itowns/lib/Core/3DTiles/C3DTFeature.js

A JS/WebGL framework for 3D geospatial data visualization

// eslint-disable-next-line no-unused-vars
import { Object3D, Box3 } from 'three';

/**
 * Finds the batch table of an object in a 3D Tiles layer. This is
 * for instance needed when picking because we pick the geometric
 * object which is not at the same level in the layer structure as
 * the batch table.
 * @param {THREE.Object3D} object - a 3D geometric object
 * @returns {C3DTBatchTable|null} - the batch table of the object
 */
function findBatchTable(object) {
  if (object.batchTable) {
    return object.batchTable;
  }
  if (object.parent) {
    return findBatchTable(object.parent);
  }
  return null;
}

/**
 * C3DTFeature is a feature of a 3DTiles
 *
 * @class      C3DTFeature
 * @param {number} tileId - tileId
 * @param {number} batchId - batch id
 * @param {Array<{start:number,count:number}>} groups - groups in geometry.attributes matching batchId
 * @param {object} [userData] - some userData
 * @param {Object3D} object3d - object3d in which feature is present
 * @property {number} tileId - tile id
 * @property {Object3D} object3d - object3d in which feature is present
 * @property {number} batchId - batch id
 * @property {Array<{start:number,count:number}>} groups - groups in geometry.attributes matching batchId
 * @property {object} [userData] - some userData
 */
class C3DTFeature {
  #info;
  constructor(tileId, batchId, groups, userData, object3d) {
    /** @type {Object3D} */
    this.object3d = object3d;

    /** @type {number} */
    this.batchId = batchId;

    /** @type {Array<{start:number,count:number}>} */
    this.groups = groups;

    /** @type {object} */
    this.userData = userData;

    /** @type {number} */
    this.tileId = tileId;

    // Lazy-loaded batch table information for this.batchId.
    this.#info = null;
  }

  /**
   * Compute world box3 of this
   *
   * @param {Box3} target - target of the result
   * @returns {Box3}
   */
  computeWorldBox3() {
    let target = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : new Box3();
    // reset
    target.max.x = -Infinity;
    target.max.y = -Infinity;
    target.max.z = -Infinity;
    target.min.x = Infinity;
    target.min.y = Infinity;
    target.min.z = Infinity;
    this.groups.forEach(group => {
      const positionIndexStart = group.start * this.object3d.geometry.attributes.position.itemSize;
      const positionIndexCount = (group.start + group.count) * this.object3d.geometry.attributes.position.itemSize;
      for (let index = positionIndexStart; index < positionIndexCount; index++) {
        const x = this.object3d.geometry.attributes.position.getX(index);
        const y = this.object3d.geometry.attributes.position.getY(index);
        const z = this.object3d.geometry.attributes.position.getZ(index);
        target.max.x = Math.max(x, target.max.x);
        target.max.y = Math.max(y, target.max.y);
        target.max.z = Math.max(z, target.max.z);
        target.min.x = Math.min(x, target.min.x);
        target.min.y = Math.min(y, target.min.y);
        target.min.z = Math.min(z, target.min.z);
      }
    });
    target.applyMatrix4(this.object3d.matrixWorld);
    return target;
  }

  /**
   * Gets the information from the tile batch table for this C3DTFeature batch id.
   * @returns {object} - batchTable info
   */
  getInfo() {
    if (this.#info) {
      return this.#info;
    }
    const batchTable = findBatchTable(this.object3d);
    if (!batchTable) {
      console.warn(`[C3DTFeature]: No batch table found for tile ${this.tileId}.`);
      return null; // or return undefined;
    }
    this.#info = batchTable.getInfoById(this.batchId);
    return this.#info;
  }
}
export default C3DTFeature;