Three.js: FrameBuffer to ImageData

Snippet code for transforming Three.js FrameBuffer to ImageData, use case: take screenshot from render and use it as texture.

Code

import * as THREE from "three";
 
// Generic Three.js scene
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(
	75,
	window.innerWidth / window.innerHeight,
	0.1,
	1000,
);
 
const renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
 
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshBasicMaterial({ color: 0x00ff00 });
const cube = new THREE.Mesh(geometry, material);
scene.add(cube);
 
camera.position.z = 5;
 
renderer.render(scene, camera);
 
// Here we go
// Copy from https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/readPixels#examples
 
const context = renderer.getContext();
 
const pixels = new Uint8ClampedArray(
	context.drawingBufferWidth * context.drawingBufferHeight * 4,
);
context.readPixels(
	0,
	0,
	context.drawingBufferWidth,
	context.drawingBufferHeight,
	context.RGBA,
	context.UNSIGNED_BYTE,
	pixels,
);
 
const result = new ImageData(
	pixels,
	context.drawingBufferWidth,
	context.drawingBufferHeight,
);

Table of Contents

Three.js: FrameBuffer to ImageData

Code

References