AssetBundle资源打包与加载
AssetBundle资源打包
1.AssetLabels资源标签
文件名:资源打包成AssetBundle后的文件名,类似于压缩包的名字
后缀:自定义
文件名和后缀名都是小写格式(大写会自动转为小写)
2. BuildPipeline.BuildAssetBundles(string outputPath, BuildAssetBundleOptions assetBundleOptions, BuildTarget targetPlatform) 打包所有设置了AssetLabel的资源
outputPath:路径,打包出来的AssetBunlde文件存放的位置
BuildAssetBundleOptions:选项,设置AssetBundle打包过程中压缩方式
BuildAssetBundleOptions枚举选项:
None使用LZMA压缩算法进行压缩,打包后资源体积最小
UncompressedAssetBundle不压缩,打包后的AssetBundle体积最大,但是加载速度最快
ChunkBasedCompression使用LZ4压缩算法进行压缩,打包后的AssetBundle体积和加载速度介于上面二者之间
BuildTarget:平台,AssetBundle是平台之间不兼容的,IOS,Android是两套资源
在AssetLabels区域填写AssetBundle名称的时候,名称是可以分目录嵌套的:文件夹名/文件名
AssetBundle打包后的资源包,分两部分组成:
1.资源打包出来的AssetBundle文件
2.AssetBundle文件配套的manifest文本文件
manifest文件
manifest文件用于专门存储打包后的AssetBundle文件的基本信息,主要包含:
CRC校验码:类似于MD5,用于计算出该资源的一个特殊信息标示
ClassTypes列表:当前资源关联使用到了Unity中的哪些类,这些类是以编号索引的形式存在的,每个编号都对应一个类文件
Assets:AssetsBundle里包含了哪些资源文件
Dependencies:依赖
在打包出来的AssetBundle文件中,有一个特殊的manifest文件,和AssetBundle存放的文件夹同名,且只在根文件夹下有唯一的一个
这个manifest文件可以称作"AssetBundle目录文件",它存储了打包出来的所有AssetBundle的文件的索引信息
通过这个目录文件,可以找到所有的AssetBundle文件
AssetBundle资源加载
将项目资源打包成AssetBundle后,一般有两种操作
一.将这些AssetBundle留着项目工程中,当成普通资源使用
1.加载AssetBundle资源到内存
AssetBundle ab = AssetBundle.LoadFromFile("路径");加载AssetBundle资源到内存,返回一个AssetBundle对象
2.从AssetBundle中获取资源
T res = ab.LoadAsset<T>("资源名");
3.实例化
打包
[MenuItem("xx/xxx")] public static void Build_WINDOWS64() { string outputPath = Path.Combine(Application.streamingAssetsPath, "Data"); if (!Directory.Exists(outputPath)) Directory.CreateDirectory(outputPath); BuildPipeline.BuildAssetBundles(outputPath, BuildAssetBundleOptions.None, BuildTarget.StandaloneWindows64);//自己选择平台 AssetDatabase.Refresh(); }
加载
using System.Collections; using System.Collections.Generic; public class AssetBundleManager { private readonly string _path = UnityEngine.Application.streamingAssetsPath + "/Data/"; private static AssetBundleManager _instance; private bool mIsLoadingEnd = false; public bool IsLoadingEnd { get { return mIsLoadingEnd; } } private List<string> mLoadingNames; private Dictionary<string, UnityEngine.Object> mAssets; private Dictionary<string, UnityEngine.Texture2D> mTexture2Ds; public static AssetBundleManager GetInstance() { if (_instance == null) { _instance = new AssetBundleManager(); } return _instance; } private AssetBundleManager() { mLoadingNames = new List<string>(){ //todo:要加载的资源名 }; mAssets = new Dictionary<string, UnityEngine.Object>(); mTexture2Ds = new Dictionary<string, UnityEngine.Texture2D>(); } /// <summary> /// 加载assetsbundle
/// 记得先加载到内存StartCoroutine(AssetBundleManager.GetInstance().Loading()); /// </summary> public IEnumerator Loading() { foreach (var nameAndType in mLoadingNames) { string filename = _path + nameAndType.ToLower(); UnityEngine.AssetBundleCreateRequest request = UnityEngine.AssetBundle.LoadFromFileAsync(filename); yield return request; LoadAsset(request.assetBundle); } mIsLoadingEnd = true; } private UnityEngine.AssetBundle LoadAssetBundle(string fileName) { UnityEngine.AssetBundle AB = UnityEngine.AssetBundle.LoadFromFile(_path + fileName); return AB; } private void LoadAsset(UnityEngine.AssetBundle ab) { UnityEngine.Object[] assets = ab.LoadAllAssets(); for (int i = 0; i < assets.Length; i++) { //一张图片的AssetsBundle包含自身Texture2D和它里面全部Sprite,有可能重名 if (!typeof(UnityEngine.Texture2D).Equals(assets[i].GetType())) mAssets.Add(assets[i].name, assets[i]); else mTexture2Ds.Add(assets[i].name, assets[i] as UnityEngine.Texture2D); } } /// <summary> /// 从assetbundle获取texture2d /// </summary> public UnityEngine.Texture2D GetTexture2D(string name) { UnityEngine.Texture2D obj; mTexture2Ds.TryGetValue(name, out obj); return obj; } /// <summary> /// 从assetbundle获取Object /// </summary> public UnityEngine.Object GetAsset(string name) { UnityEngine.Object obj; mAssets.TryGetValue(name, out obj); return obj; } }
二.将这些AssetBundle上传服务器,客户端第一次运行时从服务器下载AssetBundle缓存到本地再使用(实现客户端的安装包与资源分离,降低客户端安装包的体积)
1.服务器端下载主文件
从服务器端下载AssetBundle需要web路径地址,每一个地址对应一个AssetBundle文件.我们不可能在代码中写几十上百个文件的web地址,所以我们需要先下载"目录AssetBundle文件",然后通过它来间接获取其他AssetBundle文件的下载路径地址.
需要引入命名空间using UnityEngine.Networking;
using System.Collections; using System.IO; using UnityEngine; using UnityEngine.Networking; public class TestAssetBundle : MonoBehaviour { private string mainAssetBundleURL = @"http://www.xxx.com.xxx/AssetBundleFile"; private string allAssetBundleURL = @"http://www.xxx.com.xxx/"; void Start() { StartCoroutine(DownloadMainAssetBundle()); } /// <summary> /// 下载目录AssetBundle文件 /// </summary> IEnumerator DownloadMainAssetBundle() { //创建一个获取AssetBundle文件的web请求 UnityWebRequest request = UnityWebRequestAssetBundle.GetAssetBundle(mainAssetBundleURL); //发送web请求 yield return request.SendWebRequest(); //从请求中获取内容,返回AssetBundle类型的数据 AssetBundle ab = DownloadHandlerAssetBundle.GetContent(request); //从"目录AssetBundle"中获取manifest数据 AssetBundleManifest manifest = ab.LoadAsset<AssetBundleManifest>("AssetBundleManifest"); //获取manifest文件中所有的AssetBundle的名称信息 string[] names = manifest.GetAllAssetBundles(); foreach (var name in names) { StartCoroutine(DownloadAssetBundleAndSave(allAssetBundleURL + name)); } } /// <summary> /// 下载AssetBundle并保存到本地 /// </summary> IEnumerator DownloadAssetBundleAndSave(string url) { UnityWebRequest request = UnityWebRequest.Get(url); yield return request.SendWebRequest(); // 截取路径地址中的文件名(需要引入System.IO) string fileName = Path.GetFileName(url); SaveAssetBundle(fileName, request.downloadHandler.data); } /// <summary> /// 存储AssetBundle为本地文件 /// </summary> private void SaveAssetBundle(string fileName, byte[] bytes) { //创建一个文件信息对象(System.IO) FileInfo fileInfo = new FileInfo(Application.streamingAssetsPath + "//" + fileName); //创建一个文件流对象 FileStream fs = fileInfo.Create(); //通过文件流对象,往文件内写入信息 fs.Write(bytes, 0, bytes.Length); //文件写入存储到硬盘 fs.Flush(); //关闭文件流对象 fs.Close(); //销毁文件对象 fs.Dispose(); } }
