code: function xModelHandle(gl, model, fpt) {
      if (typeof (gl) == 'undefined' || typeof (model) == 'undefined' || typeof (fpt) == 'undefined') {
          throw 'WebGL context and geometry model must be specified';
      }
  
      this._gl = gl;
      this._model = model;
      this._fpt = fpt;
  
      /**
       * unique ID which can be used to identify this handle 
       */
      this.id = xModelHandle._instancesNum++;
  
      /**
       * indicates if this model should be used in a rendering loop or not.
       */
      this.stopped = false;
  
      this.count = model.indices.length;
  
      //data structure 
      this.vertexTexture = gl.createTexture();
      this.matrixTexture = gl.createTexture();
      this.styleTexture = gl.createTexture();
      this.stateStyleTexture = gl.createTexture();
  
      this.vertexTextureSize = 0;
      this.matrixTextureSize = 0;
      this.styleTextureSize = 0;
  
      this.normalBuffer = gl.createBuffer();
      this.indexBuffer = gl.createBuffer();
      this.productBuffer = gl.createBuffer();
      this.styleBuffer = gl.createBuffer();
      this.stateBuffer = gl.createBuffer();
      this.transformationBuffer = gl.createBuffer();
  
      //small texture which can be used to overwrite appearance of the products
      this.stateStyle = new Uint8Array(15 * 15 * 4);
      this._feedCompleted = false;
  
      this.region = model.regions[0];
      //set the most populated region
      model.regions.forEach(function (region) {
          if (region.population > this.region.population) {
              this.region = region;
          }
      }, this);
      //set default region if no region is defined. This shouldn't ever happen if model contains any geometry.
      if (typeof (this.region) == 'undefined') {
          this.region = {
              population: 1,
              centre: [0.0, 0.0, 0.0],
              bbox: [0.0, 0.0, 0.0, 10 * model.meter, 10 * model.meter, 10 * model.meter]
          }
      }
  }
docs: gl: WebGL context model: xModelGeometry fpt: bool (floating point texture support)