Scampz/Assets/Scripts/GameManager/GameManager.cs

using System.Collections;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace Scampz.GameJam
{
  public class GameManager : MonoBehaviour
  {
    public Animator animator;

    private static GameManager _instance;

    public static GameManager Instance
    {
      get
      {
        if (!_instance)
        {
          _instance = new GameObject().AddComponent<GameManager>();
          _instance.name = _instance.GetType().ToString();
          DontDestroyOnLoad(_instance.gameObject);
        }

        return _instance;
      }
    }
    void OnEnable()
    {
      //SceneManager.sceneLoaded += OnSceneLoaded;
    }

    void OnDisable()
    {
      //SceneManager.sceneLoaded -= OnSceneLoaded;
    }

    public void LoadScene(string sceneName, LoadSceneMode loadSceneMode)
    {
      StartCoroutine(LoadSceneAsync(sceneName, loadSceneMode));
    }

    public void UnloadScene(string sceneName)
    {
      StartCoroutine(UnloadSceneAsync(sceneName));
    }

    private IEnumerator LoadSceneAsync(string sceneName, LoadSceneMode loadSceneMode)
    {
      yield return null;

      var loadSceneOperation = SceneManager.LoadSceneAsync(sceneName, loadSceneMode);
      loadSceneOperation.allowSceneActivation = false;
      while (!loadSceneOperation.isDone)
      {
        if (loadSceneOperation.progress >= 0.9f)
          break;
      }

      loadSceneOperation.allowSceneActivation = true;
      yield return loadSceneOperation;
    }

    private IEnumerator UnloadSceneAsync(string sceneName)
    {
      yield return null;
      if (SceneManager.GetSceneByName(sceneName).IsValid())
        SceneManager.UnloadSceneAsync(sceneName);
    }

    private void OnSceneLoaded(Scene scene, LoadSceneMode loadSceneMode)
    {
      //BGMManager.Instance.PlaySong();
    }
  }
}