From cf27a555adf330e31d8391cf862083222b20b392 Mon Sep 17 00:00:00 2001
From: ocornut <omarcornut@gmail.com>
Date: Thu, 6 Aug 2026 22:02:03 +0200
Subject: [PATCH] Example: SDL3+Metal: fixed missing multi-viewport support.

---
 examples/example_sdl3_metal/main.mm | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/examples/example_sdl3_metal/main.mm b/examples/example_sdl3_metal/main.mm
index e6e306624..ff6046ad9 100644
--- a/examples/example_sdl3_metal/main.mm
+++ b/examples/example_sdl3_metal/main.mm
@@ -62,6 +62,10 @@ 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();
@@ -71,6 +75,15 @@ 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_ImplMetal_Init(layer.device);
@@ -97,7 +110,7 @@ int main(int, char**)
     // Our state
     bool show_demo_window = true;
     bool show_another_window = false;
-    float clear_color[4] = { 0.45f, 0.55f, 0.60f, 1.00f };
+    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
 
     // Main loop
     bool done = false;
@@ -135,7 +148,7 @@ int main(int, char**)
             id<CAMetalDrawable> drawable = [layer nextDrawable];
 
             id<MTLCommandBuffer> commandBuffer = [commandQueue commandBuffer];
-            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].clearColor = MTLClearColorMake(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
             renderPassDescriptor.colorAttachments[0].texture = drawable.texture;
             renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
             renderPassDescriptor.colorAttachments[0].storeAction = MTLStoreActionStore;
@@ -192,6 +205,13 @@ int main(int, char**)
             [renderEncoder popDebugGroup];
             [renderEncoder endEncoding];
 
+            // Update and Render additional Platform Windows
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                ImGui::UpdatePlatformWindows();
+                ImGui::RenderPlatformWindowsDefault();
+            }
+
             [commandBuffer presentDrawable:drawable];
             [commandBuffer commit];
         }