Unity3D实现鼠标控制旋转转盘

ModelScreenPos = camera.WorldToScreenPoint(Model.transform.position);

q = Quaternion.FromToRotation(OA, OB);

private Vector2 ModelPos;
 private Vector2 mousePos; //当前鼠标位置
 private Vector2 premousePos;//上一帧鼠标位置
 private Quaternion q; 
 private float RotateAngle;
 private Vector3 localEluer; //模型欧拉角存储变量
 
 private bool IsSelect = false;
 void Start()
 {
  ModelPos = camera.WorldToScreenPoint(go.transform.position);
  angle = localEluer.x = info.opening;
  go.transform.localEulerAngles = localEluer;
 }
 
 public virtual void Update()
 {
  if (Input.GetMouseButtonDown(0)&&modelCamera.IsTouch())
  {
   IsSelect = true;
   premousePos = mousePos=Input.mousePosition; //每次重新点击的时候都重置鼠标上一帧点击坐标
  }
  if (Input.GetMouseButton(0)&& IsSelect)
  {
   mousePos = Input.mousePosition;
   RotateAngle = Vector2.Angle(premousePos - ModelPos, mousePos - ModelPos);
   //Debug.Log("RotateAngle+"+RotateAngle);
   if (RotateAngle == 0)
   {
    premousePos = mousePos;
   }
   else
   {
    q = Quaternion.FromToRotation(premousePos - ModelPos, mousePos - ModelPos);
    float k = q.z > 0 ? 1 : -1;
    localEluer.x += k * RotateAngle;
    //Debug.Log(localEluer.x);
    angle = localEluer.x = Mathf.Clamp(localEluer.x, 0, AllowAngle); //这里是项目需要 限制一下旋转圈数
    go.transform.localEulerAngles = localEluer;
    premousePos = mousePos;
   }
  }
  if (Input.GetMouseButtonUp(0))
  {
   IsSelect = false;
  } 
 }