Question DontDestroyOnLoad() duplicates when switch scenes

I'm making a 2D platformer game and when I switch scenes to another world, I'm using DontDestroyOnLoad() to keep all the data intact. But that means whenever I switch back scenes again, in the DontDestroyOnLoad() list duplicates the objects. (by the way, I put the DontDestroyOnLoad() in the Start() function, that might be the reason why.)

 

And also, when I switch scenes, is there any way that it enters in a certain position?

 

I have already told you the step to take here;

https://forum.unity.com/threads/res...ealth-in-between-scenes.1422564/#post-8935527

Specifically YOU MUST:

- identify parts of your game that live longer than a scene <-- essential first step; without this you are lost

- identify how long they live (game manager: life of the game ... music / menu manager: forever? etc)

- implement the parts so that they have the appropriate lifecycle

But you did NOT take that step because you posted here:

https://forum.unity.com/threads/res...ealth-in-between-scenes.1422564/#post-8936790

and you said:

Simply saying "i just used DontDestroyOnLoad()" is NOT a shortcut for the three steps I listed above.

 

Okay then, here's my list

• Player
  • The whole game
• (I don't know if relevant or not) Health
  • The whole game (Goes with the player)
• Game Manager
  • The whole game
• Camera
  • The whole game because I want it to follow and keep track of the player, or else the new camera will have to find the player and that might not work
• Enemies
  • They only follow you for one scene or level
• Boost enemies
  • They follow you around in the boost zone to give you a health boost (only one scene)

What do I do now with this list?

 

Is the Awake() method the same as Start()?

 

To avoid duplicate copies of a script you need to check if an instance of it already exists, and if it does already exist destroy the new copy of it.

Code (csharp):

1. using UnityEngine;
2.  
3. public class MyPersistentObject : MonoBehaviour
4. {
5.     public static MyPersistentObject Instance;
6.  
7.     private void Awake()
8.     {
9.         if (Instance == null)
10.         {
11.             Instance = this;
12.             DontDestroyOnLoad(gameObject);
13.         }
14.         else if (Instance != this)
15.         {
16.             Destroy(gameObject);
17.         }
18.     }
19. }

No.

Spoiler: Order of Execution Chart

 

Using your code

Code (CSharp):

1. using UnityEngine;
2. public class MyPersistentObject : MonoBehaviour
3. {
4.     public static MyPersistentObject Instance;
5.     private void Awake()
6.     {
7.         if (Instance == null)
8.         {
9.             Instance = this;
10.             DontDestroyOnLoad(gameObject);
11.         }
12.         else if (Instance != this)
13.         {
14.             Destroy(gameObject);
15.         }
16.     }
17. }

apparently seems to temporarily work. However, I still see some duplicates in the scene, except, they're just like dead objects.

https://ibb.co/S5t4nfM ⬅️ image link

In this image, you can see that the camera is focused on the DontDestroyOnLoad() object, but there is still a duplicate of every object, just not used somehow.