Backends: SDL_GPU3: use MSL on macOS and MetalLib on iOS to fix shader compatibility. (#9076)

Edit original PR to keep metallib shader binary since next commit is going to use them.

backends/imgui_impl_sdlgpu3.cpp

@@ -22,6 +22,7 @@
 //   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
+//  2025-11-26: Use MSL shaders on macOS to support macOS 10.14+ (instead of Metallib shaders requiring macOS 14+). Requires calling SDL_CreateGPUDevice() with SDL_GPU_SHADERFORMAT_MSL.
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-08-20: Added ImGui_ImplSDLGPU3_InitInfo::SwapchainComposition and ImGui_ImplSDLGPU3_InitInfo::PresentMode to configure how secondary viewports are created.
 //  2025-08-08: *BREAKING* Changed ImTextureID type from SDL_GPUTextureSamplerBinding* to SDL_GPUTexture*, which is more natural and easier for user to manage. If you need to change the current sampler, you can access the ImGui_ImplSDLGPU3_RenderState struct. (#8866, #8163, #7998, #7988)
@@ -452,6 +453,19 @@ static void ImGui_ImplSDLGPU3_CreateShaders()
 #ifdef __APPLE__
     else
     {
+#include <TargetConditionals.h>
+#if TARGET_OS_OSX
+        // macOS: using MSL source
+        vertex_shader_info.entrypoint = "main0";
+        vertex_shader_info.format = SDL_GPU_SHADERFORMAT_MSL;
+        vertex_shader_info.code = msl_vertex;
+        vertex_shader_info.code_size = sizeof(msl_vertex);
+        fragment_shader_info.entrypoint = "main0";
+        fragment_shader_info.format = SDL_GPU_SHADERFORMAT_MSL;
+        fragment_shader_info.code = msl_fragment;
+        fragment_shader_info.code_size = sizeof(msl_fragment);
+#elif TARGET_OS_IPHONE
+        // iOS device: using metallib blobs
         vertex_shader_info.entrypoint = "main0";
         vertex_shader_info.format = SDL_GPU_SHADERFORMAT_METALLIB;
         vertex_shader_info.code = metallib_vertex;
@@ -460,6 +474,7 @@ static void ImGui_ImplSDLGPU3_CreateShaders()
         fragment_shader_info.format = SDL_GPU_SHADERFORMAT_METALLIB;
         fragment_shader_info.code = metallib_fragment;
         fragment_shader_info.code_size = sizeof(metallib_fragment);
+#endif
     }
 #endif
     bd->VertexShader = SDL_CreateGPUShader(v->Device, &vertex_shader_info);

backends/imgui_impl_sdlgpu3_shaders.h

@@ -221,6 +221,40 @@ const uint8_t metallib_fragment[3787]  = {
     148,161,0,0,0,0,109,97,105,110,48,97,105,114,46,115,97,109,112,108,101,95,116,101,120,116,117,114,101,95,50,100,46,118,52,102,51,50,51,50,48,50,51,46,51,54,56,97,105,114,54,52,45,97,
     112,112,108,101,45,109,97,99,111,115,120,49,52,46,48,46,48,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 };
+static uint8_t msl_vertex[800] =
+{
+    35,105,110,99,108,117,100,101,32,60,109,101,116,97,108,95,115,116,100,108,105,98,62,10,35,105,110,99,108,117,100,101,32,60,115,105,109,100,47,115,105,109,100,46,104,62,10,10,117,115,
+    105,110,103,32,110,97,109,101,115,112,97,99,101,32,109,101,116,97,108,59,10,10,115,116,114,117,99,116,32,95,57,10,123,10,32,32,32,32,102,108,111,97,116,52,32,67,111,108,111,114,59,
+    10,32,32,32,32,102,108,111,97,116,50,32,85,86,59,10,125,59,10,10,115,116,114,117,99,116,32,85,66,79,10,123,10,32,32,32,32,102,108,111,97,116,50,32,117,83,99,97,108,101,59,10,32,32,
+    32,32,102,108,111,97,116,50,32,117,84,114,97,110,115,108,97,116,101,59,10,125,59,10,10,115,116,114,117,99,116,32,109,97,105,110,48,95,111,117,116,10,123,10,32,32,32,32,102,108,111,
+    97,116,52,32,79,117,116,95,67,111,108,111,114,32,91,91,117,115,101,114,40,108,111,99,110,48,41,93,93,59,10,32,32,32,32,102,108,111,97,116,50,32,79,117,116,95,85,86,32,91,91,117,115,
+    101,114,40,108,111,99,110,49,41,93,93,59,10,32,32,32,32,102,108,111,97,116,52,32,103,108,95,80,111,115,105,116,105,111,110,32,91,91,112,111,115,105,116,105,111,110,93,93,59,10,125,
+    59,10,10,115,116,114,117,99,116,32,109,97,105,110,48,95,105,110,10,123,10,32,32,32,32,102,108,111,97,116,50,32,97,80,111,115,32,91,91,97,116,116,114,105,98,117,116,101,40,48,41,93,
+    93,59,10,32,32,32,32,102,108,111,97,116,50,32,97,85,86,32,91,91,97,116,116,114,105,98,117,116,101,40,49,41,93,93,59,10,32,32,32,32,102,108,111,97,116,52,32,97,67,111,108,111,114,32,
+    91,91,97,116,116,114,105,98,117,116,101,40,50,41,93,93,59,10,125,59,10,10,118,101,114,116,101,120,32,109,97,105,110,48,95,111,117,116,32,109,97,105,110,48,40,109,97,105,110,48,95,105,
+    110,32,105,110,32,91,91,115,116,97,103,101,95,105,110,93,93,44,32,99,111,110,115,116,97,110,116,32,85,66,79,38,32,117,98,111,32,91,91,98,117,102,102,101,114,40,48,41,93,93,41,10,123,
+    10,32,32,32,32,109,97,105,110,48,95,111,117,116,32,111,117,116,32,61,32,123,125,59,10,32,32,32,32,95,57,32,79,117,116,32,61,32,123,125,59,10,32,32,32,32,79,117,116,46,67,111,108,111,
+    114,32,61,32,105,110,46,97,67,111,108,111,114,59,10,32,32,32,32,79,117,116,46,85,86,32,61,32,105,110,46,97,85,86,59,10,32,32,32,32,111,117,116,46,103,108,95,80,111,115,105,116,105,
+    111,110,32,61,32,102,108,111,97,116,52,40,40,105,110,46,97,80,111,115,32,42,32,117,98,111,46,117,83,99,97,108,101,41,32,43,32,117,98,111,46,117,84,114,97,110,115,108,97,116,101,44,
+    32,48,46,48,44,32,49,46,48,41,59,10,32,32,32,32,111,117,116,46,103,108,95,80,111,115,105,116,105,111,110,46,121,32,42,61,32,40,45,49,46,48,41,59,10,32,32,32,32,111,117,116,46,79,117,
+    116,95,67,111,108,111,114,32,61,32,79,117,116,46,67,111,108,111,114,59,10,32,32,32,32,111,117,116,46,79,117,116,95,85,86,32,61,32,79,117,116,46,85,86,59,10,32,32,32,32,114,101,116,
+    117,114,110,32,111,117,116,59,10,125,10,10,
+};
+static uint8_t msl_fragment[580] =
+{
+    35,105,110,99,108,117,100,101,32,60,109,101,116,97,108,95,115,116,100,108,105,98,62,10,35,105,110,99,108,117,100,101,32,60,115,105,109,100,47,115,105,109,100,46,104,62,10,10,117,115,
+    105,110,103,32,110,97,109,101,115,112,97,99,101,32,109,101,116,97,108,59,10,10,115,116,114,117,99,116,32,95,49,49,10,123,10,32,32,32,32,102,108,111,97,116,52,32,67,111,108,111,114,
+    59,10,32,32,32,32,102,108,111,97,116,50,32,85,86,59,10,125,59,10,10,115,116,114,117,99,116,32,109,97,105,110,48,95,111,117,116,10,123,10,32,32,32,32,102,108,111,97,116,52,32,102,67,
+    111,108,111,114,32,91,91,99,111,108,111,114,40,48,41,93,93,59,10,125,59,10,10,115,116,114,117,99,116,32,109,97,105,110,48,95,105,110,10,123,10,32,32,32,32,102,108,111,97,116,52,32,
+    73,110,95,67,111,108,111,114,32,91,91,117,115,101,114,40,108,111,99,110,48,41,93,93,59,10,32,32,32,32,102,108,111,97,116,50,32,73,110,95,85,86,32,91,91,117,115,101,114,40,108,111,99,
+    110,49,41,93,93,59,10,125,59,10,10,102,114,97,103,109,101,110,116,32,109,97,105,110,48,95,111,117,116,32,109,97,105,110,48,40,109,97,105,110,48,95,105,110,32,105,110,32,91,91,115,116,
+    97,103,101,95,105,110,93,93,44,32,116,101,120,116,117,114,101,50,100,60,102,108,111,97,116,62,32,115,84,101,120,116,117,114,101,32,91,91,116,101,120,116,117,114,101,40,48,41,93,93,
+    44,32,115,97,109,112,108,101,114,32,115,84,101,120,116,117,114,101,83,109,112,108,114,32,91,91,115,97,109,112,108,101,114,40,48,41,93,93,41,10,123,10,32,32,32,32,109,97,105,110,48,
+    95,111,117,116,32,111,117,116,32,61,32,123,125,59,10,32,32,32,32,95,49,49,32,73,110,32,61,32,123,125,59,10,32,32,32,32,73,110,46,67,111,108,111,114,32,61,32,105,110,46,73,110,95,67,
+    111,108,111,114,59,10,32,32,32,32,73,110,46,85,86,32,61,32,105,110,46,73,110,95,85,86,59,10,32,32,32,32,111,117,116,46,102,67,111,108,111,114,32,61,32,73,110,46,67,111,108,111,114,
+    32,42,32,115,84,101,120,116,117,114,101,46,115,97,109,112,108,101,40,115,84,101,120,116,117,114,101,83,109,112,108,114,44,32,73,110,46,85,86,41,59,10,32,32,32,32,114,101,116,117,114,
+    110,32,111,117,116,59,10,125,10,10,
+};
 #elif TARGET_OS_IPHONE
 const uint8_t metallib_vertex[3876]  = {
     77,84,76,66,1,0,2,0,7,0,0,130,18,0,1,0,36,15,0,0,0,0,0,0,88,0,0,0,0,0,0,0,123,0,0,0,0,0,0,0,219,0,0,0,0,0,0,0,49,0,0,0,0,0,0,0,12,1,0,0,0,0,0,0,8,0,0,0,0,0,0,0,20,1,0,0,0,0,0,0,16,

backends/sdlgpu3/build_instructions.txt

@@ -34,6 +34,8 @@ Instructions to rebuild imgui_impl_sdlgpu3_shaders.h
     xcrun -sdk macosx metallib -o vertex.metallib -c vertex.ir
     xcrun -sdk macosx metallib -o fragment.metallib -c fragment.ir
 
+    note: use .metal outputs for updating msl_vertex / msl_fragment variables, and use .metallib outputs for metallib_vertex / metallib_fragment variables
+
     Proceed to step 4
 
 

docs/CHANGELOG.txt

@@ -54,6 +54,9 @@ Other Changes:
 - Scrollbar: fixed a codepath leading to a divide-by-zero (which would not be
   noticeable by user but detected by sanitizers). (#9089) [@judicaelclair]
 - Backends:
+  - SDL_GPU3: on macOS, use MSL shaders in order to support macOS 10.14+
+    (instead of Metallib shaders requiring macOS 14+). (#9076) [@Niminem]
+    Requires calling SDL_CreateGPUDevice() with SDL_GPU_SHADERFORMAT_MSL.
   - Vulkan: helper for creating a swapchain (used by examples and multi-viewports)
     selects `VkSwapchainCreateInfoKHR`'s `compositeAlpha` value based on
     `cap.supportedCompositeAlpha`, which seems to be required on some Android

examples/example_sdl3_sdlgpu3/main.cpp

@@ -47,7 +47,7 @@ int main(int, char**)
     SDL_ShowWindow(window);
 
     // Create GPU Device
-    SDL_GPUDevice* gpu_device = SDL_CreateGPUDevice(SDL_GPU_SHADERFORMAT_SPIRV | SDL_GPU_SHADERFORMAT_DXIL | SDL_GPU_SHADERFORMAT_METALLIB,true,nullptr);
+    SDL_GPUDevice* gpu_device = SDL_CreateGPUDevice(SDL_GPU_SHADERFORMAT_SPIRV | SDL_GPU_SHADERFORMAT_DXIL | SDL_GPU_SHADERFORMAT_MSL | SDL_GPU_SHADERFORMAT_METALLIB, true, nullptr);
     if (gpu_device == nullptr)
     {
         printf("Error: SDL_CreateGPUDevice(): %s\n", SDL_GetError());