使用quaternion旋转   四元数

void RotateToTarget(Vector3 targetPos){
   Vector3 currentPosition=this.transform.position;
   Quaternion currentRotation=this.transform.rotation;
   Vector3 direction=(targetPos-currentPosition).normalized;
   Quaternion targetRotation=Quaternion.LookRotation(direction);
   transform.rotation=Quaternion.RotateTowards(currentRotation,targetRotation,45f*Time.deltaTime);
}
Quaternion.FromToRotation()//计算两个旋转的差值