SingletonなScriptableObject基底クラス

SingletonScriptableObject.cs

/**
NYSL Version 0.9982 (en) (Unofficial)
----------------------------------------
A. This software is "Everyone'sWare". It means:
  Anybody who has this software can use it as if he/she is
  the author.

  A-1. Freeware. No fee is required.
  A-2. You can freely redistribute this software.
  A-3. You can freely modify this software. And the source
      may be used in any software with no limitation.
  A-4. When you release a modified version to public, you
      must publish it with your name.

B. The author is not responsible for any kind of damages or loss
  while using or misusing this software, which is distributed
  "AS IS". No warranty of any kind is expressed or implied.
  You use AT YOUR OWN RISK.

C. Copyrighted to Hassaku

D. Above three clauses are applied both to source and binary
  form of this software.
*/
using UnityEngine;
using UnityEngine.Assertions;

public class SingletonScriptableObject<T> : ScriptableObject where T : SingletonScriptableObject<T>{

    private static T _instance { get; set; }

    /// <summary>
    /// 唯一のインスタンスを取得する
    /// 初回呼び出しは低速なので注意
    /// </summary>
    public static T Instance {
        get {
            if (_instance == null) {
                var objects = Resources.FindObjectsOfTypeAll<T>();
                Assert.IsTrue(objects.Length <= 1);
                if (objects.Length == 1) {
                    _instance = objects[0];
                }
                else {
                    _instance = ScriptableObject.CreateInstance<T>();
                }
            }
            return _instance;
        }
    }
}

ReourcesにAssetが1つあればそれをロード
1つも無ければインスタンスを作成
複数あればAssert