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- <!DOCTYPE html>
- <html lang="en">
- <head>
- <title>three.js webgl - simple global illumination</title>
- <meta charset="utf-8">
- <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
- <link type="text/css" rel="stylesheet" href="main.css">
- </head>
- <body>
- <div id="info">
- <a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - simple global illumination (<a href="http://www.iquilezles.org/www/articles/simplegi/simplegi.htm">article</a>)
- </div>
- <script type="importmap">
- {
- "imports": {
- "three": "../build/three.module.js",
- "three/addons/": "./jsm/"
- }
- }
- </script>
- <script type="module">
- import * as THREE from 'three';
- import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
- class GIMesh extends THREE.Mesh {
- copy( source ) {
- super.copy( source );
- this.geometry = source.geometry.clone();
- return this;
- }
- }
- //
- const SimpleGI = function ( renderer, scene ) {
- const SIZE = 32, SIZE2 = SIZE * SIZE;
- const camera = new THREE.PerspectiveCamera( 90, 1, 0.01, 100 );
- scene.updateMatrixWorld( true );
- let clone = scene.clone();
- clone.matrixWorldAutoUpdate = false;
- const rt = new THREE.WebGLRenderTarget( SIZE, SIZE );
- const normalMatrix = new THREE.Matrix3();
- const position = new THREE.Vector3();
- const normal = new THREE.Vector3();
- let bounces = 0;
- let currentVertex = 0;
- const color = new Float32Array( 3 );
- const buffer = new Uint8Array( SIZE2 * 4 );
- function compute() {
- if ( bounces === 3 ) return;
- const object = scene.children[ 0 ]; // torusKnot
- const geometry = object.geometry;
- const attributes = geometry.attributes;
- const positions = attributes.position.array;
- const normals = attributes.normal.array;
- if ( attributes.color === undefined ) {
- const colors = new Float32Array( positions.length );
- geometry.setAttribute( 'color', new THREE.BufferAttribute( colors, 3 ).setUsage( THREE.DynamicDrawUsage ) );
- }
- const colors = attributes.color.array;
- const startVertex = currentVertex;
- const totalVertex = positions.length / 3;
- for ( let i = 0; i < 32; i ++ ) {
- if ( currentVertex >= totalVertex ) break;
- position.fromArray( positions, currentVertex * 3 );
- position.applyMatrix4( object.matrixWorld );
- normal.fromArray( normals, currentVertex * 3 );
- normal.applyMatrix3( normalMatrix.getNormalMatrix( object.matrixWorld ) ).normalize();
- camera.position.copy( position );
- camera.lookAt( position.add( normal ) );
- renderer.setRenderTarget( rt );
- renderer.render( clone, camera );
- renderer.readRenderTargetPixels( rt, 0, 0, SIZE, SIZE, buffer );
- color[ 0 ] = 0;
- color[ 1 ] = 0;
- color[ 2 ] = 0;
- for ( let k = 0, kl = buffer.length; k < kl; k += 4 ) {
- color[ 0 ] += buffer[ k + 0 ];
- color[ 1 ] += buffer[ k + 1 ];
- color[ 2 ] += buffer[ k + 2 ];
- }
- colors[ currentVertex * 3 + 0 ] = color[ 0 ] / ( SIZE2 * 255 );
- colors[ currentVertex * 3 + 1 ] = color[ 1 ] / ( SIZE2 * 255 );
- colors[ currentVertex * 3 + 2 ] = color[ 2 ] / ( SIZE2 * 255 );
- currentVertex ++;
- }
- attributes.color.addUpdateRange( startVertex * 3, ( currentVertex - startVertex ) * 3 );
- attributes.color.needsUpdate = true;
- if ( currentVertex >= totalVertex ) {
- clone = scene.clone();
- clone.matrixWorldAutoUpdate = false;
- bounces ++;
- currentVertex = 0;
- }
- requestAnimationFrame( compute );
- }
- requestAnimationFrame( compute );
- };
- //
- let camera, scene, renderer;
- init();
- function init() {
- camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.1, 100 );
- camera.position.z = 4;
- scene = new THREE.Scene();
- // torus knot
- const torusGeometry = new THREE.TorusKnotGeometry( 0.75, 0.3, 128, 32, 1 );
- const material = new THREE.MeshBasicMaterial( { vertexColors: true } );
- const torusKnot = new GIMesh( torusGeometry, material );
- scene.add( torusKnot );
- // room
- const materials = [];
- for ( let i = 0; i < 8; i ++ ) {
- materials.push( new THREE.MeshBasicMaterial( { color: Math.random() * 0xffffff, side: THREE.BackSide } ) );
- }
- const boxGeometry = new THREE.BoxGeometry( 3, 3, 3 );
- const box = new THREE.Mesh( boxGeometry, materials );
- scene.add( box );
- //
- renderer = new THREE.WebGLRenderer();
- renderer.setPixelRatio( window.devicePixelRatio );
- renderer.setSize( window.innerWidth, window.innerHeight );
- renderer.setAnimationLoop( animate );
- document.body.appendChild( renderer.domElement );
- new SimpleGI( renderer, scene );
- const controls = new OrbitControls( camera, renderer.domElement );
- controls.minDistance = 1;
- controls.maxDistance = 10;
- window.addEventListener( 'resize', onWindowResize );
- }
- function onWindowResize() {
- camera.aspect = window.innerWidth / window.innerHeight;
- camera.updateProjectionMatrix();
- renderer.setSize( window.innerWidth, window.innerHeight );
- }
- function animate() {
- renderer.setRenderTarget( null );
- renderer.render( scene, camera );
- }
- </script>
- </body>
- </html>
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