一次【自定义编辑器功能脚本】【调用时内存爆仓】事故排查

一 、事故描述

我有一个需求：在工程文件中找得到所有的图片（Texture 2D），然后把WebGL发布打包时的图片压缩规则进行修改。
项目中有图片2千多张，其中2k分辨率的图片上百张，当我右键进行批量处理的时候，内存蹭蹭蹭往上冒，直接吃满，然后显示Unity挂掉，接着其他程序也会挂，最后电脑卡住…

二、原因分析

当我全选整个项目中的图片，然后右键菜单执行该脚本后，它加载图片的代码如下：

 Object[] textures = Selection.GetFiltered(typeof(Texture2D), SelectionMode.DeepAssets);

这个数组会爆仓内存。

其次：每张图单独处理的时候，我new了两个东西，如下

new的第一个组件

// 创建特定平台压缩实例
TextureImporterPlatformSettings platformSettings = new TextureImporterPlatformSettings();
//设置属性

new的第二个组件

//设置importSettings
TextureImporter importer = AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(texture)) as TextureImporter;
//设置属性

这两个组件是在一个for循环里面，用完之后，没有设置为null。

三、换种思路

• 1、只抓取资源id

string[] guids = AssetDatabase.FindAssets("t:texture2d");

• 2、用id取获取图片对象

Texture2D texture = AssetDatabase.LoadAssetAtPath<Texture2D>(path);

• 3、new 出来的组件记得清空

Texture2D texture = AssetDatabase.LoadAssetAtPath<Texture2D>(path) ;
TextureImporterPlatformSettings platformSettings = new TextureImporterPlatformSettings();
TextureImporter importer = AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(texture)) as TextureImporter;

//属性赋值
//.....

//-----------------清空对象-----------------至于什么时候触发GC，那就不知道了
platformSettings = null;
importer = null;
texture = null;

• 3、图片上的组件用完及时清空

  static void FindAllTexture2D()
    {

        //****************************************参数设置区**********begin
        //TODO 做成EditWindow类型

        TextureImporterFormat format = TextureImporterFormat.ASTC_12x12; //图片压缩格式
        int compressionQuality = 60; //压缩比例
        string platform = "WebGL"; //发布的平台 

        //************************************************************end

        //查找工程文件中的所有精灵图片
        string[] guids = AssetDatabase.FindAssets("t:texture2d");
        Debug.Log($"Found {guids.Length} Texture2d assets.");
        foreach (string guid in guids)
        {
            try
            {
                string path = AssetDatabase.GUIDToAssetPath(guid);

                Debug.Log($"{path}");
                // 使用AssetDatabase加载Texture2D
                Texture2D texture = AssetDatabase.LoadAssetAtPath<Texture2D>(path);
                //Debug.Log($"{texture.name}");

                if (texture == null) continue;

                // 创建特定平台压缩实例
                TextureImporterPlatformSettings platformSettings = new TextureImporterPlatformSettings();
                platformSettings.overridden = true;
                platformSettings.name = platform;

                // 设置为压缩
                platformSettings.textureCompression = TextureImporterCompression.Compressed;

                // 设置压缩格式
                platformSettings.format = format; //TextureImporterFormat.ASTC_12x12;
                platformSettings.compressionQuality = compressionQuality; //40
                platformSettings.maxTextureSize = GetMaxSize(texture as Texture2D); //32

                //设置importSettings
                TextureImporter importer =
                    AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(texture)) as TextureImporter;
                if (importer == null) continue;

                importer.SetPlatformTextureSettings(platformSettings);

                //Apply 设置
                importer.SetPlatformTextureSettings(platformSettings);

                //保存资源
                importer.SaveAndReimport();

                //资源清空
                platformSettings = null;
                importer = null;
                texture = null;
            }
            catch (Exception ex)
            {
                Debug.Log( $" ~~~~~error~~~~~ 设置报错：{ex.Message}");
            }
        }
    }

四、附录：出错的脚本

using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEditor;

public class SetTextureCompression
{
    //****************************************参数设置区**********begin
    //TODO 做成EditWindow类型

    private static TextureImporterFormat format = TextureImporterFormat.ASTC_12x12;  //图片压缩格式
    private static int compressionQuality = 60;                                      //压缩比例
    private static string platform = "WebGL";                                        //发布的平台 

    //************************************************************end

    /// 

    /// 设置贴图在build时的压缩选项
    /// 
    [MenuItem("Assets/设置发布WebGL时贴图的压缩格式")]
    static void SetCompression()
    {
        int count = 0;

        Object[] textures = Selection.GetFiltered(typeof(Texture2D), SelectionMode.DeepAssets);
        if (textures.Length > 0)
        {
            foreach (Object texture in textures)
            {
                // 创建特定平台压缩实例
                TextureImporterPlatformSettings platformSettings = new TextureImporterPlatformSettings();
                platformSettings.overridden = true;
                platformSettings.name = platform;

                // 设置为压缩
                platformSettings.textureCompression = TextureImporterCompression.Compressed;

                // 设置压缩格式
                platformSettings.format = format;                                    
                platformSettings.compressionQuality = compressionQuality;             
                platformSettings.maxTextureSize = GetMaxSize(texture as Texture2D);   

                //设置importSettings
                TextureImporter importer = AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(texture)) as TextureImporter;
                importer.SetPlatformTextureSettings(platformSettings);

                //Apply 设置
                importer.SetPlatformTextureSettings(platformSettings);

                //保存资源
                importer.SaveAndReimport();

                count++;
            }
            //Debug.Log("Texture Compression Set!");
        }
        else
        {
            Debug.LogWarning("没有选中图片!");
        }
        Debug.Log($"一共处理了{count}张图片！");
    }

    /// 

    /// 获取图片的分辨率，取分辨率中高宽的最大值，然后返回图片的【MaxSize】
    /// MaxSize的定义：assets->Image->【Texture2D ImportSettings】->【Override For WebGL】->【Max Size】 
    /// 区间：16,32,64,128,256,512,1024,2048,4096,8192,16384
    ///
    /// 举例：图片分辨率 = 12 * 24，那么图片的MaxSize = 32
    /// 
    /// 
    /// 
    static int GetMaxSize(Texture2D texture)
    {
        //分辨率区间的预备
        var start = new List<int> { 0, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384 };
        var end = new List<int> { 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 100000 };
        var zones = start.Zip(end, (item1, item2) => (startIdx: item1, endIdx: item2)).ToList();

        //取分辨率高宽的最大值
        var size = new List<int> { texture.width, texture.height }.Max();  //取【宽】【高】中的最大值

        //判断所属的区间
        var maxSize = zones
            .First(x => x.startIdx <= size && size <= x.endIdx)
            .endIdx;
        //Debug.Log($"图的分辨率 = {texture.width} * {texture.height} size = {size}, MaxSize = {maxSize}");
        return maxSize;
    }
}