timestamp expertiments

examples/jsm/renderers/webgpu/WebGPUBackend.js

@@ -333,6 +333,15 @@ class WebGPUBackend extends Backend {
 		const encoder = device.createCommandEncoder( { label: 'renderContext_' + renderContext.id } );
 		const currentPass = encoder.beginRenderPass( descriptor );
 
+
+		// timestamps
+
+		const tsQuerySet = device.createQuerySet( { type: 'timestamp', count: 2 } );
+
+		renderContextData.tsQuerySet = tsQuerySet;
+
+		encoder.writeTimestamp( tsQuerySet, 0 );
+
 		//
 
 		renderContextData.descriptor = descriptor;
@@ -358,7 +367,7 @@ class WebGPUBackend extends Backend {
 
 	}
 
-	finishRender( renderContext ) {
+	async finishRender( renderContext ) {
 
 		const renderContextData = this.get( renderContext );
 		const occlusionQueryCount = renderContext.occlusionQueryCount;
@@ -413,11 +422,33 @@ class WebGPUBackend extends Backend {
 
 		}
 
+		renderContextData.encoder.writeTimestamp( renderContextData.tsQuerySet, 1 );
+
+		const tsQueryBuffer = this.device.createBuffer( {
+			size: 2 * 8,
+			usage: GPUBufferUsage.QUERY_RESOLVE | GPUBufferUsage.COPY_SRC
+		} );
+
+		const tsReadBuffer = this.device.createBuffer( {
+				size: 2 * 8,
+			usage: GPUBufferUsage.COPY_DST | GPUBufferUsage.MAP_READ
+		} );
+
+		renderContextData.encoder.resolveQuerySet( renderContextData.tsQuerySet, 0, 2 , tsQueryBuffer, 0 );
+		renderContextData.encoder.copyBufferToBuffer( tsQueryBuffer, 0, tsReadBuffer, 0, 2* 8 );
+
 		this.device.queue.submit( [ renderContextData.encoder.finish() ] );
 
 		//
 
-		if ( renderContext.textures !== null ) {
+		await tsReadBuffer.mapAsync( GPUMapMode.READ );
+
+		const tsBuffer = tsReadBuffer.getMappedRange();
+		const tsResults = new BigUint64Array( tsBuffer );
+
+		console.log( 'time:', new Intl.NumberFormat().format( ( tsResults[ 1 ] - tsResults[ 0 ] ) / 1000n ), 'us' );
+
+		if ( renderContext.texture !== null && renderContext.texture.generateMipmaps === true ) {
 
 			const textures = renderContext.textures;