SDL3 GPU WebGPU Backend

.github/workflows/generic.yml

@@ -53,7 +53,7 @@ jobs:
       - uses: mymindstorm/setup-emsdk@v14
         if: ${{ matrix.platform.platform == 'emscripten' }}
         with:
-          version: 3.1.35
+          version: 3.1.74
       - uses: browser-actions/setup-chrome@v1
         id: setup-chrome
         if: ${{ matrix.platform.platform == 'emscripten' }}
@@ -386,4 +386,4 @@ jobs:
         with:
           if-no-files-found: error
           name: '${{ matrix.platform.artifact }}-apks'
-          path: build/test/*.apk
+          path: build/test/*.apk

CMakeLists.txt

@@ -206,6 +206,7 @@ set(SDL_STATIC_AVAILABLE ON)
 # All these *_DEFAULT vars will default to ON if not specified,
 # so you only need to override them if they need to be disabled.
 if(EMSCRIPTEN)
+
   # Set up default values for the currently supported set of subsystems:
   # Emscripten/Javascript does not have assembly support, a dynamic library
   # loading architecture, or low-level CPU inspection.
@@ -365,8 +366,10 @@ dep_option(SDL_RENDER_D3D12        "Enable the Direct3D 12 render driver" ON "SD
 dep_option(SDL_RENDER_METAL        "Enable the Metal render driver" ON "SDL_RENDER;${APPLE}" OFF)
 dep_option(SDL_RENDER_GPU          "Enable the SDL_GPU render driver" ON "SDL_RENDER;SDL_GPU" OFF)
 dep_option(SDL_VIVANTE             "Use Vivante EGL video driver" ON "${UNIX_SYS};SDL_CPU_ARM32" OFF)
+dep_option(SDL_WEBGPU              "Enable WebGPU support" ON "SDL_RENDER;${EMSCRIPTEN}" OFF)
 dep_option(SDL_VULKAN              "Enable Vulkan support" ON "SDL_VIDEO;ANDROID OR APPLE OR LINUX OR FREEBSD OR WINDOWS" OFF)
 dep_option(SDL_RENDER_VULKAN       "Enable the Vulkan render driver" ON "SDL_RENDER;SDL_VULKAN" OFF)
+dep_option(SDL_RENDER_WEBGPU       "Enable the WebGPU render driver" ON "SDL_RENDER;SDL_WEBGPU" OFF)
 dep_option(SDL_METAL               "Enable Metal support" ON "APPLE" OFF)
 set_option(SDL_OPENVR              "Use OpenVR video driver" OFF)
 dep_option(SDL_KMSDRM              "Use KMS DRM video driver" ${UNIX_SYS} "SDL_VIDEO" OFF)
@@ -1535,14 +1538,19 @@ elseif(EMSCRIPTEN)
     set(SDL_VIDEO_DRIVER_EMSCRIPTEN 1)
     sdl_glob_sources("${SDL3_SOURCE_DIR}/src/video/emscripten/*.c")
     set(HAVE_SDL_VIDEO TRUE)
-
-    #enable gles
-    if(SDL_OPENGLES)
-      set(SDL_VIDEO_OPENGL_EGL 1)
-      set(HAVE_OPENGLES TRUE)
-      set(SDL_VIDEO_OPENGL_ES2 1)
-      set(SDL_VIDEO_RENDER_OGL_ES2 1)
+    if(SDL_GPU)
+      set(SDL_WEBGPU ON)
+      set(SDL_RENDER_WEBGPU ON)
+      set(HAVE_WEBGPU TRUE)
+      set(HAVE_RENDER_WEBGPU TRUE)
     endif()
+    # #enable gles
+    # if(SDL_OPENGLES)
+    #   set(SDL_VIDEO_OPENGL_EGL 1)
+    #   set(HAVE_OPENGLES TRUE)
+    #   set(SDL_VIDEO_OPENGL_ES2 1)
+    #   set(SDL_VIDEO_RENDER_OGL_ES2 1)
+    # endif()
   endif()
 
   CheckPTHREAD()
@@ -3017,6 +3025,11 @@ if(SDL_GPU)
     set(SDL_GPU_VULKAN 1)
     set(HAVE_SDL_GPU TRUE)
   endif()
+  if(SDL_RENDER_WEBGPU AND EMSCRIPTEN)
+    sdl_glob_sources("${SDL3_SOURCE_DIR}/src/gpu/webgpu/*.c")
+    set(SDL_GPU_WEBGPU 1)
+    set(HAVE_SDL_GPU TRUE)
+  endif()
   if(SDL_RENDER_GPU)
     set(SDL_VIDEO_RENDER_GPU 1)
     set(HAVE_RENDER_GPU TRUE)

src/gpu/SDL_sysgpu.h

@@ -18,8 +18,8 @@
      misrepresented as being the original software.
   3. This notice may not be removed or altered from any source distribution.
 */
-#include "../video/SDL_sysvideo.h"
 #include "SDL_internal.h"
+#include "../video/SDL_sysvideo.h"
 
 #ifndef SDL_GPU_DRIVER_H
 #define SDL_GPU_DRIVER_H
@@ -977,6 +977,7 @@ extern "C" {
 extern SDL_GPUBootstrap VulkanDriver;
 extern SDL_GPUBootstrap D3D12Driver;
 extern SDL_GPUBootstrap MetalDriver;
+extern SDL_GPUBootstrap WebGPUDriver;
 extern SDL_GPUBootstrap PS5Driver;
 
 #ifdef __cplusplus

src/gpu/webgpu/README.md

@@ -0,0 +1,37 @@
+# SDL3 GPU WebGPU Backend
+Status: Work In Progress
+
+Author: Kyle Lukaszek
+
+## Compiling with Emscripten
+**Emscripten version 3.1.69+ is required to make use of SDL3 WebGPU.**
+**There is an issue with Emscripten versions (>=3.1.65 & < 3.1.69) that breaks buffer copying**
+
+To clone and build SDL WebGPU from source:
+```
+git clone https://github.com/klukaszek/SDL
+cd SDL
+mkdir build
+cd build
+emcmake cmake .. -DCMAKE_BUILD_TYPE=Release -DSDL_WEBGPU=ON -DSDL_RENDER_WEBGPU=ON
+cmake --build . --config Release --parallel
+sudo cmake --install . --config Release
+```
+
+To clone and build examples:
+```
+git clone https://github.com/klukaszek/SDL3-WebGPU-Examples
+cd SDL3-WebGPU-Examples
+git submodule update --init
+git submodule update --remote
+mkdir build
+cd build
+emcmake cmake .. -DSDL3_DIR="full/path/to/SDL/build"
+make
+```
+
+You can also provide the `-GNinja` flag to any of the `emcmake` commands to use Ninja instead of Make.
+
+## More Info
+
+- See checklist for a list of completed SDL3 API functions.

src/gpu/webgpu/SDL_WebGPU_Checklist.md

@@ -0,0 +1,136 @@
+# SDL WebGPU Driver Roadmap / Checklist
+
+These methods are tested by the example suite:
+- https://github.com/klukaszek/SDL3-WebGPU-Examples
+
+Getting my fork of the example suite merged with the original shouldn't be too much work but it needs to tested first.
+
+The original example suite can be found at:
+- https://github.com/TheSpydog/SDL_gpu_examples/
+
+Currently, the WebGPU backend only supports Emscripten as the compilation target, though I've added Elie Michel's cross-platform surface configuration logic to the backend. I have not tested it with any native implementations however. 
+
+# Checklist
+
+## General
+- [x] DestroyDevice
+- [x] SupportsPresentMode
+- [x] ClaimWindow
+- [x] ReleaseWindow
+
+## Swapchains
+- [x] SetSwapchainParameters
+- [x] SupportsTextureFormat
+- [x] SupportsSampleCount
+- [x] SupportsSwapchainComposition
+
+## Command Buffers and Fences
+- [x] AcquireCommandBuffer
+- [x] AcquireSwapchainTexture
+- [x] GetSwapchainTextureFormat
+- [x] Submit
+- [x] SubmitAndAcquireFence (Should just call Submit)
+- [x] Cancel (Should be no-op for WebGPU)
+- [x] Wait (Should be no-op for WebGPU)
+- [x] WaitForFences (Should be no-op for WebGPU)
+- [x] QueryFence (Should be no-op for WebGPU)
+- [x] ReleaseFence (Should be no-op for WebGPU)
+
+Note: WebGPU has no exposed fence API.
+
+## Buffers
+- [x] CreateBuffer
+- [x] ReleaseBuffer
+- [x] SetBufferName
+- [x] CreateTransferBuffer
+- [x] ReleaseTransferBuffer
+- [x] MapTransferBuffer
+- [x] UnmapTransferBuffer
+- [x] UploadToBuffer
+- [x] DownloadFromBuffer
+- [x] CopyBufferToBuffer
+
+## Textures
+- [x] CreateTexture
+- [x] ReleaseTexture
+- [x] SetTextureName
+- [x] UploadToTexture
+- [x] DownloadFromTexture (needs to be tested)
+- [x] CopyTextureToTexture (needs to be tested)
+- [ ] GenerateMipmaps
+    - Requires custom compute pipeline implementation.
+    - https://eliemichel.github.io/LearnWebGPU/basic-compute/image-processing/mipmap-generation.html
+
+## Samplers
+- [x] CreateSampler
+- [x] ReleaseSampler
+
+## Debugging
+- [x] InsertDebugLabel
+- [x] PushDebugGroup
+- [x] PopDebugGroup
+
+## Graphics Pipelines
+- [x] CreateGraphicsPipeline
+- [x] BindGraphicsPipeline
+- [x] ReleaseGraphicsPipeline
+
+## Compute Pipelines
+- [ ] CreateComputePipeline
+- [ ] BindComputePipeline
+- [ ] ReleaseComputePipeline
+
+## Shaders
+- [x] CreateShader
+- [x] ReleaseShader
+
+## Rendering
+- [x] BeginRenderPass
+- [x] EndRenderPass
+- [x] DrawPrimitivesIndirect
+- [x] DrawPrimitives
+- [x] DrawIndexedPrimitives
+- [x] DrawIndexedPrimitivesIndirect
+
+## Copy Passes
+- [x] BeginCopyPass
+- [x] EndCopyPass
+
+## Compute Passes
+- [ ] BeginComputePass
+- [ ] EndComputePass
+- [ ] DispatchCompute
+- [ ] DispatchComputeIndirect
+- [ ] BindComputeSamplers
+- [ ] BindComputeStorageTextures
+- [ ] BindComputeStorageBuffers
+- [ ] PushComputeUniformData
+
+## Fragment Stage
+- [x] BindFragmentSamplers
+- [ ] BindFragmentStorageTextures
+- [ ] BindFragmentStorageBuffers
+- [ ] PushFragmentUniformData
+    - Needs to be rewritten.
+
+## Vertex Stage
+- [x] BindVertexBuffers
+- [x] BindIndexBuffer
+- [x] BindVertexSamplers
+- [ ] BindVertexStorageTextures
+- [ ] BindVertexStorageBuffers
+- [ ] PushVertexUniformData
+    - Needs to be rewritten.
+
+## Rendering States
+- [x] SetViewport
+- [x] SetScissor
+- [x] SetBlendConstants
+- [x] SetStencilReference
+
+## Composition
+- [ ] Blit 
+    - Mostly functional.
+    - Bug: Example "Blit2DArray.c" has a sampler issue where the RHS is not downsampled.
+    - Bug: Example "TriangleMSAA.c" does not cycle between different sample counts.
+