最简单的一种就是先设置好摄像机跟物体的相对距离，
在脚本里就可以由物体的位置，跟相对距离，就可以求出摄像机的位置，
用插值的方法可以让摄像机平滑跟随。
1 public class CamFollow1 : MonoBehaviour
2 {
3
4 private Vector3 offset;
5 public Transform player;
6
7 void Start()
8 {
9 offset = player.position - transform.position;
10 }
11
12 void Update()
13 {
14 transform.position = Vector3.Lerp(transform.position, player.position - offset,Time.deltaTime*5);
15 }
16 }
实现一种注视的效果，可以对rotation做下处理
void Update()
{
transform.position = Vector3.Lerp(transform.position, player.position - offset,Time.deltaTime*5);
Quaternion rotation = Quaternion.LookRotation(player.position - transform.position);
transform.rotation = Quaternion.Slerp(transform.rotation, rotation,Time.deltaTime*3f);
}
这样子，人物在走动的时候，摄像机就是一边注视着人物，一边跟着移动。
但是，当有墙体，或其他高大的物体遮挡住人物，
摄像机就无法看到人物，玩家自然也看不到，
在上面的基础上做更近一步的扩展
在人物头顶往下看，肯定可以看得到人物，
所以我们要做的就是把摄像机的位置向人物头顶去调整，直到可以看到人物。
1 using UnityEngine;
2 using System.Collections;
3
4 public class CamFollow3 : MonoBehaviour
5 {
6
7
8 private Transform player;//英雄位置
9 private Vector3 offset; //摄像机和英雄相对位置
10 private float distance;//距离
11 private Vector3[] points = new Vector3[5];//5个点作为摄像机位置的选择
12
13 private Vector3 targetPos;//筛选后的摄像机位置
14
15 void Awake()
16 {
17 player = GameObject.FindWithTag("Player").transform;
18 offset = transform.position - player.position;
19 distance = offset.magnitude;
20 }
21
22 void FixedUpdate()
23 {
24 //更新5个点的位置
25 points[0] = player.position + offset;
26 points[4] = player.position + Vector3.up*distance;
27
28 points[1] = Vector3.Lerp(points[0], points[4], 0.25f);
29 points[2] = Vector3.Lerp(points[0], points[4], 0.5f);
30 points[3] = Vector3.Lerp(points[0], points[4], 0.75f);
31 points[4] = Vector3.Lerp(points[0], points[4], 0.9f);
32
33 targetPos = FindCameraTarget();
34
35 AdjustCamera();
36 }
37
38 private Vector3 FindCameraTarget()
39 {
40 Vector3 result = points[points.Length - 1];//头顶位置
41
42 //从低到高遍历
43 for (int i = 0; i < points.Length; ++i)
44 {
45 if (IsHitPlayer(points[i], player.position))
46 {
47 result = points[i];
48 break;
49 }
50 }
51
52 return result;
53 }
54
55 private Ray ray;
56 private RaycastHit hit;
57 /// <summary>
58 /// 从origin发射一条射线检测是否碰到player，
59 /// 碰到则表示摄像机在此位置可以看到player
60 /// </summary>
61 /// <param name="origin"></param>
62 /// <param name="target"></param>
63 /// <returns></returns>
64 bool IsHitPlayer(Vector3 origin, Vector3 target)
65 {
66 bool result = false;
67
68 Vector3 dir = target - origin;
69 ray = new Ray(origin,dir);
70 if (Physics.Raycast(ray, out hit))
71 {
72 if (hit.transform.tag == "Player")
73 {
74 result = true;
75 }
76 }
77 return result;
78 }
79
80 /// <summary>
81 /// 调整摄像机位置
82 /// </summary>
83 void AdjustCamera()
84 {
85
86 transform.position = Vector3.Slerp(transform.position, targetPos, Time.deltaTime * 6);
87
88 Quaternion rotation = Quaternion.LookRotation(player.position - transform.position);
89 transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * 33f);
90
91 }
92 }