midas
/
threejs-obj-space


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - buffergeometry - particles</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="container"></div>
		<div id="info"><a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgl - buffergeometry - particles</div>

		<script type="module">

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

			import Stats from './jsm/libs/stats.module.js';

			var container, stats;

			var camera, scene, renderer;

			var points;

			init();
			animate();

			function init() {

				container = document.getElementById( 'container' );

				camera = new THREE.PerspectiveCamera( 27, window.innerWidth / window.innerHeight, 5, 3500 );
				camera.position.z = 2750;

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

				//

				var particles = 500000;

				var geometry = new THREE.BufferGeometry();

				// create a generic buffer of binary data (a single particle has 16 bytes of data)

				var arrayBuffer = new ArrayBuffer( particles * 16 );

				// the following typed arrays share the same buffer

				var interleavedFloat32Buffer = new Float32Array( arrayBuffer );
				var interleavedUint8Buffer = new Uint8Array( arrayBuffer );

				//

				var color = new THREE.Color();

				var n = 1000, n2 = n / 2; // particles spread in the cube

				for ( var i = 0; i < interleavedFloat32Buffer.length; i += 4 ) {

					// position (first 12 bytes)

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

					interleavedFloat32Buffer[ i + 0 ] = x;
					interleavedFloat32Buffer[ i + 1 ] = y;
					interleavedFloat32Buffer[ i + 2 ] = z;

					// color (last 4 bytes)

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

					color.setRGB( vx, vy, vz );

					var j = ( i + 3 ) * 4;

					interleavedUint8Buffer[ j + 0 ] = color.r * 255;
					interleavedUint8Buffer[ j + 1 ] = color.g * 255;
					interleavedUint8Buffer[ j + 2 ] = color.b * 255;
					interleavedUint8Buffer[ j + 3 ] = 0; // not needed

				}

				var interleavedBuffer32 = new THREE.InterleavedBuffer( interleavedFloat32Buffer, 4 );
				var interleavedBuffer8 = new THREE.InterleavedBuffer( interleavedUint8Buffer, 16 );

				geometry.setAttribute( 'position', new THREE.InterleavedBufferAttribute( interleavedBuffer32, 3, 0, false ) );
				geometry.setAttribute( 'color', new THREE.InterleavedBufferAttribute( interleavedBuffer8, 3, 12, true ) );

				//

				var material = new THREE.PointsMaterial( { size: 15, vertexColors: THREE.VertexColors } );

				points = new THREE.Points( geometry, material );
				scene.add( points );

				//

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

				container.appendChild( renderer.domElement );

				//

				stats = new Stats();
				container.appendChild( stats.dom );

				//

				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;

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

				renderer.render( scene, camera );

			}

		</script>

	</body>
</html>