@pnext/three-loader/src/utils/box3-helper.ts

Potree loader for ThreeJS, converted and adapted to Typescript.

import {
  Box3,
  BufferAttribute,
  BufferGeometry,
  Color,
  LineBasicMaterial,
  LineSegments,
} from 'three';

/**
 *
 * code adapted from three.js BoxHelper.js
 * https://github.com/mrdoob/three.js/blob/dev/src/helpers/BoxHelper.js
 *
 * @author mrdoob / http://mrdoob.com/
 * @author Mugen87 / http://github.com/Mugen87
 * @author mschuetz / http://potree.org
 */

export class Box3Helper extends LineSegments {
  constructor(box: Box3, color: Color = new Color(0xffff00)) {
    // prettier-ignore
    const indices = new Uint16Array([ 0, 1, 1, 2, 2, 3, 3, 0, 4, 5, 5, 6, 6, 7, 7, 4, 0, 4, 1, 5, 2, 6, 3, 7 ]);
    // prettier-ignore
    const positions = new Float32Array([
      box.min.x, box.min.y, box.min.z,
      box.max.x, box.min.y, box.min.z,
      box.max.x, box.min.y, box.max.z,
      box.min.x, box.min.y, box.max.z,
      box.min.x, box.max.y, box.min.z,
      box.max.x, box.max.y, box.min.z,
      box.max.x, box.max.y, box.max.z,
      box.min.x, box.max.y, box.max.z
    ]);

    const geometry = new BufferGeometry();
    geometry.setIndex(new BufferAttribute(indices, 1));
    geometry.setAttribute('position', new BufferAttribute(positions, 3));

    const material = new LineBasicMaterial({ color: color });

    super(geometry, material);
  }
}