关于Unity C# Mathf.Abs()取绝对值性能测试详解

using UnityEngine;
using UnityEditor;
using System.Diagnostics;

/// <summary>
/// 执行时间测试
/// ZhangYu 2019-04-04
/// </summary>
public class TimeTest : MonoBehaviour {

 public int executeTimes = 1;
 private static Stopwatch watch;

 private void OnValidate() {
 times = executeTimes;
 }

 private static int times = 1;
 [MenuItem("CONTEXT/TimeTest/执行")]
 private static void Execute() {
 watch = new Stopwatch();

 // 数据
 float a = 1;

 // Mathf.Abs
 watch.Reset();
 watch.Start();
 for (int i = 0; i < times; i++) {
 a = Mathf.Abs(a);
 }
 watch.Stop();
 string msgMathfAbs = string.Format("Mathf.Abs: {0}s", watch.Elapsed);

 // 自己实现Abs
 watch.Reset();
 watch.Start();
 for (int i = 0; i < times; i++) {
 a = MyAbs(a);
 }
 watch.Stop();
 string msgMyAbs = string.Format("自定义Abs: {0}s", watch.Elapsed);

 // 三目运算符Abs
 watch.Reset();
 watch.Start();
 for (int i = 0; i < times; i++) {
 a = a < 0 ? -a : a;
 }
 watch.Stop();
 string msg3Abs = string.Format("三目运算符Abs: {0}s", watch.Elapsed);

 print(msgMathfAbs);
 print(msgMyAbs);
 print(msg3Abs);
 }

 // == 执行次数：10000000

 // Mathf.Abs
 // (1)0.2803558s
 // (2)0.2837749s
 // (3)0.2831089s
 // (4)0.2829929s
 // (5)0.2839846s

 // 自定义Abs
 // (1)0.2162217s
 // (2)0.2103635s
 // (3)0.2103390s
 // (4)0.2092863s
 // (5)0.2097648s
 private static float MyAbs(float a) {
 return a < 0 ? -a : a;
 }

 // 三目运算符Abs
 // (1)0.0893028s
 // (2)0.1000181s
 // (3)0.1017959s
 // (4)0.1001749s
 // (5)0.1005737s

}

// Returns the absolute value of /f/.
public static float Abs(float f) { return (float)Math.Abs(f); }

// Returns the absolute value of /value/.
public static int Abs(int value) { return Math.Abs(value); }