itowns/lib/Core/TileGeometry.js

A JS/WebGL framework for 3D geospatial data visualization

import * as THREE from 'three';
import { computeBuffers, getBufferIndexSize } from "./Prefab/computeBufferTileGeometry.js";
import { Coordinates } from '@itowns/geographic';
function defaultBuffers(builder, params) {
  const fullParams = {
    disableSkirt: false,
    hideSkirt: false,
    buildIndexAndUv_0: true,
    segments: 16,
    coordinates: new Coordinates(builder.crs),
    center: builder.center(params.extent).clone(),
    ...params
  };
  const buffers = computeBuffers(builder, fullParams);
  const bufferAttributes = {
    index: buffers.index ? new THREE.BufferAttribute(buffers.index, 1) : null,
    uvs: [...(buffers.uvs[0] ? [new THREE.BufferAttribute(buffers.uvs[0], 2)] : []), ...(buffers.uvs[1] ? [new THREE.BufferAttribute(buffers.uvs[1], 1)] : [])],
    position: new THREE.BufferAttribute(buffers.position, 3),
    normal: new THREE.BufferAttribute(buffers.normal, 3)
  };
  return bufferAttributes;
}
export class TileGeometry extends THREE.BufferGeometry {
  /** Oriented Bounding Box of the tile geometry. */

  /** Ground area covered by this tile geometry. */

  /** Resolution of the tile geometry in segments per side. */

  /**
   * [TileGeometry] instances are shared between tiles. Since a geometry
   * handles its own GPU resource, it needs a reference counter to dispose of
   * that resource only when it is discarded by every single owner of a
   * reference to the geometry.
   */
  // https://github.com/iTowns/itowns/pull/2440#discussion_r1860743294
  // TODO: Remove nullability by reworking OBB:setFromExtent

  constructor(builder, params) {
    let bufferAttributes = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : defaultBuffers(builder, params);
    super();
    this.extent = params.extent;
    this.segments = params.segments;
    this.setIndex(bufferAttributes.index);
    this.setAttribute('position', bufferAttributes.position);
    this.setAttribute('normal', bufferAttributes.normal);
    this.setAttribute('uv', bufferAttributes.uvs[0]);
    for (let i = 1; i < bufferAttributes.uvs.length; i++) {
      this.setAttribute(`uv_${i}`, bufferAttributes.uvs[i]);
    }
    this.computeBoundingBox();
    this.OBB = null;
    if (params.hideSkirt) {
      this.hideSkirt = params.hideSkirt;
    }
    this._refCount = null;
  }

  /**
   * Enables or disables skirt rendering.
   *
   * @param toggle - Whether to hide the skirt; true hides, false shows.
   */
  set hideSkirt(toggle) {
    this.setDrawRange(0, getBufferIndexSize(this.segments, toggle));
  }

  /**
   * Initialize reference count for this geometry if it is currently null.
   *
   * @param cacheTile - The [Cache] used to store this geometry.
   * @param keys - The [south, level, epsg] key of this geometry.
   */
  initRefCount(cacheTile, key) {
    if (this._refCount !== null) {
      return;
    }
    this._refCount = {
      count: 0,
      fn: () => {
        this._refCount.count--;
        if (this._refCount.count <= 0) {
          // To avoid remove index buffer and attribute buffer uv
          //  error un-bound buffer in webgl with VAO rendering.
          // Could be removed if the attribute buffer deleting is
          //  taken into account in the buffer binding state
          //  (in THREE.WebGLBindingStates code).
          this.index = null;
          delete this.attributes.uv;
          cacheTile.delete(key);
          super.dispose();
          // THREE.BufferGeometry.prototype.dispose.call(this);
        }
      }
    };
  }

  /**
   * Increase reference count.
   *
   * @throws If reference count has not been initialized.
   */
  increaseRefCount() {
    if (this._refCount === null) {
      throw new Error('[TileGeometry::increaseRefCount] ' + 'Tried to increment an unitialized reference count.');
    }
    this._refCount.count++;
  }

  /**
   * The current reference count of this [TileGeometry] if it has been
   * initialized.
   */
  get refCount() {
    return this._refCount?.count;
  }
  dispose() {
    if (this._refCount == null) {
      super.dispose();
    } else {
      this._refCount.fn();
    }
  }
}