Initialize WebGPU properly

engine/gfx/webgpu/src/gfx_webgpu.cpp

@@ -1,6 +1,12 @@
 #include "gfx_webgpu.hpp"
 
+#include <emscripten/html5_webgpu.h>
+
 bool GFXWebGPU::initialize(const GFXCreateInfo& createInfo) {
+    auto device = emscripten_webgpu_get_device();
+
+    prism::log("Initialized WebGPU!");
+
     return true;
 }
 

platforms/web/CMakeLists.txt

@@ -1,6 +1,7 @@
 include(../../cmake/AddPlatformExecutable.cmake)
 
 add_platform(
+        SRC ${CMAKE_CURRENT_SOURCE_DIR}/glue.cpp
         MAIN_FILE
         main.cpp.in
         LINK_LIBRARIES
@@ -15,6 +16,9 @@ function(add_platform_commands target)
             PROPERTIES
             SUFFIX ".html"
     )
+    target_link_options(${target}
+            PRIVATE "SHELL:-s USE_WEBGPU=1"
+    )
 
     set(DUMMY_NAME ${target}-CopyShaders)
 

platforms/web/glue.cpp

@@ -0,0 +1,80 @@
+// taken from https://github.com/kainino0x/webgpu-cross-platform-demo :-) thank you!
+#include <emscripten/em_js.h>
+#include <emscripten/emscripten.h>
+
+/**
+ * \def KEEP_IN_MODULE
+ * Marks a function to be kept in the \c Module and exposed to script. An
+ * alternative to Emscripten's \c bind or \c cwrap.
+ * \code
+ *	// C++
+ *	KEEP_IN_MODULE int getValue() {
+ *		return 42;
+ *	}
+ *	// JavaScript
+ *	console.log(Module._getValue());
+ * \endcode
+ */
+#ifndef KEEP_IN_MODULE
+#define KEEP_IN_MODULE extern "C" __attribute__((used, visibility("default")))
+#endif
+
+/**
+ * Entry point for the 'real' application.
+ *
+ * \param[in] argc count of program arguments in argv
+ * \param[in] argv program arguments (excluding the application)
+ */
+extern "C" int __main__(int /*argc*/, char* /*argv*/[]);
+
+//****************************************************************************/
+
+namespace impl {
+/**
+ * JavaScript async calls that need to finish before calling \c main().
+ */
+    EM_JS(void, glue_preint, (), {
+        var entry = __glue_main_;
+        if (entry) {
+            /*
+             * None of the WebGPU properties appear to survive Closure, including
+             * Emscripten's own `preinitializedWebGPUDevice` (which from looking at
+             *`library_html5` is probably designed to be inited in script before
+             * loading the Wasm).
+             */
+            if (navigator["gpu"]) {
+                navigator["gpu"]["requestAdapter"]().then(function (adapter) {
+                    adapter["requestDevice"]().then( function (device) {
+                        Module["preinitializedWebGPUDevice"] = device;
+                        entry();
+                    });
+                }, function () {
+                    console.error("No WebGPU adapter; not starting");
+                });
+            } else {
+                console.error("No support for WebGPU; not starting");
+            }
+        } else {
+            console.error("Entry point not found; unable to start");
+        }
+    });
+}
+
+//****************************************************************************/
+
+/**
+ * Redirector to call \c __main__() (exposed to Emscripten's \c Module).
+ *
+ * \todo pass URL query string for args
+ */
+KEEP_IN_MODULE void _glue_main_() {
+    __main__(0, nullptr);
+}
+
+/**
+ * Entry point. Workaround for Emscripten needing an \c async start.
+ */
+int main(int /*argc*/, char* /*argv*/[]) {
+    impl::glue_preint();
+    return 0;
+}

platforms/web/main.cpp.in

@@ -23,7 +23,7 @@ EM_BOOL draw(double time, void *userData) {
     return true;
 }
 
-int main(int argc, char* argv[]) {
+extern "C" int __main__(int argc, char* argv[]) {
     engine = new prism::engine(argc, argv);
 
     app = new @APP_CLASS@();
@@ -39,7 +39,7 @@ int main(int argc, char* argv[]) {
 
     app_main(engine);
 
-    engine->add_window(nullptr, (void*)1, {100, 100}});
+    engine->add_window((void*)1, (void*)1, {100, 100});
     app->initialize_render();
 
     emscripten_request_animation_frame_loop(draw, nullptr);