GameObjectManager.cs

public class GameObjectManager : MonoBehaviour, ISerializationCallbackReceiver
{
    private static GameObjectManager _instance;

    public static GameObjectManager Instance { get { return _instance; } }

    public List<GameObjectList> gameObjects; //public list so it can be accessed in inspector

    private Dictionary<GameObject, Texture2D> gameObjectDictionary; //pricate list for use

    private List<GameObject> placedGameObjects = new List<GameObject>();

    private void Awake()
    {
        if (_instance != null && _instance != this)
        {
            Destroy(this.gameObject);
        }
        else
        {
            _instance = this;
        }
    }

    /// <summary>
    /// Maps the Dictionary into a list of Mapped Objects containing
    /// name, id, and img
    /// </summary>
    /// <returns>List of GameObjectMapped</returns>
    public List<GameObjectMapped> GetGameObjectsList()
    {
        List<GameObjectMapped> map = new List<GameObjectMapped>();
        foreach(var entry in gameObjectDictionary)
        {
            map.Add(new GameObjectMapped(entry.Key, entry.Key.name, entry.Value));
        }

        return map;
    }

    /// <summary>
    /// Creates a GameObject in the Scene
    /// </summary>
    /// <param name="id">ID of the GameObejct</param>
    /// <param name="position">Position the Object should be placed at</param>
    /// <param name="scale">Optional Scale of the Object default is (1,1,1)</param>
    public GameObject CreateGameObjectAtById(GameObject id, Vector3 position, Vector3? scale = null)
    {
        if (!gameObjectDictionary.ContainsKey(id))
        {
            Debug.LogError("CreateGameObjectAtById: ID not found");
            return null;
        }

        var obj = Instantiate(id, position, Quaternion.identity) as GameObject;
        if (scale != null)
            obj.transform.localScale = scale.Value;

        placedGameObjects.Add(obj);

        return obj;
    }

    /// <summary>
    /// Removes a given Object from the Scene Deleting it.
    /// only Destroys Objects created by GameObjectManager
    /// </summary>
    /// <param name="id">id of the Obejct to Destroy</param>
    public void RemoveGameObjectById(GameObject id)
    {
        var obj = placedGameObjects.Find(x => x.Equals(id));

        if (obj == null)
            return;

        placedGameObjects.Remove(obj);

        Object.Destroy(obj);
    }

    /// <summary>
    /// Callback stuff
    /// </summary>
    public void OnBeforeSerialize()
    {
        gameObjects.Clear();

        foreach (var kvp in gameObjectDictionary)
        {
            gameObjects.Add(new GameObjectList(kvp.Key, kvp.Value));
        }
    }

    /// <summary>
    /// Callback stuff
    /// </summary>
    public void OnAfterDeserialize()
    {
        gameObjectDictionary = new Dictionary<GameObject, Texture2D>();

        foreach (var entry in gameObjects)
        {
            gameObjectDictionary.Add(entry.obj, entry.img);
        }
    }

    //some debug
    void OnGUI()
    {
        #if DICTIONARY_DEBUG
            foreach (var kvp in gameObjectDictionary)
                GUILayout.Label("Key: " + kvp.Key + " value: " + kvp.Value);
        #endif
    }
}