Terrain Tags

#===============================================================================
#   http://thiagodd.blogspot.com.br
# [TSDA] Terrain Tags
#   --> Version 1.1
#   by thiago_d_d
#
# -----------------------------------------------------------------------------
# * Features
# -----------------------------------------------------------------------------
#  This script changes one variable value or executes a code based on the terrain
#  the player steps. This is nearly identical with the RPG Maker XP terrain tags.
# -----------------------------------------------------------------------------
# * Install
# -----------------------------------------------------------------------------
#  Paste the script in the aditional scripts section.
# -----------------------------------------------------------------------------
# * Configuration
# -----------------------------------------------------------------------------
#  Para implementar uma ação que irá acontecer num tile, é necessário
#  Seguir os seguintes passos:
#  ----------------------
#   ===> If the tile is contained in the Tileset - A
#  ----------------------
#  Go to TILES_A_VALUE and add an code in this format
#   [x,y] => k
#  In x place, put the x position of tile tile in the Tileset A.
#  In y place, put the y position of tile tile in the Tileset A
#  In place of k, put an value to atribute to the variable, or put an code to execute.
#----------------------
#   ===> If the tile is not contained in the Tileset - A
#  ----------------------
# You have to discover the index. First, put that tile on any map.
# After that, create an event with that script code:
# p $game_map.data[x,y,2]
# Test the game, activate the event, and the tile index will be printed.
# Use the tile index and go to TILES_OTHER_VALUE, and add an line like this:
#    Found_index => action
# in place of action, put an value to atribute to the variable,
# or put an code to execute.
#
# If you have any question, see the examples below.
#===============================================================================
module TSDA
  #Id of the variable that will be changed
  TILES_VAR_ID = 1
  TILES_A_VALUE =
  {
     [0,0] => 1,
     [0,1] => 2
  }
  TILES_OTHER_VALUE =
  {
    7 => 1
  }
end

class Game_Player
  include TSDA
  def var_change
    @changed = 0
    tile_id = $game_map.data[@x,@y,0]
    tile_id2 = $game_map.data[@x,@y,2]
    x = (tile_id / 128 % 2 * 8 + tile_id % 8)
    y = tile_id % 256 / 8 % 16
    pos = [x,y]
    if !TILES_A_VALUE[pos].nil?
      value = TILES_A_VALUE[pos]
      if value.is_a?(Integer)
        $game_variables[TILES_VAR_ID] = value
      elsif value != nil
        eval(value)
      end
    end
    if !TILES_OTHER_VALUE[tile_id2].nil?
      value = TILES_OTHER_VALUE[tile_id2]
      if value.is_a?(Integer)
        $game_variables[TILES_VAR_ID] = value
      else
        eval(value)
      end
    end
  end
  alias tiles_th_updt update
  def update
    if !@changed.nil? & !moving?
      @changed = nil
    end
    var_change if (moving? and @changed.nil?)
    tiles_th_updt
  end
end