Determining player's priority (...Is he under a tree?)

[Kain Nobel]

How do I basically tell if the player/event is under a tile layer? Like for instance, they're walking under a tree or a scaffolding or whatever?

I've looked through a bunch of different sections like Sprite_Character, Spriteset_Map, Game_Character, Scene_Map, etc and found a couple things on $game_map.priorities, tile_id and even screen_z, I'm just not sure to piece them all together to determine if player/event is 'under something'...

 

[Tindy]

{Supposed "spamming" due to misunderstanding of OP originally went here.}

 

[Kain Nobel]

Well, the 'script' I'm writting doesn't know that !

The script spawns an arrow over the player's head if you're 'under' a tree and can't really see yourself. Thank you for spamming my topic, next please!

 

[poccil]

The following script I wrote checks the Z of the map's tiles and determines whether the player is under the tiles.  It defines two functions:

$game_player.isHidden? - returns true if the player is under the map's tileset, and false otherwise.
$game_map.z(x,y) - returns the Z of the map's tiles located at the specified x and y position.

Put the script in the script editor before the last script found there (normally "Main").  The code below follows.

class Bitmap
  # Fast methods for retrieving bitmap data
  RtlMoveMemory_pi = Win32API.new('kernel32', 'RtlMoveMemory', 'pii', 'i')
  RtlMoveMemory_ip = Win32API.new('kernel32', 'RtlMoveMemory', 'ipi', 'i')
  def setData(x)
    RtlMoveMemory_ip.call(self.address, x, x.length)    
  end
  def getData
    data = "rgba" * width * height
    RtlMoveMemory_pi.call(data, self.address, data.length)
    return data
  end
  def address
    if !@address
      buffer, ad = "rgba", object_id * 2 + 16
      RtlMoveMemory_pi.call(buffer, ad, 4)
      ad = buffer.unpack("L")[0] + 8
      RtlMoveMemory_pi.call(buffer, ad, 4)
      ad = buffer.unpack("L")[0] + 16
      RtlMoveMemory_pi.call(buffer, ad, 4)
      @address=buffer.unpack("L")[0]
    end
    return @address
  end
end

class Game_Player
  def isHidden?
    return self.screen_z < $game_map.z(self.x,self.y)
  end
end

class Game_Map
 def isFullyBlank?(tileid)
  return false if tileid<384
  tile=RPG::Cache.tile(@tileset_name,tileid,0)
  if tile.getData[/^(...\0)+$/] # Fast way to check whether alpha of all pixels is 0
    return true
  end
  return false
 end
 def z(x, y)
  zMax=0
  if @map_id != 0
   for i in [2, 1, 0]
    tile_id = data[x, y, i]
    next if tile_id == nil || tile_id==0 # Ignore blank tiles
    # Ignore tiles with priority nil or 0
    next if @priorities[tile_id] == nil
    if @priorities[tile_id]!=0
     ypos=(y*32)-((self.display_y) / 4)
     # Ignore if tile is fully blank
     if !isFullyBlank?(tile_id)
       # Now calculate Z of tile
       zMax=[zMax,ypos+@priorities[tile_id]*32+32].max
     end
    end
   end
  end
  return zMax
 end
end

 

[Kain Nobel]

Thanks, works like a charm!

If you don't mind me asking, what does your bitmap class do? Is it supposed to determine transparency of a bitmap or something?

 

[poccil]

The Bitmap class used above enables a bitmap's data to be read very quickly, instead of using the very slow functions "set_pixel" and "get_pixel".  Since the data is read as a string, it can even be saved to a file.