code: function PointsBuilder(is2D, api) {
      this.rootNode = new graphicGL.Node();
  
      /**
       * @type {boolean}
       */
      this.is2D = is2D;
  
      this._labelsBuilder = new LabelsBuilder(256, 256, api);
  
      // Give a large render order.
      this._labelsBuilder.getMesh().renderOrder = 100;
      this.rootNode.add(this._labelsBuilder.getMesh());
  
      this._api = api;
  
      this._spriteImageCanvas = document.createElement('canvas');
  
      this._startDataIndex = 0;
      this._endDataIndex = 0;
  
      this._sizeScale = 1;
  }
docs: TODO gl_PointSize has max value.