纯代码 没什么好说的

using System.IO;
using UnityEditor;
using UnityEditor.U2D;
using UnityEngine;
using UnityEngine.U2D;

namespace Framework
{
    /// <summary>
    /// 图集生成
    /// </summary>
    public class BuildSpriteAtlas : Editor
    {
        /// <summary>
        /// 图集磁盘路径
        /// </summary>
        public static string SpritePath = Application.dataPath + "/GameData/Art/Sprite";

        [MenuItem("YSFramework/Build SpriteAtlas")]
        public static void BuildAtlas()
        {
            Debug.Log("Start Build SpriteAtlas Path=" + SpritePath);

            var pathDir = new DirectoryInfo(SpritePath);
            //循环目录下的文件和子目录 但是不包含子目录下的文件和子目录
            foreach (var item in pathDir.GetFileSystemInfos("*.*", SearchOption.TopDirectoryOnly))
            {
                var parentDir = item as DirectoryInfo;
                //空值就代表它是文件
                if (parentDir != null)
                {
                    var file = new FileInfo(parentDir.FullName + "/" + parentDir.Name + ".spriteatlas");
                    if (file.Exists)
                    {
                        File.Delete(file.FullName);
                    }

                    var atlas = new SpriteAtlas();// 设置参数 可根据项目具体情况进行设置
                    SpriteAtlasPackingSettings packSetting = new SpriteAtlasPackingSettings()
                    {
                        blockOffset = 1,
                        enableRotation = false,
                        enableTightPacking = false,
                        padding = 2,
                    };
                    atlas.SetPackingSettings(packSetting);

                    SpriteAtlasTextureSettings textureSetting = new SpriteAtlasTextureSettings()
                    {
                        readable = false,
                        generateMipMaps = false,
                        sRGB = true,
                        filterMode = FilterMode.Bilinear,
                    };
                    atlas.SetTextureSettings(textureSetting);

                    TextureImporterPlatformSettings platformSetting = new TextureImporterPlatformSettings()
                    {
                        maxTextureSize = 2048,
                        format = TextureImporterFormat.Automatic,
                        crunchedCompression = true,
                        textureCompression = TextureImporterCompression.Compressed,
                        compressionQuality = 50,
                    };
                    atlas.SetPlatformSettings(platformSetting);

                    var assetPath = "Assets/GameData/Art/Sprite/";
                    AssetDatabase.CreateAsset(atlas, assetPath + parentDir.Name + "/" + file.Name);
                    // 2、添加文件夹
                    Object obj = AssetDatabase.LoadAssetAtPath(assetPath + parentDir.Name, typeof(Object));
                    atlas.Add(new[] { obj });
                    AssetDatabase.SaveAssets();
                }
            }

            Debug.Log("Build SpriteAtlas Success!");
            //回收资源
            System.GC.Collect();
            //刷新编辑器
            AssetDatabase.Refresh();
        }
    }
}