平滑的2D摄像机

using UnityEngine;
using System.Collections;

public class SmoothCamera:MonoBehaviour{
    private GameObject player;
    public Vector3 XiangCha;
    private CameraSmoothUpdate posFollow;
    void Start()
    {
        posFollow = new CameraSmoothUpdate(0.65f, 0.65f);
    }
    void LateUpdate()
    {
        if (player == null) { FindPlayer(); return; }
        transform.position = posFollow.Update(player.transform.position+XiangCha, Time.deltaTime);
    }
    void FindPlayer()
    {
        player = GameObject.Find("Player");
    }
}
public class CameraSmoothUpdate {
    private Vector3 targetPosition;
    private Vector3 position;
    private Vector3 velocity;
    private float smoothingTime;
    /// 

    /// 预测时间
    /// 
    private float prediction;
    public CameraSmoothUpdate(float smoothingTime):this(smoothingTime,1f) {}
    public CameraSmoothUpdate(float smoothingTime, float prediction)
    {
        targetPosition = Vector3.zero;
        position = Vector3.zero;
        velocity = Vector3.zero;
        this.smoothingTime = smoothingTime;
        this.prediction = prediction;
    }
    public Vector3 Update(Vector3 targetPositionNew,float deltaTime)
    {
        Vector3 targetVelocity = (targetPositionNew - targetPosition) / deltaTime;//每个deltaTime移动的距离
        targetPosition = targetPositionNew;
        float d = Mathf.Min(1, deltaTime / smoothingTime);//获取??
        velocity = velocity * (1 - d) + (targetPositionNew + targetVelocity * prediction - position) * d;
        position += velocity * Time.deltaTime;
        return position;
    }
    public Vector3 Update(Vector3 targetPositionNew,float deltaTime,bool reset)
    {
        if(reset)
        {
            targetPosition = targetPositionNew;
            position = targetPositionNew;
            velocity = Vector3.zero;
            return position;
        }
        return Update(targetPositionNew, deltaTime);
    }
    public Vector3 GetPosition() { return position; }
    public Vector3 GetVelocity() { return velocity; }
}