优化版UGUI打图集代码

首先是代码的原版，雨松MOMO的博客
http://www.xuanyusong.com/archives/3304
雨松MOMO 2014年10月24日 于 雨松MOMO程序研究院 发表

代码很好用，但在使用过程中，遇到了一点问题。即便精灵图没发生改变，代码每次生成出来的Prefab文件都会发生细微的改变，提交版本库的时候，每次都要提交所有的Prefab，而且过时的Prefab没有被删除，于是自己在原代码的基础上加以改进，忽略了没有变化的Prefab，并删除了过时的Prefab，废话不多说，贴上代码。

using System.Collections.Generic;
using System.IO;
using UnityEditor;
using UnityEngine;

public class AtlasMaker {
    [MenuItem("MyMenu/AtlasMaker")]
    static private void MakeAtlasTest()
    {
        string spriteDir = Application.dataPath + "/Resources/Sprite";
        DirectoryInfo prefabDir = new DirectoryInfo(spriteDir);
        Dictionary<string,string> prefabDict = new Dictionary<string, string>();
        Dictionary<string, string> prefabDictRemain = new Dictionary<string, string>();
        foreach (var fileInfo in prefabDir.GetFiles("*.prefab", SearchOption.AllDirectories))
        {
            prefabDict[fileInfo.Name.Replace(".prefab", "")] = fileInfo.FullName;
            prefabDictRemain[fileInfo.Name.Replace(".prefab", "")] = fileInfo.FullName;
        }
        foreach (var dir in prefabDir.GetDirectories())
        {
            foreach (var fileInfo in dir.GetFiles("*.prefab", SearchOption.AllDirectories))
            {
                prefabDict[fileInfo.Name.Replace(".prefab", "")] = fileInfo.FullName;
                prefabDictRemain[fileInfo.Name.Replace(".prefab", "")] = fileInfo.FullName;
            }
        }
        if (!Directory.Exists(spriteDir))
        {
            Directory.CreateDirectory(spriteDir);
        }

        DirectoryInfo rootDirInfo = new DirectoryInfo(Application.dataPath + "/Atlas");
        foreach (DirectoryInfo dirInfo in rootDirInfo.GetDirectories())
        {
            foreach (FileInfo pngFile in dirInfo.GetFiles("*.png", SearchOption.AllDirectories))
            {
                string allPath = pngFile.FullName;
                string assetPath = allPath.Substring(allPath.IndexOf("Assets"));
                Sprite sprite = AssetDatabase.LoadAssetAtPath<Sprite>(assetPath);
                GameObject go;
                if (prefabDict.ContainsKey(sprite.name))
                {
                    string path = prefabDict[sprite.name].Substring(prefabDict[sprite.name].IndexOf("Assets"));
                    go = AssetDatabase.LoadAssetAtPath<GameObject>(path);
                    prefabDictRemain.Remove(sprite.name);
                    var spriteRed = go.GetComponent<SpriteRenderer>();
                    if (spriteRed.sprite != sprite)
                    {
                        spriteRed.sprite = sprite;
                    }
                }
                else
                {
                    go = new GameObject(sprite.name);
                    go.AddComponent<SpriteRenderer>().sprite = sprite;
                    allPath = spriteDir + "/" + sprite.name + ".prefab";
                    string prefabPath = allPath.Substring(allPath.IndexOf("Assets"));
                    PrefabUtility.CreatePrefab(prefabPath, go);
                    GameObject.DestroyImmediate(go);
                }
            }
        }
        foreach (var remain in prefabDictRemain)
        {
            string path = remain.Value.Substring(remain.Value.IndexOf("Assets"));
            AssetDatabase.DeleteAsset(path);
        }
        AssetDatabase.SaveAssets();
    }
}