A82ED72139413C0078D120 /* imgui_widgets.cpp */; };
 		5079822E257677DB0038A28D /* imgui_tables.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5079822D257677DB0038A28D /* imgui_tables.cpp */; };
@@ -33,7 +36,11 @@
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
+		050450AC276863B000AB6805 /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = System/Library/Frameworks/QuartzCore.framework; sourceTree = SDKROOT; };
 		05318E0E274C397200A8DE2E /* GameController.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = GameController.framework; path = System/Library/Frameworks/GameController.framework; sourceTree = SDKROOT; };
+		05A2754027728F5B0084EF39 /* imgui_impl_metal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = imgui_impl_metal.h; path = ../../backends/imgui_impl_metal.h; sourceTree = "<group>"; };
+		05A2754127728F5B0084EF39 /* imgui_impl_osx.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = imgui_impl_osx.h; path = ../../backends/imgui_impl_osx.h; sourceTree = "<group>"; };
+		05A275432773BEA20084EF39 /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS15.2.sdk/System/Library/Frameworks/QuartzCore.framework; sourceTree = DEVELOPER_DIR; };
 		07A82ED62139413C0078D120 /* imgui_internal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = imgui_internal.h; path = ../../imgui_internal.h; sourceTree = "<group>"; };
 		07A82ED72139413C0078D120 /* imgui_widgets.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = imgui_widgets.cpp; path = ../../imgui_widgets.cpp; sourceTree = "<group>"; };
 		5079822D257677DB0038A28D /* imgui_tables.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = imgui_tables.cpp; path = ../../imgui_tables.cpp; sourceTree = "<group>"; };
@@ -66,6 +73,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				05A275442773BEA20084EF39 /* QuartzCore.framework in Frameworks */,
 				8309BD8F253CCAAA0045E2A1 /* UIKit.framework in Frameworks */,
 				83BBE9E720EB46BD00295997 /* MetalKit.framework in Frameworks */,
 				83BBE9E520EB46B900295997 /* Metal.framework in Frameworks */,
@@ -76,6 +84,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				050450AD276863B000AB6805 /* QuartzCore.framework in Frameworks */,
 				8309BDC6253CCCFE0045E2A1 /* AppKit.framework in Frameworks */,
 				83BBE9EC20EB471700295997 /* MetalKit.framework in Frameworks */,
 				05318E0F274C397200A8DE2E /* GameController.framework in Frameworks */,
@@ -136,6 +145,8 @@
 		83BBE9E320EB46B800295997 /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				050450AC276863B000AB6805 /* QuartzCore.framework */,
+				05A275432773BEA20084EF39 /* QuartzCore.framework */,
 				05318E0E274C397200A8DE2E /* GameController.framework */,
 				8309BDC5253CCCFE0045E2A1 /* AppKit.framework */,
 				8309BD8E253CCAAA0045E2A1 /* UIKit.framework */,
@@ -153,7 +164,9 @@
 			isa = PBXGroup;
 			children = (
 				5079822D257677DB0038A28D /* imgui_tables.cpp */,
+				05A2754027728F5B0084EF39 /* imgui_impl_metal.h */,
 				8309BDB5253CCC9D0045E2A1 /* imgui_impl_metal.mm */,
+				05A2754127728F5B0084EF39 /* imgui_impl_osx.h */,
 				8309BDB6253CCC9D0045E2A1 /* imgui_impl_osx.mm */,
 				83BBEA0420EB54E700295997 /* imconfig.h */,
 				83BBEA0320EB54E700295997 /* imgui.cpp */,
@@ -285,7 +298,7 @@
 				83BBEA0A20EB54E700295997 /* imgui.cpp in Sources */,
 				83BBEA0820EB54E700295997 /* imgui_demo.cpp in Sources */,
 				83BBEA0620EB54E700295997 /* imgui_draw.cpp in Sources */,
-				5079822E257677DB0038A28D /* imgui_tables.cpp in Sources */,
+				050450AB2768052600AB6805 /* imgui_tables.cpp in Sources */,
 				07A82ED92139418F0078D120 /* imgui_widgets.cpp in Sources */,
 				8309BDA8253CCC080045E2A1 /* main.mm in Sources */,
 			);

examples/example_apple_metal/main.mm

@@ -60,11 +60,21 @@
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Renderer backend
     ImGui_ImplMetal_Init(_device);
 
@@ -197,6 +207,13 @@
     // Present
     [commandBuffer presentDrawable:view.currentDrawable];
     [commandBuffer commit];
+
+    // Update and Render additional Platform Windows
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindowsDefault();
+    }
 }
 
 -(void)mtkView:(MTKView*)view drawableSizeWillChange:(CGSize)size

examples/example_apple_opengl2/main.mm

@@ -6,6 +6,8 @@
 // - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
 // - Introduction, links and more at the top of imgui.cpp
 
+// FIXME: Multi-viewports is not yet functional in this example. May need backend rework/coordination.
+
 #import <Cocoa/Cocoa.h>
 #import <OpenGL/gl.h>
 #import <OpenGL/glu.h>
@@ -47,11 +49,21 @@
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplOSX_Init(self);
     ImGui_ImplOpenGL2_Init();
@@ -138,6 +150,13 @@
 
     ImGui_ImplOpenGL2_RenderDrawData(draw_data);
 
+    // Update and Render additional Platform Windows
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindowsDefault();
+    }
+
     // Present
     [[self openGLContext] flushBuffer];
 

examples/example_glfw_metal/main.mm

@@ -44,6 +44,8 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -53,6 +55,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     id <MTLDevice> device = MTLCreateSystemDefaultDevice();
     id <MTLCommandQueue> commandQueue = [device newCommandQueue];
@@ -164,6 +175,13 @@ int main(int, char**)
             ImGui::Render();
             ImGui_ImplMetal_RenderDrawData(ImGui::GetDrawData(), commandBuffer, renderEncoder);
 
+            // Update and Render additional Platform Windows
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                ImGui::UpdatePlatformWindows();
+                ImGui::RenderPlatformWindowsDefault();
+            }
+
             [renderEncoder popDebugGroup];
             [renderEncoder endEncoding];
 

examples/example_glfw_opengl2/example_glfw_opengl2.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_glfw_opengl2/main.cpp

@@ -53,6 +53,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -62,6 +66,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOpenGL(window, true);
@@ -163,6 +176,17 @@ int main(int, char**)
         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
         //glUseProgram(last_program);
 
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call glfwMakeContextCurrent(window) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            GLFWwindow* backup_current_context = glfwGetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            glfwMakeContextCurrent(backup_current_context);
+        }
+
         glfwMakeContextCurrent(window);
         glfwSwapBuffers(window);
     }

examples/example_glfw_opengl3/example_glfw_opengl3.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_glfw_opengl3/main.cpp

@@ -41,26 +41,29 @@ int main(int, char**)
     if (!glfwInit())
         return 1;
 
-    // Select GL version + let the backend select a GLSL version
-    const char* glsl_version = nullptr;
+    // Decide GL+GLSL versions
 #if defined(IMGUI_IMPL_OPENGL_ES2)
     // GL ES 2.0 + GLSL 100 (WebGL 1.0)
+    const char* glsl_version = "#version 100";
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
     glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
 #elif defined(IMGUI_IMPL_OPENGL_ES3)
     // GL ES 3.0 + GLSL 300 es (WebGL 2.0)
+    const char* glsl_version = "#version 300 es";
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
     glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
 #elif defined(__APPLE__)
-    // GL 3.2 + generally GLSL 150
+    // GL 3.2 + GLSL 150
+    const char* glsl_version = "#version 150";
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
     glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // Required on Mac
 #else
-    // GL 3.0 + generally GLSL 130
+    // GL 3.0 + GLSL 130
+    const char* glsl_version = "#version 130";
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
     //glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
@@ -81,6 +84,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -90,6 +97,17 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+#if GLFW_VERSION_MAJOR >= 3 && GLFW_VERSION_MINOR >= 3
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+#endif
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOpenGL(window, true);
@@ -195,6 +213,17 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call glfwMakeContextCurrent(window) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            GLFWwindow* backup_current_context = glfwGetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            glfwMakeContextCurrent(backup_current_context);
+        }
+
         glfwSwapBuffers(window);
     }
 #ifdef __EMSCRIPTEN__

examples/example_glfw_vulkan/example_glfw_vulkan.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_glfw_vulkan/main.cpp

@@ -193,8 +193,7 @@ static void SetupVulkan(ImVector<const char*> instance_extensions)
     {
         VkDescriptorPoolSize pool_sizes[] =
         {
-            { VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, IMGUI_IMPL_VULKAN_MINIMUM_SAMPLED_IMAGE_POOL_SIZE },
-            { VK_DESCRIPTOR_TYPE_SAMPLER, IMGUI_IMPL_VULKAN_MINIMUM_SAMPLER_POOL_SIZE },
+            { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, IMGUI_IMPL_VULKAN_MINIMUM_IMAGE_SAMPLER_POOL_SIZE },
         };
         VkDescriptorPoolCreateInfo pool_info = {};
         pool_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
@@ -390,6 +389,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -399,6 +402,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForVulkan(window, true);
@@ -513,17 +525,25 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        ImDrawData* draw_data = ImGui::GetDrawData();
-        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);
-        if (!is_minimized)
+        ImDrawData* main_draw_data = ImGui::GetDrawData();
+        const bool main_is_minimized = (main_draw_data->DisplaySize.x <= 0.0f || main_draw_data->DisplaySize.y <= 0.0f);
+        wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
+        wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
+        wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
+        wd->ClearValue.color.float32[3] = clear_color.w;
+        if (!main_is_minimized)
+            FrameRender(wd, main_draw_data);
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
-            wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
-            wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
-            wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
-            wd->ClearValue.color.float32[3] = clear_color.w;
-            FrameRender(wd, draw_data);
-            FramePresent(wd);
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
         }
+
+        // Present Main Platform Window
+        if (!main_is_minimized)
+            FramePresent(wd);
     }
 
     // Cleanup

examples/example_glfw_wgpu/CMakeLists.txt

@@ -14,7 +14,7 @@
 #   * build/example_glfw_wgpu[.exe] or build/Debug/example_glfw_wgpu[.exe]
 
 # Building for desktop with WGVK (MUCH EASIER)
-#  1. git clone https://github.com/manuel5975p/WGVK wgvk
+#  1. git clone https://github.com/manuel5975p/WGVK dawn
 #  2. cmake -B build -DIMGUI_WGVK_DIR=wgvk
 #  3. cmake --build build
 # The resulting binary will be found at one of the following locations:
@@ -37,7 +37,7 @@ if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE Debug CACHE STRING "" FORCE)
 endif()
 
-set(CMAKE_CXX_STANDARD 20) # Dawn requires C++20
+set(CMAKE_CXX_STANDARD 17) # Dawn requires C++17
 
 # Dear ImGui
 set(IMGUI_DIR ../../)
@@ -146,28 +146,6 @@ else() # Native/Desktop build
     endif()
 
     if(IMGUI_WGVK_DIR)
-        find_package(Vulkan REQUIRED)
-        set(WGVK_PLATFORM_LIBS)
-        set(WGVK_PLATFORM_DEFS)
-        if(WIN32)
-            list(APPEND WGVK_PLATFORM_DEFS SUPPORT_WIN32_SURFACE=1)
-        elseif(APPLE)
-            list(APPEND WGVK_PLATFORM_DEFS SUPPORT_METAL_SURFACE=1)
-        elseif(UNIX)
-            find_package(PkgConfig QUIET)
-            pkg_check_modules(WAYLAND_CLIENT QUIET wayland-client)
-            if(WAYLAND_CLIENT_FOUND)
-                list(APPEND WGVK_PLATFORM_DEFS SUPPORT_WAYLAND_SURFACE=1)
-                list(APPEND WGVK_PLATFORM_LIBS ${WAYLAND_CLIENT_LIBRARIES})
-            endif()
-            find_package(X11 QUIET)
-            if(X11_FOUND)
-                list(APPEND WGVK_PLATFORM_DEFS SUPPORT_XLIB_SURFACE=1)
-                list(APPEND WGVK_PLATFORM_LIBS X11::X11)
-            endif()
-            list(APPEND WGVK_PLATFORM_LIBS m dl pthread)
-        endif()
-        set(LIBRARIES glfw Vulkan::Vulkan ${WGVK_PLATFORM_LIBS})
     endif()
 endif()
 
@@ -209,7 +187,6 @@ if(NOT EMSCRIPTEN) # WegGPU-Native settings
     if(IMGUI_WGVK_DIR)
         target_sources(${IMGUI_EXECUTABLE} PRIVATE ${IMGUI_WGVK_DIR}/src/wgvk.c)
         target_compile_definitions(${IMGUI_EXECUTABLE} PUBLIC "IMGUI_IMPL_WEBGPU_BACKEND_WGVK")
-        target_compile_definitions(${IMGUI_EXECUTABLE} PRIVATE ${WGVK_PLATFORM_DEFS})
         target_include_directories(${IMGUI_EXECUTABLE} PUBLIC ${IMGUI_WGVK_DIR}/include)
         if (MSVC)
            target_compile_options(${IMGUI_EXECUTABLE} PUBLIC /std:clatest /experimental:c11atomics)

examples/example_glfw_wgpu/main.cpp

@@ -87,6 +87,7 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();

examples/example_glut_opengl2/example_glut_opengl2.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_glut_opengl2/main.cpp

@@ -61,6 +61,7 @@ int main(int argc, char** argv)
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();

examples/example_null/example_null.vcxproj

@@ -21,34 +21,33 @@
   <PropertyGroup Label="Globals">
     <ProjectGuid>{1A0BF63C-18EF-4BAE-A8DA-055481B11F5D}</ProjectGuid>
     <RootNamespace>example_win32_directx11</RootNamespace>
-    <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl2_directx11/example_sdl2_directx11.vcxproj

@@ -29,27 +29,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl2_directx11/main.cpp

@@ -75,6 +75,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -84,6 +88,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForD3D(window);
@@ -192,6 +205,13 @@ int main(int, char**)
         g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         g_pSwapChain->Present(1, 0); // Present with vsync
         //g_pSwapChain->Present(0, 0); // Present without vsync
     }
@@ -239,6 +259,16 @@ bool CreateDeviceD3D(HWND hWnd)
     if (res != S_OK)
         return false;
 
+    // Disable DXGI's default Alt+Enter fullscreen behavior.
+    // - You are free to leave this enabled, but it will not work properly with multiple viewports.
+    // - This must be done for all windows associated to the device. Our DX11 backend does this automatically for secondary viewports that it creates.
+    IDXGIFactory* pSwapChainFactory;
+    if (SUCCEEDED(g_pSwapChain->GetParent(IID_PPV_ARGS(&pSwapChainFactory))))
+    {
+        pSwapChainFactory->MakeWindowAssociation(hWnd, DXGI_MWA_NO_ALT_ENTER);
+        pSwapChainFactory->Release();
+    }
+
     CreateRenderTarget();
     return true;
 }

examples/example_sdl2_metal/main.mm

@@ -24,11 +24,21 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;      // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;    // Enable Multi-Viewport / Platform Windows
 
     // Setup style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Load Fonts
     // - If fonts are not explicitly loaded, Dear ImGui will select an embedded font: either AddFontDefaultVector() or AddFontDefaultBitmap().
     //   This selection is based on (style.FontSizeBase * style.FontScaleMain * style.FontScaleDpi) reaching a small threshold.
@@ -170,6 +180,13 @@ int main(int, char**)
             ImGui::Render();
             ImGui_ImplMetal_RenderDrawData(ImGui::GetDrawData(), commandBuffer, renderEncoder);
 
+            // Update and Render additional Platform Windows
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                ImGui::UpdatePlatformWindows();
+                ImGui::RenderPlatformWindowsDefault();
+            }
+
             [renderEncoder popDebugGroup];
             [renderEncoder endEncoding];
 

examples/example_sdl2_opengl2/example_sdl2_opengl2.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl2_opengl2/main.cpp

@@ -64,6 +64,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -73,6 +77,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
@@ -174,6 +187,19 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
+
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
+            SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+        }
+
         SDL_GL_SwapWindow(window);
     }
 

examples/example_sdl2_opengl3/example_sdl2_opengl3.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl2_opengl3/main.cpp

@@ -39,28 +39,31 @@ int main(int, char**)
         return 1;
     }
 
-    // Select GL version + let the backend select a GLSL version
-    const char* glsl_version = nullptr;
+    // Decide GL+GLSL versions
 #if defined(IMGUI_IMPL_OPENGL_ES2)
     // GL ES 2.0 + GLSL 100 (WebGL 1.0)
+    const char* glsl_version = "#version 100";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 #elif defined(IMGUI_IMPL_OPENGL_ES3)
     // GL ES 3.0 + GLSL 300 es (WebGL 2.0)
+    const char* glsl_version = "#version 300 es";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 #elif defined(__APPLE__)
-    // GL 3.2 Core + generally GLSL 150
+    // GL 3.2 Core + GLSL 150
+    const char* glsl_version = "#version 150";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
 #else
-    // GL 3.0 + generally GLSL 130
+    // GL 3.0 + GLSL 130
+    const char* glsl_version = "#version 130";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
@@ -101,6 +104,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -110,6 +117,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
@@ -218,6 +234,19 @@ int main(int, char**)
         glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
+            SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+        }
+
         SDL_GL_SwapWindow(window);
     }
 #ifdef __EMSCRIPTEN__

examples/example_sdl2_sdlrenderer2/example_sdl2_sdlrenderer2.vcxproj

@@ -29,27 +29,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">
@@ -184,4 +184,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>

examples/example_sdl2_sdlrenderer2/main.cpp

@@ -66,6 +66,7 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -75,6 +76,8 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForSDLRenderer(window, renderer);

examples/example_sdl2_vulkan/example_sdl2_vulkan.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">
@@ -187,4 +187,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>

examples/example_sdl2_vulkan/main.cpp

@@ -184,8 +184,7 @@ static void SetupVulkan(ImVector<const char*> instance_extensions)
     {
         VkDescriptorPoolSize pool_sizes[] =
         {
-            { VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, IMGUI_IMPL_VULKAN_MINIMUM_SAMPLED_IMAGE_POOL_SIZE },
-            { VK_DESCRIPTOR_TYPE_SAMPLER, IMGUI_IMPL_VULKAN_MINIMUM_SAMPLER_POOL_SIZE },
+            { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, IMGUI_IMPL_VULKAN_MINIMUM_IMAGE_SAMPLER_POOL_SIZE },
         };
         VkDescriptorPoolCreateInfo pool_info = {};
         pool_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
@@ -386,7 +385,7 @@ int main(int, char**)
 
     // Create Framebuffers
     int w, h;
-    SDL_GetWindowSizeInPixels(window, &w, &h);
+    SDL_GetWindowSize(window, &w, &h);
     ImGui_ImplVulkanH_Window* wd = &g_MainWindowData;
     SetupVulkanWindow(wd, surface, w, h);
 
@@ -396,6 +395,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoTaskBarIcons;
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoMerge;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -405,6 +408,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForVulkan(window);
@@ -475,7 +487,7 @@ int main(int, char**)
 
         // Resize swap chain?
         int fb_width, fb_height;
-        SDL_GetWindowSizeInPixels(window, &fb_width, &fb_height);
+        SDL_GetWindowSize(window, &fb_width, &fb_height);
         if (fb_width > 0 && fb_height > 0 && (g_SwapChainRebuild || g_MainWindowData.Width != fb_width || g_MainWindowData.Height != fb_height))
         {
             ImGui_ImplVulkan_SetMinImageCount(g_MinImageCount);
@@ -528,17 +540,25 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        ImDrawData* draw_data = ImGui::GetDrawData();
-        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);
-        if (!is_minimized)
+        ImDrawData* main_draw_data = ImGui::GetDrawData();
+        const bool main_is_minimized = (main_draw_data->DisplaySize.x <= 0.0f || main_draw_data->DisplaySize.y <= 0.0f);
+        wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
+        wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
+        wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
+        wd->ClearValue.color.float32[3] = clear_color.w;
+        if (!main_is_minimized)
+            FrameRender(wd, main_draw_data);
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
-            wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
-            wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
-            wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
-            wd->ClearValue.color.float32[3] = clear_color.w;
-            FrameRender(wd, draw_data);
-            FramePresent(wd);
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
         }
+
+        // Present Main Platform Window
+        if (!main_is_minimized)
+            FramePresent(wd);
     }
 
     // Cleanup

examples/example_sdl2_wgpu/CMakeLists.txt

@@ -14,7 +14,7 @@
 #   * build/example_sdl2_wgpu[.exe] or build/Debug/example_sdl2_wgpu[.exe]
 
 # Building for desktop with WGVK (MUCH EASIER)
-#  1. git clone https://github.com/manuel5975p/WGVK wgvk
+#  1. git clone https://github.com/manuel5975p/WGVK dawn
 #  2. cmake -B build -DIMGUI_WGVK_DIR=wgvk
 #  3. cmake --build build
 # The resulting binary will be found at one of the following locations:
@@ -37,7 +37,7 @@ if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE Debug CACHE STRING "" FORCE)
 endif()
 
-set(CMAKE_CXX_STANDARD 10) # Dawn requires C++20
+set(CMAKE_CXX_STANDARD 17) # Dawn requires C++17
 
 # Dear ImGui
 set(IMGUI_DIR ../../)
@@ -141,28 +141,6 @@ else() # Native/Desktop build
     endif()
 
     if(IMGUI_WGVK_DIR)
-        find_package(Vulkan REQUIRED)
-        set(WGVK_PLATFORM_LIBS)
-        set(WGVK_PLATFORM_DEFS)
-        if(WIN32)
-            list(APPEND WGVK_PLATFORM_DEFS SUPPORT_WIN32_SURFACE=1)
-        elseif(APPLE)
-            list(APPEND WGVK_PLATFORM_DEFS SUPPORT_METAL_SURFACE=1)
-        elseif(UNIX)
-            find_package(PkgConfig QUIET)
-            pkg_check_modules(WAYLAND_CLIENT QUIET wayland-client)
-            if(WAYLAND_CLIENT_FOUND)
-                list(APPEND WGVK_PLATFORM_DEFS SUPPORT_WAYLAND_SURFACE=1)
-                list(APPEND WGVK_PLATFORM_LIBS ${WAYLAND_CLIENT_LIBRARIES})
-            endif()
-            find_package(X11 QUIET)
-            if(X11_FOUND)
-                list(APPEND WGVK_PLATFORM_DEFS SUPPORT_XLIB_SURFACE=1)
-                list(APPEND WGVK_PLATFORM_LIBS X11::X11)
-            endif()
-            list(APPEND WGVK_PLATFORM_LIBS m dl pthread)
-        endif()
-        set(LIBRARIES glfw Vulkan::Vulkan ${WGVK_PLATFORM_LIBS})
     endif()
 
 endif()
@@ -205,7 +183,6 @@ if(NOT EMSCRIPTEN) # WegGPU-Native settings
     if(IMGUI_WGVK_DIR)
         target_sources(${IMGUI_EXECUTABLE} PRIVATE ${IMGUI_WGVK_DIR}/src/wgvk.c)
         target_compile_definitions(${IMGUI_EXECUTABLE} PUBLIC "IMGUI_IMPL_WEBGPU_BACKEND_WGVK")
-        target_compile_definitions(${IMGUI_EXECUTABLE} PRIVATE ${WGVK_PLATFORM_DEFS})
         target_include_directories(${IMGUI_EXECUTABLE} PUBLIC ${IMGUI_WGVK_DIR}/include)
         if (MSVC)
            target_compile_options(${IMGUI_EXECUTABLE} PUBLIC /std:clatest /experimental:c11atomics)

examples/example_sdl3_directx11/example_sdl3_directx11.vcxproj

@@ -29,27 +29,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl3_directx11/main.cpp

@@ -66,6 +66,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -75,6 +79,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForD3D(window);
@@ -186,6 +199,13 @@ int main(int, char**)
         g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         g_pSwapChain->Present(1, 0); // Present with vsync
         //g_pSwapChain->Present(0, 0); // Present without vsync
     }
@@ -234,6 +254,16 @@ bool CreateDeviceD3D(HWND hWnd)
     if (res != S_OK)
         return false;
 
+    // Disable DXGI's default Alt+Enter fullscreen behavior.
+    // - You are free to leave this enabled, but it will not work properly with multiple viewports.
+    // - This must be done for all windows associated to the device. Our DX11 backend does this automatically for secondary viewports that it creates.
+    IDXGIFactory* pSwapChainFactory;
+    if (SUCCEEDED(g_pSwapChain->GetParent(IID_PPV_ARGS(&pSwapChainFactory))))
+    {
+        pSwapChainFactory->MakeWindowAssociation(hWnd, DXGI_MWA_NO_ALT_ENTER);
+        pSwapChainFactory->Release();
+    }
+
     CreateRenderTarget();
     return true;
 }

examples/example_sdl3_metal4/Makefile

@@ -1,48 +0,0 @@
-#
-# You will need SDL3 (http://www.libsdl.org):
-#   brew install sdl3
-#
-
-#CXX = g++
-#CXX = clang++
-
-EXE = example_sdl3_metal4
-IMGUI_DIR = ../..
-SOURCES = main.mm
-SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
-SOURCES += $(IMGUI_DIR)/backends/imgui_impl_sdl3.cpp $(IMGUI_DIR)/backends/imgui_impl_metal4.mm
-OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
-
-LIBS = -framework Metal -framework MetalKit -framework Cocoa -framework IOKit -framework CoreVideo -framework QuartzCore
-LIBS += `pkg-config --libs sdl3`
-LIBS += -L/usr/local/lib -L/opt/local/lib
-
-CXXFLAGS += `pkg-config --cflags sdl3`
-CXXFLAGS += -I/usr/local/include -I/opt/local/include
-CXXFLAGS += -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
-CXXFLAGS += -Wall -Wformat
-CFLAGS = $(CXXFLAGS)
-
-%.o:%.cpp
-	$(CXX) $(CXXFLAGS) -c -o $@ $<
-
-%.o:$(IMGUI_DIR)/%.cpp
-	$(CXX) $(CXXFLAGS) -c -o $@ $<
-
-%.o:$(IMGUI_DIR)/backends/%.cpp
-	$(CXX) $(CXXFLAGS) -c -o $@ $<
-
-%.o:%.mm
-	$(CXX) $(CXXFLAGS) -ObjC++ -fobjc-weak -fobjc-arc -c -o $@ $<
-
-%.o:$(IMGUI_DIR)/backends/%.mm
-	$(CXX) $(CXXFLAGS) -ObjC++ -fobjc-weak -fobjc-arc -c -o $@ $<
-
-all: $(EXE)
-	@echo Build complete
-
-$(EXE): $(OBJS)
-	$(CXX) -o $@ $^ $(CXXFLAGS) $(LIBS)
-
-clean:
-	rm -f $(EXE) $(OBJS)

examples/example_sdl3_metal4/main.mm

@@ -1,240 +0,0 @@
-// Dear ImGui: standalone example application for SDL3 + Metal 4
-// (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
-// (Metal 4 requires Apple Silicon and macOS 26+.)
-
-// Learn about Dear ImGui:
-// - FAQ                  https://dearimgui.com/faq
-// - Getting Started      https://dearimgui.com/getting-started
-// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
-// - Introduction, links and more at the top of imgui.cpp
-
-#include "imgui.h"
-#include "imgui_impl_sdl3.h"
-#include "imgui_impl_metal4.h"
-#include <stdio.h>          // printf, fprintf
-#include <SDL3/SDL.h>
-
-#import <Metal/Metal.h>
-#import <QuartzCore/QuartzCore.h>
-
-#define FRAMES_IN_FLIGHT 3
-
-// Main code
-int main(int, char**)
-{
-    // Setup SDL
-    // [If using SDL_MAIN_USE_CALLBACKS: all code below until the main loop starts would likely be your SDL_AppInit() function]
-    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD))
-    {
-        printf("Error: SDL_Init(): %s\n", SDL_GetError());
-        return 1;
-    }
-
-    // Create SDL window graphics context
-    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
-    SDL_WindowFlags window_flags = SDL_WINDOW_METAL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+Metal4 example", (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
-    if (window == nullptr)
-    {
-        printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
-        return 1;
-    }
-    SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
-    SDL_ShowWindow(window);
-
-    // Create Metal device _before_ creating the view/layer
-    id<MTLDevice> metalDevice = MTLCreateSystemDefaultDevice();
-    if (!metalDevice)
-    {
-        printf("Error: failed to create Metal device.\n");
-        SDL_DestroyWindow(window);
-        SDL_Quit();
-        return 1;
-    }
-    SDL_MetalView view = SDL_Metal_CreateView(window);
-    CAMetalLayer* layer = (__bridge CAMetalLayer*)SDL_Metal_GetLayer(view);
-    layer.device = metalDevice;
-    layer.pixelFormat = MTLPixelFormatBGRA8Unorm;
-
-    id<MTL4CommandQueue> commandQueue = [layer.device newMTL4CommandQueue];
-    id<MTLSharedEvent> sharedEvent = [layer.device newSharedEvent];
-    MTL4RenderPassDescriptor* renderPassDescriptor = [MTL4RenderPassDescriptor new];
-
-    [commandQueue addResidencySet:layer.residencySet];
-
-    id<MTL4CommandBuffer> commandBuffers[FRAMES_IN_FLIGHT];
-    id<MTL4CommandAllocator> commandAllocators[FRAMES_IN_FLIGHT];
-    for (int i = 0; i < FRAMES_IN_FLIGHT; i++)
-    {
-        commandAllocators[i] = [layer.device newCommandAllocator];
-        commandBuffers[i] = [layer.device newCommandBuffer];
-    }
-    uint32_t frameIndex = 0;
-    uint32_t frameInFlight = 0;
-
-    // Setup Dear ImGui context
-    IMGUI_CHECKVERSION();
-    ImGui::CreateContext();
-    ImGuiIO& io = ImGui::GetIO(); (void)io;
-    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
-    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
-
-    // Setup Dear ImGui style
-    ImGui::StyleColorsDark();
-    //ImGui::StyleColorsLight();
-
-    // Setup scaling
-    ImGuiStyle& style = ImGui::GetStyle();
-    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
-    style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
-
-    // Setup Platform/Renderer backends
-    ImGui_ImplMetal4_Init(layer.device, commandQueue, FRAMES_IN_FLIGHT);
-    ImGui_ImplSDL3_InitForMetal(window);
-
-    // Load Fonts
-    // - If fonts are not explicitly loaded, Dear ImGui will select an embedded font: either AddFontDefaultVector() or AddFontDefaultBitmap().
-    //   This selection is based on (style.FontSizeBase * style.FontScaleMain * style.FontScaleDpi) reaching a small threshold.
-    // - You can load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
-    // - If a file cannot be loaded, AddFont functions will return a nullptr. Please handle those errors in your code (e.g. use an assertion, display an error and quit).
-    // - Read 'docs/FONTS.md' for more instructions and details.
-    // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use FreeType for higher quality font rendering.
-    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
-    //style.FontSizeBase = 20.0f;
-    //io.Fonts->AddFontDefaultVector();
-    //io.Fonts->AddFontDefaultBitmap();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
-    //IM_ASSERT(font != nullptr);
-
-    // Our state
-    bool show_demo_window = true;
-    bool show_another_window = false;
-    float clear_color[4] = { 0.45f, 0.55f, 0.60f, 1.00f };
-
-    // Main loop
-    bool done = false;
-    while (!done)
-    {
-        @autoreleasepool
-        {
-            // Poll and handle events (inputs, window resize, etc.)
-            // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
-            // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
-            // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
-            // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
-            // [If using SDL_MAIN_USE_CALLBACKS: call ImGui_ImplSDL3_ProcessEvent() from your SDL_AppEvent() function]
-            SDL_Event event;
-            while (SDL_PollEvent(&event))
-            {
-                ImGui_ImplSDL3_ProcessEvent(&event);
-                if (event.type == SDL_EVENT_QUIT)
-                    done = true;
-                if (event.type == SDL_EVENT_WINDOW_CLOSE_REQUESTED && event.window.windowID == SDL_GetWindowID(window))
-                    done = true;
-            }
-
-            // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppIterate() function]
-            if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
-            {
-                SDL_Delay(10);
-                continue;
-            }
-
-            int width, height;
-            SDL_GetWindowSizeInPixels(window, &width, &height);
-
-            layer.drawableSize = CGSizeMake(width, height);
-            id<CAMetalDrawable> drawable = [layer nextDrawable];
-
-            uint64_t waitValue = (frameIndex >= FRAMES_IN_FLIGHT) ? (frameIndex - FRAMES_IN_FLIGHT + 1) : 0;
-            [sharedEvent waitUntilSignaledValue:waitValue timeoutMS:1000];
-            [commandAllocators[frameInFlight] reset];
-            [commandBuffers[frameInFlight] beginCommandBufferWithAllocator:commandAllocators[frameInFlight]];
-
-            renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(clear_color[0] * clear_color[3], clear_color[1] * clear_color[3], clear_color[2] * clear_color[3], clear_color[3]);
-            renderPassDescriptor.colorAttachments[0].texture = drawable.texture;
-            renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
-            renderPassDescriptor.colorAttachments[0].storeAction = MTLStoreActionStore;
-            id <MTL4RenderCommandEncoder> renderEncoder = [commandBuffers[frameInFlight] renderCommandEncoderWithDescriptor:renderPassDescriptor];
-            [renderEncoder pushDebugGroup:@"ImGui demo"];
-
-            // Start the Dear ImGui frame
-            ImGui_ImplMetal4_NewFrame(renderPassDescriptor, frameInFlight);
-            ImGui_ImplSDL3_NewFrame();
-            ImGui::NewFrame();
-
-            // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
-            if (show_demo_window)
-                ImGui::ShowDemoWindow(&show_demo_window);
-
-            // 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
-            {
-                static float f = 0.0f;
-                static int counter = 0;
-
-                ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
-
-                ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
-                ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
-                ImGui::Checkbox("Another Window", &show_another_window);
-
-                ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
-                ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
-
-                if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
-                    counter++;
-                ImGui::SameLine();
-                ImGui::Text("counter = %d", counter);
-
-                ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
-                ImGui::End();
-            }
-
-            // 3. Show another simple window.
-            if (show_another_window)
-            {
-                ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
-                ImGui::Text("Hello from another window!");
-                if (ImGui::Button("Close Me"))
-                    show_another_window = false;
-                ImGui::End();
-            }
-
-            // Rendering
-            ImGui::Render();
-            ImDrawData* draw_data = ImGui::GetDrawData();
-            ImGui_ImplMetal4_RenderDrawData(draw_data, commandBuffers[frameInFlight], renderEncoder);
-
-            [renderEncoder popDebugGroup];
-            [renderEncoder endEncoding];
-            [commandBuffers[frameInFlight] endCommandBuffer];
-
-            id<MTL4CommandBuffer> to_commit[] = { commandBuffers[frameInFlight] };
-
-            [commandQueue waitForDrawable:drawable];
-            [commandQueue commit:to_commit count:1];
-
-            [commandQueue signalEvent:sharedEvent value:frameIndex + 1];
-            [commandQueue signalDrawable:drawable];
-            [drawable present];
-
-            frameIndex++;
-            frameInFlight = (frameInFlight + 1) % FRAMES_IN_FLIGHT;
-        }
-    }
-
-    // Cleanup
-    // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppQuit() function]
-    ImGui_ImplMetal4_Shutdown();
-    ImGui_ImplSDL3_Shutdown();
-    ImGui::DestroyContext();
-
-    SDL_DestroyWindow(window);
-    SDL_Quit();
-
-    return 0;
-}

examples/example_sdl3_opengl3/example_sdl3_opengl3.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl3_opengl3/main.cpp

@@ -33,28 +33,31 @@ int main(int, char**)
         return 1;
     }
 
-    // Select GL version + let the backend select a GLSL version
-    const char* glsl_version = nullptr;
+    // Decide GL+GLSL versions
 #if defined(IMGUI_IMPL_OPENGL_ES2)
     // GL ES 2.0 + GLSL 100 (WebGL 1.0)
+    const char* glsl_version = "#version 100";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 #elif defined(IMGUI_IMPL_OPENGL_ES3)
     // GL ES 3.0 + GLSL 300 es (WebGL 2.0)
+    const char* glsl_version = "#version 300 es";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 #elif defined(__APPLE__)
-    // GL 3.2 Core + generally GLSL 150
+    // GL 3.2 Core + GLSL 150
+    const char* glsl_version = "#version 150";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
 #else
-    // GL 3.0 + generally GLSL 130
+    // GL 3.0 + GLSL 130
+    const char* glsl_version = "#version 130";
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
@@ -91,6 +94,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -100,6 +107,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForOpenGL(window, gl_context);
@@ -211,6 +227,19 @@ int main(int, char**)
         glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
+            SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+        }
+
         SDL_GL_SwapWindow(window);
     }
 #ifdef __EMSCRIPTEN__

examples/example_sdl3_sdlgpu3/example_sdl3_sdlgpu3.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">
@@ -186,4 +186,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>

examples/example_sdl3_sdlgpu3/main.cpp

@@ -68,6 +68,8 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -77,6 +79,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForSDLGPU(window);
@@ -212,6 +223,13 @@ int main(int, char**)
             SDL_EndGPURenderPass(render_pass);
         }
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         // Submit the command buffer
         SDL_SubmitGPUCommandBuffer(command_buffer);
     }

examples/example_sdl3_sdlrenderer3/example_sdl3_sdlrenderer3.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl3_sdlrenderer3/main.cpp

@@ -56,6 +56,7 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -65,6 +66,8 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    //io.ConfigDpiScaleFonts = true;        // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    //io.ConfigDpiScaleViewports = true;    // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForSDLRenderer(window, renderer);

examples/example_sdl3_vulkan/example_sdl3_vulkan.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_sdl3_vulkan/main.cpp

@@ -186,8 +186,7 @@ static void SetupVulkan(ImVector<const char*> instance_extensions)
     {
         VkDescriptorPoolSize pool_sizes[] =
         {
-            { VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, IMGUI_IMPL_VULKAN_MINIMUM_SAMPLED_IMAGE_POOL_SIZE },
-            { VK_DESCRIPTOR_TYPE_SAMPLER, IMGUI_IMPL_VULKAN_MINIMUM_SAMPLER_POOL_SIZE },
+            { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, IMGUI_IMPL_VULKAN_MINIMUM_IMAGE_SAMPLER_POOL_SIZE },
         };
         VkDescriptorPoolCreateInfo pool_info = {};
         pool_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
@@ -383,7 +382,7 @@ int main(int, char**)
 
     // Create Framebuffers
     int w, h;
-    SDL_GetWindowSizeInPixels(window, &w, &h);
+    SDL_GetWindowSize(window, &w, &h);
     ImGui_ImplVulkanH_Window* wd = &g_MainWindowData;
     SetupVulkanWindow(wd, surface, w, h);
     SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
@@ -395,6 +394,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoTaskBarIcons;
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoMerge;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -404,6 +407,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForVulkan(window);
@@ -477,7 +489,7 @@ int main(int, char**)
 
         // Resize swap chain?
         int fb_width, fb_height;
-        SDL_GetWindowSizeInPixels(window, &fb_width, &fb_height);
+        SDL_GetWindowSize(window, &fb_width, &fb_height);
         if (fb_width > 0 && fb_height > 0 && (g_SwapChainRebuild || g_MainWindowData.Width != fb_width || g_MainWindowData.Height != fb_height))
         {
             ImGui_ImplVulkan_SetMinImageCount(g_MinImageCount);
@@ -530,17 +542,25 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        ImDrawData* draw_data = ImGui::GetDrawData();
-        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);
-        if (!is_minimized)
+        ImDrawData* main_draw_data = ImGui::GetDrawData();
+        const bool main_is_minimized = (main_draw_data->DisplaySize.x <= 0.0f || main_draw_data->DisplaySize.y <= 0.0f);
+        wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
+        wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
+        wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
+        wd->ClearValue.color.float32[3] = clear_color.w;
+        if (!main_is_minimized)
+            FrameRender(wd, main_draw_data);
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
-            wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
-            wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
-            wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
-            wd->ClearValue.color.float32[3] = clear_color.w;
-            FrameRender(wd, draw_data);
-            FramePresent(wd);
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
         }
+
+        // Present Main Platform Window
+        if (!main_is_minimized)
+            FramePresent(wd);
     }
 
     // Cleanup

examples/example_sdl3_wgpu/CMakeLists.txt

@@ -14,7 +14,7 @@
 #   * build/example_sdl3_wgpu[.exe] or build/Debug/example_sdl3_wgpu[.exe]
 
 # Building for desktop with WGVK (MUCH EASIER)
-#  1. git clone https://github.com/manuel5975p/WGVK wgvk
+#  1. git clone https://github.com/manuel5975p/WGVK dawn
 #  2. cmake -B build -DIMGUI_WGVK_DIR=wgvk
 #  3. cmake --build build
 # The resulting binary will be found at one of the following locations:
@@ -37,7 +37,7 @@ if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE Debug CACHE STRING "" FORCE)
 endif()
 
-set(CMAKE_CXX_STANDARD 20) # Dawn requires C++20
+set(CMAKE_CXX_STANDARD 17) # Dawn requires C++17
 
 # Dear ImGui
 set(IMGUI_DIR ../../)
@@ -141,28 +141,6 @@ else() # Native/Desktop build
     endif()
 
     if(IMGUI_WGVK_DIR)
-        find_package(Vulkan REQUIRED)
-        set(WGVK_PLATFORM_LIBS)
-        set(WGVK_PLATFORM_DEFS)
-        if(WIN32)
-            list(APPEND WGVK_PLATFORM_DEFS SUPPORT_WIN32_SURFACE=1)
-        elseif(APPLE)
-            list(APPEND WGVK_PLATFORM_DEFS SUPPORT_METAL_SURFACE=1)
-        elseif(UNIX)
-            find_package(PkgConfig QUIET)
-            pkg_check_modules(WAYLAND_CLIENT QUIET wayland-client)
-            if(WAYLAND_CLIENT_FOUND)
-                list(APPEND WGVK_PLATFORM_DEFS SUPPORT_WAYLAND_SURFACE=1)
-                list(APPEND WGVK_PLATFORM_LIBS ${WAYLAND_CLIENT_LIBRARIES})
-            endif()
-            find_package(X11 QUIET)
-            if(X11_FOUND)
-                list(APPEND WGVK_PLATFORM_DEFS SUPPORT_XLIB_SURFACE=1)
-                list(APPEND WGVK_PLATFORM_LIBS X11::X11)
-            endif()
-            list(APPEND WGVK_PLATFORM_LIBS m dl pthread)
-        endif()
-        set(LIBRARIES glfw Vulkan::Vulkan ${WGVK_PLATFORM_LIBS})
     endif()
 endif()
 
@@ -204,7 +182,6 @@ if(NOT EMSCRIPTEN) # WegGPU-Native settings
     if(IMGUI_WGVK_DIR)
         target_sources(${IMGUI_EXECUTABLE} PRIVATE ${IMGUI_WGVK_DIR}/src/wgvk.c)
         target_compile_definitions(${IMGUI_EXECUTABLE} PUBLIC "IMGUI_IMPL_WEBGPU_BACKEND_WGVK")
-        target_compile_definitions(${IMGUI_EXECUTABLE} PRIVATE ${WGVK_PLATFORM_DEFS})
         target_include_directories(${IMGUI_EXECUTABLE} PUBLIC ${IMGUI_WGVK_DIR}/include)
         if (MSVC)
            target_compile_options(${IMGUI_EXECUTABLE} PUBLIC /std:clatest /experimental:c11atomics)

examples/example_sdl3_wgpu/main.cpp

@@ -155,7 +155,7 @@ int main(int, char**)
         // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppIterate() function]
         // React to changes in screen size
         int width, height;
-        SDL_GetWindowSizeInPixels(window, &width, &height);
+        SDL_GetWindowSize(window, &width, &height);
         if (width != wgpu_surface_width || height != wgpu_surface_height)
             ResizeSurface(width, height);
 

examples/example_win32_directx10/example_win32_directx10.vcxproj

@@ -28,27 +28,27 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>Unicode</CharacterSet>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

examples/example_win32_directx10/main.cpp

@@ -57,6 +57,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -66,6 +70,15 @@ int main(int, char**)
     ImGuiStyle& style = ImGui::GetStyle();
     style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
     style.FontScaleDpi = main_scale;        // Set initial font scale. (in docking branch: using io.ConfigDpiScaleFonts=true automatically overrides this for every window depending on the current monitor)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
 
     // Setup Platform/Renderer backends
     ImGui_ImplWin32_Init(hwnd);
@@ -177,6 +190,13 @@ int main(int, char**)
         g_pd3dDevice->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX10_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         // Present
         HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
         //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
@@ -196,7 +216,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain
@@ -225,6 +244,16 @@ bool CreateDeviceD3D(HWND hWnd)
     if (res != S_OK)
         return false;
 
+    // Disable DXGI's default Alt+Enter fullscreen behavior.
+    // - You are free to leave this enabled, but it will not work properly with multiple viewports.
+    // - This must be done for all windows associated to the device. Our DX11 backend does this automatically for secondary viewports that it creates.
+    IDXGIFactory* pSwapChainFactory;
+    if (SUCCEEDED(g_pSwapChain->GetParent(IID_PPV_ARGS(&pSwapChainFactory))))
+    {
+        pSwapChainFactory->MakeWindowAssociation(hWnd, DXGI_MWA_NO_ALT_ENTER);
+        pSwapChainFactory->Release();
+    }
+
     CreateRenderTarget();
     return true;
 }