private Point getWorldCoordinates(Point screenCoordinates) {
		if (!isPlaying()) return null;
		Dimension boardSize = client.getSession().getBoardDimension();
		return new Point((int) (screenCoordinates.getX() * (boardSize.getWidth() / getSize().getWidth())),
		                 (int) (screenCoordinates.getY() * (boardSize.getHeight() / getSize().getHeight())) );
	}