public void onKeyPressed(KeyEvent e) {
		switch (e.getKeyCode()) {
		case VK_UP:
		case VK_W:
			// Arrow up key: move direction = forward (infinitely)
			moveDirection = 1;
			moveAmount = Double.POSITIVE_INFINITY;
			break;

		case VK_DOWN:
		case VK_S:
			// Arrow down key: move direction = backward (infinitely)
			moveDirection = -1;
			moveAmount = Double.POSITIVE_INFINITY;
			break;

		case VK_RIGHT:
		case VK_D:
			// Arrow right key: turn direction = right
			turnDirection = 1;
			break;

		case VK_LEFT:
		case VK_A:
			// Arrow left key: turn direction = left
			turnDirection = -1;
			break;
		}
	}