Unity-资源打包-AssetBundle

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发布于 2019-05-29 15:59:44

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发布于 2019-05-29 15:59:44

文章被收录于专栏：Unity游戏开发Unity游戏开发

AB包定义作用

1.压缩大小 2.热更新使用

使用流程

对要打包的资源进行设置

AB.PNG

C#脚本不能打成AB包，因为C#在Unity中会编译成中间文件。

参数相关

Build的路径（随意只要是在硬盘上都可以的） BuildAssetBundleOptions BuildAssetBundleOptions.None：使用LZMA算法压缩，压缩的包更小，但是加载时间更长。使用之前需要整体解压。一旦被解压，这个包会使用LZ4重新压缩。使用资源的时候不需要整体解压。在下载的时候可以使用LZMA算法，一旦它被下载了之后，它会使用LZ4算法保存到本地上。 BuildAssetBundleOptions.UncompressedAssetBundle：不压缩，包大，加载快 BuildAssetBundleOptions.ChunkBasedCompression：使用LZ4压缩，压缩率没有LZMA高，但是我们可以加载指定资源而不用解压全部注意使用LZ4压缩，可以获得可以跟不压缩想媲美的加载速度，而且比不压缩文件要小。 BuildTarget选择build出来的AB包要使用的平台

创建AB包 创建AB包，使用BuildPipeline类中的方法

    private static readonly string AbPath = Application.streamingAssetsPath;
    [MenuItem("Tools/CreateAB")]
    static void CreateAbPack()
    {
        BuildPipeline.BuildAssetBundles(AbPath, BuildAssetBundleOptions.UncompressedAssetBundle, BuildTarget.Android);
        AssetDatabase.Refresh();
    }

清除文件中的AB包

[MenuItem("Tools/ClearABFile")]
    static void ClearAbPack()
    {
        DirectoryInfo directoryInfo = new DirectoryInfo(AbPath);
        FileSystemInfo[] fileSystemInfo = directoryInfo.GetFileSystemInfos();
        foreach (FileSystemInfo item in fileSystemInfo)
        {
            if(item is DirectoryInfo)
            {
                DirectoryInfo d = new DirectoryInfo(item.FullName);
                d.Delete(true);
            }
            else
            {
                item.Delete();
            }
        }
        AssetDatabase.Refresh();
    }

读取AB包 1.直接记载一个单独的物体（无依赖）通过AssetBundle的LoadFromFile方法获取AB包，在通过LoadAsset的泛型方法获得GameObject

    private string path;
    void Start () {
        path = Application.streamingAssetsPath;
        AssetBundle ab = AssetBundle.LoadFromFile(path + "/prefab");
        //print(ab);
        GameObject go = ab.LoadAsset<GameObject>("Sphere");
        Instantiate(go);
    }

2.通过依赖加载，从本地进行加载

            path = Application.streamingAssetsPath;
            //从文件中加载StreamingAssets文件
            AssetBundle assetBundle = AssetBundle.LoadFromFile(path + "/StreamingAssets");
            //从StreamingAssets文件中获得AssetBundleManifest对象
            AssetBundleManifest assetBundleManifest = assetBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");
            //从AssetBundleManifest中加载一个AssetBundle对象的全部依赖
            string[] dps = assetBundleManifest.GetAllDependencies("prefab");
            //遍历依赖，加载所有的依赖
            for (int i = 0; i < dps.Length; i++)
            {
                AssetBundle ab1 = AssetBundle.LoadFromFile(path + "/" + dps[i]);
            }
            AssetBundle ab = AssetBundle.LoadFromFile(path + "/prefab");
            GameObject go = ab.LoadAsset<GameObject>("Sphere");
            Instantiate(go);

3.异步加载从文件中

if (GUILayout.Button("异步加载"))
        {
            StartCoroutine(LoadAB(AbLoadBP));
        }

IEnumerator LoadAB(Action action)
    {
        path = Application.streamingAssetsPath;
        AssetBundleCreateRequest assetBundle = AssetBundle.LoadFromFileAsync(path + "/prefab");
        yield return assetBundle;
        action();
    }

4.从内存中加载异步：

    IEnumerator LoadFromMemoryAsync()
    {
        string path = Application.streamingAssetsPath + "/" + "prefab";
        //byte by = byte.Parse(path);
        AssetBundleCreateRequest createRequest = AssetBundle.LoadFromMemoryAsync(File.ReadAllBytes(path));
        yield return createRequest;
        AssetBundle bundle = createRequest.assetBundle;

        GameObject prefab = bundle.LoadAsset<GameObject>("Cube");
        Instantiate(prefab);
    }

同步：

private void LoadFromMemory()
    {
        string path = Application.streamingAssetsPath + "/" + "prefab";
        AssetBundle bundle = AssetBundle.LoadFromMemory(File.ReadAllBytes(path));
        GameObject prefab = bundle.LoadAsset<GameObject>("Cube");
        Instantiate(prefab);
    }

5.从本地获得网络加载WWW.LoadFromCacheOrDownload 通过URL进行加载

IEnumerator LoadFromCacheOrDownLoadExample ()
    {
        while (!Caching.ready)
        {
            yield return null;
        }
        var www = WWW.LoadFromCacheOrDownload("http://192.168.0.250/prefab.unity3d", 5);
        //var www = WWW.LoadFromCacheOrDownload(@"D:\the9git\the9_09\UnityProject\UnityBase04\Assets\StreamingAssets\prefab", 5);
        yield return www;
        if (!string.IsNullOrEmpty(www.error))
        {
            Debug.Log(www.error);
            yield return null;
        }
        AssetBundle myLoadedAB = www.assetBundle;
        GameObject prefab = myLoadedAB.LoadAsset<GameObject>("Cube");
        Instantiate(prefab);
        //var asset = myLoadedAB.mainAsset;
    }

6.通过UnityWebRequest加载AB包

    IEnumerator InstantiateObject()
    {
        //string uri = "file:///" + Application.streamingAssetsPath + "/prefab";
        string uri = "http://192.168.0.250/StreamingAssets/perfab.unity3d";
        using (UnityWebRequest webRequest = UnityWebRequest.GetAssetBundle(uri))
        {
            yield return webRequest.SendWebRequest();
            AssetBundle bundle = DownloadHandlerAssetBundle.GetContent(webRequest);
            GameObject cube = bundle.LoadAsset<GameObject>("Cube");
            Instantiate(cube);
        }
        string uri2 = "http://192.168.0.250/StreamingAssets/StreamingAssets";
        using (UnityWebRequest webRequest2 = UnityWebRequest.GetAssetBundle(uri2))
        {
            yield return webRequest2.SendWebRequest();
            AssetBundle bundle = DownloadHandlerAssetBundle.GetContent(webRequest2);
            AssetBundleManifest assetBundleManifes = bundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");
            string[] dps = assetBundleManifes.GetAllDependencies("perfab.unity3d");
            for (int i = 0; i < dps.Length; i++)
            {
                string uri3 = "http://192.168.0.250/StreamingAssets/" + dps[i];
                using (UnityWebRequest webRequest3 = UnityWebRequest.GetAssetBundle(uri3))
                {
                    yield return webRequest3.SendWebRequest();
                    AssetBundle ab = DownloadHandlerAssetBundle.GetContent(webRequest3);
                }
            }
        }
    }

卸载有两个方面 1，减少内存使用 2，有可能导致丢失所以什么时候去卸载资源 AssetBundle.Unload(true)卸载所有资源，即使有资源被使用着（1，在关切切换、场景切换2，资源没被用的时候调用） AssetBundle.Unload(false)卸载所有没用被使用的资源个别资源怎么卸载1，通过 Resources.UnloadUnusedAssets. 2，场景切换的时候 AssetBundle卸载

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原始发表：2019.05.21 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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