2018-05-09assetbundle

打包：打成ab包

BuildPipeline.BuildAssetBundles(dir,BuildAssetBundleOptions.None,BuildTarget.StandaloneWindows64)

第一个参数是输出路径

第二个参数如下

BuildAssetBundleOptions.None 使用LZMA算法压缩，体积最小，加载时间最长

BuildAssetBundleOptions.UncompressedAssetBundle 不压缩，体积最大，加载时间最短

BuildAssetBundleOptions.ChunkBasedCompression 使用LZ4压缩 体积较小，加载时间较长（分块压缩分块加载；比如包里有abc 要加载a不用解压bc）

第三个参数是平台选择（比如苹果安卓台式机）

加载：加载ab包

1，AssetBundle.LoadFromMemoryAsync 异步（异步需要等待加载完成）在内存里加载（先把文件读取到内存中（byte数组的形式），再从内存中读取）

例：

AssetBundleCreateRequest request = AssetBundle.LoadFromMemoryAsync(File.ReadAllBytes(path));

yield return request;

AssetBundle ab=request.assetB

(同步的方式(不用协程)：AssetBundle ab=AssetBundle.LoadFromMemory(File.ReadAllBytes(path));)

GameObject wallPrefab=ab.LoadAsset<GameObject>("CubeWall");

Instantiate(wallPrefab);

2，AssetBundle.LoadFromFile,直接加载本地文件

AssetBundleCreateRequest request = AssetBundle.LoadFromFileAsync(path);

yield return request;

AssetBundle ab = request.assetBundle;

3，UnityWebRequest.GetAssetBundle(uri);从服务器加载资源

UnityWebRequest request = UnityWebRequest.GetAssetBundle(uri);

yield return request.Send();

AssetBundle ab = DownloadHandlerAssetBundle.GetContent(request);

或者AssetBundle ab= (request.downloadHandler as DownloadHandlerAssetBundle).assetBundle;

扩展：request.downloadHandler.data(下载的byte字节数组，可以通过File.WriteAllBytes保存到本地)

加载：加载ab包中的资源

1， T objectFromBundle = bundleObject.LoadAsset<T>(assetName);加载指定类型和名字的资源

2，Unity.Object[] objectArray=loadedAssetBundle.LoadAllAssets();加载单个包里所有资源

3，GameObject gameObject = loadedAssetBundle.LoadAsset<GameObject>(assetName);单个资源

例：AssetBundleRequest request = loadedAssetBundleObject.LoadAssetAsync<GameObject>(assetName);

yield return request;

var loadedAsset = request.asset;

加载：加载manifest文件

AssetBundle manifestAB=AssetBundle.LoadFromFile("AssetBundles/AssetBundles");

AssetBundleManifest manifest = manifestAB.LoadAsset<AssetBundleManifest>("AssetBundleManifest");

foreach(string name in manifest.GetAllAssetBundles()){

print(name);所有ab包的名字

}

string[] strs = manifest.GetAllDependencies("cubewall.untiy3d");

foreach(string name in strs){

print(name);cubewall.untiy3d的依赖关系

AssetBundle.LoadFromFile("AssetBundle/"+name);

}

string[] dependencies = manifest.GetAllDependencies("assetBundle");

foreach(string dependency in dependencies){

AssetBundle.LoadFromFile(Path.Combine(assetBundlePath,dependency));加载所有的依赖项

}

卸载：优化内存

AssetBundle.Unload(true)卸载所有资源，即使有资源正在被使用（在适当的时候调用比如在关卡，场景切换的时候）推荐使用

AssetBundle.Unload(false)卸载所有没有被使用的资源，个别的资源通过Resources.UnloadUnusedAssets（场景切换的时候会自动调用）卸载

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