midas
/
threejs-obj-space


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js vr - lorenz attractor</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
		<link type="text/css" rel="stylesheet" href="main.css">
	</head>
	<body>

		<script src="js/vr/HelioWebXRPolyfill.js"></script>

		<script type="module">

			import * as THREE from '../build/three.module.js';
			import { VRButton } from './jsm/webxr/VRButton.js';

			var camera, scene, renderer;
			var attractor, light;

			var x = 15 * Math.random();
			var y = 15 * Math.random();
			var z = 15 * Math.random();

			var scale = .02; // for reducing overall displayed size
			var speed = 5; // integer, increase for faster visualization

			var steps = 100000;
			var current = 1;
			var shown = 10000;

			var beta = 8 / 3;
			var rho = 28;
			var sigma = 10;

			var dt = .005;

			init();
			animate();

			function draw() {

				var geometry = attractor.geometry;

				geometry.attributes.position.array.copyWithin( 3 );
				geometry.attributes.color.array.copyWithin( 3 );

				if ( current < steps ) {

					var dx = sigma * ( y - x ) * dt;
					var dy = ( x * ( rho - z ) - y ) * dt;
					var dz = ( x * y - beta * z ) * dt;

					x += dx;
					y += dy;
					z += dz;

					geometry.attributes.position.set( [ scale * x, scale * y, scale * z ], 0 );

					light.color.setHSL( current / steps, 1, .5 );

					geometry.attributes.color.set( light.color.toArray(), 0 );

				}

				if ( current < steps + shown ) {

					current ++;

				} else {

					current = 0;

				}

			}

			function init() {

				scene = new THREE.Scene();

				camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 0.1, 10 );
				camera.position.set( 0, 1.6, 1 );

				//

				var geometry = new THREE.BufferGeometry();

				var positions = new Float32Array( 3 * shown );

				for ( var i = 0; i < positions.length; i += 3 ) {

					positions.set( [ scale * x, scale * y, scale * z ], i );

				}

				geometry.setAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );

				var colors = new Float32Array( 3 * shown );

				for ( var i = 0; i < positions.length; i += 3 ) {

					colors.set( [ 1, 0, 0 ], i );

				}

				geometry.setAttribute( 'color', new THREE.BufferAttribute( colors, 3 ) );

				var material = new THREE.LineBasicMaterial( { vertexColors: THREE.VertexColors } );

				attractor = new THREE.Line( geometry, material );
				attractor.position.set( 0, 1.5, - 2 );
				attractor.frustumCulled = false; // critical to avoid blackouts!
				scene.add( attractor );

				//

				light = new THREE.PointLight( 0xffffff, 1 );
				light.distance = 2;
				attractor.add( light );

				var ground = new THREE.Mesh(
					new THREE.PlaneBufferGeometry( 10, 10 ),
					new THREE.MeshPhongMaterial()
				);
				ground.geometry.rotateX( - 90 * Math.PI / 180 );
				scene.add( ground );

				//

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

				document.body.appendChild( VRButton.createButton( renderer ) );

				//

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

			}

			function onWindowResize() {

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

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

			}

			function animate() {

				renderer.setAnimationLoop( render );

			}

			function render() {

				for ( var i = 0; i < speed; i ++ ) draw();

				attractor.geometry.attributes.position.needsUpdate = true;
				attractor.geometry.attributes.color.needsUpdate = true;
				attractor.rotation.z += .001;

				renderer.render( scene, camera );

			}

		</script>
	</body>
</html>