Import されたテクスチャを自動的に Sprite の Prefab 化するプログラム

using UnityEngine;
using UnityEditor;

class MyPostprocessorTexture : AssetPostprocessor
{
    void OnPostprocessTexture(Texture2D texture)
    {
        TextureImporter importer = assetImporter as TextureImporter;
        if (importer.textureType != TextureImporterType.Sprite ||
            importer.spriteImportMode != SpriteImportMode.Single) {
            importer.textureType = TextureImporterType.Sprite;
            importer.spriteImportMode = SpriteImportMode.Single;
            importer.SaveAndReimport();
            return;
        }
        var sp = AssetDatabase.LoadAssetAtPath<Sprite>(assetPath);
        if (sp)
        {
            GameObject go = new GameObject(sp.name);
            go.AddComponent<SpriteRenderer>().sprite = sp;
            Object prefab = PrefabUtility.CreateEmptyPrefab(string.Format("Assets/{0}.prefab", go.name));
            if (prefab != null)
            {
                PrefabUtility.ReplacePrefab(go, prefab, ReplacePrefabOptions.ConnectToPrefab);
            }
            else
            {
                Debug.Log("Failed to create prefab.");
            }
            GameObject.DestroyImmediate(go);
        }
    }
}