itowns/lib/Core/PotreeNode.js

A JS/WebGL framework for 3D geospatial data visualization

import * as THREE from 'three';
import PointCloudNode from "./PointCloudNode.js";

// Create an A(xis)A(ligned)B(ounding)B(ox) for the child `childIndex` of one aabb.
// (PotreeConverter protocol builds implicit octree hierarchy by applying the same
// subdivision algo recursively)
const dHalfLength = new THREE.Vector3();
class PotreeNode extends PointCloudNode {
  constructor() {
    let numPoints = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
    let childrenBitField = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 0;
    let layer = arguments.length > 2 ? arguments[2] : undefined;
    super(numPoints, layer);
    this.childrenBitField = childrenBitField;
    this.depth = 0;
    this.hierarchyKey = '';
    this.baseurl = layer.source.baseurl;
  }
  get octreeIsLoaded() {
    return !(this.childrenBitField && this.children.length === 0);
  }
  get url() {
    return `${this.baseurl}/r${this.hierarchyKey}.${this.layer.source.extension}`;
  }
  get id() {
    return this.hierarchyKey;
  }
  add(node, indexChild) {
    node.hierarchyKey = this.hierarchyKey + indexChild;
    node.depth = this.depth + 1;
    super.add(node, indexChild);
  }
  createChildAABB(node, childIndex) {
    // Code inspired from potree
    node.bbox.copy(this.bbox);
    this.bbox.getCenter(node.bbox.max);
    dHalfLength.copy(node.bbox.max).sub(this.bbox.min);
    if (childIndex === 1) {
      node.bbox.min.z += dHalfLength.z;
      node.bbox.max.z += dHalfLength.z;
    } else if (childIndex === 3) {
      node.bbox.min.z += dHalfLength.z;
      node.bbox.max.z += dHalfLength.z;
      node.bbox.min.y += dHalfLength.y;
      node.bbox.max.y += dHalfLength.y;
    } else if (childIndex === 0) {
      //
    } else if (childIndex === 2) {
      node.bbox.min.y += dHalfLength.y;
      node.bbox.max.y += dHalfLength.y;
    } else if (childIndex === 5) {
      node.bbox.min.z += dHalfLength.z;
      node.bbox.max.z += dHalfLength.z;
      node.bbox.min.x += dHalfLength.x;
      node.bbox.max.x += dHalfLength.x;
    } else if (childIndex === 7) {
      node.bbox.min.add(dHalfLength);
      node.bbox.max.add(dHalfLength);
    } else if (childIndex === 4) {
      node.bbox.min.x += dHalfLength.x;
      node.bbox.max.x += dHalfLength.x;
    } else if (childIndex === 6) {
      node.bbox.min.y += dHalfLength.y;
      node.bbox.max.y += dHalfLength.y;
      node.bbox.min.x += dHalfLength.x;
      node.bbox.max.x += dHalfLength.x;
    }
  }
  load() {
    // Query octree/HRC if we don't have children potreeNode yet.
    if (!this.octreeIsLoaded) {
      this.loadOctree();
    }
    return super.load();
  }
  loadOctree() {
    const octreeUrl = `${this.baseurl}/r${this.hierarchyKey}.${this.layer.source.extensionOctree}`;
    return this.layer.source.fetcher(octreeUrl, this.layer.source.networkOptions).then(blob => {
      const view = new DataView(blob);
      const stack = [];
      let offset = 0;
      this.childrenBitField = view.getUint8(0);
      offset += 1;
      this.numPoints = view.getUint32(1, true);
      offset += 4;
      stack.push(this);
      while (stack.length && offset < blob.byteLength) {
        const snode = stack.shift();
        // look up 8 children
        for (let indexChild = 0; indexChild < 8; indexChild++) {
          // does snode have a #indexChild child ?
          if (snode.childrenBitField & 1 << indexChild && offset + 5 <= blob.byteLength) {
            const childrenBitField = view.getUint8(offset);
            offset += 1;
            const numPoints = view.getUint32(offset, true) || this.numPoints;
            offset += 4;
            const child = new PotreeNode(numPoints, childrenBitField, this.layer);
            snode.add(child, indexChild);
            if (child.id.length % this.layer.hierarchyStepSize == 0) {
              child.baseurl = `${this.baseurl}/${child.id}`;
            } else {
              child.baseurl = this.baseurl;
            }
            stack.push(child);
          }
        }
      }
    });
  }
}
export default PotreeNode;