SDL3 GPU WebGPU Backend

CMakeLists.txt

@@ -373,8 +373,10 @@ 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" OFF "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" OFF "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" ${UNIX_SYS} "SDL_VIDEO" OFF)
@@ -1543,6 +1545,12 @@ elseif(EMSCRIPTEN)
     set(SDL_VIDEO_DRIVER_EMSCRIPTEN 1)
     sdl_glob_sources("${SDL3_SOURCE_DIR}/src/video/emscripten/*.c")
     set(HAVE_SDL_VIDEO TRUE)
+    #enable webgpu
+    if(SDL_GPU AND SDL_WEBGPU)
+      set(SDL_RENDER_WEBGPU ON)
+      set(HAVE_WEBGPU TRUE)
+      set(HAVE_RENDER_WEBGPU TRUE)
+    endif()
 
     #enable gles
     if(SDL_OPENGLES)
@@ -1890,6 +1898,42 @@ elseif(UNIX AND NOT APPLE AND NOT RISCOS AND NOT HAIKU)
     set (HAVE_VSNPRINTF 0)
     set (USE_POSIX_SPAWN 1)
   endif()
+
+  if(SDL_WEBGPU)  # Native platform WebGPU handling
+    set(SDL_VIDEO_WEBGPU 1)
+
+    # This should probably require a compilation flag with the path but for now
+    # SDL3/SDL_webgpu.h points to wgpu/ for the webgpu header.
+    # The user must provide a wgpu library of their choice.
+    set(SDL_WEBGPU_PATH "wgpu" CACHE PATH 
+              "Path to WebGPU library (must contain include/ and lib/ directories)")
+    if(NOT SDL_WEBGPU_PATH)
+        message(FATAL_ERROR "SDL_WEBGPU enabled but SDL_WEBGPU_PATH not specified! "
+              "Please provide path to WebGPU library installation.")
+    endif()
+
+    # Verify library structure
+    find_path(WEBGPU_INCLUDE_DIR webgpu.h
+        PATHS "${SDL_WEBGPU_PATH}/include/webgpu/"
+        NO_DEFAULT_PATH
+        REQUIRED
+    )
+    find_library(WEBGPU_LIBRARY
+        NAMES wgpu_native
+        PATHS "${SDL_WEBGPU_PATH}/lib/"
+        NO_DEFAULT_PATH
+        REQUIRED
+    )
+
+    # Add to build system
+    sdl_include_directories(PRIVATE SYSTEM "${WEBGPU_INCLUDE_DIR}")
+    sdl_link_dependency(WebGPU LIBS "${WEBGPU_LIBRARY}")
+
+    set(SDL_RENDER_WEBGPU ON)
+    set(HAVE_WEBGPU TRUE)
+    set(HAVE_RENDER_WEBGPU TRUE)
+  endif()
+
 elseif(WINDOWS)
   check_c_source_compiles("
     #include <windows.h>
@@ -2107,6 +2151,39 @@ elseif(WINDOWS)
         set(HAVE_RENDER_VULKAN TRUE)
       endif()
     endif()
+    if(SDL_WEBGPU)  # Native platform WebGPU handling
+      set(SDL_VIDEO_WEBGPU 1)  
+      # This should probably require a compilation flag with the path but for now
+      # SDL3/SDL_webgpu.h points to wgpu/ for the webgpu header.
+      # The user must provide a webgpu library of their choice.
+      set(SDL_WEBGPU_PATH "wgpu" CACHE PATH 
+                "Path to WebGPU library (must contain include/ and lib/ directories)")
+      if(NOT SDL_WEBGPU_PATH)
+          message(FATAL_ERROR "SDL_WEBGPU enabled but SDL_WEBGPU_PATH not specified! "
+                "Please provide path to WebGPU library installation.")
+      endif()      
+      # Locate headers and static library
+      find_path(WEBGPU_INCLUDE_DIR webgpu.h
+          PATHS "${SDL_WEBGPU_PATH}/include/webgpu/"
+          NO_DEFAULT_PATH
+          REQUIRED
+      )
+      find_library(WEBGPU_LIBRARY
+          NAMES wgpu_native
+          PATHS "${SDL_WEBGPU_PATH}/lib/"
+          NO_DEFAULT_PATH
+          REQUIRED
+      )
+
+      # Add include directories
+      sdl_include_directories(PRIVATE SYSTEM "${WEBGPU_INCLUDE_DIR}")
+      sdl_link_dependency(WebGPU LIBS "${WEBGPU_LIBRARY}")
+
+      set(SDL_RENDER_WEBGPU ON)
+      set(HAVE_WEBGPU TRUE)
+      set(HAVE_RENDER_WEBGPU TRUE)
+    endif()
+
 
     sdl_glob_sources("${SDL3_SOURCE_DIR}/src/tray/windows/*.c")
     set(HAVE_SDL_TRAY TRUE)
@@ -3026,6 +3103,11 @@ if(SDL_GPU)
     set(SDL_GPU_VULKAN 1)
     set(HAVE_SDL_GPU TRUE)
   endif()
+  if(SDL_RENDER_WEBGPU)
+    sdl_glob_sources("${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)

include/SDL3/SDL_gpu.h

@@ -954,6 +954,7 @@ typedef Uint32 SDL_GPUShaderFormat;
 #define SDL_GPU_SHADERFORMAT_DXIL     (1u << 3) /**< DXIL SM6_0 shaders for D3D12. */
 #define SDL_GPU_SHADERFORMAT_MSL      (1u << 4) /**< MSL shaders for Metal. */
 #define SDL_GPU_SHADERFORMAT_METALLIB (1u << 5) /**< Precompiled metallib shaders for Metal. */
+#define SDL_GPU_SHADERFORMAT_WGSL     (1u << 6) /**< WGSL shaders for WebGPU. */
 
 /**
  * Specifies the format of a vertex attribute.
@@ -2187,6 +2188,7 @@ extern SDL_DECLSPEC SDL_GPUDevice * SDLCALL SDL_CreateGPUDeviceWithProperties(
 #define SDL_PROP_GPU_DEVICE_CREATE_SHADERS_MSL_BOOLEAN        "SDL.gpu.device.create.shaders.msl"
 #define SDL_PROP_GPU_DEVICE_CREATE_SHADERS_METALLIB_BOOLEAN   "SDL.gpu.device.create.shaders.metallib"
 #define SDL_PROP_GPU_DEVICE_CREATE_D3D12_SEMANTIC_NAME_STRING "SDL.gpu.device.create.d3d12.semantic"
+#define SDL_PROP_GPU_DEVICE_CREATE_SHADERS_WGSL_BOOLEAN       "SDL.gpu.device.create.shaders.wgsl"
 
 /**
  * Destroys a GPU context previously returned by SDL_CreateGPUDevice.

include/SDL3/SDL_webgpu.h

@@ -0,0 +1,49 @@
+/*
+  // Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/**
+ * # CategoryWebGPU
+**/
+
+/*
+NOTE: Some of the enum conversion functions are a nightmare to manage between the different flavours of webgpu.h
+
+wgpu-native source code pulls it's header from here: https://github.com/webgpu-native/webgpu-headers/blob/main/webgpu.h
+however the header provided in the release version of the library: https://github.com/gfx-rs/wgpu-native/releases
+have some changes to the enum values that kind of screw everything up.
+
+Gotta wait until the header is finalized to get this fixed.
+
+webgpu.h from webgpu-headers SHOULD work for all backends, except for Emscripten and wgpu-native apparently!
+So as I suspected, Dawn would have been the best pick to work with like I had originally done before swapping to wgpu-native out of convenience.
+*/
+
+#ifndef __EMSCRIPTEN__
+// #include "../../wgpu/include/webgpu/webgpu.h"
+#include "../../wgpu/include/webgpu/wgpu.h"
+#endif // webgpu.h is provided by emscripten when using emcc with -sUSE_WEBGPU=1
+
+#include <SDL3/SDL_stdinc.h>
+#include <SDL3/SDL_video.h>
+
+extern SDL_DECLSPEC bool SDLCALL SDL_WebGPU_CreateSurface(SDL_Window *window,
+                                                          WGPUInstance instance,
+                                                          WGPUSurface *retSurface);

include/build_config/SDL_build_config.h.cmake

@@ -430,11 +430,15 @@
 /* Enable Metal support */
 #cmakedefine SDL_VIDEO_METAL 1
 
+/* Enable WebGPU support */
+#cmakedefine SDL_VIDEO_WEBGPU 1
+
 /* Enable GPU support */
 #cmakedefine SDL_GPU_D3D11 1
 #cmakedefine SDL_GPU_D3D12 1
 #cmakedefine SDL_GPU_VULKAN 1
 #cmakedefine SDL_GPU_METAL 1
+#cmakedefine SDL_GPU_WEBGPU 1
 
 /* Enable system power support */
 #cmakedefine SDL_POWER_ANDROID 1

include/build_config/SDL_build_config_macos.h

@@ -235,6 +235,7 @@
 #define SDL_GPU_METAL 1
 #define SDL_VIDEO_VULKAN 1
 #define SDL_GPU_VULKAN 1
+#define SDL_GPU_WEBGPU 1
 #define SDL_VIDEO_RENDER_GPU 1
 #endif
 

src/gpu/SDL_gpu.c

@@ -169,6 +169,9 @@ static const SDL_GPUBootstrap *backends[] = {
 #endif
 #ifdef SDL_GPU_D3D12
     &D3D12Driver,
+#endif
+#ifdef SDL_GPU_WEBGPU
+    &WebGPUDriver,
 #endif
     NULL
 };
@@ -404,6 +407,9 @@ static const SDL_GPUBootstrap * SDL_GPUSelectBackend(SDL_PropertiesID props)
     if (SDL_GetBooleanProperty(props, SDL_PROP_GPU_DEVICE_CREATE_SHADERS_METALLIB_BOOLEAN, false)) {
         format_flags |= SDL_GPU_SHADERFORMAT_METALLIB;
     }
+    if (SDL_GetBooleanProperty(props, SDL_PROP_GPU_DEVICE_CREATE_SHADERS_WGSL_BOOLEAN, false)) {
+        format_flags |= SDL_GPU_SHADERFORMAT_WGSL;
+    }
 
     gpudriver = SDL_GetHint(SDL_HINT_GPU_DRIVER);
     if (gpudriver == NULL) {
@@ -466,6 +472,9 @@ static void SDL_GPU_FillProperties(
     if (format_flags & SDL_GPU_SHADERFORMAT_METALLIB) {
         SDL_SetBooleanProperty(props, SDL_PROP_GPU_DEVICE_CREATE_SHADERS_METALLIB_BOOLEAN, true);
     }
+    if (format_flags & SDL_GPU_SHADERFORMAT_WGSL) {
+        SDL_SetBooleanProperty(props, SDL_PROP_GPU_DEVICE_CREATE_SHADERS_WGSL_BOOLEAN, true);        
+    }
     SDL_SetBooleanProperty(props, SDL_PROP_GPU_DEVICE_CREATE_DEBUGMODE_BOOLEAN, debug_mode);
     SDL_SetStringProperty(props, SDL_PROP_GPU_DEVICE_CREATE_NAME_STRING, name);
 }

src/gpu/SDL_sysgpu.h

@@ -989,6 +989,7 @@ extern "C" {
 extern SDL_GPUBootstrap VulkanDriver;
 extern SDL_GPUBootstrap D3D12Driver;
 extern SDL_GPUBootstrap MetalDriver;
+extern SDL_GPUBootstrap WebGPUDriver;
 extern SDL_GPUBootstrap PrivateGPUDriver;
 
 #ifdef __cplusplus

src/gpu/webgpu/README.md

@@ -0,0 +1,40 @@
+# SDL3 GPU WebGPU Backend
+Status: Work In Progress
+
+Author: Kyle Lukaszek
+
+# Currently Native Only
+Web demo will be back eventually.
+
+# Building
+Find your flavour of [wgpu-native](https://github.com/gfx-rs/wgpu-native/releases) and download then unzip the contents into a `wgpu/` directory.
+
+To clone and build SDL WebGPU from source:
+```
+git clone https://github.com/klukaszek/SDL
+mv wgpu/ SDL/wgpu/ 
+cd SDL
+mkdir build
+cd build
+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
+cmake .. -DSDL3_DIR="full/path/to/SDL/build" -DWEBGPU_PATH="full/path/to/your-wgpu-install/"
+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.