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 = ;
     float pitch = ;

     float idealDistance = ;

     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 = ;

         UpdateCamera();
     }

     void Update()
     {
         if (Input.GetMouseButtonDown ())
             rotate = true;
         if (Input.GetMouseButtonUp ())
             rotate = false;

         if( rotate )
         {
             yaw += Input.GetAxis ("Mouse X") * yawSensitivity;
             pitch -=  Input.GetAxis ("Mouse Y") *pinchSensitivity;
         }

         IdealDistance -= Mathf.Lerp (, 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, );

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

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

         transform.LookAt (target);
     }

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

         if( angle >  )
             angle -= ;

         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。