[游戏开发]Unity2021 AssetBundle资源打包

Unity2021 AssetBundle资源打包

AssetBundle是一种动态地资源加载方式。如果一次性地把资源导到游戏里，会使得游戏过大。可以把一些资源（例如：预制体、image、材质、music）与游戏主体分离，然后把这些分离的资源放到服务器上。当游戏需要该资源的时候就从服务器加载该资源，从而实现了资源的动态更新。

1. 打包的主要步骤

• 设置打包的对象

• 生成AssetBundle

• 上传到服务器

• 下载AssetBundle

• 加载对象

• 使用对象

2.设置打包对象

• 首先，设置打包对象。

  • 新建Prefabs文件夹，把图片放在Prefabs文件夹中。

  • 新建一个材质球，把材质球添加到beijing中。

  • 点击beijing预制体，可以看到Inspector窗口的右下角有个AssetBudle选项，第一个下拉菜单设置打包名称，第二个设置拓展名，都可以通过new自定义。

  • 在这里，把三幅图片预制体都设置成allres打包名，以及u3d拓展名。

3.生成AssetBundle

• 设置能够快速打包的编辑菜单

  using System.IO;
  using UnityEngine;
  using UnityEditor;
  public class MyTools : Editor
  {
      [MenuItem("Tools/CreateBundle")]
      static void CreateAssetBundle()
      {
          string path = "AB";//写入文件
          if (!Directory.Exists(path))
          {
              Directory.CreateDirectory(path);
          }
          //path:打包路径，BuildAssetBundleOptions.None：打包方式， BuildTarget.StandaloneWindows64：打包的目标平台
          BuildPipeline.BuildAssetBundles(path, BuildAssetBundleOptions.None, BuildTarget.StandaloneWindows64);
          Debug.Log("Created Bundle!");
      }
  }
  
  

• 打包参数的设置

  None	不使用任何特殊选项构建 assetBundle。
  UncompressedAssetBundle	Don’t compress the data when creating the AssetBundle.
  DisableWriteTypeTree	不包括 AssetBundle 中的类型信息。
  DeterministicAssetBundle	使用存储在资源包中对象的 ID 的哈希构建资源包。
  ForceRebuildAssetBundle	强制重新构建 assetBundle。
  IgnoreTypeTreeChanges	在执行增量构建检查时忽略类型树更改。
  AppendHashToAssetBundleName	向 assetBundle 名称附加哈希。
  ChunkBasedCompression	创建 AssetBundle 时使用基于语块的 LZ4 压缩。
  StrictMode	如果在此期间报告任何错误，则构建无法成功。
  DryRunBuild	进行干运行构建。
  DisableLoadAssetByFileName	禁用按照文件名称查找资源包 LoadAsset。
  DisableLoadAssetByFileNameWithExtension	禁用按照带扩展名的文件名称查找资源包 LoadAsset。
  AssetBundleStripUnityVersion	在构建过程中删除存档文件和序列化文件头中的 Unity 版本号。

• 设置完成后，经过引擎的编译，编辑栏上会出现Tools工具栏，点击Tools->CreateBundle，就会在工程目录下生成AB文件夹，里面有各种刚刚设置好的打包对象资源。

• u3d拓展名的文件为资源文件。
• manifest文件为资源的一些信息

• 打开manifest文件

  • ①为资源路径。

  • ②为依赖对象的路径，因为beijing预制体绑定了一个材质，因此此依赖对象也使beijing预制体的材质对象。

4.读取打包资源

? 读取打包资源，一般有4种方法。分别为从内存种读取、从文件中读取、通过WWW方式读取、unityWebRequest读取（推荐）。

1. 从内存中读取

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

public class LoadAssetBundle : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        StartCoroutine(fromMemory());
        //StartCoroutine(fromFile()); //读取单个文件
        //StartCoroutine(fromAllFile());//读取多个文件
        //StartCoroutine(fromWWW1());
        //StartCoroutine(fromWWW2());
        //StartCoroutine(fromunityWebRequest());

    }

    // Update is called once per frame
    void Update()
    {
        
    }
    //内存
    IEnumerator fromMemory()
    {

        string path = @"D:\Unity3d\Project\AssetBundleDemo\AB\background.u3d";
        string matpath = @"D:\Unity3d\Project\AssetBundleDemo\AB\mat1.u3d";
        byte[] bytes = File.ReadAllBytes(path);
        byte[] matbytes = File.ReadAllBytes(matpath);
        
        AssetBundle assetBundle = AssetBundle.LoadFromMemory(bytes);//以内存的方式加载
        AssetBundle matassetBundle = AssetBundle.LoadFromMemory(matbytes);//材质不需要实例化，只需要加载到内存就可以了
        
        
        GameObject prefabGo = assetBundle.LoadAsset("beijing") as GameObject;//实例化游戏对象
        GameObject.Instantiate(prefabGo);
        
        yield return null;
    }
}

• 点击运行，beijing的资源和beijing所依赖的材质都加载到场景了。

2. 从文件中读取

• 单文件方式

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

public class LoadAssetBundle : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        //StartCoroutine(fromMemory());
        StartCoroutine(fromFile()); //读取单个文件
        //StartCoroutine(fromAllFile());//读取多个文件
        //StartCoroutine(fromWWW1());
        //StartCoroutine(fromWWW2());
        //StartCoroutine(fromunityWebRequest());

    }
    
    //文件
    IEnumerator fromFile()
    {
        string path = @"D:\Unity3d\Project\AssetBundleDemo\AB\background.u3d";
        string matpath = @"D:\Unity3d\Project\AssetBundleDemo\AB\mat1.u3d";
        AssetBundle assetBundle = AssetBundle.LoadFromFile(path);
        AssetBundle matassetBundle = AssetBundle.LoadFromFile(matpath);
        
        GameObject preobj = assetBundle.LoadAsset("beijing") as GameObject;
        GameObject.Instantiate(preobj);
        
        yield return null;
    }
}

• 多文件方式

  using System.Collections;
  using System.IO;
  using UnityEngine;
  using UnityEngine.Networking;
  
  public class LoadAssetBundle : MonoBehaviour
  {
      // Start is called before the first frame update
      void Start()
      {
          //StartCoroutine(fromMemory());
          //StartCoroutine(fromFile()); //读取单个文件
          StartCoroutine(fromAllFile());//读取多个文件
          //StartCoroutine(fromWWW1());
          //StartCoroutine(fromWWW2());
          //StartCoroutine(fromunityWebRequest());
  
      }
  
      IEnumerator fromAllFile()
      {
          string path = @"D:\Unity3d\Project\AssetBundleDemo\AB\allres.u3d";
          string matpath = @"D:\Unity3d\Project\AssetBundleDemo\AB\mat1.u3d";
          AssetBundle assetBundle = AssetBundle.LoadFromFile(path);
          Object[] objlist = assetBundle.LoadAllAssets();
          
          foreach (var obj in objlist)
          {
              GameObject.Instantiate(obj as GameObject);
          }
          
          
          AssetBundle matassetBundle = AssetBundle.LoadFromFile(matpath);
          yield return null;
      }
  }
  

  • 点击运行，所有的资源都加载到场景里

3.通过WWW方式读取

• 无缓存WWW方式

  using System.Collections;
  using System.IO;
  using UnityEngine;
  using UnityEngine.Networking;
  
  public class LoadAssetBundle : MonoBehaviour
  {
      // Start is called before the first frame update
      void Start()
      {
          //StartCoroutine(fromMemory());
          //StartCoroutine(fromFile()); //读取单个文件
          //StartCoroutine(fromAllFile());//读取多个文件
          StartCoroutine(fromWWW1());
          //StartCoroutine(fromWWW2());
          //StartCoroutine(fromunityWebRequest());
  
      }
      
      //WWW无缓存机制
      IEnumerator fromWWW1()
      {
          //物体部分
          string path = @"file:///D:\Unity3d\Project\AssetBundleDemo\AB\allres.u3d";
          WWW www = new WWW(path);
          yield return www;
          
          //如果错误信息不空，则打印错误信息，并且中断
          if (!string.IsNullOrEmpty(www.error))
          {
              Debug.Log(www.error);
              yield break;
          }
  
          AssetBundle asset = www.assetBundle;
          GameObject pre = asset.LoadAsset("beijing") as GameObject;
          GameObject.Instantiate(pre);
          
          //材质部分
          string matpath = @"file:///D:\Unity3d\Project\AssetBundleDemo\AB\mat1.u3d";
          WWW matwww = new WWW(matpath);
          if (!string.IsNullOrEmpty(matwww.error))
          {
              Debug.Log(matwww.error);
              yield break;
          }
          AssetBundle matasset = matwww.assetBundle;
          
          www.Dispose();
          www = null;
          matwww.Dispose();
          matwww = null;
          
          yield return null;
      }
  }
  

• 有缓存方式

  using System.Collections;
  using System.IO;
  using UnityEngine;
  using UnityEngine.Networking;
  
  public class LoadAssetBundle : MonoBehaviour
  {
      // Start is called before the first frame update
      void Start()
      {
          //StartCoroutine(fromMemory());
          //StartCoroutine(fromFile()); //读取单个文件
          //StartCoroutine(fromAllFile());//读取多个文件
          //StartCoroutine(fromWWW1());
          StartCoroutine(fromWWW2());
          //StartCoroutine(fromunityWebRequest());
  
      }
      //WWW缓存机制
      IEnumerator fromWWW2()
      {
          //物体部分
          string path = @"file:///D:\Unity3d\Project\AssetBundleDemo\AB\allres.u3d";
          WWW www = WWW.LoadFromCacheOrDownload(path, 1);//如果缓存中有对应的版本，则直接从缓存中读取,如果没有则返回一个错误信息
          //如果错误信息不空，则打印错误信息，并且中断
          //得到错误信息后，可以重定向路径
          if (!string.IsNullOrEmpty(www.error))
          {
              Debug.Log(www.error);
              yield break;
          }
  
          AssetBundle asset = www.assetBundle;
          GameObject pre = asset.LoadAsset("beijing") as GameObject;
          GameObject.Instantiate(pre);
          
          //材质部分
          string matpath = @"file:///D:\Unity3d\Project\AssetBundleDemo\AB\mat1.u3d";
          WWW matwww = WWW.LoadFromCacheOrDownload(matpath,1);
          if (!string.IsNullOrEmpty(matwww.error))
          {
              Debug.Log(matwww.error);
              yield break;
          }
          AssetBundle matasset = matwww.assetBundle;
          
          www.Dispose();
          www = null;
          matwww.Dispose();
          matwww = null;
          
          yield return null;
      }
  }
  

4.通过unityWebRequest读取

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

public class LoadAssetBundle : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        //StartCoroutine(fromMemory());
        //StartCoroutine(fromFile()); //读取单个文件
        //StartCoroutine(fromAllFile());//读取多个文件
        //StartCoroutine(fromWWW1());
        //StartCoroutine(fromWWW2());
        StartCoroutine(fromunityWebRequest());

    }
    
    //unityWebRequest
    IEnumerator fromunityWebRequest()
    {
        //物体部分
        string path = @"file:///D:\Unity3d\Project\AssetBundleDemo\AB\allres.u3d";
        UnityWebRequest unityWebRequest;
        unityWebRequest = UnityWebRequestAssetBundle.GetAssetBundle(path);
        yield return unityWebRequest.SendWebRequest();//发送请求获取资源

        AssetBundle asset = DownloadHandlerAssetBundle.GetContent(unityWebRequest);//获取上面请求得到的资源
        GameObject pre = asset.LoadAsset("beijing") as GameObject;
        GameObject.Instantiate(pre);
        
        //材质部分
        string matpath = @"file:///D:\Unity3d\Project\AssetBundleDemo\AB\mat1.u3d";
        UnityWebRequest matunityWebRequest;
        matunityWebRequest = UnityWebRequestAssetBundle.GetAssetBundle(matpath);
        yield return matunityWebRequest.SendWebRequest();
        AssetBundle matasset = DownloadHandlerAssetBundle.GetContent(matunityWebRequest);
        
        
        yield return null;
    }
}