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

using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using UnityEngine;

public class TestTransformWithCache : MonoBehaviour
{
    private Transform myCameraCacheTransform;
    [SerializeField] private uint calls;
 
    private void Start() {
        myCameraCacheTransform = Camera.main.transform;
        print("No caching:");
        Stopwatch watch = new Stopwatch();
        watch.Start();
        for (uint i = 0; i < calls; i++) TestNoCache();
        watch.Stop();
        print("TotalMilliseconds:"+ watch.Elapsed.TotalMilliseconds);
        
        print("Caching:");
        Stopwatch watch2 = new Stopwatch();
        watch2.Start();
        for (uint i = 0; i < calls; i++) TestCache();
        watch2.Stop();
        print("TotalMilliseconds:"+ watch2.Elapsed.TotalMilliseconds);
    }
 
    private void TestNoCache() {
        Vector3 v = Vector3.zero;
        v = Camera.main.transform.position;
    }
 
    private void TestCache() {
        Vector3 v = Vector3.zero;
        v = myCameraCacheTransform.position;
    }
}