module Csk_Parallax
  def self.parallax_sprite
    spr = Parallax_sprite.new
    $game_map.parallax_sprites << spr
    return spr
  end
end

class Parallax_Sprite
  attr_accessor :active, :visible, :filename, :opacity,
                :x, :y, :ox, :oy, :parallax_x, :parallax_y
  def initialize
    clear
  end

  def clear
    @active = false
    @visible = true
    @filename = ""
    @opacity = 255
    @x = 0
    @y = 0
    @z = -100000
    @ox = 0
    @oy = 0
    @parallax_x = 1.0
    @parallax_y = 1.0
    @sprite = nil
    @remove_x = 0
    @remove_y = 0
  end

  def setup(filename)
    @active = true
    @filename = filename

    @sprite ||= Sprite.new(@viewport)
    @sprite.bitmap     = Cache.picture(@filename)
    @sprite.visible    = @visible
    w = @sprite.bitmap.width
    h = @sprite.bitmap.height
    @sprite.x          = @x - $game_map.display_x * @parallax_x * 32
    @sprite.y          = @y - $game_map.display_y * @parallax_y * 32
    @sprite.z          = @z
    @sprite.ox         = @ox * w
    @sprite.oy         = @oy * h
    @sprite.opacity    = @opacity
  end

  def set_pos(x, y)
    @x = x
    @y = y
  end

  def set_origin(ox, oy)
    @ox = ox
    @oy = oy
  end

  def set_parallax(x, y)
    @parallax_x = x
    @parallax_y = y
  end

  def set_opacity(opacity)
    @opacity = opacity
  end

  def set_z(z)
    @z = z
    @sprite.z = @z unless @sprite == nil
  end

  def set_remove_pos(x, y)
    @remove_x = x
    @remove_y = y
  end

  def update
    if @sprite != nil
      @sprite.x = @x - $game_map.display_x * @parallax_x * 32
      @sprite.y = @y - $game_map.display_y * @parallax_y * 32
      @sprite.update unless @sprite

      @active = false if (@remove_x != 0 and @sprite.x < @remove_x)
      @active = false if (@remove_y != 0 and @sprite.y < @remove_y)
    end
  end
end

class Game_Map
  attr_reader :parallax_sprites

  alias csk_parallax_setup setup
  def setup(map_id)
    csk_parallax_setup(map_id)
    @parallax_sprites  ||= []
  end

  alias csk_parallax_update update
  def update(*args)
    csk_parallax_update(*args)
    @parallax_sprites.each {|data|
      data.update
      @parallax_sprites.delete(data) unless data.active
    }
  end

  def parallax_sprite
    spr = Parallax_Sprite.new
    @parallax_sprites << spr
    return spr
  end
end