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<title>three.js webgl - texture - partial update</title>
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<a href="https://threejs.org" target="_blank" rel="noopener noreferrer">three.js</a> - partial texture update <br/>
replace parts of an existing texture with all data of another texture
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<!-- 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';
let camera, scene, renderer, clock, dataTexture, diffuseMap;
let last = 0;
const position = new THREE.Vector2();
const color = new THREE.Color();
init();
function init() {
camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.01, 10 );
camera.position.z = 2;
scene = new THREE.Scene();
clock = new THREE.Clock();
const loader = new THREE.TextureLoader();
diffuseMap = loader.load( 'textures/floors/FloorsCheckerboard_S_Diffuse.jpg', animate );
diffuseMap.colorSpace = THREE.SRGBColorSpace;
diffuseMap.minFilter = THREE.LinearFilter;
diffuseMap.generateMipmaps = false;
const geometry = new THREE.PlaneGeometry( 2, 2 );
const material = new THREE.MeshBasicMaterial( { map: diffuseMap } );
const mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
//
const width = 32;
const height = 32;
const data = new Uint8Array( width * height * 4 );
dataTexture = new THREE.DataTexture( data, width, height );
//
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
//
window.addEventListener( 'resize', onWindowResize );
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
requestAnimationFrame( animate );
const elapsedTime = clock.getElapsedTime();
if ( elapsedTime - last > 0.1 ) {
last = elapsedTime;
position.x = ( 32 * THREE.MathUtils.randInt( 1, 16 ) ) - 32;
position.y = ( 32 * THREE.MathUtils.randInt( 1, 16 ) ) - 32;
// generate new color data
updateDataTexture( dataTexture );
// perform copy from src to dest texture to a random position
renderer.copyTextureToTexture( position, dataTexture, diffuseMap );
}
renderer.render( scene, camera );
}
function updateDataTexture( texture ) {
const size = texture.image.width * texture.image.height;
const data = texture.image.data;
// generate a random color and update texture data
color.setHex( Math.random() * 0xffffff );
const r = Math.floor( color.r * 255 );
const g = Math.floor( color.g * 255 );
const b = Math.floor( color.b * 255 );
for ( let i = 0; i < size; i ++ ) {
const stride = i * 4;
data[ stride ] = r;
data[ stride + 1 ] = g;
data[ stride + 2 ] = b;
data[ stride + 3 ] = 1;
}
}
</script>
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