def get_screen_pos(map_x, map_y)
      return Vector.new(map_x * @tile_size.x - @cam.x, map_y * @tile_size.y - @cam.y) unless @isometric
      Vector.new ((map_x - map_y - 1) * @tile_size.x * 0.5) - @cam.x + @x_offset,
                 ((map_x + map_y) * @tile_size.y * 0.5) - @cam.y
    end
def get_screen_pos(map_x, map_y)
      return Vector.new(map_x * @tile_size.x - @cam.x, map_y * @tile_size.y - @cam.y) unless @isometric
      Vector.new ((map_x - map_y - 1) * @tile_size.x * 0.5) - @cam.x + @x_offset,
                 ((map_x + map_y) * @tile_size.y * 0.5) - @cam.y
    end
Returns the position in the screen corresponding to the given tile
 indices.

 Parameters:
 [map_x] The index of the tile in the horizontal direction. It must be in
         the interval <code>0..t_x_count</code>.
 [map_y] The index of the tile in the vertical direction. It must be in
         the interval <code>0..t_y_count</code>.