Implement wgpuCreateInstance (#19762)

Author: beaufortfrancois

src/library_webgpu.js

@@ -2332,27 +2332,20 @@ var LibraryWebGPU = {
   // Instance
 
   wgpuCreateInstance: function() {
-#if ASSERTIONS
-    // Once implemented, Instance should create and own the object management tables.
-    abort('TODO: wgpuCreateInstance unimplemented');
-#endif
+    return 1;
   },
 
   wgpuInstanceReference: function() {
-#if ASSERTIONS
-    abort('TODO: no WGPUInstance object should exist');
-#endif
+    // no-op
   },
   wgpuInstanceRelease: function() {
-#if ASSERTIONS
-    abort('TODO: no WGPUInstance object should exist');
-#endif
+    // no-op
   },
 
   wgpuInstanceCreateSurface__deps: ['$findCanvasEventTarget'],
   wgpuInstanceCreateSurface: function(instanceId, descriptor) {
     {{{ gpu.makeCheck('descriptor') }}}
-    {{{ gpu.makeCheck('instanceId === 0, "WGPUInstance is ignored"') }}}
+    {{{ gpu.makeCheck('instanceId === 1, "WGPUInstance must be created by wgpuCreateInstance"') }}}
     var nextInChainPtr = {{{ makeGetValue('descriptor', C_STRUCTS.WGPUSurfaceDescriptor.nextInChain, '*') }}};
 #if ASSERTIONS
     assert(nextInChainPtr !== 0);
@@ -2386,7 +2379,7 @@ var LibraryWebGPU = {
 
   wgpuInstanceRequestAdapter__deps: ['$callUserCallback', '$stringToUTF8OnStack'],
   wgpuInstanceRequestAdapter: function(instanceId, options, callback, userdata) {
-    {{{ gpu.makeCheck('instanceId === 0, "WGPUInstance is ignored"') }}}
+    {{{ gpu.makeCheck('instanceId === 1, "WGPUInstance must be created by wgpuCreateInstance"') }}}
 
     var opts;
     if (options) {

test/webgpu_basic_rendering.cpp

@@ -17,13 +17,12 @@
 #include <emscripten/html5.h>
 #include <emscripten/html5_webgpu.h>
 
-void GetDevice(void (*callback)(wgpu::Device)) {
-    // Left as null (until supported in Emscripten)
-    static const WGPUInstance instance = nullptr;
+static const wgpu::Instance instance = wgpuCreateInstance(nullptr);
 
-    wgpuInstanceRequestAdapter(instance, nullptr, [](WGPURequestAdapterStatus status, WGPUAdapter adapter, const char* message, void* userdata) {
+void GetDevice(void (*callback)(wgpu::Device)) {
+    instance.RequestAdapter(nullptr, [](WGPURequestAdapterStatus status, WGPUAdapter cAdapter, const char* message, void* userdata) {
         if (message) {
-            printf("wgpuInstanceRequestAdapter: %s\n", message);
+            printf("RequestAdapter: %s\n", message);
         }
         if (status == WGPURequestAdapterStatus_Unavailable) {
             printf("WebGPU unavailable; exiting cleanly\n");
@@ -32,13 +31,14 @@ void GetDevice(void (*callback)(wgpu::Device)) {
         }
         assert(status == WGPURequestAdapterStatus_Success);
 
-        wgpuAdapterRequestDevice(adapter, nullptr, [](WGPURequestDeviceStatus status, WGPUDevice dev, const char* message, void* userdata) {
+        wgpu::Adapter adapter = wgpu::Adapter::Acquire(cAdapter);
+        adapter.RequestDevice(nullptr, [](WGPURequestDeviceStatus status, WGPUDevice cDevice, const char* message, void* userdata) {
             if (message) {
-                printf("wgpuAdapterRequestDevice: %s\n", message);
+                printf("RequestDevice: %s\n", message);
             }
             assert(status == WGPURequestDeviceStatus_Success);
 
-            wgpu::Device device = wgpu::Device::Acquire(dev);
+            wgpu::Device device = wgpu::Device::Acquire(cDevice);
             reinterpret_cast<void (*)(wgpu::Device)>(userdata)(device);
         }, userdata);
     }, reinterpret_cast<void*>(callback));
@@ -377,7 +377,6 @@ void run() {
 
         wgpu::SurfaceDescriptor surfDesc{};
         surfDesc.nextInChain = &canvasDesc;
-        wgpu::Instance instance{};  // null instance
         wgpu::Surface surface = instance.CreateSurface(&surfDesc);
 
         wgpu::SwapChainDescriptor scDesc{};