FaceColorBoxGeometry.js

class FaceColorBoxGeometry extends THREE.BoxGeometry {
    constructor(width: number, height: number, depth: number, widthSegments?: number, heightSegments?: number, depthSegments?: number) {
        super(width, height, depth, widthSegments, heightSegments, depthSegments);

        for (let face of this.faces) {
            let color = new THREE.Color();
            if (face.normal.x < 0 || face.normal.y < 0 || face.normal.z < 0) {
                color.setRGB(1, 1, 1);
                if (face.normal.x < 0) color.r = 0;
                if (face.normal.y < 0) color.g = 0;
                if (face.normal.z < 0) color.b = 0;
            } else {
                color.setRGB(face.normal.x, face.normal.y, face.normal.z);
            }
            face.color = color;
        }
    }
}