yawn/addons/handles/src/shapes/Cube.ts

import { Mesh, type MeshOptions } from "../Mesh";
import type { Scene } from "../Scene";

export type CubeOptions = Omit<MeshOptions, "geometryId" | "vertexData"> & {
  size?: number;
  width?: number;
  height?: number;
  depth?: number;
};

function dimension(value: number, name: string) {
  if (!Number.isFinite(value) || value <= 0) throw new RangeError(name);
  return value / 2;
}

/** A six-sided mesh with independent vertices and normals for every face. */
export class Cube extends Mesh {
  constructor(scene: Scene, options: CubeOptions = {}) {
    const {
      size = 1,
      width = size,
      height = size,
      depth = size,
      ...meshOptions
    } = options;
    const x = dimension(width, "width");
    const y = dimension(height, "height");
    const z = dimension(depth, "depth");
    const positions = [
      [-x, -y, z, x, -y, z, x, y, z, -x, y, z],
      [x, -y, -z, -x, -y, -z, -x, y, -z, x, y, -z],
      [x, -y, z, x, -y, -z, x, y, -z, x, y, z],
      [-x, -y, -z, -x, -y, z, -x, y, z, -x, y, -z],
      [-x, y, z, x, y, z, x, y, -z, -x, y, -z],
      [-x, -y, -z, x, -y, -z, x, -y, z, -x, -y, z],
    ].flat();
    const normals = [
      [0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1],
      [0, 0, -1, 0, 0, -1, 0, 0, -1, 0, 0, -1],
      [1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0],
      [-1, 0, 0, -1, 0, 0, -1, 0, 0, -1, 0, 0],
      [0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0],
      [0, -1, 0, 0, -1, 0, 0, -1, 0, 0, -1, 0],
    ].flat();
    const uvs = Array.from({ length: 6 }, () => [
      0, 0, 1, 0, 1, 1, 0, 1,
    ]).flat();
    const indices = Array.from({ length: 6 }, (_, face) => {
      const vertex = face * 4;
      return [vertex, vertex + 1, vertex + 2, vertex, vertex + 2, vertex + 3];
    }).flat();
    super(scene, {
      ...meshOptions,
      vertexData: { positions, normals, uvs, indices },
    });
  }
}