examples/webgl_buffergeometry_points.html

<!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="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'three/addons/libs/stats.module.js';

			let container, stats;

			let camera, scene, renderer;

			let 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 );

				//

				const particles = 500000;

				const geometry = new THREE.BufferGeometry();

				const positions = [];
				const colors = [];

				const color = new THREE.Color();

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

				for ( let i = 0; i < particles; i ++ ) {

					// positions

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

					positions.push( x, y, z );

					// colors

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

					color.setRGB( vx, vy, vz, THREE.SRGBColorSpace );

					colors.push( color.r, color.g, color.b );

				}

				geometry.setAttribute( 'position', new THREE.Float32BufferAttribute( positions, 3 ) );
				geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );

				geometry.computeBoundingSphere();

				//

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

				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 );

			}

			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() {

				const time = Date.now() * 0.001;

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

				renderer.render( scene, camera );

			}

		</script>

	</body>
</html>