CMake + Dawn + Emscripten Build Refactor

.gitignore

@@ -1,13 +1,15 @@
 build/*
 # any build subdirectory in the tree
 **/build/
+**/build_web/
 examples/hello_gpu/build/*
 examples/raymarch/build/*
 docs/html
 source
 .DS_Store
 third_party/lib/*
 third_party/local/*
+third_party/dawn/*
 
 # formatter files
 .cmake-format.py
@@ -20,3 +22,6 @@ build
 .cache
 compile_commands.json
 
+# editor specific
+.vscode/*
+

CMakeLists.txt

@@ -1,23 +1,13 @@
+# This only builds a shared lib, see cmake/example.cmake
+# and cmake/gpu.cmake for more details
 cmake_minimum_required(VERSION 3.28)
 project(gpu)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/cmake/webgpu.cmake")
-
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON) # export compile_commands.json to use with
                                       # LSP
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-option(USE_LOCAL_LIBS
-       "Use local libraries instead of fetching from the internet" OFF)
-
-# Ensure the build type is set
-if(NOT CMAKE_BUILD_TYPE)
-    set(CMAKE_BUILD_TYPE
-        Release
-        CACHE STRING "Choose the type of build: Debug or Release" FORCE)
-endif()
-
 option(FASTBUILD "Option to enable fast builds" OFF)
 if(FASTBUILD)
     set(CMAKE_BUILD_TYPE None) # Avoid default flags of predefined build types
@@ -30,21 +20,9 @@ if(DEBUG)
     set(CMAKE_CXX_FLAGS "-O0 -g")
 endif()
 
-if(WIN64)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DWEBGPU_BACKEND_DAWN")
-endif()
-
+include("${CMAKE_CURRENT_SOURCE_DIR}/cmake/dawn.cmake")
 include("${CMAKE_CURRENT_SOURCE_DIR}/cmake/gpu.cmake")
 
-message(STATUS "CMAKE_CURRENT_SOURCE_DIR: ${CMAKE_CURRENT_SOURCE_DIR}")
-message(
-    STATUS
-        "Include directories for wgpu: ${CMAKE_CURRENT_SOURCE_DIR}/third_party/headers"
-)
-
 add_library(gpud SHARED gpu.hpp)
 set_target_properties(gpud PROPERTIES LINKER_LANGUAGE CXX)
-target_link_libraries(gpud PRIVATE wgpu)
-target_link_libraries(gpud PRIVATE webgpu)
 target_link_libraries(gpud PRIVATE gpu)
-install(TARGETS gpud)

cmake/dawn.cmake

@@ -0,0 +1,122 @@
+# Setup directories
+set(FETCHCONTENT_BASE_DIR "${PROJECT_ROOT}/third_party")
+set(DAWN_DIR "${FETCHCONTENT_BASE_DIR}/dawn" CACHE INTERNAL "")
+set(DAWN_BUILD_DIR "${DAWN_DIR}/build" CACHE INTERNAL "")
+
+if(EMSCRIPTEN)
+    set(EM_SDK_DIR $ENV{EMSDK} CACHE INTERNAL "")
+    set(DAWN_BUILD_DIR "${DAWN_DIR}/build_web" CACHE INTERNAL "")
+    set(DAWN_EMSCRIPTEN_TOOLCHAIN ${EM_SDK_DIR}/upstream/emscripten CACHE INTERNAL "" FORCE)
+endif()
+
+# Enable find for no dawn rebuilds with flutter run
+set(ENABLE_DAWN_FIND OFF CACHE BOOL "Enable finding Dawn" FORCE)
+set(DAWN_BUILD_FOUND OFF CACHE BOOL "Dawn build found" FORCE)
+if(ENABLE_DAWN_FIND)
+    # find_library, windows adds extra folder
+    if(MSVC)
+        find_library(WEBGPU_DAWN_DEBUG webgpu_dawn
+        NAMES webgpu_dawn
+        HINTS "${DAWN_BUILD_DIR}/src/dawn/native/Debug"
+        )
+        find_library(WEBGPU_DAWN_RELEASE webgpu_dawn
+        NAMES webgpu_dawn
+        HINTS "${DAWN_BUILD_DIR}/src/dawn/native/Release"
+        )
+        set(DAWN_BUILD_FOUND ON)
+    elseif(NOT EMSCRIPTEN AND NOT MSVC)
+        find_library(WEBGPU_DAWN_LIB
+        NAMES webgpu_dawn
+        PATHS "${DAWN_BUILD_DIR}/src/dawn/native"
+        REQUIRED
+        )
+        set(DAWN_BUILD_FOUND ON)
+    else()
+        set(DAWN_BUILD_FOUND ON)
+    endif()
+endif()
+
+# Dawn options for more,
+# see https://dawn.googlesource.com/dawn/+/refs/heads/main/CMakeLists.txt
+set(DAWN_ALWAYS_ASSERT     OFF CACHE INTERNAL "Always assert in Dawn" FORCE)
+set(DAWN_BUILD_MONOLITHIC_LIBRARY ON CACHE INTERNAL "Build Dawn monolithically" FORCE)
+set(DAWN_BUILD_EXAMPLES      OFF CACHE INTERNAL "Build Dawn examples" FORCE)
+set(DAWN_BUILD_SAMPLES      OFF CACHE INTERNAL "Build Dawn samples" FORCE)
+set(DAWN_BUILD_TESTS         OFF CACHE INTERNAL "Build Dawn tests" FORCE)
+set(DAWN_ENABLE_INSTALL      OFF  CACHE INTERNAL "Enable Dawn installation" FORCE)
+set(DAWN_FETCH_DEPENDENCIES ON  CACHE INTERNAL "Fetch Dawn dependencies" FORCE)
+set(TINT_BUILD_TESTS        OFF CACHE INTERNAL "Build Tint Tests" FORCE)
+set(TINT_BUILD_IR_BINARY    OFF CACHE INTERNAL "Build Tint IR binary" FORCE)
+set(TINT_BUILD_CMD_TOOLS   OFF CACHE INTERNAL "Build Tint command line tools" FORCE)
+
+if(NOT DAWN_BUILD_FOUND)
+    include(FetchContent)
+    message("webgpu_dawn not found start building")
+    if(EMSCRIPTEN)
+        set(EMSCRIPTEN_DIR "${EM_SDK_DIR}/upstream/emscripten" CACHE INTERNAL "" FORCE)
+        set(DAWN_EMSCRIPTEN_TOOLCHAIN ${EMSCRIPTEN_DIR} CACHE INTERNAL "" FORCE)
+    endif()
+
+    FetchContent_Declare(
+        dawn
+        DOWNLOAD_DIR ${DAWN_DIR}
+        SOURCE_DIR ${DAWN_DIR}
+        SUBBUILD_DIR ${DAWN_BUILD_DIR}/tmp
+        BINARY_DIR ${DAWN_BUILD_DIR}
+        DOWNLOAD_COMMAND
+        cd ${DAWN_DIR} &&
+        git init &&
+        git fetch --depth=1 https://dawn.googlesource.com/dawn &&
+        git reset --hard FETCH_HEAD
+    )
+
+    # Download the repository and add it as a subdirectory.
+    FetchContent_MakeAvailable(dawn)
+
+    # attempt fix flutter rebuilds
+    set(CMAKE_INCLUDE_PATH "${CMAKE_INCLUDE_PATH};${DAWN_DIR}/src" CACHE INTERNAL "")
+
+    execute_process(
+        WORKING_DIRECTORY ${DAWN_DIR}
+        COMMAND ${CMAKE_COMMAND} -S ${DAWN_DIR}
+            -B ${DAWN_BUILD_DIR}
+    )
+
+    # Build Dawn
+    execute_process(
+        COMMAND ${CMAKE_COMMAND} --build ${DAWN_BUILD_DIR}
+    )
+
+    # find_library, windows adds extra folder
+    if(MSVC)
+        find_library(WEBGPU_DAWN_DEBUG webgpu_dawn
+        NAMES webgpu_dawn
+        HINTS "${DAWN_BUILD_DIR}/src/dawn/native/Debug"
+        )
+        find_library(WEBGPU_DAWN_RELEASE webgpu_dawn
+        NAMES webgpu_dawn
+        HINTS "${DAWN_BUILD_DIR}/src/dawn/native/Release"
+        )
+        set(DAWN_BUILD_FOUND ON)
+    elseif(NOT EMSCRIPTEN AND NOT MSVC)
+        find_library(WEBGPU_DAWN_LIB
+        NAMES webgpu_dawn
+        PATHS "${DAWN_BUILD_DIR}/src/dawn/native"
+        REQUIRED
+        )
+        set(DAWN_BUILD_FOUND ON)
+    else()
+        set(DAWN_BUILD_FOUND ON)
+    endif()
+endif()
+
+if(EMSCRIPTEN)
+    add_library(webgpu_dawn INTERFACE IMPORTED)
+    target_include_directories(webgpu_dawn INTERFACE ${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/include)
+    target_include_directories(webgpu_dawn INTERFACE ${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/include/webgpu/webgpu.h)
+    target_link_libraries(webgpu_dawn INTERFACE ${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/library_webgpu_enum_tables.js)
+    target_link_libraries(webgpu_dawn INTERFACE ${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/library_webgpu_generated_struct_info.js)
+    target_link_libraries(webgpu_dawn INTERFACE ${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/library_webgpu_generated_sig_info.js)
+    target_link_libraries(webgpu_dawn INTERFACE ${DAWN_DIR}/third_party/emdawnwebgpu/library_webgpu.js)
+else()
+endif()

cmake/example.cmake

@@ -1,68 +1,97 @@
-set(CMAKE_EXPORT_COMPILE_COMMANDS ON) # export compile_commands.json to use with
-                                      # LSP
-set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
+# Getting Started with CMAKE
+# Each example includes this and sets PROJECT_NAME.
+#
+# Example usage:
+#   cd examples/hello_world
+#   cmake -S . build/ -DCMAKE_BUILD_TYPE=Release
+#   cmake --build build/ --config Release
+#   ./build/hello_world   (or serve the output .js/.wasm for Emscripten)
+#   or for emscripten
+#   emcmake cmake -S . -B ./build_web -DCMAKE_BUILD_TYPE=Release
+#   cmake --build build_web --config Release
+#   python3 -m http.server 8080 --d build_web
 
+if(NOT MSVC)
+    set(CMAKE_CXX_STANDARD 17)
+else()
+    set(CMAKE_CXX_STANDARD 20)
+endif()
+
+# Locate the project root (two levels up from the current source dir)
 get_filename_component(PROJECT_ROOT ${CMAKE_CURRENT_SOURCE_DIR} DIRECTORY)
 get_filename_component(PROJECT_ROOT ${PROJECT_ROOT} DIRECTORY)
 
-# Construct potential paths
-set(FILEPATH_CURRENT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/${FILENAME}")
-set(FILEPATH_PROJECT_ROOT "${PROJECT_ROOT}/${FILENAME}")
+# Include external libraries and helper scripts (dawn and gpu)
+include("${PROJECT_ROOT}/cmake/dawn.cmake")
+include("${PROJECT_ROOT}/cmake/gpu.cmake")
 
-# Include file finding utility script
-include("${CMAKE_CURRENT_SOURCE_DIR}/cmake/find_gpu.cmake")
+# Create the executable
+add_executable(${PROJECT_NAME} run.cpp)
 
-# Check if the file exists in the current directory
-find_project_root(${CMAKE_CURRENT_SOURCE_DIR} ${FILENAME}
-                  TARGET_FILE_PATH)
-if("${TARGET_FILE_PATH}" STREQUAL "")
-    find_project_root(${FILEPATH_CURRENT_DIR} ${FILENAME}
-                      TARGET_FILE_PATH)
-    if("${TARGET_FILE_PATH}" STREQUAL "")
-        message(
-            FATAL_ERROR
-                "File ${FILENAME} not found in either ${CMAKE_CURRENT_SOURCE_DIR} or ${CMAKE_CURRENT_SOURCE_DIR}/../../"
-        )
-    endif()
-endif()
+# Platform-specific linking & build settings
+if(EMSCRIPTEN)
+    # Emscripten-specific configuration
 
-# Ensure the build type is set
-if(NOT CMAKE_BUILD_TYPE)
-    set(CMAKE_BUILD_TYPE
-        Release
-        CACHE STRING "Choose the type of build: Debug or Release" FORCE)
-endif()
+    # Define a web output directory (adjust as needed)
+    set(WEB_OUTPUT_DIR "${CMAKE_CURRENT_BINARY_DIR}/web_build")
 
-# Define architecture and build type directories or file names
-if(CMAKE_SIZEOF_VOID_P EQUAL 8)
-    set(ARCH "x64")
-else()
-    set(ARCH "x86")
-endif()
+    # If necessary, include the generated WebGPU include dirs first.
+    include_directories(BEFORE "${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/include/")
 
-if(CMAKE_BUILD_TYPE STREQUAL "Debug")
-    set(BUILD_TYPE "Debug")
-else()
-    set(BUILD_TYPE "Release")
-endif()
+    # Create a helper library for WebGPU support.
+    add_library(webgpu_web "${DAWN_DIR}/third_party/emdawnwebgpu/webgpu.cpp")
+    target_link_libraries(${PROJECT_NAME} PRIVATE webgpu_web)
+
+    # Set Emscripten-specific link flags that enable WASM output and expose certain symbols.
+    # Needed to use updated version, emdawnwebgpu
+    set_target_properties(${PROJECT_NAME} PROPERTIES LINK_FLAGS "\
+        -sUSE_WEBGPU=0 \
+        -sWASM=1 \
+        -DDAWN_EMSCRIPTEN_TOOLCHAIN=${EMSCRIPTEN_DIR} \
+        -sEXPORTED_FUNCTIONS=_main,_malloc,_free,_memcpy \
+        -sEXPORTED_RUNTIME_METHODS=ccall \
+        -sUSE_GLFW=3 \
+        -sALLOW_MEMORY_GROWTH=1 -sSTACK_SIZE=5MB \
+        -sASYNCIFY \
+        --js-library=${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/library_webgpu_enum_tables.js \
+        --js-library=${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/library_webgpu_generated_struct_info.js \
+        --js-library=${DAWN_BUILD_DIR}/gen/src/emdawnwebgpu/library_webgpu_generated_sig_info.js \
+        --js-library=${DAWN_DIR}/third_party/emdawnwebgpu/library_webgpu.js \
+        --closure-args=--externs=${EMSCRIPTEN_DIR}/src/closure-externs/webgpu-externs.js \
+    ")
 
-if(NOT TARGET gpu)
-    message(STATUS "GPU_LIB not found")
-    include("${TARGET_FILE_PATH}/cmake/webgpu.cmake")
-    include("${TARGET_FILE_PATH}/cmake/gpu.cmake")
+else()
+    # Non-Emscripten (desktop) linking
+    if(MSVC)
+        target_link_libraries(gpu 
+            PRIVATE 
+                $<$<CONFIG:Debug>:${WEBGPU_DAWN_DEBUG}>
+                $<$<CONFIG:Release>:${WEBGPU_DAWN_RELEASE}>
+        )
+    else()
+        target_link_libraries(gpu PRIVATE webgpu_dawn)
+    endif()
 endif()
 
-add_executable(${PROJECT_NAME} run.cpp)
+# Link the gpu/dawn library to the executable.
 target_link_libraries(${PROJECT_NAME} PRIVATE gpu)
-target_link_libraries(${PROJECT_NAME} PRIVATE wgpu)
-target_link_libraries(${PROJECT_NAME} PRIVATE webgpu)
 
-if(WIN32)
-    # Ensure DLL is copied if on Windows
+# Platform-specific post-build actions (e.g. copying DLLs for MSVC)
+if(MSVC)
     add_custom_command(
-        TARGET ${PROJECT_NAME}
-        POST_BUILD
-        COMMAND ${CMAKE_COMMAND} -E copy_if_different ${DLL_PATH}
-                $<TARGET_FILE_DIR:${PROJECT_NAME}>)
+        TARGET ${PROJECT_NAME} POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy
+                ${DAWN_BUILD_DIR}/$<CONFIG>/webgpu_dawn.dll
+                $<TARGET_FILE_DIR:${PROJECT_NAME}>
+        COMMENT "Copying webgpu_dawn.dll to the build directory"
+    )
+endif()
+
+if(EMSCRIPTEN)
+
+    # Configure the HTML file by replacing @PROJECT_NAME@ with the actual target name.
+    configure_file(${PROJECT_ROOT}cmake/templates/index.html.in
+                   ${CMAKE_CURRENT_BINARY_DIR}/index.html
+                   @ONLY)
+
 endif()