using UnityEngine;

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
 private static T _instance;
 private static object _lock = new object();
 public static T instance
 {
 get
 {
 if (applicationIsQuitting)
 {
 return null;
 }
 lock (_lock)
 {
 if (_instance == null)
 {
 _instance = (T)FindObjectOfType(typeof(T));

 if (FindObjectsOfType(typeof(T)).Length > 1)
 {
 return _instance;
 }

 if (_instance == null)
 {
 GameObject singleton = new GameObject();
 _instance = singleton.AddComponent<T>();
 singleton.name = "(singleton)" + typeof(T).ToString();

 DontDestroyOnLoad(singleton);
 }
 }

 return _instance;
 }
 }
 }

 private static bool applicationIsQuitting = false;

 public void OnDestroy()
 {
 applicationIsQuitting = true;
 }
}