Sqrt9

实现简单地控制相机距离和角度

附加于相机上的代码：

	private Transform player;  //跟随目标

    Vector3 tempPosition=Vector3.zero;
    
    Vector3 offsetPosition;    //相机距离目标之间的差向量
    
    float distance = 0.0f;
    
    public float speed = 1;
    
    public float rotateSpeed = 4;
    
	// Use this for initialization
	void Start () {
        player = GameObject.FindGameObjectWithTag(tags.player).transform;
        transform.LookAt(player.position);
		//计算差向量
        offsetPosition = transform.position - player.position;
	}
	
	// Update is called once per frame
	void Update () {
		//控制相机跟随目标
        transform.position = offsetPosition + player.position;
        Rotate();
        Distance();
    }
	//控制相机的拉近及拉远
    void Distance()
    {
        distance = offsetPosition.magnitude;
		//滚轮控制相机距离目标的距离
        distance = distance + Input.GetAxis("Mouse ScrollWheel") * speed;
		//控制最小与最大距离
        distance = Mathf.Clamp(distance, 5, 20);
        offsetPosition = offsetPosition.normalized * distance;
    }
	//控制相机围绕目标旋转
    void Rotate()
    {
        if(Input.GetMouseButton(0))
        {
            Vector3 tempPos = transform.position;
            Quaternion tempRot = transform.rotation;

            transform.RotateAround(player.position, player.up, rotateSpeed * Input.GetAxis("Mouse X"));
//**注意这里围绕旋转的轴是相机本身的x轴，类似天体运动中的自转**
            transform.RotateAround(player.position, transform.right, rotateSpeed * Input.GetAxis("Mouse Y"));
            float x = transform.eulerAngles.x;
//限制旋转角度在10 - 80 之间
            if(x<10||x>80)
            {
                transform.position = tempPos;
                transform.rotation = tempRot;
            }
        }
//注意一定要在旋转后更新差向量
        offsetPosition = transform.position - player.position;
    }