Unity3D

【Unity3D】基于AssetBundle实现资源热更新

2023-03-17  本文已影响0人  LittleFatSheep

1 前言

Unity3D 本地资源一般放在 Resources 目录下,但是 Resouces 文件夹的大小不能超过 2G,使用 AssetBundle 管理资源可以解决 Resources 文件夹受限问题。

本文代码资源见→基于AssetBundle实现资源热更新(更新版)

AssetBundle 主要用于管理资源,配合 AssetDatabase 和 AssetImporter 可以实现资源重命名,配合 BuildPipeline 可以实现资源压缩,配合 WWW 或 UnityWebRequest 可以实现加载服务器资源。下面简单介绍下相关接口:

1)AssetBundle 获取资源名,加载、卸载资源

静态方法:

// 从文件中加载AssetBundle
public static AssetBundle LoadFromFile(string path)
// 从二进制数组中加载AssetBundle
public static AssetBundle LoadFromMemory(byte[] binary)
// 从流中加载AssetBundle
public static AssetBundle LoadFromStream(Stream stream)
// 卸载所有AssetBundle
public static void UnloadAllAssetBundles(bool unloadAllObjects)
// 销毁对象
public static void Destroy(Object obj)

实例方法:

// 获取所有资源名
public string[] GetAllAssetNames()
// 判断是否包含资源
public bool Contains(string name)
// 加载资源
public Object[] LoadAllAssets()
public T[] LoadAllAssets<T>() where T : Object
public Object[] LoadAllAssets(Type type)
public Object LoadAsset(string name)
public T LoadAsset<T>(string name) where T : Object
public Object LoadAsset(string name, Type type)
// 卸载资源, unloadAllLoadedObjects为false时不卸载已从Bundle中加载出的资源
public void Unload(bool unloadAllLoadedObjects)

说明:入参 name 不区分大小写,建议使用小写,如果使用大写会自动转换为小写。

2)AssetBundleManifest 获取资源依赖

// 获取所有AssetBundles
public string[] GetAllAssetBundles()
// 获取指定assetBundleName的直接依赖
public string[] GetDirectDependencies(string assetBundleName)
// 获取指定assetBundleName的所有依赖
public string[] GetAllDependencies(string assetBundleName)

说明:入参 assetBundleName 不区分大小写,建议使用小写,如果使用大写会自动转换为小写。

3)AssetDatabase 获取所有资源名、删除资源

// 获取所有AssetBundle资源名
public static string[] GetAllAssetBundleNames()
// 根据assetBundleName删除AssetBundle
public static bool RemoveAssetBundleName(string assetBundleName, bool forceRemove)
// 刷新Project视图目录, 相当于右键手动刷新
public static void Refresh()

4)AssetImporter 设置资源名

// 获取AssetImporter, 资源文件路径
public static AssetImporter GetAtPath(string path)
// 获取/设置资源文件名
public string assetBundleName { get; set; }

5)BuildPipeline 压缩资源

// 压缩所有标记为AssetBundle的资源
public static AssetBundleManifest BuildAssetBundles(
    string outputPath, // 压缩文件输出路径
    BuildAssetBundleOptions assetBundleOptions, // 压缩算法
    BuildTarget targetPlatform // 平台
)
// BuildAssetBundleOptions.None: LZMA压缩算法, 压缩比大, 加载慢, 使用前需要整体解压
// BuildAssetBundleOptions.ChunkBasedCompression: LZ4压缩算法, 压缩比中等, 加载快可以加载指定资源而不用解压全部
// BuildAssetBundleOptions.UncompressedAssetBundle: 不压缩, 加载快

6)WWW 获取网络资源

// 获取WWW
public static WWW LoadFromCacheOrDownload(string url, int version)
// 获取AssetBundle
public AssetBundle assetBundle { get; }
说明:WWW 被 Unity3D 官方标记为过时了,建议使用 UnityWebRequest。

7)UnityWebRequest 获取网络资源

UnityWebRequest webRequest = UnityWebRequestAssetBundle.GetAssetBundle(uri)
yield return webRequest.SendWebRequest()
AssetBundle assetBundle = DownloadHandlerAssetBundle.GetContent(webRequest)

2 资源命名

Asset 资源主要有脚本、图片、网格、模型、预设体等,在 Assets 窗口选中资源,在 Inspector 窗口选择 AssetBundle 下拉列表,选择 New 给资源添加 AssetBundle 名,如下:

说明:AssetBundle 名不区分大小写,如果输入大写会自动转换为小写。只有添加了 AssetBundle 名的资源才能通过 BuildPipeline.BuildAssetBundles() 打包压缩。

3 资源压缩

1)创建目录及原资源

在 Assets 目录下创建 AssetBundles 目录(存放资源)和 Editor 目录(存放资源压缩脚本),在 AssetBundles 目录下创建 Compress 目录(存放压缩文件)和 Raw 目录(存放原资源文件),再在 Raw 目录下创建 Textures 目录(存放了一张图片 Picture)、Materials 目录(存放了一个材质 Material,并且依赖 Picture)、Prefabs 目录(存放了一个预设体 Quad,并且依赖 Material),目录结构如下:

2)自动压缩脚本

AssetCompressor.cs

using System.IO;
using UnityEditor;
using UnityEngine;

public class AssetCompressor : Editor {
    // G:/Unity3d/AssetBundleDemo/Assets/AssetBundles/Raw
    private static string rawPath = Application.dataPath + "/AssetBundles/Raw";
    // G:/Unity3d/AssetBundleDemo/Assets/AssetBundles/Compress
    private static string compressPath = Application.dataPath + "/AssetBundles/Compress";

    [MenuItem("AssetBundle/CompressAssets")]
    public static void CompressAssets() { // 打包rawPath目录的资源, 生成压缩资源到compressPath目录
        ClearAllFilesBundleName();
        SetAssetBundlesName(rawPath);
        BuildAssetBundles();
        ClearAllFilesBundleName();
        AssetDatabase.Refresh(); // 刷新Project视图目录, 相当于右键手动刷新
    }

    private static void BuildAssetBundles() { // 压缩资源
        BuildPipeline.BuildAssetBundles(compressPath, // 压缩包输出包路径
            BuildAssetBundleOptions.ChunkBasedCompression, // 压缩算法
            BuildTarget.StandaloneWindows64 // Windows平台
        );
    }

    private static void ClearAllFilesBundleName() { // 删除所有AssetBundle名
        string[] names = AssetDatabase.GetAllAssetBundleNames();
        foreach (string name in names) {
            AssetDatabase.RemoveAssetBundleName(name, true);
        }
    }

    private static void SetAssetBundlesName(string rootPath) { // 设置资源的Bundle名
        DirectoryInfo rootInfo = new DirectoryInfo(rootPath);
        FileSystemInfo[] fileInfos = rootInfo.GetFileSystemInfos();
        foreach (FileSystemInfo fileInfo in fileInfos) {
            if (fileInfo is DirectoryInfo) {
                SetAssetBundlesName(fileInfo.FullName); // 递归遍历子文件夹下所有文件
            } else if (!fileInfo.Name.EndsWith(".meta")) {
                SetAssetBundleName(fileInfo.FullName);
            }
        }
    }

    private static void SetAssetBundleName(string filePath) { // 设置资源的Bundle名
        // 导入的相对路径(G:/Unity3d/AssetBundleDemo/Assets/AssetBundles/Compress/prefabs/quad.prefab)
        string impoterPath = "Assets/" + filePath.Substring(Application.dataPath.Length + 1);
        AssetImporter assetImporter = AssetImporter.GetAtPath(impoterPath);
        if (assetImporter != null) {
            filePath = filePath.Substring(rawPath.Length + 1); // 去源文件前缀(可选, 建议使用)
            // filePath = filePath.Substring(filePath.LastIndexOf("\\") + 1); // 去所有前缀(可选, 不建议使用)
            // 去后缀(可选, 不去后缀刷新目录后会报错, 但不影响资源压缩和后续资源加载)
            filePath = filePath.Remove(filePath.LastIndexOf("."));
            assetImporter.assetBundleName = filePath;
        }
    }
}

说明:AssetCompressor.cs 文件需要放在 Editor 目录下,编译成功后,在菜单栏可以看到 AssetBundle 菜单,如下:

点击 CompressAssets 选项,会将 Assets/AssetBundles/Raw 目录下的资源打包压缩至 Assets/AssetBundles/Compress 目录,如下:

注意:如果压缩名不去后缀,会报以下错误,这是因为文件已经压缩了,但还是以 “.prefab”、“.jpg”、“.mat” 为后缀,被 Unity3D 识别为损坏文件。该错误不影响压缩文件生成,也不影响后续资源加载,可以忽略。如果不想出现以下报错,可以将去后缀的注释代码打开。

3)压缩文件

打开 Compress.manifest 文件如下:

ManifestFileVersion: 0
CRC: 2688481811
AssetBundleManifest:
  AssetBundleInfos:
    Info_0:
      Name: materials/material
      Dependencies:
        Dependency_0: textures/picture
    Info_1:
      Name: prefabs/quad
      Dependencies:
        Dependency_0: materials/material
    Info_2:
      Name: textures/picture
      Dependencies: {}

说明:后续要加载资源时,如果不清楚 AssetBundle 名,可以在 Compress.manifest 文件中查看相应 Name 值。可以看到,这里的 Name 值也全都自动转换为小写了,在加载资源时,如果传入大写的也能正常获取到相应资源。

4 加载本地资源

1)加载简单资源

// targetPath="ptextures/picture"
public static T LoadAsset<T>(string targetPath) { // 加载资源
    // G:/Unity3d/AssetBundleDemo/Assets/AssetBundles/Compress/ptextures/picture
    AssetBundle targetBundle = AssetBundle.LoadFromFile(compressPath + "/" + targetPath);
    string fileName = targetPath.Substring(targetPath.LastIndexOf("/") + 1); // picture.jpg
    object obj = targetBundle.LoadAsset(fileName);
    if (obj != null) {
        return (T) obj;
    }
    return default(T);
}

说明:如果没有依赖资源,可以使用该方法;如果有依赖资源,就会出现异常。当 targetPath = "prefabs/quad" 时,创建的 Quad 显示如下,Quad 显示品红,表示它依赖的材质和图片缺失。

2)加载有依赖的资源

LocalAssetLoader.cs

using UnityEngine;

public class LocalAssetLoader {
    // G:/Unity3d/AssetBundleDemo/Assets/AssetBundles/Compress
    private static string compressPath = Application.dataPath + "/AssetBundles/Compress"; // 压缩文件根路径
    // G:/Unity3d/AssetBundleDemo/Assets/AssetBundles/Compress/Compress
    private static string rootManifestPath = compressPath + "/Compress"; // 根manifest文件路径(Compress.manifest文件绝对路径)

    public static T LoadAsset<T>(string targetPath) { // 加载资源
        LoadDependencies(targetPath);
        return LoadTarget<T>(targetPath);
    }

    private static void LoadDependencies(string targetPath) { // 加载目标资源的依赖
        AssetBundle manifestBundle = AssetBundle.LoadFromFile(rootManifestPath);
        // 解压Manifest文件, 传入的参数不区分大小写(如果是大写, 会自动转换为小写)
        AssetBundleManifest manifest = manifestBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");
        string[] dependencies = manifest.GetAllDependencies(targetPath); // 获取目标文件的所有依赖
        for (int i = 0; i < dependencies.Length; i++) {
            string filePath = compressPath + "/" + dependencies[i];
            AssetBundle.LoadFromFile(filePath);
        }
    }

    private static T LoadTarget<T>(string targetPath) { // 加载目标资源
        AssetBundle targetBundle = AssetBundle.LoadFromFile(compressPath + "/" + targetPath);
        string fileName = targetPath.Substring(targetPath.LastIndexOf("/") + 1);
        object obj = targetBundle.LoadAsset(fileName);
        if (obj != null) {
            return (T) obj;
        }
        return default(T);
    }
}

说明:manifest.GetAllDependencies()、AssetBundle.LoadFromFile()、targetBundle.LoadAsset() 的入参不区分大小写,因此传入的 targetPath 也可以不区分大小写。

3)调用 LocalAssetLoader 加载资源

SimpleLoad.cs

using UnityEngine;

public class SimpleLoad : MonoBehaviour {
    private void Start() {
        GameObject obj = LocalAssetLoader.LoadAsset<GameObject>("prefabs/quad"); // 加载预设体
        // GameObject obj = LocalAssetLoader.LoadAsset<GameObject>("Prefabs/Quad"); // 加载预设体
        Instantiate(obj);
    }
}

说明: 由于 LocalAssetLoader.LoadAsset 的入参不区分大小写,因此传入 "prefabs/quad" 和 "Prefabs/Quad" 都能正确加载资源。

运行效果如下:

5 使用 WWW 加载服务器资源

W3AssetLoader.cs

using System;
using System.Collections;
using UnityEngine;

public class W3AssetLoader : MonoBehaviour {
    private string compressPath; // 压缩文件根路径
    private string rootManifestPath; // 根manifest文件路径
    private static W3AssetLoader instance; // 单例

    private void Awake() {
        instance = this;
        // compressPath = GetW3Path(Application.dataPath + "/AssetBundle/Compress");
        compressPath = "https://gitcode.net/m0_37602827/AssetBundleDemo/-/raw/master/Assets/AssetBundles/Compress";
        rootManifestPath = compressPath + "/Compress";
    }

    public static void LoadAsset<T>(string targetPath, Action<T> action) { // 加载资源
        instance.StartCoroutine(instance.LoadAssetCorutine<T>(targetPath, action));
    }

    private IEnumerator LoadAssetCorutine<T>(string targetPath, Action<T> action) { // 加载资源的协程
        yield return LoadDependencies(targetPath);
        yield return LoadTarget(targetPath, action);
    }

    private IEnumerator LoadDependencies(string targetPath) { // 加载目标资源的依赖
        WWW w3 = WWW.LoadFromCacheOrDownload(rootManifestPath, 1);
        yield return w3;
        AssetBundle assetBundle = w3.assetBundle;
        if (assetBundle != null) {
            AssetBundleManifest manifest = assetBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");
            if (manifest != null) {
                string[] dependencies = manifest.GetAllDependencies(targetPath); // 获取目标文件的所有依赖
                for (int i = 0; i < dependencies.Length; i++) {
                    string filePath = compressPath + "/" + dependencies[i];
                    w3 = WWW.LoadFromCacheOrDownload(filePath, 1);
                    yield return w3;
                    assetBundle = w3.assetBundle;
                }
            }
        }
    }

    private IEnumerator LoadTarget<T>(string targetPath, Action<T> action) { // 加载目标文件
        string fullPath = compressPath + "/" + targetPath;
        WWW w3 = WWW.LoadFromCacheOrDownload(fullPath, 1);
        yield return w3;
        AssetBundle assetBundle = w3.assetBundle;
        if (assetBundle != null) {
            string fileName = targetPath.Substring(targetPath.LastIndexOf("/") + 1);
            object obj = assetBundle.LoadAsset(fileName); // 解压文件
            if (obj != null && action != null) {
                action.Invoke((T) obj);
            }
        }
    }

    private string GetW3Path(string path) {
        #if UNITY_EDITOR_WIN || UNITY_STANDALONE_WIN
            path = "file:///" + path;
        #elif UNITY_EDITOR_OSX || UNITY_STANDALONE_OSX
            path = "file://" + path;
        #endif
        return path;
    }
}

SimpleLoad.cs

using UnityEngine;

public class SimpleLoad : MonoBehaviour {

    private void Start() {
        W3AssetLoader.LoadAsset<GameObject>("prefabs/quad.prefab", Callback);
        // W3AssetLoader.LoadAsset<GameObject>("Prefabs/Quad.prefab", Callback);
    }

    private void Callback(GameObject obj) {
        Instantiate(obj);
    }
}

说明:W3AssetLoader.LoadAsset() 方法的入参不区分大小写。

6 使用 UnityWebRequest 加载服务器资源

WebAssetLoader.cs

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Networking;

public class WebAssetLoader : MonoBehaviour {
    private string compressPath; // 压缩文件根路径
    private string rootManifestPath; // 根manifest文件路径
    private static WebAssetLoader instance; // 单例

    private void Awake() {
        instance = this;
        // compressPath = GetW3Path(Application.dataPath + "/AssetBundle/Compress");
        compressPath = "https://gitcode.net/m0_37602827/AssetBundleDemo/-/raw/master/Assets/AssetBundles/Compress";
        rootManifestPath = compressPath + "/Compress";
    }

    public static void LoadAsset<T>(string targetPath, Action<T> action) { // 加载资源
        instance.StartCoroutine(instance.LoadAssetCorutine<T>(targetPath, action));
    }

    private IEnumerator LoadAssetCorutine<T>(string targetPath, Action<T> action) { // 加载资源的协程
        yield return LoadDependencies(targetPath);
        yield return LoadTarget(targetPath, action);
    }

    private IEnumerator LoadDependencies(string targetPath) { // 加载目标资源的依赖
        UnityWebRequest webRequest = UnityWebRequestAssetBundle.GetAssetBundle(rootManifestPath);
        yield return webRequest.SendWebRequest();
        AssetBundle assetBundle = DownloadHandlerAssetBundle.GetContent(webRequest);
        if (assetBundle != null) {
            AssetBundleManifest manifest = assetBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");
            if (manifest != null) {
                string[] dependencies = manifest.GetAllDependencies(targetPath); // 获取目标文件的所有依赖
                for (int i = 0; i < dependencies.Length; i++) {
                    string filePath = compressPath + "/" + dependencies[i];
                    webRequest = UnityWebRequestAssetBundle.GetAssetBundle(filePath);
                    yield return webRequest.SendWebRequest();
                    assetBundle = DownloadHandlerAssetBundle.GetContent(webRequest);
                }
            }
        }
    }

    private IEnumerator LoadTarget<T>(string targetPath, Action<T> action) { // 加载目标文件
        string fullPath = compressPath + "/" + targetPath;
        UnityWebRequest webRequest = UnityWebRequestAssetBundle.GetAssetBundle(fullPath);
        yield return webRequest.SendWebRequest();
        AssetBundle assetBundle = DownloadHandlerAssetBundle.GetContent(webRequest);
        if (assetBundle != null) {
            string fileName = targetPath.Substring(targetPath.LastIndexOf("/") + 1);
            object obj = assetBundle.LoadAsset(fileName); // 解压文件
            if (obj != null && action != null) {
                action.Invoke((T) obj);
            }
        }
    }

    private string GetW3Path(string path) {
        #if UNITY_EDITOR_WIN || UNITY_STANDALONE_WIN
            path = "file:///" + path; // Windows平台
        #elif UNITY_EDITOR_OSX || UNITY_STANDALONE_OSX
            path = "file://" + path; // Mac平台
        #endif
        return path;
    }
}

SimpleLoad.cs

using UnityEngine;

public class SimpleLoad : MonoBehaviour {

    private void Start() {
        WebAssetLoader.LoadAsset<GameObject>("prefabs/quad", Callback);
    }

    private void Callback(GameObject obj) {
        Instantiate(obj);
    }
}

说明:WebAssetLoader.LoadAsset() 的入参区分大小写。

声明:本文转自【Unity3D】基于AssetBundle实现资源热更新

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