midas
/
threejs-obj-space


			
				
					
						
						
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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="module">

			import * as THREE from '../build/three.module.js';

			import { OrbitControls } from './jsm/controls/OrbitControls.js';

			// HACK:

			THREE.Mesh.prototype.clone = function () {

				var newMaterial = ( this.material.isMaterial ) ? this.material.clone() : this.material.slice();

				return new this.constructor( this.geometry.clone(), newMaterial ).copy( this );

			};

			//

			var SimpleGI = function ( renderer, scene ) {

				var SIZE = 32, SIZE2 = SIZE * SIZE;

				var camera = new THREE.PerspectiveCamera( 90, 1, 0.01, 100 );

				scene.updateMatrixWorld( true );

				var clone = scene.clone();
				clone.autoUpdate = false;

				var rt = new THREE.WebGLRenderTarget( SIZE, SIZE, {
					wrapS: THREE.ClampToEdgeWrapping,
					wrapT: THREE.ClampToEdgeWrapping,
					stencilBuffer: false,
					depthBuffer: true
				} );

				var normalMatrix = new THREE.Matrix3();

				var position = new THREE.Vector3();
				var normal = new THREE.Vector3();

				var bounces = 0;
				var currentVertex = 0;

				var color = new Float32Array( 3 );
				var buffer = new Uint8Array( SIZE2 * 4 );

				function compute() {

					if ( bounces === 3 ) return;

					var object = scene.children[ 0 ];
					var geometry = object.geometry;

					var attributes = geometry.attributes;
					var positions = attributes.position.array;
					var normals = attributes.normal.array;

					if ( attributes.color === undefined ) {

						var colors = new Float32Array( positions.length );
						geometry.setAttribute( 'color', new THREE.BufferAttribute( colors, 3 ).setUsage( THREE.DynamicDrawUsage ) );

					}

					var colors = attributes.color.array;

					var startVertex = currentVertex;
					var totalVertex = positions.length / 3;

					for ( var 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 ( var 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.updateRange.offset = startVertex * 3;
					attributes.color.updateRange.count = ( currentVertex - startVertex ) * 3;
					attributes.color.needsUpdate = true;

					if ( currentVertex >= totalVertex ) {

						clone = scene.clone();
						clone.autoUpdate = false;

						bounces ++;
						currentVertex = 0;

					}

					requestAnimationFrame( compute );

				}

				requestAnimationFrame( compute );

			};

			//

			var camera, scene, renderer;

			init();
			animate();

			function init() {

				camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.1, 100 );
				camera.position.z = 4;

				scene = new THREE.Scene();

				// sphere

				var geometry = new THREE.TorusKnotBufferGeometry( 0.75, 0.3, 128, 32, 1 );
				var material = new THREE.MeshBasicMaterial( { vertexColors: THREE.VertexColors } );

				var mesh = new THREE.Mesh( geometry, material );
				scene.add( mesh );

				// room

				var materials = [];

				for ( var i = 0; i < 8; i ++ ) {

					materials.push( new THREE.MeshBasicMaterial( { color: Math.random() * 0xffffff, side: THREE.BackSide } ) );

				}

				var geometry = new THREE.BoxBufferGeometry( 3, 3, 3 );

				var mesh = new THREE.Mesh( geometry, materials );
				scene.add( mesh );

				//

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				document.body.appendChild( renderer.domElement );

				new SimpleGI( renderer, scene );

				var controls = new OrbitControls( camera, renderer.domElement );

				window.addEventListener( 'resize', onWindowResize, false );

			}

			function onWindowResize() {

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

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

			}

			function animate() {

				requestAnimationFrame( animate );

				renderer.setRenderTarget( null );
				renderer.render( scene, camera );

			}

		</script>

	</body>
</html>