Unity3d 5.x AssetBundle打包与加载

1.AssetBundle打包

unity 5.x版本AssetBundle打包，只需要设置好AssetBundle的名称后，unity会自动将其打包，无需处理其他，唯独需要做的是设置好个AssetBundle的名称。

注意：AssetBunlde的名称只能设置小写字母，即使你写成大写也会被自动转置成大写字母，而且名称中支持“/”，如：“AssetBundles/cube.unity3d”，.unity3d的后缀是自己设置的，可以不设置

代码：

using UnityEngine;
using UnityEditor;
using System.IO;

public class CreateAssetBundles : Editor {

    [MenuItem("Tools/Build AssetBundles")]
    static void BuildAllAssetBundles()
    {
        BuildPipeline.BuildAssetBundles(Application.dataPath + "/AssetBundles", BuildAssetBundleOptions.ChunkBasedCompression, BuildTarget.Android);
        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();
        Debug.LogWarning("打包成功");
    }

    [MenuItem("Tools/设置固定名")]
    public static void saveAsStaticName()
    {
        string Path = "Prefabs";
        string abName = "building.ab";
        SetVersionDirAssetName(Path, abName);//第一个参数是路径 第二个参数是Ab名字 默认前缀为 Application.dataPath + "/"＋ Path  
    }

    [MenuItem("Tools/设定文件名")]
    public static void saveAsPrefabName()
    {
        string Path = "Prefabs";
        SetAssetNameAsPrefabName(Path);//第一个参数是路径   
    }

    public static void SetVersionDirAssetName(string fullPath, string abName)
    {
        var relativeLen = fullPath.Length + 8; // Assets 长度  
        fullPath = Application.dataPath + "/" + fullPath + "/";

        if (Directory.Exists(fullPath))
        {
            EditorUtility.DisplayProgressBar("设置AssetName名称", "正在设置AssetName名称中...", 0f);
            var dir = new DirectoryInfo(fullPath);
            var files = dir.GetFiles("*", SearchOption.AllDirectories);
            for (var i = 0; i < files.Length; ++i)
            {
                var fileInfo = files[i];
                EditorUtility.DisplayProgressBar("设置AssetName名称", "正在设置AssetName名称中...", 1f * i / files.Length);
                if (!fileInfo.Name.EndsWith(".meta"))
                {
                    var basePath = fileInfo.FullName.Substring(fullPath.Length - relativeLen);//.Replace('\', '/');  
                    var importer = AssetImporter.GetAtPath(basePath);
                    if (importer && importer.assetBundleName != abName)
                    {
                        importer.assetBundleName = abName;
                    }
                }
            }
            EditorUtility.ClearProgressBar();
        }
    }

    public static void SetAssetNameAsPrefabName(string fullPath)
    {
        var relativeLen = fullPath.Length + 8; // Assets 长度  
        fullPath = Application.dataPath + "/" + fullPath + "/";

        if (Directory.Exists(fullPath))
        {
            EditorUtility.DisplayProgressBar("设置AssetName名称", "正在设置AssetName名称中...", 0f);
            var dir = new DirectoryInfo(fullPath);
            var files = dir.GetFiles("*", SearchOption.AllDirectories);
            for (var i = 0; i < files.Length; ++i)
            {
                var fileInfo = files[i];
                string abName = fileInfo.Name;
                EditorUtility.DisplayProgressBar("设置AssetName名称", "正在设置AssetName名称中...", 1f * i / files.Length);
                if (!fileInfo.Name.EndsWith(".meta"))
                {
                    var basePath = fileInfo.FullName.Substring(fullPath.Length - relativeLen);//.Replace('\', '/');  
                    var importer = AssetImporter.GetAtPath(basePath);
                    //abName = AssetDatabase.AssetPathToGUID(basePath);
                    if (importer && importer.assetBundleName != abName)
                    {
                        importer.assetBundleName = abName;
                    }
                }
            }
            EditorUtility.ClearProgressBar();
        }
    }

    /// <summary>  
    /// AssetBundleManifestName == 对应AB依赖列表文件  
    /// </summary>  

    private static string AssetBundle_BuildDirectory_Path = @Application.streamingAssetsPath + "/../../../" + "AssetBundles";
    private static string AssetBundle_TargetDirectory_Path = @Application.streamingAssetsPath + "/" + "ABFiles";
    [MenuItem("Tools/Asset Bundle/Build Asset Bundles", false, 0)]
    public static void BuildAssetBundleAndroid()
    {
        //Application.streamingAssetsPath对应的StreamingAssets的子目录  
        DirectoryInfo AB_Directory = new DirectoryInfo(AssetBundle_BuildDirectory_Path);
        if (!AB_Directory.Exists)
        {
            AB_Directory.Create();
        }
        FileInfo[] filesAB = AB_Directory.GetFiles();
        foreach (var item in filesAB)
        {
            Debug.Log("******删除旧文件：" + item.FullName + "******");
            item.Delete();
        }
#if UNITY_ANDROID
        BuildPipeline.BuildAssetBundles(AB_Directory.FullName, BuildAssetBundleOptions.ChunkBasedCompression, BuildTarget.Android);  
#elif UNITY_IPHONE
        BuildPipeline.BuildAssetBundles(AB_Directory.FullName, BuildAssetBundleOptions.ChunkBasedCompression, BuildTarget.iOS); 
#else
        BuildPipeline.BuildAssetBundles(AB_Directory.FullName, BuildAssetBundleOptions.ChunkBasedCompression, BuildTarget.StandaloneWindows64);
#endif
        Debug.Log("******AssetBundle打包完成******");

        Debug.Log("将要转移的文件夹是：" + AssetBundle_TargetDirectory_Path);
        FileInfo[] filesAB_temp = AB_Directory.GetFiles();

        DirectoryInfo streaming_Directory = new DirectoryInfo(AssetBundle_TargetDirectory_Path);

        FileInfo[] streaming_files = streaming_Directory.GetFiles();
        foreach (var item in streaming_files)
        {
            item.Delete();
        }
        AssetDatabase.Refresh();
        foreach (var item in filesAB_temp)
        {
            if (item.Extension == "")
            {
                item.CopyTo(AssetBundle_TargetDirectory_Path + "/" + item.Name, true);
            }
        }
        AssetDatabase.Refresh();
        Debug.Log("******文件传输完成******");
    }

    private static string _dirName = "";
    /// <summary>  
    /// 批量命名所选文件夹下资源的AssetBundleName.  
    /// </summary>  
    [MenuItem("Tools/Asset Bundle/Set Asset Bundle Name")]
    static void SetSelectFolderFileBundleName()
    {
        UnityEngine.Object[] selObj = Selection.GetFiltered(typeof(Object), SelectionMode.Unfiltered);
        foreach (Object item in selObj)
        {
            string objPath = AssetDatabase.GetAssetPath(item);
            DirectoryInfo dirInfo = new DirectoryInfo(objPath);
            if (dirInfo == null)
            {
                Debug.LogError("******请检查，是否选中了非文件夹对象******");
                return;
            }
            _dirName = dirInfo.Name;

            string filePath = dirInfo.FullName.Replace('\', '/');
            filePath = filePath.Replace(Application.dataPath, "Assets");
            AssetImporter ai = AssetImporter.GetAtPath(filePath);
            ai.assetBundleName = _dirName;

            SetAssetBundleName(dirInfo);
        }
        AssetDatabase.Refresh();
        Debug.Log("******批量设置AssetBundle名称成功******");
    }
    static void SetAssetBundleName(DirectoryInfo dirInfo)
    {
        FileSystemInfo[] files = dirInfo.GetFileSystemInfos();
        foreach (FileSystemInfo file in files)
        {
            if (file is FileInfo && file.Extension != ".meta" && file.Extension != ".txt")
            {
                string filePath = file.FullName.Replace('\', '/');
                filePath = filePath.Replace(Application.dataPath, "Assets");
                AssetImporter ai = AssetImporter.GetAtPath(filePath);
                ai.assetBundleName = _dirName;
            }
            else if (file is DirectoryInfo)
            {
                string filePath = file.FullName.Replace('\', '/');
                filePath = filePath.Replace(Application.dataPath, "Assets");
                AssetImporter ai = AssetImporter.GetAtPath(filePath);
                ai.assetBundleName = _dirName;
                SetAssetBundleName(file as DirectoryInfo);
            }
        }
    }
    /// <summary>  
    /// 批量清空所选文件夹下资源的AssetBundleName.  
    /// </summary>  
    [MenuItem("Tools/Asset Bundle/Reset Asset Bundle Name")]
    static void ResetSelectFolderFileBundleName()
    {
        UnityEngine.Object[] selObj = Selection.GetFiltered(typeof(UnityEngine.Object), SelectionMode.Unfiltered);
        foreach (UnityEngine.Object item in selObj)
        {
            string objPath = AssetDatabase.GetAssetPath(item);
            DirectoryInfo dirInfo = new DirectoryInfo(objPath);
            if (dirInfo == null)
            {
                Debug.LogError("******请检查，是否选中了非文件夹对象******");
                return;
            }
            _dirName = null;

            string filePath = dirInfo.FullName.Replace('\', '/');
            filePath = filePath.Replace(Application.dataPath, "Assets");
            AssetImporter ai = AssetImporter.GetAtPath(filePath);
            ai.assetBundleName = _dirName;

            SetAssetBundleName(dirInfo);
        }
        AssetDatabase.Refresh();
        Debug.Log("******批量清除AssetBundle名称成功******");
    }
}

上述代码中有一些测试函数，使用时可进行测试

2.AssetBundle加载

下述代码中，cube，sphere等都是在unity项目中自己创建的3d预制体，自行创建即可。创建完成使用1中的方法打包AssetBundle。注意代码中的cube大小写问题，小写的是设置的AssetBundle名称，大写的是Cube预制体的名称，不要混淆。

代码：

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

public class AssetBundleLoad : MonoBehaviour {

    // Use this for initialization
    void Start () {
        this.load1();
        //this.load2();
        //this.load3();
        //this.load4();
    }

    void load1()
    {
        //1.先加载cube后加载sphere
        //这种方式并没有先加载cube的依赖文件，按理说应该加载出来的cube上是sphere是missing的，但是unity5.6.3f1
        //加载并未missing，不知是不是unity版本的优化，不过好习惯还是先加载依赖文件，如load2()。

        //加载assetbundlemanifest文件
        AssetBundle assetBundleManifest = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/AssetBundles");
        if(null != assetBundleManifest)
        {
            AssetBundleManifest manifest = assetBundleManifest.LoadAsset<AssetBundleManifest>("AssetBundleManifest");

            //加载cube
            AssetBundle bundle = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/cube.prefab");
            GameObject obj = bundle.LoadAsset<GameObject>("Cube");
            if(null != obj)
            {
                GameObject cube = Instantiate(obj);
                cube.transform.SetParent(GameObject.Find("UIRoot").transform);
            }

            //加载cube的依赖文件
            string[] depends = manifest.GetAllDependencies("cube.prefab");
            AssetBundle[] dependsAssetbundle = new AssetBundle[depends.Length];
            for(int index = 0; index < depends.Length; ++index)
            {
                dependsAssetbundle[index] = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/" + depends[index]);

                obj = dependsAssetbundle[index].LoadAsset<GameObject>("Sphere");
                if (null != obj)
                {
                    GameObject sphere = Instantiate(obj);
                    sphere.transform.SetParent(GameObject.Find("UIRoot").transform);
                }
            }
        }
    }

    void load2()
    {
        //2.先加载sphere再加载cube

        //加载assetBundleManifest文件
        AssetBundle assetBundleManifest = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/AssetBundles");
        if(null != assetBundleManifest)
        {
            AssetBundleManifest manifest = assetBundleManifest.LoadAsset<AssetBundleManifest>("AssetBundleManifest");

            //加载cube依赖文件
            string[] depends = manifest.GetAllDependencies("cube.prefab");
            AssetBundle[] dependsAssetbundle = new AssetBundle[depends.Length];
            for (int index = 0; index < depends.Length; ++index)
            {
                dependsAssetbundle[index] = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/" + depends[index]);

                GameObject obj1 = dependsAssetbundle[index].LoadAsset<GameObject>("Sphere");
                if (null != obj1)
                {
                    GameObject sphere = Instantiate(obj1);
                    sphere.transform.SetParent(GameObject.Find("UIRoot").transform);
                }
            }

            //加载cube
            AssetBundle bundle = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/cube.prefab");
            GameObject obj = bundle.LoadAsset<GameObject>("Cube");
            if(null != obj)
            {
                GameObject sphere = Instantiate(obj);
                sphere.transform.SetParent(GameObject.Find("UIRoot").transform);
            }
        }
    }

    void load3()
    {
        //3.只加载cube不加载sphere

        //无需加载assetBundleManifest文件，直接加载cube
        AssetBundle bundle = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/cube.prefab");
        GameObject obj = bundle.LoadAsset<GameObject>("Cube");
        if (null != obj)
        {
            GameObject sphere = Instantiate(obj);
            sphere.transform.SetParent(GameObject.Find("UIRoot").transform);
        }
    }

    void load4()
    {
        //4.两个预制打包成同一个AssetBundle

        //无需加载assetBundleManifest文件，直接加载cube
        AssetBundle bundle = AssetBundle.LoadFromFile(Application.dataPath + "/AssetBundles/cube2.prefab");
        GameObject obj = bundle.LoadAsset<GameObject>("Cube_1");
        if (null != obj)
        {
            GameObject cube = Instantiate(obj);
            cube.transform.SetParent(GameObject.Find("UIRoot").transform);
        }

        obj = bundle.LoadAsset<GameObject>("Cube_2");
        if (null != obj)
        {
            GameObject cube = Instantiate(obj);
            cube.transform.SetParent(GameObject.Find("UIRoot").transform);
        }
    }
}

using UnityEngine;

public class Relation : MonoBehaviour {
    //挂在cube预制上的测试脚本
    public GameObject sphere_go;
    public GameObject capsule_go;
    // Use this for initialization
    void Start () {
        ScriptRelation t = new ScriptRelation();
        t.printLog();
    }
    
    // Update is called once per frame
    void Update () {
        
    }
}

using UnityEngine;

public class ScriptRelation{

    public void printLog()
    {
        Debug.Log("xxxxxxxxxxxxxxxxxx");
    }
}

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

public class TestAssetBundle : MonoBehaviour {

    public string AssetBundleName = "cube";

    private string dir = "";
    private AssetBundle bundle = null;
    private Object asset = null;
    private GameObject go = null;

    private AssetBundleManifest manifest = null;

    // Use this for initialization
    void Start () {
        dir = Application.dataPath + "/AssetBundles/";
    }
    
    void OnGUI()
    {
        if (GUILayout.Button("LoadAssetBundle", GUILayout.Width(200), GUILayout.Height(50))) { LoadBundle(); }
        if (GUILayout.Button("LoadAsset", GUILayout.Width(200), GUILayout.Height(50))) { LoadAsset(); }
        if (GUILayout.Button("Instantiate", GUILayout.Width(200), GUILayout.Height(50))) { Instantiate(); }
        if (GUILayout.Button("Destory", GUILayout.Width(200), GUILayout.Height(50))) { Destroy(); }
        if (GUILayout.Button("Unload", GUILayout.Width(200), GUILayout.Height(50))) { UnLoad(); }
        if (GUILayout.Button("UnloadForce", GUILayout.Width(200), GUILayout.Height(50))) { UnLoadForce(); }
        if (GUILayout.Button("UnloadUnusedAssets", GUILayout.Width(200), GUILayout.Height(50))) { UnloadUnusedAssets(); }

        //bundle依赖包加载
        if (GUILayout.Button("LoadAssetBundleManifest", GUILayout.Width(200), GUILayout.Height(50))) { LoadAssetBundleManifest(); }
        if (GUILayout.Button("LoadBundleAndDeps", GUILayout.Width(200), GUILayout.Height(50))) { LoadBundleAndDeps(); }
    }

    void LoadBundle()
    {
        bundle = AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, AssetBundleName));
        if(null == bundle)
        {
            Debug.LogError("LoadBundle Failed");
        }
    }

    void LoadAsset()
    {
        if (null == bundle) return;

        asset = bundle.LoadAsset<Object>("Cube");
        if (null == asset) Debug.LogError("LoadAsset Failed");
    }

    void Instantiate()
    {
        if (null == asset) return;

        go = GameObject.Instantiate<Object>(asset) as GameObject;
        if (null == go) Debug.LogError("Instantiate Failed");
        else
        {
            go.transform.SetParent(GameObject.Find("UIRoot").transform);
        }
    }

    void Destroy()
    {
        if (null == go) return;

        GameObject.Destroy(go);
        go = null;
    }

    /**
     *  AssetBundle.unload(bool unloadAllLoadedObjects) 接口用来卸载AssetBundle文件。
     *  参数为false时，调用该接口后，只会卸载AssetBundle对象自身，并不会影响AssetBundle中加载的Assets。
     *  参数为true时，除了AssetBundle对象自身，所有从当前AssetBundle中加载的Assets也会被同时卸载，不管这个Assets是否还在使用中。
     *  官方推荐参数一般设置为false，只有当很明确知道从AssetsBundle中加载的Assets不会被任何对象引用时，才将参数设置成true。
     **/
    void UnLoad()
    {
        if (null == bundle) return;

        bundle.Unload(false);
        //GameObject.Instantiate<Object>(asset);  //asset可用
        asset = null;
        bundle = null;
    }

    void UnLoadForce()
    {
        if (null == bundle) return;

        bundle.Unload(true);
        //GameObject.Instantiate<Object>(asset);  //报错：asset已被销毁
        asset = null;
        bundle = null;
    }

    void UnloadUnusedAssets()
    {
        Resources.UnloadUnusedAssets();
    }

    void LoadAssetBundleManifest()
    {
        var bundle = AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, "AssetBundles"));
        manifest = bundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");

        //unload
        bundle.Unload(false);
        bundle = null;
    }

    void LoadBundleAndDeps()
    {
        string bundleName = "cube";

        string[] dependence = manifest.GetDirectDependencies(bundleName);
        for(int i=0; i<dependence.Length; ++i)
        {
            AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, dependence[i]));
        }

        var bundle = AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, bundleName));
        var asset = bundle.LoadAsset<GameObject>("Cube");
        bundle.Unload(false);
        bundle = null;
        go = GameObject.Instantiate<GameObject>(asset);
    }
}

上述代码有两个测试脚本，AssetBundleLoad.cs只做了AssetBudle加载的测试。TestAssetBundle.cs做了AssetBundle加载，卸载，使用等测试，比较完整。

3.unity项目中的3个特殊文件夹

a.Resources（只读）

Resources文件夹下的资源会被全部打包到apk或者ipa里面，相当与一个unity默认的AssetBundle，按理说是可以将游戏中所有的资源全部放在Resources进行加载，但是

Resources下的文件数量会影响游戏的启动速度，越多越慢。其次游戏为了降低drawcall，需要对相同材质的图像打包图集，但是如果放在Resources里面是没法打包图集的。

Resources下的资源打包时会进行压缩

b.StreamingAssets（只读）

StreamingAssets文件夹下的资源会被全部打包到apk或者ipa里面

StreamingAssets文件夹下的资源不会影响游戏启动速度

StreamingAssets文件夹下的资源不会被压缩，所以占用内存较大

c.persistentDataPath（可读写）

persistentDataPath文件夹在unity项目中是不存在的，他是程序的沙盒文件夹，只有你游戏安装完成之后，才会存在这个目录，但是它可读写。

综上三种文件夹，我们自己在使用时，Resources里面放的资源只是在本地开发阶段使用，打包的时候会把Resources中的文件都考本出去打成AssetBundle包，然后再将打包好的AssetBundle放到StreamingAssets文件夹下打包apk。

游戏运行时再将资源考本到persistentDataPath文件夹下，因为这个目录可读写，所以能够用来做资源热更新。

如有错误，敬请指正。

///////////****以下摘自：http://www.cnblogs.com/jiangshuai52511/p/6437239.html  作者：凉城旧巷旧少年 ******/////////

5.3.针对项目的建议

由于以上分析的几种加载手段各有各的使用情景和特点。因此建议在我们的项目中按照以下情景使用这些方法：

• 随游戏一同发布的AssetBundle（一般位于StreamingAssets文件夹中）：
• 在打AssetBundle包时，使用LZ4压缩格式进行打包（开启BuildAssetBundleOptions.ChunkBasedCompression即可）。
• 在运行时需要加载AssetBundle对象时，使用LoadFromFile方法进行加载。
• 这样做的好处是：即可以将AssetBundle文件压缩，又可以兼顾加载速度，且节约内存。
• 作为更新包，需要从服务端下载的AssetBundle：
• 在打AssetBundle包时，使用默认的LZMA格式压缩。
• 使用http://WWW.LoadFromCacheOrDownload方法下载并缓存AssetBundle包文件。
• 这样做的好处是：获得了最大的压缩率，在下载过程中可以减少数据传输量。同时，在本地磁盘创建缓存之后，又可以兼顾之后的加载速度，且节约内存。
• 我们自己进行加密的AssetBundle：
• 在打AssetBundle包时，使用LZ4压缩格式进行打包（开启BuildAssetBundleOptions.ChunkBasedCompression即可）。
• 在运行时需要加载AssetBundle对象时，使用LoadFromMemory方法进行加载。（这也是从内存中使用流数据加载AssetBundle对象的仅有的使用场景。）
• 我们自己压缩的AssetBundle：
• 我们自己也可以使用第三方库或工具对生成的AssetBundle包文件进行压缩，如果需要这样做，则我们最好不要再使用Unity3D对 AssetBundle进行压缩，因此在打包时选择开启 BuildAssetBundleOptions.UncompressedAssetBundle。
• 在运行时需要加载AssetBundle对象时，使用LoadFromFileAsync方法进行异步加载。

///////////****以上摘自：http://www.cnblogs.com/jiangshuai52511/p/6437239.html  作者：凉城旧巷旧少年 ******/////////

参考文章：

http://www.xuanyusong.com/archives/3229

http://www.cnblogs.com/AaronBlogs/p/6837682.html

http://www.cnblogs.com/kanekiken/p/7533510.html

http://www.cnblogs.com/murongxiaopifu/p/4199541.html

http://www.cnblogs.com/jiangshuai52511/p/6437239.html

http://blog.csdn.net/u010377179/article/category/6413676/3

http://blog.csdn.net/suifcd/article/details/51570003

AssetBundle内存相关：

http://blog.csdn.net/sgnyyy/article/details/39268215