push rocks in the princess_game

gistfile1.txt

class Rock(GameElement):
  IMAGE = "Rock"
	SOLID = True

	def  interact(self, player):
		
		del_x = player.x - self.x
		del_y = player.y - self.y
		next_x = self.x - del_x
		next_y = self.y - del_y

		existing_el = GAME_BOARD.get_el(next_x, next_y)

		if next_x > GAME_WIDTH - 1 or next_x < 1:
			return

		if next_y > GAME_HEIGHT - 1 or next_y < 1:
			return

		if existing_el:
			existing_el.interact(PLAYER)

		if existing_el is None or not existing_el.SOLID:
			GAME_BOARD.del_el(self.x, self.y)
			GAME_BOARD.set_el(next_x, next_y, self)