初步整理并且学习unity3d资源加载方法，预计用时两天完成入门学习Unity3d常用两种加载资源方案：Resources.Load和AssetBundle

Resources.Load就是从一个缺省打进程序包里的AssetBundle里加载资源而一般AssetBundle文件需要你自己创建，运行时动态加载，

可以指定路径和来源的。其实场景里所有静态的对象也有这么一个加载过程，只是Unity后台替你自动完成

一：Resources.Load：使用这种方式加载资源，首先需要下Asset目录下创建一个名为Resources的文件夹，这个命名是U3D规定的方式，然后把资源文件放进去，

当然也可以在Resources中再创建子文件夹，当然在代码加载时需要添加相应的资源路径，下面是一个简demo，两个预设，Cube和Sphere，

其中Cube放在Resource中的Prebs中，而Sphere放在Resources跟目录下，下面分别实现Resources.Load资源的加载

 

using UnityEngine;using System.Collections;public class LoadResDemo : MonoBehaviour {    private string cubePath = "Prebs/MyCubePreb";    private string spherePath = "MySpherePreb";    void Start () {        //把资源加载到内存中        Object  cubePreb = Resources.Load(cubePath, typeof(GameObject));        //用加载得到的资源对象，实例化游戏对象，实现游戏物体的动态加载        GameObject cube = Instantiate(cubePreb) as GameObject;        //以下同理实现Sphere的动态实例化        //把资源加载到内存中        Object spherePreb = Resources.Load(spherePath, typeof(GameObject));        //用加载得到的资源对象，实例化游戏对象，实现游戏物体的动态加载        GameObject sphere = Instantiate(spherePreb) as GameObject;    }        void Update () {        }}

　　将上面的脚本附加到某个游戏对象上，在运行游戏时就可以看到场景中动态创建的上面的游戏对象了

上面是第一种使用Resources.Load()的方式动态加载游戏对象的，然而在项目中更长用的却是第二种使用AssetBundle的方式动态加载游戏对象。

使用AssetBundle打包预设或者场景可以将与其相关的所有资源打包，这样很好地解决资源的依赖问题，使得我们可以方便的加载GameObject

首先需要打包资源：

using UnityEngine;using System.Collections;using UnityEditor;using System.IO;public class AesstBundleTest : MonoBehaviour {    [MenuItem("Custom Bundle/Create Bundel Main")]    public static void creatBundleMain()    {        //获取选择的对象的路径        Object[] os = Selection.GetFiltered(typeof(Object), SelectionMode.DeepAssets);        bool isExist = Directory.Exists(Application.dataPath + "/StreamingAssets");        if (!isExist)        {            Directory.CreateDirectory(Application.dataPath + "/StreamingAssets");        }        foreach (Object o in os)        {            string sourcePath = AssetDatabase.GetAssetPath(o);            string targetPath = Application.dataPath + "/StreamingAssets/" + o.name + ".assetbundle";            if (BuildPipeline.BuildAssetBundle(o, null, targetPath, BuildAssetBundleOptions.CollectDependencies))            {                print("create bundle cuccess!");            }            else            {                print("failure happen");            }            AssetDatabase.Refresh();        }    }    [MenuItem("Custom Bundle/Create Bundle All")]    public static void CreateBundleAll()    {        bool isExist = Directory.Exists(Application.dataPath + "/StreamingAssets");        if (!isExist)        {            Directory.CreateDirectory(Application.dataPath + "/StreamingAssets");        }        Object[] os = Selection.GetFiltered(typeof(Object), SelectionMode.DeepAssets);        if (os == null || os.Length == 0)        {            return;        }        string targetPath = Application.dataPath + "/StreamingAssets/" + "All.assetbundle";        if (BuildPipeline.BuildAssetBundle(null, os, targetPath, BuildAssetBundleOptions.CollectDependencies))        {            print("create bundle all cuccess");        }        else        {            print("failure happen");        }        AssetDatabase.Refresh();    }}

把上面的代码放在Editor中，在菜单栏中就可以看见自定的菜单项，选中需要打包的预设，就可以把对应的预设打包并输出到StreamAssets中了

然后是动态加载资源：

using UnityEngine;using System.Collections;public class LoadBundleTest : MonoBehaviour {    //不同平台下StreamingAssets的路径是不同的，这里需要注意一下。    public static readonly string PathURL =    #if UNITY_ANDROID        "jar:file://" + Application.dataPath + "!/assets/";    #elif UNITY_IPHONE        Application.dataPath + "/Raw/";    #elif UNITY_STANDALONE_WIN || UNITY_EDITOR    "file://" + Application.dataPath + "/StreamingAssets/";    #else        string.Empty;    #endif        // Update is called once per frame    void Update () {        }    void OnGUI()    {        if (GUILayout.Button("Load Bundle Main"))        {            string path_shpere = PathURL + "MySpherePreb.assetbundle";            StartCoroutine(loadBundleMain(path_shpere));            string path_cube = PathURL + "MyCubePreb.assetbundle";            StartCoroutine(loadBundleMain(path_cube));            print(path_cube);        }        if (GUILayout.Button("Load Bundle All"))        {            StartCoroutine(loadBundleAll(PathURL + "All.assetbundle"));        }    }    private IEnumerator loadBundleMain(string path)    {        WWW bundle = new WWW(path);      //  yield return bundle;         Instantiate(bundle.assetBundle.mainAsset);         bundle.assetBundle.Unload(false);         yield return 1;    }    private IEnumerator loadBundleAll(string path)    {        WWW bundle = new WWW(path);        yield return bundle;        Instantiate(bundle.assetBundle.Load("MyCubePreb"));        Instantiate(bundle.assetBundle.Load("MySpherePreb"));        yield return 1;    }}