example_glfw_wgpu does not compile with Dawn

[brccabral]

Version/Branch of Dear ImGui:

Version 1.92.0, Branch: master

Back-ends:

imgui_impl_wgpu.cpp + imgui_impl_glfw.cpp

Compiler, OS:

Linux + /usr/bin/c++

Full config/build information:

git clone --depth 1 https://dawn.googlesource.com/dawn $HOME/dawn.d
cd imgui/examples/example_glfw_wgpu
mkdir build
cd build
cmake -DIMGUI_DAWN_DIR=$HOME/dawn.d ..
cmake --build . --target example_glfw_wgpu -j10

Details:

The example_glfw_wgpu does not compile with Dawn, with Emscripten it works fine, but as Dawn is suggested in the CMakeLists.txt I tried it.

Is Dawn supported?

Screenshots/Video:

No response

Minimal, Complete and Verifiable Example code:

The examples/example_glfw_wgpu/main.cpp without any modifications.

Dawn compiles libwebgpu_dawn.so, imgui backends compiles, but examples/example_glfw_wgpu/main.cpp fails.

Is Dawn supported?

[100%] Built target dawn_native_objects
[100%] Building CXX object dawn/src/dawn/native/CMakeFiles/webgpu_dawn.dir/__/__/__/gen/src/dawn/native/webgpu_dawn_native_proc.cpp.o
[100%] Building CXX object dawn/src/dawn/native/CMakeFiles/webgpu_dawn.dir/null/NullBackend.cpp.o
[100%] Building CXX object dawn/src/dawn/native/CMakeFiles/webgpu_dawn.dir/opengl/OpenGLBackend.cpp.o
[100%] Building CXX object dawn/src/dawn/native/CMakeFiles/webgpu_dawn.dir/DawnNative.cpp.o
[100%] Building CXX object dawn/src/dawn/native/CMakeFiles/webgpu_dawn.dir/vulkan/VulkanBackend.cpp.o
[100%] Linking CXX shared library libwebgpu_dawn.so
[100%] Built target webgpu_dawn
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/main.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/imgui.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/imgui_draw.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/backends/imgui_impl_glfw.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/imgui_tables.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/imgui_widgets.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/backends/imgui_impl_wgpu.cpp.o
[100%] Building CXX object CMakeFiles/example_glfw_wgpu.dir/mnt/HDExtra/CPP_Projects/imgui/imgui_demo.cpp.o
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:38:8: error: ‘WGPUSwapChain’ does not name a type
   38 | static WGPUSwapChain     wgpu_swap_chain = nullptr;
      |        ^~~~~~~~~~~~~
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp: In function ‘void wgpu_error_callback(WGPUErrorType, const char*, void*)’:
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:59:10: error: ‘WGPUErrorType_DeviceLost’ was not declared in this scope; did you mean ‘WGPUErrorType_Force32’?
   59 |     case WGPUErrorType_DeviceLost:  error_type_lbl = "Device lost"; break;
      |          ^~~~~~~~~~~~~~~~~~~~~~~~
      |          WGPUErrorType_Force32
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp: In function ‘int main(int, char**)’:
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:225:69: error: ‘wgpu_swap_chain’ was not declared in this scope; did you mean ‘wgpu_swap_chain_width’?
  225 |         color_attachments.view = wgpuSwapChainGetCurrentTextureView(wgpu_swap_chain);
      |                                                                     ^~~~~~~~~~~~~~~
      |                                                                     wgpu_swap_chain_width
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:225:34: error: ‘wgpuSwapChainGetCurrentTextureView’ was not declared in this scope; did you mean ‘wgpuSurfaceGetCurrentTexture’?
  225 |         color_attachments.view = wgpuSwapChainGetCurrentTextureView(wgpu_swap_chain);
      |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                                  wgpuSurfaceGetCurrentTexture
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:245:9: error: ‘wgpuSwapChainPresent’ was not declared in this scope; did you mean ‘wgpuSurfacePresent’?
  245 |         wgpuSwapChainPresent(wgpu_swap_chain);
      |         ^~~~~~~~~~~~~~~~~~~~
      |         wgpuSurfacePresent
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp: In function ‘WGPUAdapterImpl* RequestAdapter(WGPUInstance)’:
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:279:51: error: could not convert ‘onAdapterRequestEnded’ from ‘RequestAdapter(WGPUInstance)::<lambda(WGPURequestAdapterStatus, WGPUAdapter, const char*, void*)>’ to ‘WGPURequestAdapterCallbackInfo’
  279 |     wgpuInstanceRequestAdapter(instance, nullptr, onAdapterRequestEnded, (void*)&adapter);
      |                                                   ^~~~~~~~~~~~~~~~~~~~~
      |                                                   |
      |                                                   RequestAdapter(WGPUInstance)::<lambda(WGPURequestAdapterStatus, WGPUAdapter, const char*, void*)>
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp: In function ‘WGPUDeviceImpl* RequestDevice(WGPUAdapterImpl*&)’:
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:293:48: error: could not convert ‘onDeviceRequestEnded’ from ‘RequestDevice(WGPUAdapterImpl*&)::<lambda(WGPURequestDeviceStatus, WGPUDevice, const char*, void*)>’ to ‘WGPURequestDeviceCallbackInfo’
  293 |     wgpuAdapterRequestDevice(adapter, nullptr, onDeviceRequestEnded, (void*)&device);
      |                                                ^~~~~~~~~~~~~~~~~~~~
      |                                                |
      |                                                RequestDevice(WGPUAdapterImpl*&)::<lambda(WGPURequestDeviceStatus, WGPUDevice, const char*, void*)>
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp: In function ‘bool InitWGPU(GLFWwindow*)’:
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:332:5: error: ‘wgpuDeviceSetUncapturedErrorCallback’ was not declared in this scope; did you mean ‘WGPUUncapturedErrorCallback’?
  332 |     wgpuDeviceSetUncapturedErrorCallback(wgpu_device, wgpu_error_callback, nullptr);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |     WGPUUncapturedErrorCallback
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp: In function ‘void CreateSwapChain(int, int)’:
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:339:9: error: ‘wgpu_swap_chain’ was not declared in this scope; did you mean ‘wgpu_swap_chain_width’?
  339 |     if (wgpu_swap_chain)
      |         ^~~~~~~~~~~~~~~
      |         wgpu_swap_chain_width
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:340:9: error: ‘wgpuSwapChainRelease’ was not declared in this scope; did you mean ‘wgpuSurfaceRelease’?
  340 |         wgpuSwapChainRelease(wgpu_swap_chain);
      |         ^~~~~~~~~~~~~~~~~~~~
      |         wgpuSurfaceRelease
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:343:5: error: ‘WGPUSwapChainDescriptor’ was not declared in this scope; did you mean ‘WGPUSurfaceDescriptor’?
  343 |     WGPUSwapChainDescriptor swap_chain_desc = {};
      |     ^~~~~~~~~~~~~~~~~~~~~~~
      |     WGPUSurfaceDescriptor
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:344:5: error: ‘swap_chain_desc’ was not declared in this scope
  344 |     swap_chain_desc.usage = WGPUTextureUsage_RenderAttachment;
      |     ^~~~~~~~~~~~~~~
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:349:5: error: ‘wgpu_swap_chain’ was not declared in this scope; did you mean ‘wgpu_swap_chain_width’?
  349 |     wgpu_swap_chain = wgpuDeviceCreateSwapChain(wgpu_device, wgpu_surface, &swap_chain_desc);
      |     ^~~~~~~~~~~~~~~
      |     wgpu_swap_chain_width
/mnt/HDExtra/CPP_Projects/imgui/examples/example_glfw_wgpu/main.cpp:349:23: error: ‘wgpuDeviceCreateSwapChain’ was not declared in this scope; did you mean ‘wgpuDeviceCreateSampler’?
  349 |     wgpu_swap_chain = wgpuDeviceCreateSwapChain(wgpu_device, wgpu_surface, &swap_chain_desc);
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~
      |                       wgpuDeviceCreateSampler
At global scope:
cc1plus: note: unrecognized command-line option ‘-Wno-nullability-extension’ may have been intended to silence earlier diagnostics
cc1plus: note: unrecognized command-line option ‘-Wno-unreachable-code-break’ may have been intended to silence earlier diagnostics
cc1plus: note: unrecognized command-line option ‘-Wno-gcc-compat’ may have been intended to silence earlier diagnostics
gmake[3]: *** [CMakeFiles/example_glfw_wgpu.dir/build.make:76: CMakeFiles/example_glfw_wgpu.dir/main.cpp.o] Error 1
gmake[3]: *** Waiting for unfinished jobs....
gmake[2]: *** [CMakeFiles/Makefile2:1447: CMakeFiles/example_glfw_wgpu.dir/all] Error 2
gmake[1]: *** [CMakeFiles/Makefile2:1454: CMakeFiles/example_glfw_wgpu.dir/rule] Error 2
gmake: *** [Makefile:124: example_glfw_wgpu] Error 2

[ocornut]

Are you setting #define IMGUI_IMPL_WEBGPU_BACKEND_DAWN ?

[brccabral]

I am running the example CMakeLists.txt as is. It does

  target_compile_definitions(example_glfw_wgpu PUBLIC
    "IMGUI_IMPL_WEBGPU_BACKEND_DAWN"
  )

[adembudak]

This commit at Dawn repo might be related.

[bjconlan]

Yeah, I was just playing around with this over the weekend. It was trivial to change. In the below patch I'm only assuming dawn has these changes as per the preprocessor conditions but wouldn't be surprised if it has also landed in the wgpu implementation.

diff --git a/backends/imgui_impl_wgpu.cpp b/backends/imgui_impl_wgpu.cpp
index 3187be29..f117e69c 100644
--- a/backends/imgui_impl_wgpu.cpp
+++ b/backends/imgui_impl_wgpu.cpp
@@ -49,10 +49,10 @@
     #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) == defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
     #error exactly one of IMGUI_IMPL_WEBGPU_BACKEND_DAWN or IMGUI_IMPL_WEBGPU_BACKEND_WGPU must be defined!
     #endif
-#else
-    #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) || defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
-    #error neither IMGUI_IMPL_WEBGPU_BACKEND_DAWN nor IMGUI_IMPL_WEBGPU_BACKEND_WGPU may be defined if targeting emscripten!
-    #endif
+// #else
+//     #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) || defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
+//     #error neither IMGUI_IMPL_WEBGPU_BACKEND_DAWN nor IMGUI_IMPL_WEBGPU_BACKEND_WGPU may be defined if targeting emscripten!
+//     #endif
 #endif
 
 #ifndef IMGUI_DISABLE
@@ -263,7 +263,11 @@ static void SafeRelease(FrameResources& res)
     SafeRelease(res.VertexBufferHost);
 }
 
+#if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN)
+static WGPUComputeState ImGui_ImplWGPU_CreateShaderModule(const char* wgsl_source)
+#else
 static WGPUProgrammableStageDescriptor ImGui_ImplWGPU_CreateShaderModule(const char* wgsl_source)
+#endif
 {
     ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData();
 
@@ -280,7 +284,11 @@ static WGPUProgrammableStageDescriptor ImGui_ImplWGPU_CreateShaderModule(const c
     WGPUShaderModuleDescriptor desc = {};
     desc.nextInChain = reinterpret_cast<WGPUChainedStruct*>(&wgsl_desc);
 
+#if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN)
+    WGPUComputeState stage_desc = {};
+#else
     WGPUProgrammableStageDescriptor stage_desc = {};
+#endif
     stage_desc.module = wgpuDeviceCreateShaderModule(bd->wgpuDevice, &desc);
 
 #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) || defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
@@ -680,7 +688,11 @@ bool ImGui_ImplWGPU_CreateDeviceObjects()
     graphics_pipeline_desc.layout = wgpuDeviceCreatePipelineLayout(bd->wgpuDevice, &layout_desc);
 
     // Create the vertex shader
+#if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN)
+    WGPUComputeState vertex_shader_desc = ImGui_ImplWGPU_CreateShaderModule(__shader_vert_wgsl);
+#else
     WGPUProgrammableStageDescriptor vertex_shader_desc = ImGui_ImplWGPU_CreateShaderModule(__shader_vert_wgsl);
+#endif
     graphics_pipeline_desc.vertex.module = vertex_shader_desc.module;
     graphics_pipeline_desc.vertex.entryPoint = vertex_shader_desc.entryPoint;
 
@@ -708,7 +720,11 @@ bool ImGui_ImplWGPU_CreateDeviceObjects()
     graphics_pipeline_desc.vertex.buffers = buffer_layouts;
 
     // Create the pixel shader
+#if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN)
+    WGPUComputeState pixel_shader_desc = ImGui_ImplWGPU_CreateShaderModule(__shader_frag_wgsl);
+#else
     WGPUProgrammableStageDescriptor pixel_shader_desc = ImGui_ImplWGPU_CreateShaderModule(__shader_frag_wgsl);
+#endif
 
     // Create the blending setup
     WGPUBlendState blend_state = {};

I have a very butchered working example (which I based from https://developer.chrome.com/docs/web-platform/webgpu/build-app (but instead using the 'webgpu.h' api instead of the 'webgpu_cpp.h' which in retrospect I would probably revert) and the GLFW + WebGPU imgui example. If you would like me to share here as a gist (but it isn't of a high quality; hopefully over the next few days I may get time to provide a PR against the example code; which might actually be of use with regards to resolving this ticket)