Unity 类似FingerGestures 的相机跟随功能

本文原创，转载请注明出处：http://www.cnblogs.com/AdvancePikachu/p/6555188.html

最近在做一款VR项目，有一个查看功能，分为自由查看和跟随查看。

自由查看：

第一人称自由控制查看。使用firstPersonControl即可。

跟随查看：

摄像机可自由旋转并跟随查看的物体移动（摄像机不可为子物体）。

刚开始使用固定坐标的方法，但摄像机无法自由旋转。后来换用rotatearound，可以自由旋转，可一旦物体移动，旋转半径会拉大。

最后，模仿手势插件写了一个方法，代码如下：

public Transform target;


    public float minDistance = 1.5f;
    public float maxDistance = 10.0f;

    public float yawSensitivity =30f;
    public float pinchSensitivity = 5.0f;

    public float smoothZoomSpeed = 30.0f;
    public float smoothOrbitSpeed = 10.0f;

    float distance = 5.0f;
    float yaw = 0;
    float pitch = 0;

    float idealDistance = 0;

    bool rotate;

    public float IdealDistance
    {
        get { return idealDistance; }
        set { idealDistance = Mathf.Clamp( value, minDistance, maxDistance ); }
    }

    public float Yaw
    {
        get { return yaw; }
    }

    void Start()
    {
        Vector3 angles = transform.eulerAngles;

        distance = IdealDistance = 5f;
        yaw =  angles.y;
        pitch = 25;

        UpdateCamera();
    }


    void Update()
    {
        if (Input.GetMouseButtonDown (1))
            rotate = true;
        if (Input.GetMouseButtonUp (1))
            rotate = false;
        
        if( rotate )
        {
            yaw += Input.GetAxis ("Mouse X") * yawSensitivity;
            pitch -=  Input.GetAxis ("Mouse Y") *pinchSensitivity;
        }

        IdealDistance -= Mathf.Lerp (0, Input.GetAxis ("Mouse ScrollWheel") * smoothZoomSpeed, Time.deltaTime);
        IdealDistance = Mathf.Clamp (IdealDistance, minDistance, maxDistance);
    }

    void LateUpdate()
    {
        UpdateCamera ();
    }

    void UpdateCamera()
    {
        distance = Mathf.Lerp (distance, IdealDistance, Time.deltaTime * smoothZoomSpeed);

        Vector3 lookAtPos = target.position;
        Quaternion rotaetAngle = Quaternion.Euler (pitch, yaw, 0);

        Vector3 desiredPos = lookAtPos - rotaetAngle * new Vector3 (0, 0, distance);

        transform.position = desiredPos;
        transform.rotation = rotaetAngle;

        transform.LookAt (target);
    }

    static float ClampAngle( float angle, float min, float max )
    {
        if( angle < -360 )
            angle += 360;

        if( angle > 360 )
            angle -= 360;

        return Mathf.Clamp( angle, min, max );
    }

以上，完美实现摄像机跟随，并可以右键旋转，滚轮拉近功能。