Unity 测试Transform cache和不cache的区别

关于Transform的cache问题：

大致看了下：

https://forum.unity.com/threads/cache-transform-really-needed.356875/

Transform cache的却会好一点点

有种Lazy的方式可以在使用的时候lazy cache 去get ：

Lazy<Transform> _cameraTransform = new Lazy<Transform>(() => Camera.main.transform);

不过。。。。

在开发期也许不需要太关注这件事情，而且cache后由于赋值顺序问题也许还要处理一些logic的bug。最后依Profiler为准，并先处理大头的overhead。大概率在Profiler的前期是轮不到Transform 。。。

测试的结果：

result:

Not much difference 10000 times:
No caching:
TotalMilliseconds:1.6433
Caching:
TotalMilliseconds:0.5658

little different:
100000 times:
TotalMilliseconds:14.2513
TotalMilliseconds:5.1719

 1 using System.Collections;
 2 using System.Collections.Generic;
 3 using System.Diagnostics;
 4 using UnityEngine;
 5 
 6 public class TestTransformWithCache : MonoBehaviour
 7 {
 8     private Transform myCameraCacheTransform;
 9     [SerializeField] private uint calls;
10  
11     private void Start() {
12         myCameraCacheTransform = Camera.main.transform;
13         print("No caching:");
14         Stopwatch watch = new Stopwatch();
15         watch.Start();
16         for (uint i = 0; i < calls; i++) TestNoCache();
17         watch.Stop();
18         print("TotalMilliseconds:"+ watch.Elapsed.TotalMilliseconds);
19         
20         print("Caching:");
21         Stopwatch watch2 = new Stopwatch();
22         watch2.Start();
23         for (uint i = 0; i < calls; i++) TestCache();
24         watch2.Stop();
25         print("TotalMilliseconds:"+ watch2.Elapsed.TotalMilliseconds);
26     }
27  
28     private void TestNoCache() {
29         Vector3 v = Vector3.zero;
30         v = Camera.main.transform.position;
31     }
32  
33     private void TestCache() {
34         Vector3 v = Vector3.zero;
35         v = myCameraCacheTransform.position;
36     }
37 }