javascript
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three.js
mirror of https://github.com/tazdij/three.js.git


			
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	<head>
		<title>three.js webgpu - mrt readback</title>
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		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgpu - mrt readback
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/tsl": "../build/three.webgpu.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';
			import { mix, modelNormalMatrix, normalGeometry, normalize, outputStruct, step, texture, uniform, uv, varying, vec2, vec4 } from 'three/tsl';

			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';

			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

			let camera, scene, renderer, torus;
			let quadMesh, renderTarget, readbackTarget, material, readbackMaterial, pixelBuffer, pixelBufferTexture;

			const gui = new GUI();

			const options = {
				selection: 'mrt',
			};

			gui.add( options, 'selection', [ 'mrt', 'diffuse', 'normal' ] );

			class WriteGBufferMaterial extends THREE.NodeMaterial {

				constructor( diffuseTexture ) {

					super();

					this.lights = false;
					this.fog = false;
					this.colorSpaced = false;

					this.diffuseTexture = diffuseTexture;

					const vUv = varying( uv() );

					const transformedNormal = modelNormalMatrix.mul( normalGeometry );
					const vNormal = varying( normalize( transformedNormal ) );

					const repeat = uniform( vec2( 5, 0.5 ) );

					const gColor = texture( this.diffuseTexture, vUv.mul( repeat ) );
					const gNormal = vec4( normalize( vNormal ), 1.0 );

					this.fragmentNode = outputStruct( gColor, gNormal );

				}

			}

			class ReadGBufferMaterial extends THREE.NodeMaterial {

				constructor( tDiffuse, tNormal ) {

					super();

					this.lights = false;
					this.fog = false;

					const vUv = varying( uv() );

					const diffuse = texture( tDiffuse, vUv );
					const normal = texture( tNormal, vUv );

					this.fragmentNode = mix( diffuse, normal, step( 0.5, vUv.x ) );

				}

			}

			init();

			function init() {

				renderer = new THREE.WebGPURenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( render );
				document.body.appendChild( renderer.domElement );

				// Create a multi render target with Float buffers

				renderTarget = new THREE.RenderTarget(
					window.innerWidth * window.devicePixelRatio,
					window.innerHeight * window.devicePixelRatio,
					{ count: 2, minFilter: THREE.NearestFilter, magFilter: THREE.NearestFilter }
				);

				// Name our G-Buffer attachments for debugging

				renderTarget.textures[ 0 ].name = 'diffuse';
				renderTarget.textures[ 1 ].name = 'normal';


				// Init readback render target, readback data texture, readback material
				// Be careful with the size! 512 is already big. Reading data back from the GPU is computationally intensive

				const size = 512;

				readbackTarget = new THREE.RenderTarget( size, size, { count: 2 } );

				pixelBuffer = new Uint8Array( size ** 2 * 4 ).fill( 0 );
				pixelBufferTexture = new THREE.DataTexture( pixelBuffer, size, size );
				pixelBufferTexture.type = THREE.UnsignedByteType;
				pixelBufferTexture.format = THREE.RGBAFormat;

				readbackMaterial = new THREE.MeshBasicNodeMaterial();
				readbackMaterial.colorNode = texture( pixelBufferTexture );


				// Scene setup

				scene = new THREE.Scene();
				scene.background = new THREE.Color( 0x222222 );

				camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.1, 50 );
				camera.position.z = 4;


				const loader = new THREE.TextureLoader();

				const diffuse = loader.load( 'textures/hardwood2_diffuse.jpg' );
				diffuse.colorSpace = THREE.SRGBColorSpace;
				diffuse.wrapS = THREE.RepeatWrapping;
				diffuse.wrapT = THREE.RepeatWrapping;

				torus = new THREE.Mesh(
					new THREE.TorusKnotGeometry( 1, 0.3, 128, 32 ),
					new WriteGBufferMaterial( diffuse )
				);

				scene.add( torus );


				material = new ReadGBufferMaterial( renderTarget.textures[ 0 ], renderTarget.textures[ 1 ] );
				quadMesh = new THREE.QuadMesh( material );

				// Controls

				new OrbitControls( camera, renderer.domElement );

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

				const dpr = renderer.getPixelRatio();
				renderTarget.setSize( window.innerWidth * dpr, window.innerHeight * dpr );

			}

			async function render( time ) {

				const selection = options.selection;

				torus.rotation.y = ( time / 1000 ) * .4;

				// render scene into target
				renderer.setRenderTarget( selection === 'mrt' ? renderTarget : readbackTarget );
				renderer.render( scene, camera );

				// render post FX
				renderer.setRenderTarget( null );

				if ( selection === 'mrt' ) {

					quadMesh.material = material;

				} else {

					quadMesh.material = readbackMaterial;

					await readback();

				}

				quadMesh.render( renderer );

			}

			async function readback() {

				const width = readbackTarget.width;
				const height = readbackTarget.height;

				const selection = options.selection;

				if ( selection === 'diffuse' ) {

					pixelBuffer = await renderer.readRenderTargetPixelsAsync( readbackTarget, 0, 0, width, height, 0 ); // zero is optional

					pixelBufferTexture.image.data = pixelBuffer;
					pixelBufferTexture.needsUpdate = true;

				} else if ( selection === 'normal' ) {

					pixelBuffer = await renderer.readRenderTargetPixelsAsync( readbackTarget, 0, 0, width, height, 1 );

					pixelBufferTexture.image.data = pixelBuffer;
					pixelBufferTexture.needsUpdate = true;

				}

			}

		</script>

	</body>
</html>