itowns/lib/Renderer/OBB.js

A JS/WebGL framework for 3D geospatial data visualization

import * as THREE from 'three';
import { TileGeometry } from "../Core/TileGeometry.js";
import { GlobeTileBuilder } from "../Core/Prefab/Globe/GlobeTileBuilder.js";
import { CRS, Coordinates } from '@itowns/geographic';

// get oriented bounding box of tile
const builder = new GlobeTileBuilder({
  uvCount: 1
});
const size = new THREE.Vector3();
const dimension = new THREE.Vector2();
const center = new THREE.Vector3();
const coord = new Coordinates('EPSG:4326', 0, 0, 0);
let obb;

// it could be considered to remove THREE.Object3D extend.
/**
 * Oriented bounding box
 * @extends THREE.Object3D
 */
class OBB extends THREE.Object3D {
  /**
   * @param {THREE.Vector3}  min representing the lower (x, y, z) boundary of the box. Default is ( + Infinity, + Infinity, + Infinity ).
   * @param {THREE.Vector3}  max representing the lower upper (x, y, z) boundary of the box. Default is ( - Infinity, - Infinity, - Infinity ).
   */
  constructor() {
    let min = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : new THREE.Vector3(+Infinity, +Infinity, +Infinity);
    let max = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : new THREE.Vector3(-Infinity, -Infinity, -Infinity);
    super();
    this.box3D = new THREE.Box3(min.clone(), max.clone());
    this.natBox = this.box3D.clone();
    this.z = {
      min: 0,
      max: 0,
      scale: 1.0
    };
  }

  /**
   * Creates a new instance of the object with same properties than original.
   *
   * @return     {OBB}  Copy of this object.
   */
  clone() {
    return new OBB().copy(this);
  }

  /**
   * Copy the property of OBB
   *
   * @param      {OBB}  cOBB OBB to copy
   * @return     {OBB}  the copy
   */
  copy(cOBB) {
    super.copy(cOBB);
    this.box3D.copy(cOBB.box3D);
    this.natBox.copy(cOBB.natBox);
    this.z.min = cOBB.z.min;
    this.z.max = cOBB.z.max;
    this.z.scale = cOBB.z.scale;
    return this;
  }

  /**
   * Update z min, z max and z scale of oriented bounding box
   *
   * @param {Object}  [elevation={}]
   * @param {number}  [elevation.min]             The minimum of oriented bounding box
   * @param {number}  [elevation.max]             The maximum of oriented bounding box
   * @param {number}  [elevation.scale]           The scale of oriented bounding box Z axis
   * @param {number}  [elevation.geoidHeight]     The geoid height added to ellipsoid.
   */
  updateZ() {
    let elevation = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
    this.z.min = elevation.min ?? this.z.min;
    this.z.max = elevation.max ?? this.z.max;
    this.z.scale = elevation.scale > 0 ? elevation.scale : this.z.scale;
    this.z.delta = Math.abs(this.z.max - this.z.min) * this.z.scale;
    const geoidHeight = elevation.geoidHeight || 0;
    this.box3D.min.z = this.natBox.min.z + this.z.min * this.z.scale + geoidHeight;
    this.box3D.max.z = this.natBox.max.z + this.z.max * this.z.scale + geoidHeight;
  }

  /**
   * Determines if the sphere is above the XY space of the box
   *
   * @param      {Sphere}   sphere  The sphere
   * @return     {boolean}  True if sphere is above the XY space of the box, False otherwise.
   */
  isSphereAboveXYBox(sphere) {
    const localSpherePosition = this.worldToLocal(sphere.center);
    // get obb closest point to sphere center by clamping
    const x = Math.max(this.box3D.min.x, Math.min(localSpherePosition.x, this.box3D.max.x));
    const y = Math.max(this.box3D.min.y, Math.min(localSpherePosition.y, this.box3D.max.y));

    // this is the same as isPointInsideSphere.position
    const distance = Math.sqrt((x - localSpherePosition.x) * (x - localSpherePosition.x) + (y - localSpherePosition.y) * (y - localSpherePosition.y));
    return distance < sphere.radius;
  }

  /**
   * Compute OBB from extent.
   * The OBB resulted can be only in the system 'EPSG:3946'.
   *
   * @param      {Extent}        extent     The extent (with crs 'EPSG:4326') to compute oriented bounding box
   * @param      {number}        minHeight  The minimum height of OBB
   * @param      {number}        maxHeight  The maximum height of OBB
   * @return     {OBB}           return this object
   */
  setFromExtent(extent) {
    let minHeight = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : extent.min || 0;
    let maxHeight = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : extent.max || 0;
    if (extent.crs == 'EPSG:4326') {
      const {
        shareableExtent,
        quaternion,
        position
      } = builder.computeShareableExtent(extent);
      // Compute the minimum count of segment to build tile
      const segments = Math.max(Math.floor(shareableExtent.planarDimensions(dimension).x / 90 + 1), 2);
      const geometry = new TileGeometry(builder, {
        extent: shareableExtent,
        level: 0,
        segments,
        disableSkirt: true
      });
      obb.box3D.copy(geometry.boundingBox);
      obb.natBox.copy(geometry.boundingBox);
      this.copy(obb);
      this.updateZ({
        min: minHeight,
        max: maxHeight
      });
      this.position.copy(position);
      this.quaternion.copy(quaternion);
      this.updateMatrixWorld(true);
    } else if (CRS.isMetricUnit(extent.crs)) {
      extent.center(coord).toVector3(this.position);
      extent.planarDimensions(dimension);
      size.set(dimension.x, dimension.y, Math.abs(maxHeight - minHeight));
      this.box3D.setFromCenterAndSize(center, size);
      this.updateMatrixWorld(true);
    } else {
      throw new Error('Unsupported extent crs');
    }
    return this;
  }
}
obb = new OBB();
export default OBB;