Unity中Asset Bundle的Emission Map在移动端失效问题求助

问题描述 #

我制作的包含Emission Map的Asset Bundle在Unity编辑器及桌面端运行完全正常，但打包到移动端后，Emission Map完全没有效果，其他功能均正常。以下是我的Asset Bundle构建代码：

using UnityEditor;
using System.IO;
using UnityEngine;

public class CreateAssetBundles {

    public static string assetBundleDirectory = "Assets/AssetBundles/";

    [MenuItem("Assets/Build AssetBundles")]
    static void BuildAllAssetBundles() {

        //if main directory doesnt exist create it
        if (Directory.Exists(assetBundleDirectory)) {
            Directory.Delete(assetBundleDirectory, true);
        }
        
        Directory.CreateDirectory(assetBundleDirectory);
        
        //create bundles for all platform (use IOS for editor support on MAC but must be on IOS build platform)
        BuildPipeline.BuildAssetBundles(assetBundleDirectory,BuildAssetBundleOptions.None, BuildTarget.iOS);
        AppendPlatformToFileName("IOS");
        Debug.Log("IOS bundle created...");

        BuildPipeline.BuildAssetBundles(assetBundleDirectory, BuildAssetBundleOptions.None, BuildTarget.Android);
        AppendPlatformToFileName("Android");
        Debug.Log("Android bundle created...");

        RemoveSpacesInFileNames();

        AssetDatabase.Refresh();
        Debug.Log("Process complete!");
    }

    static void RemoveSpacesInFileNames() {
        foreach (string path in Directory.GetFiles(assetBundleDirectory)) {
            string oldName = path;
            string newName = path.Replace(' ', '-');
            File.Move(oldName, newName);
        }
    }

        static void AppendPlatformToFileName(string platform) {
        foreach (string path in Directory.GetFiles(assetBundleDirectory)) {
            //get filename
            string[] files = path.Split('/');
            string fileName = files[files.Length - 1];

            //delete files we dont need
            if (fileName.Contains(".") || fileName.Contains("Bundle")) {
                File.Delete(path);
            } else if (!fileName.Contains("-")){
                //append platform to filename
                FileInfo info = new FileInfo(path);
                info.MoveTo(path + "-" + platform);
            }
        }
    }
}

解决方法 #

1. 检查Shader与Material的Emission配置 #

• 确认使用的Shader支持移动端Emission：比如Standard Shader要确保Emission选项已勾选，且Emission Color不为纯黑色（纯黑会被Unity自动禁用Emission）。
• 手动启用Emission关键字：在Material的代码中添加material.EnableKeyword("_EMISSION");，确保移动端渲染时识别到发光属性。

2. 修正Asset Bundle构建代码的问题 #

你的构建代码中存在两个关键问题：

• 误删必要文件：AppendPlatformToFileName方法删除了带"."的文件，这会删掉Asset Bundle的.manifest附属文件，导致资源加载时无法正确识别依赖。
• 路径处理不跨平台：用Split('/')处理路径在Windows系统下会出错，建议改用Unity的Path类方法。

修改后的构建代码如下：

using UnityEditor;
using System.IO;
using UnityEngine;

public class CreateAssetBundles {

    public static string assetBundleDirectory = "Assets/AssetBundles/";

    [MenuItem("Assets/Build AssetBundles")]
    static void BuildAllAssetBundles() {

        if (Directory.Exists(assetBundleDirectory)) {
            Directory.Delete(assetBundleDirectory, true);
        }
        
        Directory.CreateDirectory(assetBundleDirectory);
        
        BuildPipeline.BuildAssetBundles(assetBundleDirectory, BuildAssetBundleOptions.None, BuildTarget.iOS);
        AppendPlatformToFileName(BuildTarget.iOS.ToString());
        Debug.Log("IOS bundle created...");

        BuildPipeline.BuildAssetBundles(assetBundleDirectory, BuildAssetBundleOptions.None, BuildTarget.Android);
        AppendPlatformToFileName(BuildTarget.Android.ToString());
        Debug.Log("Android bundle created...");

        RemoveSpacesInFileNames();

        AssetDatabase.Refresh();
        Debug.Log("Process complete!");
    }

    static void RemoveSpacesInFileNames() {
        foreach (string path in Directory.GetFiles(assetBundleDirectory)) {
            string fileName = Path.GetFileName(path);
            if (fileName.Contains(" ")) {
                string newPath = Path.Combine(Path.GetDirectoryName(path), fileName.Replace(' ', '-'));
                File.Move(path, newPath);
            }
        }
    }

    static void AppendPlatformToFileName(string platform) {
        foreach (string path in Directory.GetFiles(assetBundleDirectory)) {
            string fileName = Path.GetFileName(path);
            // 仅处理主Asset Bundle文件，保留manifest文件
            if (!fileName.EndsWith(".manifest") && !fileName.Contains("-")) {
                string newPath = Path.Combine(Path.GetDirectoryName(path), $"{fileName}-{platform}");
                // 同步重命名对应的manifest文件
                string manifestPath = $"{path}.manifest";
                if (File.Exists(manifestPath)) {
                    string newManifestPath = $"{newPath}.manifest";
                    File.Move(manifestPath, newManifestPath);
                }
                File.Move(path, newPath);
            }
        }
    }
}

3. 移动端纹理与渲染设置检查 #

• Emission Map压缩格式：在Texture Import Settings中，为移动端（iOS/Android）选择合适的压缩格式，比如ASTC（iOS）、ETC2（Android），避免使用桌面端的压缩格式导致纹理无法正确解析。
• Quality Settings配置：在Edit > Project Settings > Quality中，切换到Mobile平台，确保Rendering Path为Forward或Deferred（部分低端机可能需要Forward，但要开启Emission支持），同时检查Allow HDR是否启用（发光效果依赖HDR）。
• Lighting Settings：如果使用了烘焙GI，要确保Asset Bundle中的物体在构建前完成了光照烘焙；若使用实时GI，需在移动端开启实时GI支持。

4. 加载Asset Bundle后的验证 #

加载Asset Bundle后，手动检查Material的Emission属性：

// 加载Asset Bundle示例代码
AssetBundle bundle = AssetBundle.LoadFromFile(path);
GameObject obj = bundle.LoadAsset<GameObject>("YourObject");
Material mat = obj.GetComponent<Renderer>().material;
// 验证Emission是否启用
if (!mat.IsKeywordEnabled("_EMISSION")) {
    mat.EnableKeyword("_EMISSION");
}
// 确保Emission Color不为黑
if (mat.GetColor("_EmissionColor") == Color.black) {
    mat.SetColor("_EmissionColor", Color.white * 2f); // 示例：设置发光颜色
}

内容的提问来源于stack exchange，提问作者SRIVASTAVA PRAKHAR SUNIL