@loaders.gl/3d-tiles/src/lib/utils/obb/s2-corners-to-obb.ts

3D Tiles, an open standard for streaming massive heterogeneous 3D geospatial datasets.

// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright vis.gl contributors

import {Vector3} from '@math.gl/core';
import {OrientedBoundingBox, makeOrientedBoundingBoxFromPoints} from '@math.gl/culling';

import type {S2HeightInfo} from '../../utils/s2/index';
import {getS2OrientedBoundingBoxCornerPoints, getS2LngLat} from '../../utils/s2/index';

import {Ellipsoid} from '@math.gl/geospatial';

export type S2VolumeInfo = {
  /** S2 key or token */
  token: string;
  /** minimum height in meters */
  minimumHeight: number;
  /** maximum height in meters */
  maximumHeight: number;
};

/**
 * Converts S2VolumeInfo to OrientedBoundingBox
 * @param {S2VolumeInfo} s2VolumeInfo - s2 volume to convert
 * @returns Oriented Bounding Box of type Box
 */
export function convertS2BoundingVolumetoOBB(s2VolumeInfo: S2VolumeInfo): number[] {
  const token: string = s2VolumeInfo.token;
  const heightInfo: S2HeightInfo = {
    minimumHeight: s2VolumeInfo.minimumHeight,
    maximumHeight: s2VolumeInfo.maximumHeight
  };

  const corners: Vector3[] = getS2OrientedBoundingBoxCornerPoints(token, heightInfo);

  // Add a point that doesn't allow the box dive under the Earth

  const center = getS2LngLat(token);
  const centerLng: number = center[0];
  const centerLat: number = center[1];
  const point = Ellipsoid.WGS84.cartographicToCartesian([
    centerLng,
    centerLat,
    heightInfo.maximumHeight
  ]);
  const centerPointAdditional = new Vector3(point[0], point[1], point[2]);
  corners.push(centerPointAdditional);

  // corners should be an array of Vector3 (XYZ)
  const obb: OrientedBoundingBox = makeOrientedBoundingBoxFromPoints(corners);
  const box: number[] = [...obb.center, ...obb.halfAxes];

  return box;
}