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webgl_buffergeometry_glbufferattribute.html
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<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - buffergeometry - custom VBOs</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 - custom VBOs</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;
const particles = 300000;
let drawCount = 10000;
init();
animate();
function init() {
container = document.getElementById( 'container' );
//
renderer = new THREE.WebGLRenderer( { antialias: false } );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
container.appendChild( renderer.domElement );
//
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 geometry = new THREE.BufferGeometry();
const positions = [];
const positions2 = [];
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 );
positions2.push( z * 0.3, x * 0.3, y * 0.3 );
// 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 );
}
const gl = renderer.getContext();
const pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( positions ), gl.STATIC_DRAW );
const pos2 = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, pos2 );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( positions2 ), gl.STATIC_DRAW );
const rgb = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, rgb );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( colors ), gl.STATIC_DRAW );
const posAttr1 = new THREE.GLBufferAttribute( pos, gl.FLOAT, 3, 4, particles );
const posAttr2 = new THREE.GLBufferAttribute( pos2, gl.FLOAT, 3, 4, particles );
geometry.setAttribute( 'position', posAttr1 );
setInterval( function () {
const attr = geometry.getAttribute( 'position' );
geometry.setAttribute( 'position', ( attr === posAttr1 ) ? posAttr2 : posAttr1 );
}, 2000 );
geometry.setAttribute( 'color', new THREE.GLBufferAttribute( rgb, gl.FLOAT, 3, 4, particles ) );
//
const material = new THREE.PointsMaterial( { size: 15, vertexColors: true } );
points = new THREE.Points( geometry, material );
// Choose one:
// geometry.boundingSphere = ( new THREE.Sphere() ).set( new THREE.Vector3(), Infinity );
points.frustumCulled = false;
scene.add( points );
//
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() {
drawCount = ( Math.max( 5000, drawCount ) + Math.floor( 500 * Math.random() ) ) % particles;
points.geometry.setDrawRange( 0, drawCount );
const time = Date.now() * 0.001;
points.rotation.x = time * 0.1;
points.rotation.y = time * 0.2;
renderer.render( scene, camera );
}
</script>
</body>
</html>