itowns/lib/Layer/FeatureGeometryLayer.js

A JS/WebGL framework for 3D geospatial data visualization

import { Group } from 'three';
import GeometryLayer from "./GeometryLayer.js";
import FeatureProcessing from "../Process/FeatureProcessing.js";
import Feature2Mesh from "../Converter/Feature2Mesh.js";

/**
 * `FeatureGeometryLayer` displays geographic vector data (geojson, kml...) in object 3D.
 * `FeatureGeometryLayer` is a pre-configured `GeometryLayer` to load and convert vector data.
 * In deed, `GeometryLayer` allows customizing data loading (`update` method)
 * and their conversion (`convert` method),
 *
 * @property {boolean} isFeatureGeometryLayer - Used to checkout whether this layer is
 * a FeatureGeometryLayer. Default is true. You should not change this, as it is used
 * internally for optimisation.
 *
 * @extends GeometryLayer
 */
class FeatureGeometryLayer extends GeometryLayer {
  /**
   *
   * @param {string} id - The id of the layer, that should be unique. It is
   * not mandatory, but an error will be emitted if this layer is added a
   * {@link View} that already has a layer going by that id.
   * @param {Object} [options] - Optional configuration, all elements in it
   * will be merged as is in the layer.
   * @param {function} [options.batchId] - optional function to create batchId attribute.
   * It is passed the feature property and the feature index.
   * As the batchId is using an unsigned int structure on 32 bits, the batchId could be between 0 and 4,294,967,295.
   * @param {THREE.Object3D} [options.object3d=new THREE.Group()] root object3d layer.
   * @param {function} [options.onMeshCreated] this callback is called when the mesh is created. The callback parameters are the
   * `mesh` and the `context`.
   * @param {function} [options.filter] callback which filters the features of
   * this layer. It takes an object with a `properties` property as argument
   * and shall return a boolean.
   * @param {boolean} [options.accurate=TRUE] If `accurate` is `true`, data are re-projected with maximum geographical accuracy.
   * With `true`, `proj4` is used to transform data source.
   *
   * If `accurate` is `false`, re-projecting is faster but less accurate.
   * With `false`, an affine transformation is used to transform data source.
   * This method is an approximation. The error increases with the extent
   * dimension of the object or queries.
   *
   * For example :
   * * for a **100** meter dimension, there's a difference of **0.001** meter with the accurate method
   * * for a **500** meter dimension, there's a difference of **0.05** meter with the accurate method
   * * for a **20000** meter dimension, there's a difference of **40** meter with the accurate method
   *
   * **WARNING** If the source is `VectorTilesSource` then `accurate` is always false.
   */
  constructor(id) {
    let options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
    const {
      object3d,
      batchId,
      onMeshCreated,
      accurate = true,
      filter,
      ...geometryOptions
    } = options;
    super(id, object3d || new Group(), geometryOptions);
    this.update = FeatureProcessing.update;
    this.convert = Feature2Mesh.convert({
      batchId
    });
    this.onMeshCreated = onMeshCreated;
    this.isFeatureGeometryLayer = true;
    this.accurate = accurate;
    this.buildExtent = !this.accurate;
    this.filter = filter;
  }
  preUpdate(context, sources) {
    if (sources.has(this.parent)) {
      this.object3d.clear();
    }
  }
}
export default FeatureGeometryLayer;