Add sdl2glue to vendor:wgpu package + triangle example

vendor/wgpu/examples/glfw/os_js.odin

@@ -0,0 +1,60 @@
+package vendor_wgpu_example_triangle
+
+import "vendor:wgpu"
+import "vendor:wasm/js"
+
+OS :: struct {
+	initialized: bool,
+}
+
+@(private="file")
+g_os: ^OS
+
+os_init :: proc(os: ^OS) {
+	g_os = os
+	assert(js.add_window_event_listener(.Resize, nil, size_callback))
+}
+
+// NOTE: frame loop is done by the runtime.js repeatedly calling `step`.
+os_run :: proc(os: ^OS) {
+	os.initialized = true
+}
+
+os_get_render_bounds :: proc(os: ^OS) -> (width, height: u32) {
+	rect := js.get_bounding_client_rect("body")
+	return u32(rect.width), u32(rect.height)
+}
+
+os_get_surface :: proc(os: ^OS, instance: wgpu.Instance) -> wgpu.Surface {
+	return wgpu.InstanceCreateSurface(
+		instance,
+		&wgpu.SurfaceDescriptor{
+			nextInChain = &wgpu.SurfaceDescriptorFromCanvasHTMLSelector{
+				sType = .SurfaceDescriptorFromCanvasHTMLSelector,
+				selector = "#wgpu-canvas",
+			},
+		},
+	)
+}
+
+@(private="file", export)
+step :: proc(dt: f32) -> bool {
+	if !g_os.initialized {
+		return true
+	}
+
+	frame(dt)
+	return true
+}
+
+@(private="file", fini)
+os_fini :: proc() {
+	js.remove_window_event_listener(.Resize, nil, size_callback)
+
+	finish()
+}
+
+@(private="file")
+size_callback :: proc(e: js.Event) {
+	resize()
+}