unity 相机平滑跟随游戏角色

using UnityEngine;
using System.Collections;

public class SmoothFollowerObj {
    
    private Vector3 targetPosition;
    private Vector3 position;
    private Vector3 velocity;
    private float smoothingTime;
    private float prediction;
    
    public SmoothFollowerObj(float smoothingTime) {
        targetPosition = Vector3.zero;
        position = Vector3.zero;
        velocity = Vector3.zero;
        this.smoothingTime = smoothingTime;
        prediction = 1;
    }
    
    public SmoothFollowerObj(float smoothingTime, float prediction) {
        targetPosition = Vector3.zero;
        position = Vector3.zero;
        velocity = Vector3.zero;
        this.smoothingTime = smoothingTime;
        this.prediction = prediction;
    }
    
    // Update should be called once per frame
    public Vector3 Update(Vector3 targetPositionNew, float deltaTime) {
        Vector3 targetVelocity = (targetPositionNew-targetPosition)/deltaTime;
        targetPosition = targetPositionNew;
        
        float d = Mathf.Min(1,deltaTime/smoothingTime);
        velocity = velocity*(1-d) + (targetPosition+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; }
}
public class NoGravityCamera : MonoBehaviour {　　　　// 这里的NoGravityCamera修改成你的脚本名

    public GameObject character;
    public Vector3 positionVector;
    public Vector3 lookVector;
    private SmoothFollowerObj posFollow;
    private SmoothFollowerObj lookFollow;
    private Vector3 lastVelocityDir;
    private Vector3 lastPos;
    
    // Use this for initialization
    void Start () {
        positionVector=new Vector3(0,2,4);
        lookVector=new Vector3(0,0,1.5f);
        posFollow = new SmoothFollowerObj(0.5f,0.5f);
        lookFollow = new SmoothFollowerObj(0.1f,0.0f);
        posFollow.Update(transform.position,0,true);
        lookFollow.Update(character.transform.position,0,true);
        lastVelocityDir = character.transform.forward;
        lastPos = character.transform.position;
    }
    
    // Update is called once per frame
    void LateUpdate () {
        lastVelocityDir += (character.transform.position-lastPos)*8;
        lastPos = character.transform.position;
        lastVelocityDir += character.transform.forward*Time.deltaTime;
        lastVelocityDir = lastVelocityDir.normalized;
        Vector3 horizontal = transform.position-character.transform.position;
        Vector3 horizontal2 = horizontal;
        Vector3 vertical = character.transform.up;
        Vector3.OrthoNormalize(ref vertical,ref horizontal2);
        if (horizontal.sqrMagnitude > horizontal2.sqrMagnitude) horizontal = horizontal2;
        transform.position = posFollow.Update(
            character.transform.position + horizontal*Mathf.Abs(positionVector.z) + vertical*positionVector.y,
            Time.deltaTime
        );
        
        horizontal = lastVelocityDir;
        Vector3 look = lookFollow.Update(character.transform.position + horizontal*lookVector.z - vertical*lookVector.y, Time.deltaTime);
        transform.rotation = Quaternion.FromToRotation(transform.forward, look-transform.position) * transform.rotation;
    }
}