code: function (renderer, x, y, tmxTile) {
              var tileset = tmxTile.tileset;
              // draw the tile
              tileset.drawTile(
                  renderer,
                  ((this.cols - 1) * tileset.tilewidth + (x - y) * tileset.tilewidth >> 1),
                  (-tileset.tilewidth + (x + y) * tileset.tileheight >> 2),
                  tmxTile
              );
          }
docs: draw the tile map
  @ignore