[游戏开发]Unity 2D切割Texture2D，图集转成单独PNG报错问题，Copy其他博主的代码实现

Unity版本：2020.3.12f1c1

图集切割并且输出单独PNG

目标

1. 把头像集合切割成单独的头像图集
2. 把切割好的图集输出成单独的PNG文件

大图集切割成小图方法

切割成功后，我这里单独修改了图集里面的PNG名字

输出单独的 PNG 图片

参考 Unity切割图集工具

1. Texture2D 设置
   
2. 新建脚本：

	using UnityEngine;
	using System.Collections;
	using UnityEditor;
	using System.IO;
	using System.Collections.Generic;
	/// <summary>
	/// 切割
	/// </summary>
	public static class ImageSlicer
	{
	    [MenuItem("Assets/ImageSlicer/Process to Sprites")]
	    static void ProcessToSprite()
	    {
	        Texture2D image = Selection.activeObject as Texture2D;//获取旋转的对象
	        string rootPath = Path.GetDirectoryName(AssetDatabase.GetAssetPath(image));//获取路径名称
	        string path = rootPath + "/" + image.name + ".PNG";//图片路径名称
	
	
	        TextureImporter texImp = AssetImporter.GetAtPath(path) as TextureImporter;//获取图片入口
	
	
	        AssetDatabase.CreateFolder(rootPath, image.name);//创建文件夹
	
	
	        foreach (SpriteMetaData metaData in texImp.spritesheet)//遍历小图集
	        {
	            Texture2D myimage = new Texture2D((int)metaData.rect.width, (int)metaData.rect.height);
	
	            //abc_0:(x:2.00, y:400.00, width:103.00, height:112.00)
	            for (int y = (int)metaData.rect.y; y < metaData.rect.y + metaData.rect.height; y++)//Y轴像素
	            {
	                for (int x = (int)metaData.rect.x; x < metaData.rect.x + metaData.rect.width; x++)
	                    myimage.SetPixel(x - (int)metaData.rect.x, y - (int)metaData.rect.y, image.GetPixel(x, y));
	            }
	
	
	            //转换纹理到EncodeToPNG兼容格式
	            if (myimage.format != TextureFormat.ARGB32 && myimage.format != TextureFormat.RGB24)
	            {
	                Texture2D newTexture = new Texture2D(myimage.width, myimage.height);
	                newTexture.SetPixels(myimage.GetPixels(0), 0);
	                myimage = newTexture;
	            }
	            var pngData = myimage.EncodeToPNG();
	
	
	            //AssetDatabase.CreateAsset(myimage, rootPath + "/" + image.name + "/" + metaData.name + ".PNG");
	            File.WriteAllBytes(rootPath + "/" + image.name + "/" + metaData.name + ".PNG", pngData);
	            // 刷新资源窗口界面
	            AssetDatabase.Refresh();
	        }
	    }
	}

该代码在Unity 2020.3版本运行后报错：
unityexception: texture 'avatarcollection' is not readable, the texture memory can not be accessed from scripts. you can make the texture readable in the texture import settings.

解决方法：按照此 dalao 所写 Texture2D转字节数组出错问题

在函数 EncodeToPNG() 把 Texture2D 传进这个函数，然后再调用 EncodeToPNG() 即可

public static Texture2D DeCompress(Texture2D source)
 {
      RenderTexture renderTex = RenderTexture.GetTemporary(
                  source.width,
                  source.height,
                  0,
                  RenderTextureFormat.Default,
                  RenderTextureReadWrite.Linear);

      Graphics.Blit(source, renderTex);
      RenderTexture previous = RenderTexture.active;
      RenderTexture.active = renderTex;
      Texture2D readableText = new Texture2D(source.width, source.height);
      readableText.ReadPixels(new Rect(0, 0, renderTex.width, renderTex.height), 0, 0);
      readableText.Apply();
      RenderTexture.active = previous;
      RenderTexture.ReleaseTemporary(renderTex);
      return readableText;
  }

最终跑通运行的代码：

using UnityEngine;
using System.Collections;
using UnityEditor;
using System.IO;
using System.Collections.Generic;
/// <summary>
/// 切割
/// </summary>
public static class ImageSlicer
{
    [MenuItem("Assets/ImageSlicer/Process to Sprites")]
    static void ProcessToSprite()
    {
        Texture2D image = Selection.activeObject as Texture2D;//获取旋转的对象
        string rootPath = Path.GetDirectoryName(AssetDatabase.GetAssetPath(image));//获取路径名称
        string path = rootPath + "/" + image.name + ".PNG";//图片路径名称


        TextureImporter texImp = AssetImporter.GetAtPath(path) as TextureImporter;//获取图片入口


        AssetDatabase.CreateFolder(rootPath, image.name);//创建文件夹


        foreach (SpriteMetaData metaData in texImp.spritesheet)//遍历小图集
        {
            Texture2D myimage = new Texture2D((int)metaData.rect.width, (int)metaData.rect.height);

            //abc_0:(x:2.00, y:400.00, width:103.00, height:112.00)
            for (int y = (int)metaData.rect.y; y < metaData.rect.y + metaData.rect.height; y++)//Y轴像素
            {
                for (int x = (int)metaData.rect.x; x < metaData.rect.x + metaData.rect.width; x++)
                    myimage.SetPixel(x - (int)metaData.rect.x, y - (int)metaData.rect.y, image.GetPixel(x, y));
            }


            //转换纹理到EncodeToPNG兼容格式
            if (myimage.format != TextureFormat.ARGB32 && myimage.format != TextureFormat.RGB24)
            {
                Texture2D newTexture = new Texture2D(myimage.width, myimage.height);
                newTexture.SetPixels(myimage.GetPixels(0), 0);
                myimage = newTexture;
            }
            DeCompress(myimage);
            var pngData = myimage.EncodeToPNG();


            //AssetDatabase.CreateAsset(myimage, rootPath + "/" + image.name + "/" + metaData.name + ".PNG");
            File.WriteAllBytes(rootPath + "/" + image.name + "/" + metaData.name + ".PNG", pngData);
            // 刷新资源窗口界面
            AssetDatabase.Refresh();
        }
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="source"></param>
    /// <returns></returns>
    public static Texture2D DeCompress(Texture2D source)
    {
        RenderTexture renderTex = RenderTexture.GetTemporary(
                    source.width,
                    source.height,
                    0,
                    RenderTextureFormat.Default,
                    RenderTextureReadWrite.Linear);

        Graphics.Blit(source, renderTex);
        RenderTexture previous = RenderTexture.active;
        RenderTexture.active = renderTex;
        Texture2D readableText = new Texture2D(source.width, source.height);
        readableText.ReadPixels(new Rect(0, 0, renderTex.width, renderTex.height), 0, 0);
        readableText.Apply();
        RenderTexture.active = previous;
        RenderTexture.ReleaseTemporary(renderTex);
        return readableText;
    }
}

使用方法

输出整个图集的单独PNG文件