摄像机绕一个物体在一定范围内旋转

if(transform.position.y >=1.5f && transform.position .y <=4.8f )
{                
transform.RotateAround (target.position ,target.right  ,Input.GetAxis ("Mouse Y")*4  );            
    rotationX = transform.rotation.x ;            
}
else if(transform.position .y <1.5f)
{
    transform.position = new Vector3 (rotationX ,1.5f,-4.8f );
}
else
{
    transform.position = new Vector3 (rotationX,4.8f,-1.8f);
}