
private static void BuildAssetBundles(string tempDir, string outputDir, BuildTarget target)
 {
     Debug.Log("AB outputDir："+ outputDir);
     Directory.CreateDirectory(tempDir);
     Directory.CreateDirectory(outputDir);
     
     List<AssetBundleBuild> abs = new List<AssetBundleBuild>();
     {
         var prefabAssets = new List<string>();
         string testPrefab = $"{Application.dataPath}/Prefabs/Cube.prefab";
         prefabAssets.Add(testPrefab);
         AssetDatabase.Refresh(ImportAssetOptions.ForceUpdate);
         abs.Add(new AssetBundleBuild
         {
             assetBundleName = "prefabs",
             assetNames = prefabAssets.Select(s => ToRelativeAssetPath(s)).ToArray(),
         });
     }
 
     BuildPipeline.BuildAssetBundles(outputDir, abs.ToArray(), BuildAssetBundleOptions.None, target);
     AssetDatabase.Refresh(ImportAssetOptions.ForceUpdate);
 }

二、YooAsset

AssetBundle 的管理和使用相对复杂，需要处理依赖关系、版本控制、加载策略等问题。因此，很多开发者会选择使用如 YooAsset 这样的资源管理框架来简化 AssetBundle 的使用，自动处理这些复杂的任务。

1. 准备工作

（1）官方文档

Introduce | YooAsset

（2）通过Packages清单安装YooAsset

直接修改Packages文件夹下的清单文件manifest.json：


{
  "dependencies": {
    "com.tuyoogame.yooasset": "2.1.0",
    ......
  },
  "scopedRegistries": [
    {
      "name": "package.openupm.cn",
      "url": "https://package.openupm.cn",
      "scopes": [
        "com.tuyoogame.yooasset"
      ]
    }
  ]
}

unity2020.3.8出现以下报错，报错代码注释掉即可，貌似DownloadHandlerAssetBundle下还没有 autoLoadAssetBundle这个变量，而且支持的版本这个值默认false。

2.全局配置

Project窗体内右键 -> Create -> YooAsset -> Create YooAsset Setting可创建YooAssetSettings全局配置文件，该文件需放在Resources文件夹下：

Manifest File Name : 清单文件名称
DefaultYooFolderName：Yoo文件夹名称

3.资源配置

Project窗体内右键 -> Create -> YooAsset -> Create AssetBundle Collector Setting可创建该文件，需要注意的是一个工程只能有一个AssetBundleCollectorSetting。

重点关注Enable Addressable及Pack Rule打包规则：

（1）Enable Addressable

启用可寻址资源定位系统。启用后加载资源时可以不写全路径，只根据资源名称即可加载：

 YooAssets.LoadSceneAsync("scene_home");

（2）Pack Rule打包规则

规则可以自定义扩展。下面是内置规则：

PackSeparately 以文件路径作为资源包名，每个资源文件单独打包（比如场景文件）。
PackDirectory 以文件所在的文件夹路径作为资源包名，该文件夹下所有文件打进一个资源包。
PackTopDirectory 以收集器下顶级文件夹为资源包名，该文件夹下所有文件打进一个资源包。
PackCollector 以收集器路径作为资源包名，收集的所有文件打进一个资源包。
PackGroup 以分组名称作为资源包名，收集的所有文件打进一个资源包。
PackRawFile 目录下的资源文件会被处理为原生资源包（比如dll.byte）。

4.资源构建

（1）Build Mode

ForceRebuild：强制构建模式，会删除指定构建平台下的所有构建记录，重新构建所有资源包。
IncrementalBuild：增量构建模式，以上一次构建结果为基础，对于发生变化的资源进行增量构建。

（2）Encryption

加密类列表。Build时选的加密类型要和加载资源时的解密类型一致，否则加载资源时会报错。比如Build时选择的加密方式为FileOffsetEncryption，则文件解密服务接口也需要为FileOffset类型：


    {
        ...
        var initParameters = new HostPlayModeParameters();//HostPlayModeParameters继承自    InitializeParameters
        initParameters.BuildinQueryServices = new GameQueryServices();//内置资源查询服务接口
        initParameters.DecryptionServices = new FileOffsetDecryption();//如果资源包在构建的时候有加密，需要提供实现IDecryptionServices接口的实例类。
        ...
    }
    /// <summary>
    /// 资源文件偏移加载解密类
    /// </summary>
    private class FileOffsetDecryption : IDecryptionServices
    {
        /// <summary>
        /// 同步方式获取解密的资源包对象
        /// 注意：加载流对象在资源包对象释放的时候会自动释放
        /// </summary>
        AssetBundle IDecryptionServices.LoadAssetBundle(DecryptFileInfo fileInfo, out Stream managedStream)
        {
            managedStream = null;
            return AssetBundle.LoadFromFile(fileInfo.FileLoadPath, fileInfo.ConentCRC, GetFileOffset());
        }
 
        /// <summary>
        /// 异步方式获取解密的资源包对象
        /// 注意：加载流对象在资源包对象释放的时候会自动释放
        /// </summary>
        AssetBundleCreateRequest IDecryptionServices.LoadAssetBundleAsync(DecryptFileInfo fileInfo, out Stream managedStream)
        {
            managedStream = null;
            return AssetBundle.LoadFromFileAsync(fileInfo.FileLoadPath, fileInfo.ConentCRC, GetFileOffset());
        }
 
        private static ulong GetFileOffset()
        {
            return 32;
        }
 
    }

5.YooAsset运行时

以官方提供的Space Shooter这个Demo为例，重新编写YooAsset相关的流程。先确保Demo能正常运行：

Space Shooter在导入完成后，打开YooAsset->AssetBundle Collector窗口。
点击修复按钮，然后点击Save按钮保存配置，最后关闭窗口。
找到Boot.scene场景启动游戏。

打开Boot.cs文件，注释掉 IEnumerator Start方法，在TestLoad方法中一步一步进行YooAsset资源的加载：


    private void Start()
    {
        StartCoroutine(TestLoad());
    }
    IEnumerator TestLoad()
    {
        ...
    }

（1）初始化


    IEnumerator TestLoad()
    {
        // 初始化资源系统
        YooAssets.Initialize();
 
        // 创建默认的资源包
        var package = YooAssets.CreatePackage("DefaultPackage");
 
        // 设置该资源包为默认的资源包，可以使用YooAssets相关加载接口加载该资源包内容。
        YooAssets.SetDefaultPackage(package);
        ...    
    }

（2）资源系统的运行模式


...
if (PlayMode == EPlayMode.EditorSimulateMode)
{
    var initParameters = new EditorSimulateModeParameters();//EditorSimulateModeParameters继承自InitializeParameters
    string simulateManifestFilePath = EditorSimulateModeHelper.SimulateBuild(EDefaultBuildPipeline.BuiltinBuildPipeline.ToString(), "DefaultPackage");
    initParameters.SimulateManifestFilePath = simulateManifestFilePath;
    yield return package.InitializeAsync(initParameters);
}
else if (PlayMode == EPlayMode.OfflinePlayMode)
{
    var initParameters = new OfflinePlayModeParameters();//OfflinePlayModeParameters继承自InitializeParameters
    initParameters.DecryptionServices = new FileOffsetDecryption();//需要补充这个
    yield return package.InitializeAsync(initParameters);
}
else if (PlayMode == EPlayMode.HostPlayMode)
{
    // 注意：GameQueryServices.cs 太空战机的脚本类，详细见StreamingAssetsHelper.cs
    string defaultHostServer = "https://static0.xesimg.com/project-yooasset/0130Offset";
    string fallbackHostServer = "https://static0.xesimg.com/project-yooasset/0130Offset";
    var initParameters = new HostPlayModeParameters();//HostPlayModeParameters继承自InitializeParameters
    initParameters.BuildinQueryServices = new GameQueryServices();//内置资源查询服务接口
    initParameters.DecryptionServices = new FileOffsetDecryption();//如果资源包在构建的时候有加密，需要提供实现IDecryptionServices接口的实例类。
    initParameters.RemoteServices = new RemoteServices(defaultHostServer, fallbackHostServer);//远端服务器查询服务接口
    var initOperation = package.InitializeAsync(initParameters);
    yield return initOperation;
 
    if (initOperation.Status == EOperationStatus.Succeed)
    {
        Debug.Log("资源包初始化成功！");
    }
    else
    {
        Debug.LogError($"资源包初始化失败：{initOperation.Error}");
    }
}
else if (PlayMode == EPlayMode.WebPlayMode)
{
    string defaultHostServer = "http://127.0.0.1/CDN/WebGL/V1.0";
    string fallbackHostServer = "http://127.0.0.1/CDN/WebGL/V1.0";
    var initParameters = new WebPlayModeParameters();//WebPlayModeParameters继承自InitializeParameters
    initParameters.BuildinQueryServices = new GameQueryServices();
    initParameters.RemoteServices = new RemoteServices(defaultHostServer, fallbackHostServer);
    var initOperation = package.InitializeAsync(initParameters);
    yield return initOperation;
 
    if (initOperation.Status == EOperationStatus.Succeed)
    {
        Debug.Log("资源包初始化成功！");
    }
    else
    {
        Debug.LogError($"资源包初始化失败：{initOperation.Error}");
    }
}

补充两个类：


    /// <summary>
    /// 资源文件偏移加载解密类
    /// </summary>
    private class FileOffsetDecryption : IDecryptionServices
    {
        /// <summary>
        /// 同步方式获取解密的资源包对象
        /// 注意：加载流对象在资源包对象释放的时候会自动释放
        /// </summary>
        AssetBundle IDecryptionServices.LoadAssetBundle(DecryptFileInfo fileInfo, out Stream managedStream)
        {
            managedStream = null;
            return AssetBundle.LoadFromFile(fileInfo.FileLoadPath, fileInfo.ConentCRC, GetFileOffset());
        }
 
        /// <summary>
        /// 异步方式获取解密的资源包对象
        /// 注意：加载流对象在资源包对象释放的时候会自动释放
        /// </summary>
        AssetBundleCreateRequest IDecryptionServices.LoadAssetBundleAsync(DecryptFileInfo fileInfo, out Stream managedStream)
        {
            managedStream = null;
            return AssetBundle.LoadFromFileAsync(fileInfo.FileLoadPath, fileInfo.ConentCRC, GetFileOffset());
        }
 
        private static ulong GetFileOffset()
        {
            return 32;
        }
 
    }
 
 
    /// <summary>
    /// 远端资源地址查询服务类
    /// </summary>
    private class RemoteServices : IRemoteServices
    {
        private readonly string _defaultHostServer;
        private readonly string _fallbackHostServer;
 
        public RemoteServices(string defaultHostServer, string fallbackHostServer)
        {
            _defaultHostServer = defaultHostServer;
            _fallbackHostServer = fallbackHostServer;
        }
        string IRemoteServices.GetRemoteMainURL(string fileName)
        {
            return $"{_defaultHostServer}/{fileName}";
        }
        string IRemoteServices.GetRemoteFallbackURL(string fileName)
        {
            return $"{_fallbackHostServer}/{fileName}";
        }
    }

（3）获取资源版本


    ...
    var package = YooAssets.GetPackage("DefaultPackage");
    var operation = package.UpdatePackageVersionAsync();
    yield return operation;
 
    if (operation.Status == EOperationStatus.Succeed)
    {
        //更新成功
        string packageVersion = operation.PackageVersion;
        Debug.Log($"Updated package Version : {packageVersion}");
    }
    else
    {
        //更新失败
        Debug.LogError(operation.Error);
    }

（4）更新资源清单

对于联机运行模式，在获取到资源版本号之后，就可以利用UpdatePackageManifestAsync更新资源清单了：


    ...    
    bool savePackageVersion = true;
    var package = YooAssets.GetPackage("DefaultPackage");
    var operation = package.UpdatePackageManifestAsync(packageVersion, savePackageVersion);
    yield return operation;
 
    if (operation.Status == EOperationStatus.Succeed)
    {
        //更新成功
    }
    else
    {
        //更新失败
        Debug.LogError(operation.Error);
    }

（5）资源包下载


    IEnumerator Download()
    {
        int downloadingMaxNum = 10;
        int failedTryAgain = 3;
        var package = YooAssets.GetPackage("DefaultPackage");
 
        //创建资源下载器，下载所有资源
        var downloader = package.CreateResourceDownloader(downloadingMaxNum, failedTryAgain);
 
        //没有需要下载的资源
        if (downloader.TotalDownloadCount == 0)
        {
            Debug.Log("TotalDownloadCount = 0");
          
            yield break;
        }
 
        //需要下载的文件总数和总大小
        int totalDownloadCount = downloader.TotalDownloadCount;
        long totalDownloadBytes = downloader.TotalDownloadBytes;
 
        //注册回调方法
        downloader.OnDownloadErrorCallback = OnDownloadErrorFunction;
        downloader.OnDownloadProgressCallback = OnDownloadProgressUpdateFunction;
        downloader.OnDownloadOverCallback = OnDownloadOverFunction;
        downloader.OnStartDownloadFileCallback = OnStartDownloadFileFunction;
 
        //开启下载
        downloader.BeginDownload();
        yield return downloader;
 
        //检测下载结果
        if (downloader.Status == EOperationStatus.Succeed)
        {
            Debug.Log("Finish");
        }
        else
        {
            Debug.Log("DownLoad Failed");
        }
    }
 
    private void OnStartDownloadFileFunction(string fileName, long sizeBytes)
    {
        Debug.Log("fileName:" + fileName + ",sizeBytes:" + sizeBytes);
    }
 
    private void OnDownloadOverFunction(bool isSucceed)
    {
        Debug.Log("isSucceed");
    }
 
    private void OnDownloadProgressUpdateFunction(int totalDownloadCount, int currentDownloadCount, long totalDownloadBytes, long currentDownloadBytes)
    {
        Debug.Log("totalDownloadCount:" + totalDownloadCount + ",currentDownloadCount" + currentDownloadCount + ",totalDownloadBytes:" + totalDownloadBytes + ",currentDownloadBytes" + currentDownloadBytes);
    }
 
    private void OnDownloadErrorFunction(string fileName, string error)
    {
        Debug.Log("DownloadError:" + fileName + ",error:" + error);
    }

（6）资源加载


//加载场景，启用可寻址功能（Enable Addressable）后，不用写全路径，直接写资源名称即可
string location = "scene_home";
var sceneMode = UnityEngine.SceneManagement.LoadSceneMode.Single;
bool suspendLoad = false;
SceneHandle handle = package.LoadSceneAsync(location, sceneMode, suspendLoad);
yield return handle;
Debug.Log($"Scene name is {handle.SceneObject.name}");
 
//加载预制体
AssetHandle handle0 = package.LoadAssetAsync<GameObject>("UIHome");//不用加后缀
yield return handle0;
GameObject go = handle0.InstantiateSync();
Debug.Log($"Prefab name is {go.name}");
 
//加载音频
AssetHandle handle1 = package.LoadAssetAsync<AudioClip>("music_background");
yield return handle1;
AudioClip audioClip = handle1.AssetObject as AudioClip;
GameObject audio = new GameObject("AudioSource");
audio.AddComponent<AudioSource>().clip= audioClip;
audio.GetComponent<AudioSource>().Play();

（7）完整TestLoad


    IEnumerator TestLoad()
    {
        //0.别忘初始化项目中这两个事件相关的类
        // 游戏管理器 注册场景事件
        GameManager.Instance.Behaviour = this;
        // 初始化事件系统
        UniEvent.Initalize();
 
 
        //1.初始化
        Debug.Log("1. 初始化");
        // 初始化资源系统
        YooAssets.Initialize();
 
        // 创建默认的资源包
        var package = YooAssets.CreatePackage("DefaultPackage");
 
        // 设置该资源包为默认的资源包，可以使用YooAssets相关加载接口加载该资源包内容。
        YooAssets.SetDefaultPackage(package);
 
        //2.资源系统的运行模式
        Debug.Log("2. 资源系统的运行模式");
        if (PlayMode == EPlayMode.EditorSimulateMode)
        {
            var initParameters = new EditorSimulateModeParameters();//EditorSimulateModeParameters继承自InitializeParameters
            string simulateManifestFilePath = EditorSimulateModeHelper.SimulateBuild(EDefaultBuildPipeline.BuiltinBuildPipeline.ToString(), "DefaultPackage");
            initParameters.SimulateManifestFilePath = simulateManifestFilePath;
            yield return package.InitializeAsync(initParameters);
        }
        else if (PlayMode == EPlayMode.OfflinePlayMode)
        {
            var initParameters = new OfflinePlayModeParameters();//OfflinePlayModeParameters继承自InitializeParameters
            initParameters.DecryptionServices = new FileOffsetDecryption();//需要补充这个
            yield return package.InitializeAsync(initParameters);
        }
        else if (PlayMode == EPlayMode.HostPlayMode)
        {
            // 注意：GameQueryServices.cs 太空战机的脚本类，详细见StreamingAssetsHelper.cs
            string defaultHostServer = "https://static0.xesimg.com/project-yooasset/0130Offset";
            string fallbackHostServer = "https://static0.xesimg.com/project-yooasset/0130Offset";
            var initParameters = new HostPlayModeParameters();//HostPlayModeParameters继承自InitializeParameters
            initParameters.BuildinQueryServices = new GameQueryServices();//内置资源查询服务接口
            initParameters.DecryptionServices = new FileOffsetDecryption();//如果资源包在构建的时候有加密，需要提供实现IDecryptionServices接口的实例类。
            initParameters.RemoteServices = new RemoteServices(defaultHostServer, fallbackHostServer);//远端服务器查询服务接口
            var initOperation = package.InitializeAsync(initParameters);
            yield return initOperation;
 
            if (initOperation.Status == EOperationStatus.Succeed)
            {
                Debug.Log("资源包初始化成功！");
            }
            else
            {
                Debug.LogError($"资源包初始化失败：{initOperation.Error}");
            }
        }
        else if (PlayMode == EPlayMode.WebPlayMode)
        {
            string defaultHostServer = "http://127.0.0.1/CDN/WebGL/V1.0";
            string fallbackHostServer = "http://127.0.0.1/CDN/WebGL/V1.0";
            var initParameters = new WebPlayModeParameters();//WebPlayModeParameters继承自InitializeParameters
            initParameters.BuildinQueryServices = new GameQueryServices();
            initParameters.RemoteServices = new RemoteServices(defaultHostServer, fallbackHostServer);
            var initOperation = package.InitializeAsync(initParameters);
            yield return initOperation;
 
            if (initOperation.Status == EOperationStatus.Succeed)
            {
                Debug.Log("资源包初始化成功！");
            }
            else
            {
                Debug.LogError($"资源包初始化失败：{initOperation.Error}");
            }
        }
 
        //3.获取资源版本：UpdatePackageVersionAsync
        Debug.Log("3. 获取资源版本");
        var operation = package.UpdatePackageVersionAsync();
        yield return operation;
 
        if (operation.Status == EOperationStatus.Succeed)
        {
 
            string packageVersion = operation.PackageVersion;
            Debug.Log($"Updated package Version : {packageVersion}");
 
            //4.更新资源清单：对于联机运行模式，在获取到资源版本号之后，就可以更新资源清单了：UpdatePackageManifestAsync
            //联机运行模式
            //通过传入的清单版本，优先比对当前激活清单的版本，如果相同就直接返回成功。如果有差异就从缓存里去查找匹配的清单，如果缓存里不存在，就去远端下载并保存到沙盒里。最后加载沙盒内匹配的清单文件。
            Debug.Log("4. 更新资源清单");
            bool savePackageVersion = true;
            var operation2 = package.UpdatePackageManifestAsync(packageVersion, savePackageVersion);
            yield return operation2;
 
            if (operation2.Status == EOperationStatus.Succeed)
            {
                //5.资源包下载
                Debug.Log("5. 资源包下载");
                yield return Download();
                //6.加载场景，启用可寻址功能（Enable Addressable）后，不用写全路径，直接写资源名称即可
                //YooAssets.LoadSceneAsync("scene_home");
                string location = "scene_home";
                var sceneMode = UnityEngine.SceneManagement.LoadSceneMode.Single;
                bool suspendLoad = false;
                SceneHandle handle = package.LoadSceneAsync(location, sceneMode, suspendLoad);
                yield return handle;
                Debug.Log($"Scene name is {handle.SceneObject.name}");
                //7.加载预制体
                AssetHandle handle0 = package.LoadAssetAsync<GameObject>("UIHome");//不用加后缀
                yield return handle0;
                GameObject go = handle0.InstantiateSync();
                Debug.Log($"Prefab name is {go.name}");
                //8.加载音频
                AssetHandle handle1 = package.LoadAssetAsync<AudioClip>("music_background");
                yield return handle1;
                AudioClip audioClip = handle1.AssetObject as AudioClip;
                GameObject audio = new GameObject("AudioSource");
                audio.AddComponent<AudioSource>().clip= audioClip;
                audio.GetComponent<AudioSource>().Play();
 
                //9.资源释放
                handle0.Release();
                package.UnloadUnusedAssets();
            }
            else
            {
                //更新失败
                Debug.LogError(operation.Error);
            }
        }
        else
        {
            //更新失败
            Debug.LogError(operation.Error);
        }
 
    }