[Resolved] How to determine if map tile is blocked?

[kds71]

Hello,

I'm newbie to RGSS (and Ruby), but I consider myself as good programmer.
I've read all the FAQ and searched forum, but I couldn't find answer to my question.

I'm creating my own game system (ABS / CMS / HUD) from scratch. Everything is going fine (as I've found many solutions on this great forum). But now I encountered problem, which is unsolvable for me.

I need to determine if tile on map blocks line of sight (LoS):
- tile with other character blocks LoS
- tile with something on middle layer (like tree) blocks LoS
- tile with something blocking movement doesn't need to block LoS (for example: water)
- tile with event doesn't need to block LoS (events without graphics, events which doesn't block movement)

All I need is to write method which takes two parameters (coordinates of tile) and returns true (when tile blocks LoS) or false (when it doesn't).

Any help will be appreciated

Edit:
I solved it (partially):

  def tile_is_blocked(x, y)
    tile_id = $game_map.data[x, y, 1]
    if  tile_id > 0
      pass = $tileset.passages[tile_id]
      return true if ((pass & 1) == 1) and @dir = 0
      return true if ((pass & 2) == 2) and @dir = 1
      return true if ((pass & 4) == 4) and @dir = 2
      return true if ((pass & 8) == 8) and @dir = 3
    end
    return false
  end

Now I have problem with events. I think I need to view game map events array and check every event coordinates. But it shall return true only if through parameter is false. But I have no idea how to check value of this parameter...

(sorry if my English is poor, it isn't my native language)

 

[kds71]

Bump...

 

[Chaosg1]

Its simple $game_map.events[id].through
returns that parameter info..

 

[kds71]

Heh, stupid me
Thanks a lot, I couldn't find it anywhere.

 

[Icarus Featherfight]

Edit:
I solved it (partially):

  def tile_is_blocked(x, y)
    tile_id = $game_map.data[x, y, 1]
    if  tile_id > 0
      pass = $tileset.passages[tile_id]
      return true if ((pass & 1) == 1) and @dir = 0
      return true if ((pass & 2) == 2) and @dir = 1
      return true if ((pass & 4) == 4) and @dir = 2
      return true if ((pass & 8) == 8) and @dir = 3
    end
    return false
  end

I think this method is what you are looking for.

$Game_Map.passable?(x, y, d, self_event = nil)

Spoiler: Complete Code of Method

  #--------------------------------------------------------------------------
  # * Determine if Passable
  #     x          : x-coordinate
  #     y          : y-coordinate
  #     d          : direction (0,2,4,6,8,10)
  #                  *  0,10 = determine if all directions are impassable
  #     self_event : Self (If event is determined passable)
  #--------------------------------------------------------------------------
  def passable?(x, y, d, self_event = nil)
    # If coordinates given are outside of the map
    unless valid?(x, y)
      # impassable
      return false
    end
    # Change direction (0,2,4,6,8,10) to obstacle bit (0,1,2,4,8,0)
    bit = (1 << (d / 2 - 1)) & 0x0f
    # Loop in all events
    for event in events.values
      # If tiles other than self are consistent with coordinates
      if event.tile_id >= 0 and event != self_event and
         event.x == x and event.y == y and not event.through
        # If obstacle bit is set
        if @passages[event.tile_id] & bit != 0
          # impassable
          return false
        # If obstacle bit is set in all directions
        elsif @passages[event.tile_id] & 0x0f == 0x0f
          # impassable
          return false
        # If priorities other than that are 0
        elsif @priorities[event.tile_id] == 0
          # passable
          return true
        end
      end
    end
    # Loop searches in order from top of layer
    for i in [2, 1, 0]
      # Get tile ID
      tile_id = data[x, y, i]
      # Tile ID acquistion failure
      if tile_id == nil
        # impassable
        return false
      # If obstacle bit is set
      elsif @passages[tile_id] & bit != 0
        # impassable
        return false
      # If obstacle bit is set in all directions
      elsif @passages[tile_id] & 0x0f == 0x0f
        # impassable
        return false
      # If priorities other than that are 0
      elsif @priorities[tile_id] == 0
        # passable
        return true
      end
    end
    # passable
    return true
  end

Then again I could be wrong...