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<title>three.js webgl - buffergeometry - indexed</title>
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<div id="info"><a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgl - buffergeometry - indexed</div>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.8.0/dist/es-module-shims.js"></script>
<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';
import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
let camera, scene, renderer, stats;
let mesh;
init();
animate();
function init() {
//
camera = new THREE.PerspectiveCamera( 27, window.innerWidth / window.innerHeight, 1, 3500 );
camera.position.z = 64;
scene = new THREE.Scene();
scene.background = new THREE.Color( 0x050505 );
//
const light = new THREE.HemisphereLight();
light.intensity = 3;
scene.add( light );
//
const geometry = new THREE.BufferGeometry();
const indices = [];
const vertices = [];
const normals = [];
const colors = [];
const size = 20;
const segments = 10;
const halfSize = size / 2;
const segmentSize = size / segments;
const _color = new THREE.Color();
// generate vertices, normals and color data for a simple grid geometry
for ( let i = 0; i <= segments; i ++ ) {
const y = ( i * segmentSize ) - halfSize;
for ( let j = 0; j <= segments; j ++ ) {
const x = ( j * segmentSize ) - halfSize;
vertices.push( x, - y, 0 );
normals.push( 0, 0, 1 );
const r = ( x / size ) + 0.5;
const g = ( y / size ) + 0.5;
_color.setRGB( r, g, 1, THREE.SRGBColorSpace );
colors.push( _color.r, _color.g, _color.b );
}
}
// generate indices (data for element array buffer)
for ( let i = 0; i < segments; i ++ ) {
for ( let j = 0; j < segments; j ++ ) {
const a = i * ( segments + 1 ) + ( j + 1 );
const b = i * ( segments + 1 ) + j;
const c = ( i + 1 ) * ( segments + 1 ) + j;
const d = ( i + 1 ) * ( segments + 1 ) + ( j + 1 );
// generate two faces (triangles) per iteration
indices.push( a, b, d ); // face one
indices.push( b, c, d ); // face two
}
}
//
geometry.setIndex( indices );
geometry.setAttribute( 'position', new THREE.Float32BufferAttribute( vertices, 3 ) );
geometry.setAttribute( 'normal', new THREE.Float32BufferAttribute( normals, 3 ) );
geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );
const material = new THREE.MeshPhongMaterial( {
side: THREE.DoubleSide,
vertexColors: true
} );
mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
//
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
//
stats = new Stats();
document.body.appendChild( stats.dom );
//
const gui = new GUI();
gui.add( material, 'wireframe' );
//
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;
mesh.rotation.x = time * 0.25;
mesh.rotation.y = time * 0.5;
renderer.render( scene, camera );
}
</script>
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