Question by N3rg4l · Apr 03, 2020 at 08:32 AM · c#scripting problem destroy scene-loading dontdestroyonload

Execution order of Destroy() and DontDestroyOnLoad() between Scenes

Hello people,

I am writing here because i did not find anything helpful for my question.

I am working with GameManager, its static Instance and its use while changing scenes.

I have this scenario: 3 scenes ("GameMenu", "SPGame", "MPGame") and each one has a GameManager instance. Then I have written this code:

1) First Unity Methods:

 private void Awake()
     {        
         PrintExecutionLocation(this);
         SetUpGameManager();                     
     }
 
     private void OnEnable()
     {
         PrintExecutionLocation(this);
         SceneManager.sceneLoaded += OnSceneLoaded;
     }

OnSceneLoaded():

 private void OnSceneLoaded(Scene scene, LoadSceneMode mode)
     {
         PrintExecutionLocation(this);
         Debug.Log(scene.name + " loaded with " + mode.ToString() + " mode");
         Debug.Log("Looking for necessary parameters for the current scene...");
         GetSceneComponents(scene.name);
     }

2) Custom Methods

SetupGameManager():

 private void SetUpGameManager()
     {
         PrintExecutionLocation(this);
         if (CheckInstance() is true)
         {
             CheckMode();            
         }
         GetSceneComponents(SceneManager.GetActiveScene().name);
     }

CheckInstance():

 private bool CheckInstance()
 {
     PrintExecutionLocation(this);
     // if there is another istance of GameManager
     if (instance != null && instance != this)
     {
         Debug.LogWarning("There is already a GameManager instance, i destroy myself (ID: " + GetHashCode() +").");
         
         // destroy it
         Destroy(gameObject);
         return false;           
     }
     else
     {
         Debug.LogWarning("There is not a GameManager, i will not destroy myself when loading new scenes (ID: " + GetHashCode() + ").");
         instance = this;
         // don't destroy the game manager (mainly to keep the score) while changing the levels (aka scenes)
         DontDestroyOnLoad(gameObject);
         return true;
     }
 }

CheckMode():

 private void CheckMode()
 {
     PrintExecutionLocation(this);
     //If i'm not in main menu scene, activate development mode
     Debug.Log("Defining the current scene.");
     switch (SceneManager.GetActiveScene().buildIndex)
     {
         case 0:
             //Debug.Log("Sto cominciando dal menù principale.");
             _developerMode = false;
             Debug.Log("Developer Mode: OFF");
             break;
         case 1:
             //Debug.Log("Sto cominciando dal Single player.");
             _developerMode = true;
             Debug.Log("Developer Mode: ON");
             isSPG = true;
             break;
         case 2:
             //Debug.Log("Sto cominciando dal Multiplayer.");
             _developerMode = true;
             Debug.Log("Developer Mode: ON");
             isSPG = false;
             break;
         default:
             Debug.LogError(SceneManager.GetActiveScene().buildIndex.ToString() + " is not recognized as Scene Index.");
             break;
     }
 }

GetSceneComponents():

 private void GetSceneComponents(string index)
 {
     PrintExecutionLocation(this);
     switch (index)
     {
         case "GameMenu":
             Debug.Log("Looking for Canvas references of main menu, settings menu, highscores menu...");
             mainMenu = GameObject.Find("MainMenuCanvas").GetComponent<Canvas>();
             settings = GameObject.Find("SettingsCanvas").GetComponent<Canvas>();
             highscore = GameObject.Find("HighscoreCanvas").GetComponent<Canvas>();
             if (mainMenu && settings && highscore)
             {
                 Debug.Log("All Canvas references found.");
             }
             else
             {
                 Debug.LogError("I did not find all Canvas references.\nWrite more code to find what's missing.");
             }
             break;

         case "SPGame":
             Debug.Log("Taking Player reference...");
             player1 = GameObject.Find("Paddle1").GetComponent<Paddle>();
             if (player1)
             {
                 Debug.Log("Player reference found.");
             }
             else
             {
                 Debug.LogError("Player reference not found.");
             }
             break;

         case "MPGame":
             Debug.Log("Taking 1st Player reference...");
             player1 = GameObject.Find("Paddle1").GetComponent<Paddle>();
             if (player1 != null)
             {
                 Debug.Log("1st Player reference found, taking 2nd Player reference...");
                 player2 = GameObject.Find("Paddle2").GetComponent<Paddle>();
                 if (player2 != null)
                 {
                     Debug.Log("2nd Player reference found.");
                 }
                 else
                 {
                     Debug.LogError("2nd Player reference not found.");
                 }
             }
             else
             {
                 Debug.LogError("1st Player reference not found.");
             }
             break;

         default:
             Debug.LogError("Scene not correct.");
             break;
     }
     highscoreSystem = GetComponent<HighscoreSystem>();
 }

And i got this Log: alt text