Cesium 获取 3dtileset的包围盒各顶点坐标

/**
 * 获取 3dtileset的包围盒各顶点坐标, z 方向取高度最低的位置
 * @param {*} tileset
 * @param {*} options
 * @returns
 * @ref https://blog.csdn.net/STANDBYF/article/details/135012273
 * @ref https://community.cesium.com/t/accurate-bounding-box-for-3d-tiles/5890/10
 */
export function getTilesetBoudingBoxPoints(tileset, options = {}) {
  const { center, halfAxes } = tileset._root._boundingVolume._orientedBoundingBox;
  const pointsVec3 = [];

  // 获取三个轴的位置
  const x = new Cartesian3();
  const y = new Cartesian3();
  const z = new Cartesian3();

  Matrix3.getColumn(halfAxes, 0, x);
  Matrix3.getColumn(halfAxes, 1, y);
  Matrix3.getColumn(halfAxes, 2, z);

  const halfXNegative = new Cartesian3();
  const halfXPositive = new Cartesian3();

  Cartesian3.subtract(center, x, halfXNegative)
  Cartesian3.add(center, x, halfXPositive)

  Cartesian3.subtract(halfXNegative, z, halfXNegative)
  Cartesian3.subtract(halfXPositive, z, halfXPositive)

  pointsVec3.push(Cartesian3.add(halfXNegative, y, new Cartesian3()))
  pointsVec3.push(Cartesian3.subtract(halfXNegative, y, new Cartesian3()))

  pointsVec3.push(Cartesian3.subtract(halfXPositive, y, new Cartesian3()))
  pointsVec3.push(Cartesian3.add(halfXPositive, y, new Cartesian3()))

  const pointsLL = [];
  pointsVec3.forEach(item=>{
    const ll = Cartographic.fromCartesian(item);
    pointsLL.push(
      Math.toDegrees(ll.longitude),
      Math.toDegrees(ll.latitude),
    )
  })

  return pointsLL;
}