unity3d加密资源并缓存加载

// C# Example 


// Builds an asset bundle from the selected objects in the project view. 


// Once compiled go to "Menu" -> "Assets" and select one of the choices 


// to build the Asset Bundle 


using UnityEngine; 


using UnityEditor; 


using System.IO; 


public class ExportAssetBundles { 


[MenuItem("Assets/Build AssetBundle Binary file From Selection - Track dependencies ")] 


static void ExportResource () { 


// Bring up save panel 


string path = EditorUtility.SaveFilePanel ("Save Resource", "", "New Resource", "unity3d"); 


if (path.Length != 0) { 


// Build the resource file from the active selection. 


Object[] selection = Selection.GetFiltered(typeof(Object), SelectionMode.DeepAssets); 


BuildPipeline.BuildAssetBundle(Selection.activeObject, selection, path, BuildAssetBundleOptions.CollectDependencies | BuildAssetBundleOptions.CompleteAssets); 


Selection.objects = selection; 


FileStream fs = new FileStream(path,FileMode.Open,FileAccess.ReadWrite); 


byte[] buff = new byte[fs.Length+1]; 


fs.Read(buff,0,(int)fs.Length); 


buff[buff.Length-1] = 0; 


fs.Close(); 


File.Delete(path); 


string BinPath = path.Substring(0,path.LastIndexOf('.'))+".bytes"; 


//              FileStream cfs = new FileStream(BinPath,FileMode.Create); 


cfs.Write(buff,0,buff.Length); 


buff =null; 


cfs.Close(); 


//              string AssetsPath = BinPath.Substring(BinPath.IndexOf("Assets")); 


//              Object ta = AssetDatabase.LoadAssetAtPath(AssetsPath,typeof(Object)); 


//              BuildPipeline.BuildAssetBundle(ta, null, path); 


} 


} 


[MenuItem("Assets/Build AssetBundle From Selection - No dependency tracking")] 


static void ExportResourceNoTrack () { 


// Bring up save panel 


string path = EditorUtility.SaveFilePanel ("Save Resource", "", "New Resource", "unity3d"); 


if (path.Length != 0) { 


// Build the resource file from the active selection. 


BuildPipeline.BuildAssetBundle(Selection.activeObject, Selection.objects, path); 


} 


} 


} 

把打包的文件转换成了binary文件并多加了一个字节加密。

　　当bytes文件生成好后再选中它，使用"Assets/Build AssetBundle From Selection - No dependency tracking"再次打包。

using UnityEngine;
using System.Collections;
using System;
public class WWWLoadTest : MonoBehaviour
{
public string BundleURL;
public string AssetName;
IEnumerator Start()
{
WWW www =WWW.LoadFromCacheOrDownload(BundleURL,2);
yield return www;
TextAsset txt = www.assetBundle.Load("characters",typeof(TextAsset)) as TextAsset;
byte[]  data = txt.bytes;
byte[] decryptedData = Decryption(data);
Debug.LogError("decryptedData length:"+decryptedData.Length);
StartCoroutine(LoadBundle(decryptedData));
}
IEnumerator LoadBundle(byte[] decryptedData){
AssetBundleCreateRequest acr = AssetBundle.CreateFromMemory(decryptedData);
yield return acr;
AssetBundle bundle = acr.assetBundle;
Instantiate(bundle.Load(AssetName));
}
byte[] Decryption(byte[] data){
byte[] tmp = new byte[data.Length-1];
for(int i=0;i<data.Length-1;i++){
tmp[i] = data[i];
}
return tmp;
}
}

WWW.LoadFromCacheOrDownload的作用就是下载并缓存资源，要注意后面的版本号参数，如果替换了资源却没有更新版本号，客户端依然会加载缓存中的文件。

www.assetBundle.Load("characters",typeof(TextAsset)) as TextAsset  //characters是加密文件的名字

AssetBundleCreateRequest acr = AssetBundle.CreateFromMemory(decryptedData);           

这句是官网最坑爹的，AssetBundle.CreateFromMemory明明返回的是AssetBundleCreateRequest官网却写得是AssetBundle，而且AssetBundleCreateRequest是一个异步加载，必须用协程的方式加载官网也没有提到。跟多兄弟就倒在了这里