AssetBundle 1 (Building And Loading)

1. Build

using UnityEngine;using System.Collections;using UnityEditor;public class BuildBundle {    private const string VARIANT = "ab";    [MenuItem("Test/Build Asset Bundles")]    static void BuildABs() {    // Create the array of bundle build details.    AssetBundleBuild[] buildMap = new AssetBundleBuild[2];        // prfab    buildMap[0].assetBundleName = "111";    string[] assetNames = new string[1];        assetNames[0] = "Assets/res/Prefabs/char/307005/307005.prefab";        buildMap[0].assetNames = assetNames;        //texture        buildMap[1].assetBundleName = "222";        assetNames = new string[1];        assetNames[0] = "Assets/res/Models/char/307005/Materials/307005_001.tga";        buildMap[1].assetNames = assetNames;        string outputPath = Application.dataPath + "/ABs";        BuildAssetBundleOptions op  = BuildAssetBundleOptions.ChunkBasedCompression; // LZ4        //BuildAssetBundleOptions op = BuildAssetBundleOptions.UncompressedAssetBundle;        BuildPipeline.BuildAssetBundles(outputPath, buildMap, op);        AssetDatabase.Refresh();    }}

2.

Load

using UnityEngine;using System.Collections;using System.Collections.Generic;public class LoadAB : MonoBehaviour {// Use this for initializationvoid Start () {        string ABDir = Application.dataPath + "/ABs/";        string mainManifestPath = ABDir + "ABs";        var rootBundle = AssetBundle.LoadFromFile(mainManifestPath);        AssetBundleManifest manifest = rootBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");                string prefabBundleName = "111";        //dependBundle        List<AssetBundle> dependBundleList = new List<AssetBundle>();        string[] dependPath = manifest.GetAllDependencies(prefabBundleName);        for (int i = 0; i < dependPath.Length; i++)        {            Debug.Log(dependPath[i]);            var dependBundle = AssetBundle.LoadFromFile(ABDir + dependPath[i]);            dependBundleList.Add(dependBundle);        }        var myLoadedAssetBundle = AssetBundle.LoadFromFile(ABDir + prefabBundleName);        if (myLoadedAssetBundle == null)        {            Debug.Log("Failed to load AssetBundle!");            return;        }        string prefabAssetPath = "Assets/res/Prefabs/char/307005/307005.prefab";        var prefab = myLoadedAssetBundle.LoadAsset<Object>(prefabAssetPath);        Instantiate(prefab);        // unload        for (int i = 0; i < dependBundleList.Count; i++)        {            dependBundleList[i].Unload(false);        }        myLoadedAssetBundle.Unload(false);}}

Node:

Each AssetBundle will have an associated file with a .manifest extension. This manifest file is a text file that you can open with any text editor. It provides information such as the file CRC and asset dependencies. The AssetBundle in the example above has a manifest file that looks like this:

ManifestFileVersion: 0CRC: 4036177110Hashes:  AssetFileHash:    serializedVersion: 2    Hash: 2adb3efdc80c7f64bf065717f6e98867  TypeTreeHash:    serializedVersion: 2    Hash: 8e187a830a7454c6df7fc214f8624bacHashAppended: 0ClassTypes:- Class: 1  Script: {instanceID: 0}- Class: 4  Script: {instanceID: 0}- Class: 21  Script: {instanceID: 0}- Class: 28  Script: {instanceID: 0}- Class: 43  Script: {instanceID: 0}- Class: 48  Script: {instanceID: 0}- Class: 74  Script: {instanceID: 0}- Class: 90  Script: {instanceID: 0}- Class: 91  Script: {instanceID: 0}- Class: 95  Script: {instanceID: 0}- Class: 136  Script: {instanceID: 0}- Class: 137  Script: {instanceID: 0}Assets:- Assets/res/Prefabs/char/307005/307005.prefabDependencies:- D:/U3D Pro/2017_1_4_Study_AssetBundle/Assets/ABs/222

In addition to these, there are another two files created: Another AssetBundle and another manifest file. These two are always created whenever AssetBundles are created. They are created for each folder that AssetBundles are created in, thus if you always create AssetBundles in the same place, you will only get two extra files. The additional manifest file - in this example AssetBundles.manifest - can be used in much the same way as other manifest files but will show information on how AssetBundles relate and depend on each other. In this case, since we only have a single AssetBundle, it has no other dependencies.

ManifestFileVersion: 0CRC: 2131931493AssetBundleManifest:  AssetBundleInfos:    Info_0:      Name: 111      Dependencies:        Dependency_0: 222    Info_1:      Name: 222      Dependencies: {}

Compress:

BuildAssetBundleOptions.ChunkBasedCompression

-- Use chunk-based LZ4 compression when creating the AssetBundle.

LZ4 Format

Unity also supports LZ4 compression, which results in larger compressed file sizes, but does not require the entire bundle to be decompressed before use. LZ4 is a “chunk-based” algorithm, and therefore when objects are loaded from an LZ4-compressed bundle, only the corresponding chunks for that object are decompressed. This occurs on-the-fly, meaning there are no wait times for the entire bundle to be decompressed before use. The LZ4 Format was introduced in Unity 5.3 and was unavailable in prior versions.