AssetBundle系列——游戏资源打包（一）

将本地资源打包，然后放到资源服务器上供游戏客户端下载或更新。服务器上包含以下资源列表：
(1)游戏内容资源assetbundle
(2)资源维护列表，包含每个资源的名字(完整路径名)和对应的版本号[资源名，版本号]，如下表所示（VersionNum.xml）:

<VersionNum>
  <File FileName="Assets.Resources.BigLevelTexture.TestLevel.assetbundle" Num="" />
  <File FileName="Assets.Resources.EquipmentTexture.Test001.assetbundle" Num="" />
  <File FileName="Assets.Resources.EquipmentTexture.Test002.assetbundle" Num="" />
  <File FileName="Assets.Resources.EquipmentTexture.Test003.assetbundle" Num="" />
  <File FileName="Assets.Resources.EquipmentTexture.Test004.assetbundle" Num="" />
  <File FileName="Assets.Resources.PetTexture.Empty.assetbundle" Num="" />
</VersionNum>

那么本地客户端的资源打包编辑器就需要完成以下工作：将资源打包、生成版本号。
我们采用通过MD5码对比的方式来对版本号进行管理，如果某资源的MD5码变更了，则将其版本号+1，否则不变。那么，可以将编辑器的具体任务划分如下：
(1)将资源打包成assetbundle，并放到指定目录下
(2)为每个assetbund生成最新MD5码，用于检查资源是否有修改
(3)比较新旧MD5码列表，产生资源变更列表，对于每个变更的资源，将其版本号+1
(4)将变更列表文件也打包成assetbundle

各个平台使用的资源包时各自独立的，打包资源代码时的选项不一样，编辑器界面如下，图2中的4个按钮每个对应上述的一步操作：

最终生成的资源目录结构如下所示：

编辑器代码如下所示（包括菜单项和窗口）：

using UnityEditor;
using UnityEngine;
using System.IO;
using System.Collections;
using System.Collections.Generic;

public class AssetBundleController : EditorWindow
{
    public static AssetBundleController window;
    public static UnityEditor.BuildTarget buildTarget = BuildTarget.StandaloneWindows;

    [MenuItem("XiYouEditor/AssetBundle/AssetBundle For Windows32", false, )]
    public static void ExecuteWindows32()
    {
        if (window == null)
        {
            window = (AssetBundleController)GetWindow(typeof(AssetBundleController));
        }
        buildTarget = UnityEditor.BuildTarget.StandaloneWindows;
        window.Show();
    }

    [MenuItem("XiYouEditor/AssetBundle/AssetBundle For IPhone", false, )]
    public static void ExecuteIPhone()
    {
        if (window == null)
        {
            window = (AssetBundleController)GetWindow(typeof(AssetBundleController));
        }
        buildTarget = UnityEditor.BuildTarget.iPhone;
        window.Show();
    }

    [MenuItem("XiYouEditor/AssetBundle/AssetBundle For Mac", false, )]
    public static void ExecuteMac()
    {
        if (window == null)
        {
            window = (AssetBundleController)GetWindow(typeof(AssetBundleController));
        }
        buildTarget = UnityEditor.BuildTarget.StandaloneOSXUniversal;
        window.Show();
    }

    [MenuItem("XiYouEditor/AssetBundle/AssetBundle For Android", false, )]
    public static void ExecuteAndroid()
    {
        if (window == null)
        {
            window = (AssetBundleController)GetWindow(typeof(AssetBundleController));
        }
        buildTarget = UnityEditor.BuildTarget.Android;
        window.Show();
    }

    [MenuItem("XiYouEditor/AssetBundle/AssetBundle For WebPlayer", false, )]
    public static void ExecuteWebPlayer()
    {
        if (window == null)
        {
            window = (AssetBundleController)GetWindow(typeof(AssetBundleController));
        }
        buildTarget = UnityEditor.BuildTarget.WebPlayer;
        window.Show();
    }

    void OnGUI()
    {
        if (GUI.Button(new Rect(10f, 10f, 200f, 50f), "(1)CreateAssetBundle"))
        {
            CreateAssetBundle.Execute(buildTarget);
            EditorUtility.DisplayDialog("", "Step (1) Completed", "OK");
        }

        if (GUI.Button(new Rect(10f, 80f, 200f, 50f), "(2)Generate MD5"))
        {
            CreateMD5List.Execute(buildTarget);
            EditorUtility.DisplayDialog("", "Step (2) Completed", "OK");
        }

        if (GUI.Button(new Rect(10f, 150f, 200f, 50f), "(3)Compare MD5"))
        {
            CampareMD5ToGenerateVersionNum.Execute(buildTarget);
            EditorUtility.DisplayDialog("", "Step (3) Completed", "OK");
        }

        if (GUI.Button(new Rect(10f, 220f, 200f, 50f), "(4)Build VersionNum.xml"))
        {
            CreateAssetBundleForXmlVersion.Execute(buildTarget);
            EditorUtility.DisplayDialog("", "Step (4) Completed", "OK");
        }
    }

    public static string GetPlatformPath(UnityEditor.BuildTarget target)
    {
        string SavePath = "";
        switch (target)
        {
            case BuildTarget.StandaloneWindows:
                SavePath = "Assets/AssetBundle/Windows32/";
                break;
            case BuildTarget.StandaloneWindows64:
                SavePath = "Assets/AssetBundle/Windows64/";
                break;
            case BuildTarget.iPhone:
                SavePath = "Assets/AssetBundle/IOS/";
                break;
            case BuildTarget.StandaloneOSXUniversal:
                SavePath = "Assets/AssetBundle/Mac/";
                break;
            case BuildTarget.Android:
                SavePath = "Assets/AssetBundle/Android/";
                break;
            case BuildTarget.WebPlayer:
                SavePath = "Assets/AssetBundle/WebPlayer/";
                break;
            default:
                SavePath = "Assets/AssetBundle/";
                break;
        }

        if (Directory.Exists(SavePath) == false)
            Directory.CreateDirectory(SavePath);

        return SavePath;
    }

    public static string GetPlatformName(UnityEditor.BuildTarget target)
    {
        string platform = "Windows32";
        switch (target)
        {
            case BuildTarget.StandaloneWindows:
                platform = "Windows32";
                break;
            case BuildTarget.StandaloneWindows64:
                platform = "Windows64";
                break;
            case BuildTarget.iPhone:
                platform = "IOS";
                break;
            case BuildTarget.StandaloneOSXUniversal:
                platform = "Mac";
                break;
            case BuildTarget.Android:
                platform = "Android";
                break;
            case BuildTarget.WebPlayer:
                platform = "WebPlayer";
                break;
            default:
                break;
        }
        return platform;
    }

}

PS:每个操作的具体实现，见下一篇讲解...