code: function recalc() {
           this._super(me.Polygon, "recalc");
  
           this._width = this.points[2].x;
           this._height = this.points[2].y;
           return this;
         }
docs: Computes the calculated collision polygon.
  This **must** be called if the `points` array is modified manually.
  @ignore
  @name recalc
  @memberOf me.Rect.prototype
  @function