Aimbot-ParallelEnv/Assets/Script/Singleton.cs

using UnityEngine;

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
    private static T _instance;

    public static T Instance
    {
        get
        {
            if (_instance == null)
            {
                _instance = (T)FindObjectOfType(typeof(T));
                if (_instance == null)
                {
                    Debug.LogError("An instance of " + typeof(T) + " is needed in the scene, but there is none.");
                }
            }
            return _instance;
        }
    }

    protected virtual void Awake()
    {
        if (_instance == null)
        {
            _instance = this as T;
        }
        else
        {
            Destroy(gameObject);
        }
    }

    // keep this instance through scene change
    public void KeepThroughSceneChange()
    {
        DontDestroyOnLoad(this.gameObject);
    }
}