计算LookAt值
viewMatrix = Matrix4x4.LookAt (camera.transform.position, camera.transform.position + camera.transform.forward, camera.transform.up);
viewMatrix = Matrix4x4.LookAt (camera.transform.position, camera.transform.position + camera.transform.forward, camera.transform.up);
Mathf.SmoothDamp 阻尼函数
阻尼运动是指一个物体在受到外部力或作用下,沿着一条路径逐渐减速接近目标值的运动方式