Untiy 遍历Texture2D效率优化

因为项目中需要对2D图片进行加工，需要遍历图片中像素点的颜色首先想到的方式：

GetPixel()

Color[] colors = new Color[texture2D.width * texture2D.height];
for (int x = 0; x < texture2D.width; x++)
{
          
   
    for (int y = 0; y < texture2D.height; y++)
    {
          
   
        colors[x * y + y] = texture2D.GetPixel(x, y);
    }
}

发现执行效率比较低，一张图片的分辨率为1080*864运行时间大概是200ms,后面发现了GetPixels()这个函数，测试了一下效率是之前的约20倍：

GetPixels()

Color[] colors = new Color[texture2D.width * texture2D.height];
Color[] txtColors = texture2D.GetPixels();
for (int i= 0; i< colors.Length; i++)
{
          
   
    colors[i] = txtColors[i];
}

下面分别把两个函数分别运行10次然后对比一下时间:

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

public class Demo : MonoBehaviour
{
          
   
    public Texture2D texture2D;
    // Start is called before the first frame update
    void Start()
    {
          
   
        tick(() =>
        {
          
   
            for (int i = 0; i < 10; i++)
            {
          
   
                Color[] colors = new Color[texture2D.width * texture2D.height];
                for (int x = 0; x < texture2D.width; x++)
                {
          
   
                    for (int y = 0; y < texture2D.height; y++)
                    {
          
   
                        colors[x * y + y] = texture2D.GetPixel(x, y);
                    }

                }
            }
        }, "GetPixel");
        tick(() =>
        {
          
   
            for (int i = 0; i < 10; i++)
            {
          
   
                Color[] colors = new Color[texture2D.width * texture2D.height];
                Color[] txtColors = texture2D.GetPixels();
                for (int j = 0; j < colors.Length; j++)
                {
          
   
                    colors[j] = txtColors[j];
                }
            }
        }, "GetPixels");
    }


    void tick(Action action,string Title= "Time") 
    {
          
   
        int start = System.Environment.TickCount;
        action();

        int end = System.Environment.TickCount;

        Debug.Log(Title + ":" + (end - start) + "ms");//单位毫秒
    }
    // Update is called once per frame
    void Update()
    {
          
   
        
    }
}

可以看到结果：