Coloring faces of a Three.js BoxGeometry - colors

Question

I saw some solutions that accessed the THREE.BoxGeometry faces like that:
var geometry = new THREE.BoxGeometry(n,n,n)
let faces = geometry.faces;
for (let face of faces) {
face.color.set(Math.random() * 0xffffff);
}
But it seems that the faces-array doesn't exist in the current Three.js version r129 (Uncaught TypeError: faces is not iterable).
How can I achieve an easy coloring of the six cube faces?

Answer 1

Try it like so:
let camera, scene, renderer, mesh;
init();
animate();
function init() {
camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.01, 10 );
camera.position.z = 1;
scene = new THREE.Scene();
const geometry = new THREE.BoxGeometry( 0.2, 0.2, 0.2 ).toNonIndexed();
// vertexColors must be true so vertex colors can be used in the shader
const material = new THREE.MeshBasicMaterial( { vertexColors: true } );
// generate color data for each vertex
const positionAttribute = geometry.getAttribute( 'position' );
const colors = [];
const color = new THREE.Color();
for ( let i = 0; i < positionAttribute.count; i += 3 ) {
color.set( Math.random() * 0xffffff );
// define the same color for each vertex of a triangle
colors.push( color.r, color.g, color.b );
colors.push( color.r, color.g, color.b );
colors.push( color.r, color.g, color.b );
}
// define the new attribute
geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );
mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
}
function animate() {
requestAnimationFrame( animate );
mesh.rotation.x += 0.01;
mesh.rotation.y += 0.02;
renderer.render( scene, camera );
}
body {
margin: 0;
}
<script src="https://cdn.jsdelivr.net/npm/three#0.129.0/build/three.js"></script>
The previous geometry format was removed from the core with r125. More information in the following post at the three.js forum.
https://discourse.threejs.org/t/three-geometry-will-be-removed-from-core-with-r125/22401