[游戏开发]Unity 检测UI是否在相机视野内

我目前正在开发的产品是《青光眼白内障》，HTCCosmos版本的VR，然后现在遇到了这样子一个需求，就是体验流程中要显示的UI，如果在相机视野外，就要平滑旋转到视野内，小于视野的UI就停留在原地位置。
两段代码，两个逻辑，实现的效果都行，但是有区别，第二段优化流程，相当于UI已经跟上了头盔的转动，更倾向于第二种。

下面直接上代码：
（1）

    public Transform targetTran;//UI

脚本挂载到相机

 if (angle > 57)
        {
            if (isInView)
            {
                var v = transform.position - targetTran.position;//方向
                var s = Vector3.Cross(v.normalized, transform.forward);//向左转向右转
                angle *= s.y < 0 ? 1 : -1;
                if (coroutine != null) StopCoroutine(coroutine);
                coroutine = RotateAround(targetTran.transform, transform.position, Vector3.up, angle);
                Debug.Log("不在视野范围内");
                isInView = false;
            }
        }
        else
        {
            Debug.Log("在视野范围内");
            isInView = true;
        }
          private Coroutine coroutine;
    private Coroutine RotateAround(Transform target, Vector3 point, Vector3 axis, float angle)
    {
       return StartCoroutine(CRotateAround());
        IEnumerator CRotateAround()
        {
            var crtAngle = 0f;
            while (Mathf.Abs(crtAngle - angle) > 0.02f)
            {
                var tmp = Mathf.Lerp(crtAngle, angle, 0.15f);
                Debug.Log(crtAngle);
                target.RotateAround(point, axis, tmp - crtAngle);
                crtAngle = tmp;
                yield return null;
            }
            target.RotateAround(point, axis, angle - crtAngle);
        }
    }

（2）

        var a = transform.forward;
        a.y = 0;
        var b = targetTran.transform.position - transform.position;
        b.y = 0;
        var angle = Mathf.Acos(Vector3.Dot(a.normalized, b.normalized)) * Mathf.Rad2Deg;//计算转的角度
        //Debug.Log(angle);

        if (angle >57)
            kz_OnOff = true;
        if(angle<3)
                kz_OnOff = false;
        if (kz_OnOff)
        {
            angle *= 0.18f;
            //Vector3 v3_1 = Vector3.Cross(transform.forward, Vector3.up);
            //Vector3 v3_2 = Vector3.Cross(v3_1, Vector3.up).normalized;
            //targetTran.forward = -v3_2;
            //targetTran.position = Vector3.Lerp(targetTran.position, transform.position - v3_2 * targetTran.GetComponent<CanvasCtrol>().distance, 0.15f);

            var v = transform.position - targetTran.position;//方向
            var s = Vector3.Cross(v.normalized, transform.forward);//向左转向右转
            angle *= s.y < 0 ? 1 : -1;

            targetTran.RotateAround(transform.position,Vector3.up,angle);
        }

可自行体验效果差别