A5 TILESET? IS THAT ENOUGH? (+ VEHICLE PASSIBILITY)

class Game_Map
  #--------------------------------------------------------------------------
  # * Check Passage
  #     bit:  Inhibit passage check bit
  #--------------------------------------------------------------------------
  def check_passage(x, y, bit)
    all_tiles(x, y).each do |tile_id|
      flag = tileset.flags[tile_id]
      next if flag & 0x10 != 0            # [☆]: No effect on passage
      return true  if flag & bit == 0     # [○] : Passable
      return false if flag & bit == bit   # [×] : Impassable
    end
    return false                          # Impassable
  end
  #--------------------------------------------------------------------------
  # * Determine Passability of Normal Character
  #     d:  direction (2,4,6,8)
  #    Determines whether the tile at the specified coordinates is passable
  #    in the specified direction.
  #--------------------------------------------------------------------------
  def passable?(x, y, d)
    check_passage(x, y, (1 << (d / 2 - 1)) & 0x0f)
  end
  #--------------------------------------------------------------------------
  # * Determine if Passable by Boat
  #--------------------------------------------------------------------------
  def boat_passable?(x, y)
    check_passage(x, y, 0x0200)
  end
  #--------------------------------------------------------------------------
  # * Determine if Passable by Ship
  #--------------------------------------------------------------------------
  def ship_passable?(x, y)
    check_passage(x, y, 0x0400)
  end
end

class Game_CharacterBase
  #--------------------------------------------------------------------------
  # * Determine if Passable
  #     d : Direction (2,4,6,8)
  #--------------------------------------------------------------------------
  def passable?(x, y, d)
    x2 = $game_map.round_x_with_direction(x, d)
    y2 = $game_map.round_y_with_direction(y, d)
    return false unless $game_map.valid?(x2, y2)
    return true if terrain_tag(x, y, d)
    return true if @through || debug_through?
    return false unless map_passable?(x, y, d)
    return false unless map_passable?(x2, y2, reverse_dir(d))
    return false if collide_with_characters?(x2, y2)
    return true
  end

  # Set tiles with a terrain tag not euqal to 0 passible by an event with a
  # predefined ID.
  def terrain_tag(x, y, d)
    # First, we define which event ID we want to find.
    event_id = 1
    # We check against the parameters of the function to see if the specified
    # event is the one we're looking at.
    x2 = $game_map.events[event_id].x
    y2 = $game_map.events[event_id].y
    if x == x2 && y == y2
      # If the terrain tag is not 0, the bullet can move through it.
      if $game_map.terrain_tag(x, y) != 0
        return true
        # But wait. If the NEXT tile's terrain tag is not 0, the bullet should
        # still be able to move!
      else
        x2 = $game_map.round_x_with_direction(x, d)
        y2 = $game_map.round_y_with_direction(y, d)
        if $game_map.terrain_tag(x2, y2) != 0
          return true
        end
        # Should all that fail, treat the tile normally.
        return false
      end
    end    
  end
end