Unity 重置项目资源的guid

有时需要将多个项目的资源合并到一个项目中，但有可能有些资源是共用的，它的guid是一样的，这样合并到一个项目时，可能会超成冲突。

如果要让每个资源的guid都不相同，就需要重新生成guid，并且更新引用。下面是步骤

1. UNITY菜单-> Editor > Project Setting - > Editor 

设置 Version Controller 为Visible Meta Files

2. Asset Serialization 设置为 Force Text

3. 下面是代码

using System;using System.Collections.Generic;using System.IO;using UnityEditor;namespace UnityGuidRegenerator {    public class UnityGuidRegeneratorMenu {        [MenuItem("Tools/Regenerate asset GUIDs")]        public static void RegenerateGuids() {            if (EditorUtility.DisplayDialog("GUIDs regeneration",                "You are going to start the process of GUID regeneration. This may have unexpected results. \n\n MAKE A PROJECT BACKUP BEFORE PROCEEDING!",                "Regenerate GUIDs", "Cancel")) {                try {                    AssetDatabase.StartAssetEditing();                    string path = Path.GetFullPath(".") + Path.DirectorySeparatorChar + "Assets/_Game";//要更新guid的文件夹                    UnityGuidRegenerator regenerator = new UnityGuidRegenerator(path);                    regenerator.RegenerateGuids();                }                finally {                    AssetDatabase.StopAssetEditing();                    EditorUtility.ClearProgressBar();                    AssetDatabase.Refresh();                }            }        }    }    internal class UnityGuidRegenerator {        private static readonly string[] kDefaultFileExtensions = {            // "*.meta",            // "*.mat",            // "*.anim",            // "*.prefab",            // "*.unity",            // "*.asset"            "*.*"        };        private readonly string _assetsPath;        public UnityGuidRegenerator(string assetsPath) {            _assetsPath = assetsPath;        }        public void RegenerateGuids(string[] regeneratedExtensions = null) {            if (regeneratedExtensions == null) {                regeneratedExtensions = kDefaultFileExtensions;            }            // Get list of working files            List<string> filesPaths = new List<string>();            foreach (string extension in regeneratedExtensions) {                filesPaths.AddRange(                    Directory.GetFiles(_assetsPath, extension, SearchOption.AllDirectories)                    );            }            // Create dictionary to hold old-to-new GUID map            Dictionary<string, string> guidOldToNewMap = new Dictionary<string, string>();            Dictionary<string, List<string>> guidsInFileMap = new Dictionary<string, List<string>>();            // We must only replace GUIDs for Resources present in Assets.             // Otherwise built-in resources (shader, meshes etc) get overwritten.            HashSet<string> ownGuids = new HashSet<string>();            // Traverse all files, remember which GUIDs are in which files and generate new GUIDs            int counter = 0;            foreach (string filePath in filesPaths) {                EditorUtility.DisplayProgressBar("Scanning Assets folder", MakeRelativePath(_assetsPath, filePath), counter / (float) filesPaths.Count);                string contents = File.ReadAllText(filePath);                                IEnumerable<string> guids = GetGuids(contents);                bool isFirstGuid = true;                foreach (string oldGuid in guids) {                    // First GUID in .meta file is always the GUID of the asset itself                    if (isFirstGuid && Path.GetExtension(filePath) == ".meta") {                        ownGuids.Add(oldGuid);                        isFirstGuid = false;                    }                    // Generate and save new GUID if we haven't added it before                    if (!guidOldToNewMap.ContainsKey(oldGuid)) {                        string newGuid = Guid.NewGuid().ToString("N");                        guidOldToNewMap.Add(oldGuid, newGuid);                    }                    if (!guidsInFileMap.ContainsKey(filePath))                        guidsInFileMap[filePath] = new List<string>();                    if (!guidsInFileMap[filePath].Contains(oldGuid)) {                        guidsInFileMap[filePath].Add(oldGuid);                    }                }                counter++;            }            // Traverse the files again and replace the old GUIDs            counter = -1;            int guidsInFileMapKeysCount = guidsInFileMap.Keys.Count;            foreach (string filePath in guidsInFileMap.Keys) {                EditorUtility.DisplayProgressBar("Regenerating GUIDs", MakeRelativePath(_assetsPath, filePath), counter / (float) guidsInFileMapKeysCount);                counter++;                string contents = File.ReadAllText(filePath);                foreach (string oldGuid in guidsInFileMap[filePath]) {                    if (!ownGuids.Contains(oldGuid))                        continue;                    string newGuid = guidOldToNewMap[oldGuid];                    if (string.IsNullOrEmpty(newGuid))                        throw new NullReferenceException("newGuid == null");                    contents = contents.Replace("guid: " + oldGuid, "guid: " + newGuid);                }                File.WriteAllText(filePath, contents);            }            EditorUtility.ClearProgressBar();        }        private static IEnumerable<string> GetGuids(string text) {            const string guidStart = "guid: ";            const int guidLength = 32;            int textLength = text.Length;            int guidStartLength = guidStart.Length;            List<string> guids = new List<string>();            int index = 0;            while (index + guidStartLength + guidLength < textLength) {                index = text.IndexOf(guidStart, index, StringComparison.Ordinal);                if (index == -1)                    break;                index += guidStartLength;                string guid = text.Substring(index, guidLength);                index += guidLength;                if (IsGuid(guid)) {                    guids.Add(guid);                }            }            return guids;        }        private static bool IsGuid(string text) {            for (int i = 0; i < text.Length; i++) {                char c = text[i];                if (                    !((c >= '0' && c <= '9') ||                      (c >= 'a' && c <= 'z'))                    )                    return false;            }            return true;        }        private static string MakeRelativePath(string fromPath, string toPath) {            Uri fromUri = new Uri(fromPath);            Uri toUri = new Uri(toPath);            Uri relativeUri = fromUri.MakeRelativeUri(toUri);            string relativePath = Uri.UnescapeDataString(relativeUri.ToString());            return relativePath;        }    }}