examples/webgl_buffergeometry.html

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<html lang="en">
	<head>
		<title>three.js webgl - buffergeometry</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<style>
			body {
				color: #cccccc;
				font-family:Monospace;
				font-size:13px;
				text-align:center;

				background-color: #050505;
				margin: 0px;
				overflow: hidden;
			}

			#info {
				position: absolute;
				top: 0px; width: 100%;
				padding: 5px;
			}

			a {

				color: #0080ff;
			}

		</style>
	</head>
	<body>

		<div id="container"></div>
		<div id="info"><a href="http://threejs.org" target="_blank">three.js</a> webgl - buffergeometry</div>

		<script src="../build/three.min.js"></script>

		<script src="js/Detector.js"></script>
		<script src="js/libs/stats.min.js"></script>

		<script>

			if ( ! Detector.webgl ) Detector.addGetWebGLMessage();

			var container, stats;

			var camera, scene, renderer;

			var mesh;

			init();
			animate();

			function init() {

				container = document.getElementById( 'container' );

				//

				camera = new THREE.PerspectiveCamera( 27, window.innerWidth / window.innerHeight, 1, 3500 );
				camera.position.z = 2750;

				scene = new THREE.Scene();
				scene.fog = new THREE.Fog( 0x050505, 2000, 3500 );

				//

				scene.add( new THREE.AmbientLight( 0x444444 ) );

				var light1 = new THREE.DirectionalLight( 0xffffff, 0.5 );
				light1.position.set( 1, 1, 1 );
				scene.add( light1 );

				var light2 = new THREE.DirectionalLight( 0xffffff, 1.5 );
				light2.position.set( 0, -1, 0 );
				scene.add( light2 );

				//

				var triangles = 160000;

				var geometry = new THREE.BufferGeometry();

				// break geometry into
				// chunks of 21,845 triangles (3 unique vertices per triangle)
				// for indices to fit into 16 bit integer number
				// floor(2^16 / 3) = 21845

				var chunkSize = 21845;

				var indices = new Uint16Array( triangles * 3 );

				for ( var i = 0; i < indices.length; i ++ ) {

					indices[ i ] = i % ( 3 * chunkSize );

				}

				var positions = new Float32Array( triangles * 3 * 3 );
				var normals = new Float32Array( triangles * 3 * 3 );
				var colors = new Float32Array( triangles * 3 * 3 );

				var color = new THREE.Color();

				var n = 800, n2 = n/2;	// triangles spread in the cube
				var d = 12, d2 = d/2;	// individual triangle size

				var pA = new THREE.Vector3();
				var pB = new THREE.Vector3();
				var pC = new THREE.Vector3();

				var cb = new THREE.Vector3();
				var ab = new THREE.Vector3();

				for ( var i = 0; i < positions.length; i += 9 ) {

					// positions

					var x = Math.random() * n - n2;
					var y = Math.random() * n - n2;
					var z = Math.random() * n - n2;

					var ax = x + Math.random() * d - d2;
					var ay = y + Math.random() * d - d2;
					var az = z + Math.random() * d - d2;

					var bx = x + Math.random() * d - d2;
					var by = y + Math.random() * d - d2;
					var bz = z + Math.random() * d - d2;

					var cx = x + Math.random() * d - d2;
					var cy = y + Math.random() * d - d2;
					var cz = z + Math.random() * d - d2;

					positions[ i ]     = ax;
					positions[ i + 1 ] = ay;
					positions[ i + 2 ] = az;

					positions[ i + 3 ] = bx;
					positions[ i + 4 ] = by;
					positions[ i + 5 ] = bz;

					positions[ i + 6 ] = cx;
					positions[ i + 7 ] = cy;
					positions[ i + 8 ] = cz;

					// flat face normals

					pA.set( ax, ay, az );
					pB.set( bx, by, bz );
					pC.set( cx, cy, cz );

					cb.subVectors( pC, pB );
					ab.subVectors( pA, pB );
					cb.cross( ab );

					cb.normalize();

					var nx = cb.x;
					var ny = cb.y;
					var nz = cb.z;

					normals[ i ]     = nx;
					normals[ i + 1 ] = ny;
					normals[ i + 2 ] = nz;

					normals[ i + 3 ] = nx;
					normals[ i + 4 ] = ny;
					normals[ i + 5 ] = nz;

					normals[ i + 6 ] = nx;
					normals[ i + 7 ] = ny;
					normals[ i + 8 ] = nz;

					// colors

					var vx = ( x / n ) + 0.5;
					var vy = ( y / n ) + 0.5;
					var vz = ( z / n ) + 0.5;

					color.setRGB( vx, vy, vz );

					colors[ i ]     = color.r;
					colors[ i + 1 ] = color.g;
					colors[ i + 2 ] = color.b;

					colors[ i + 3 ] = color.r;
					colors[ i + 4 ] = color.g;
					colors[ i + 5 ] = color.b;

					colors[ i + 6 ] = color.r;
					colors[ i + 7 ] = color.g;
					colors[ i + 8 ] = color.b;

				}

				geometry.addAttribute( 'index', new THREE.BufferAttribute( indices, 1 ) );
				geometry.addAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );
				geometry.addAttribute( 'normal', new THREE.BufferAttribute( normals, 3 ) );
				geometry.addAttribute( 'color', new THREE.BufferAttribute( colors, 3 ) );

				var offsets = triangles / chunkSize;

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

					var offset = {
						start: i * chunkSize * 3,
						index: i * chunkSize * 3,
						count: Math.min( triangles - ( i * chunkSize ), chunkSize ) * 3
					};

					geometry.offsets.push( offset );

				}

				geometry.computeBoundingSphere();

				var material = new THREE.MeshPhongMaterial( {
					color: 0xaaaaaa, specular: 0xffffff, shininess: 250,
					side: THREE.DoubleSide, vertexColors: THREE.VertexColors
				} );

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

				//

				renderer = new THREE.WebGLRenderer( { antialias: false } );
				renderer.setClearColor( scene.fog.color );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );

				renderer.gammaInput = true;
				renderer.gammaOutput = true;

				container.appendChild( renderer.domElement );

				//

				stats = new Stats();
				stats.domElement.style.position = 'absolute';
				stats.domElement.style.top = '0px';
				container.appendChild( stats.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 );

				render();
				stats.update();

			}

			function render() {

				var time = Date.now() * 0.001;

				mesh.rotation.x = time * 0.25;
				mesh.rotation.y = time * 0.5;

				renderer.render( scene, camera );

			}

		</script>

	</body>
</html>