Unity 摄像机平滑跟随

using UnityEngine;
public class CameraLag : MonoBehaviour
{
public Transform    attach;
public Transform target;
public float time = 1.0f;

public Vector3 pos;
Vector3 spd = Vector3.zero;

void Start()
{
if ( attach )
pos = attach.position;
}

void LateUpdate()
{
if ( attach )
{
Vector3 cpos = attach.position;

pos = Vector3.SmoothDamp(pos, cpos, ref spd, time);
transform.position = pos;

if ( target )
{
transform.rotation = Quaternion.LookRotation(target.position - pos);
}
}
}
}