<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>Three.js - Canvas Textured Cube</title>
<style>
html, body {
height: 100%;
margin: 0;
}
#c {
width: 100%;
height: 100%;
display: block;
}
</style>
</head>
<body>
<canvas id="c"></canvas>
</body>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
<script type="importmap">
{
"imports": {
"three": "../../build/three.module.js"
}
}
</script>
<script type="module">
import * as THREE from 'three';
function main() {
const canvas = document.querySelector('#c');
const renderer = new THREE.WebGLRenderer({canvas});
const fov = 75;
const aspect = 2; // the canvas default
const near = 0.1;
const far = 5;
const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
camera.position.z = 2;
const scene = new THREE.Scene();
const boxWidth = 1;
const boxHeight = 1;
const boxDepth = 1;
const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
const cubes = []; // just an array we can use to rotate the cubes
const ctx = document.createElement('canvas').getContext('2d');
ctx.canvas.width = 256;
ctx.canvas.height = 256;
ctx.fillStyle = '#FFF';
ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height);
const texture = new THREE.CanvasTexture(ctx.canvas);
const material = new THREE.MeshBasicMaterial({
map: texture,
});
const cube = new THREE.Mesh(geometry, material);
scene.add(cube);
cubes.push(cube); // add to our list of cubes to rotate
function resizeRendererToDisplaySize(renderer) {
const canvas = renderer.domElement;
const width = canvas.clientWidth;
const height = canvas.clientHeight;
const needResize = canvas.width !== width || canvas.height !== height;
if (needResize) {
renderer.setSize(width, height, false);
}
return needResize;
}
function rand(min, max) {
if (max === undefined) {
max = min;
min = 0;
}
return Math.random() * (max - min) + min;
}
function randVelocity() {
return rand(2, 4) * (rand(2) < 1 ? -1 : 1);
}
const maxLines = 60;
const points = [
{ position: [rand(256), rand(256)], direction: [randVelocity(), randVelocity()]},
{ position: [rand(256), rand(256)], direction: [randVelocity(), randVelocity()]},
];
const lineHistory = [];
let lineCursor = 0;
function drawCurrentLine() {
const line = lineHistory[lineCursor];
ctx.beginPath();
ctx.moveTo(...line[0]);
ctx.lineTo(...line[1]);
ctx.stroke();
}
function drawLines(time) {
points.forEach((point) => {
point.position.forEach((position, ndx) => {
const newPosition = position + point.direction[ndx];
if (newPosition > 255) {
point.direction[ndx] = rand(-2, -4);
} else if (newPosition < 0) {
point.direction[ndx] = rand( 2, 4);
}
point.position[ndx] = newPosition;
});
});
if (lineHistory.length === maxLines) {
ctx.lineWidth = 3;
ctx.strokeStyle = '#FFF';
drawCurrentLine();
}
lineHistory[lineCursor] = points.map(point => point.position.slice());
ctx.lineWidth = 1;
ctx.strokeStyle = hsl(time, 1, .5);
drawCurrentLine();
lineCursor = (lineCursor + 1) % maxLines;
}
function hsl(h, s, l) {
return `hsl(${h * 360 | 0},${s * 100 | 0}%,${l * 100 | 0}%)`;
}
function render(time) {
time *= 0.001;
if (resizeRendererToDisplaySize(renderer)) {
const canvas = renderer.domElement;
camera.aspect = canvas.clientWidth / canvas.clientHeight;
camera.updateProjectionMatrix();
}
drawLines(time * 0.1);
texture.needsUpdate = true;
cubes.forEach((cube, ndx) => {
const speed = .2 + ndx * .1;
const rot = time * speed;
cube.rotation.x = rot;
cube.rotation.y = rot;
});
renderer.render(scene, camera);
requestAnimationFrame(render);
}
requestAnimationFrame(render);
}
main();
</script>
</html>