Remove/Restore Map Shadows

class Game_System

  attr_reader :remove_shadows

  alias :th_remove_shadows_initialize :initialize
  def initialize
    th_remove_shadows_initialize
    @remove_shadows = false
  end

  def remove_shadows=(val)
    @remove_shadows = val
    @remove_shadows ? $game_map.remove_shadows : $game_map.restore_shadows
  end
end

class Game_Map
  alias :th_remove_shadows_setup :setup
  def setup(map_id)
    th_remove_shadows_setup(map_id)
    @memory_shadow_map = data.clone
    remove_shadows if $game_system.remove_shadows
  end

  def remove_shadows
    for x in 0...data.xsize
      for y in 0...data.ysize
        # check lowest 4 bits
        if (data[x,y,3] & 0xF) != 0
          # data stored in 2 bytes. Zero out the shadow bits
          data[x,y,3] &= 0xFFF0
        end
      end
    end
  end

  def restore_shadows
    for x in 0 ... @memory_shadow_map.xsize
      for y in 0... @memory_shadow_map.ysize
        data[x,y,3] = @memory_shadow_map[x, y, 3]
      end
    end
  end
end