Making the old Scene "inactive" - how to handle persistent objects?

[jerotas]

I have a Game Object that marked as “do not delete” so it will stick around when a new Scene is loaded. This seems to be an old Unity concept maybe? With newer Scene Manager code, you can load a new Scene async and then tell the original Scene to become inactive when the new one is loaded. Is there a way to make a persistent object come over to the new Scene instead of just stopping running when it’s in the inactive Scene?

[methos5k]

I’m not sure about “old Unity concept”; I think it’s still a valid option.

However, there is: Unity - Scripting API: SceneManagement.SceneManager.MoveGameObjectToScene

If that’s what you want.

[rakkarage]

Unity - Scripting API: Object.DontDestroyOnLoad

Calling DontDestroyOnLoad can make the object exist on all scenes. In the example below there are two scenes - ExampleScript1 and ExampleScript2… One has a Cube and the other a Sphere. A DontDestroyOnLoad function on the first scene is connected to a Cylinder. This is loaded in Awake. When the ExampleScript1 button is pressed ExampleScript1 is closed and ExampleScript2 is loaded. The Cylinder from ExampleScript1 is copied to ExampleScript2. When ExampleScript2 is closed by pressing the Button ExampleScript1 is reloaded. This scene always has the Cylinder. The management of the Cylinder is the DontDestroyOnLoad function.

[jerotas]

@rakkarage

https://docs.unity3d.com/ScriptReference/Object.DontDestroyOnLoad.html

I’m already using that. But it doesn’t appear to continue running scripts on a game object that’s in the “inactive” scene once it becomes inactive. Is that normal? I thought that it might be.

[jerotas]

@methos5k

I’m not sure about “old Unity concept”; I think it’s still a valid option.

However, there is: https://docs.unity3d.com/ScriptReference/SceneManagement.SceneManager.MoveGameObjectToScene.html

If that’s what you want.

Thanks, would there be an event I could use there to wire that up that tells me when the Scene is done loading async?

[methos5k]

There are built-in events for scene loaded, unloaded, and active scene changed. I think beyond that, you’d have to create your own.

Just out of curiosity, does your object get destroyed when you load a new scene and unload the old one or just stop running your scripts? I haven’t a lot of experience with that, so just wondering.
Maybe I’d check that out some time to see.

[rakkarage]

@jerotas

I’m already using that. But it doesn’t appear to continue running scripts on a game object that’s in the “inactive” scene once it becomes inactive. Is that normal? I thought that it might be.

that is not normal scripts on objects that use DontDestroyOnLoad(this.gameObject); should continue to run after the new scene is loaded and the old one removed i made a simple test i can share if u like

using UnityEngine;
using UnityEngine.SceneManagement;
public class Save : MonoBehaviour
{
    private static bool created = false;
    void Awake()
    {
        if (!created)
        {
            DontDestroyOnLoad(this.gameObject);
            created = true;
            Debug.Log("Awake: " + this.gameObject);
        }
    }
    [ContextMenu("LoadScene")]
    public void LoadScene()
    {
        SceneManager.LoadSceneAsync(1, LoadSceneMode.Single);
    }
    public void FixedUpdate()
    {
        Debug.Log("Update");
    }
}