Question How to load an addtive scene AND make it the active scene?

Hey guys,

I've spent the last few days trying to get my head around this, first time I've actually done multiple scene loading, so I'm new on this stuff and struggling.

Let me set the scene, I have a managers scene that will be single loaded after the main menu, that is just kept there while the main game runs.
Then I simply load in using additive scenes for each level.

I've currently got a script on my level scenes that controls a button for next level, the idea being, you finish the level, an end level screen comes up (all in the same scene), you can click next level or retry level. Next level should load the next level additively, unload the level scene you just finished, while not affecting the managers scene.

Then, in my current system, my managers scene becomes the active scene. I need to then make my new level the actual active scene but this is where I've become to encounter a ton of problems.

How do I tackle this?



Below is my current (trash tier) script. I know I can also use .isLoaded type stuff, unsure how to do that though. Anyone able to help?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.SceneManagement;
5.  
6. public class EndLevelButtons : MonoBehaviour
7. {
8.     public int currentSceneIndex;
9.     public int maxSceneIndex;
10.     public int nextLevelIndex;
11.     public string nextLevelName;
12.     //public int previousLevelIndex;
13.     //public string previousLevelName;
14.  
15.     private void Start()
16.     {
17.         currentSceneIndex = SceneManager.GetActiveScene().buildIndex - 1; // take one number off since we start at zero index
18.         maxSceneIndex = SceneManager.sceneCountInBuildSettings;
19.  
20.         nextLevelIndex = currentSceneIndex + 1;
21.         nextLevelName = "Level_" + nextLevelIndex;
22.     }
23.  
24.     // these may not work correctly and may need step functions like coorutines to time thme out
25.  
26.     public void NextLevel()
27.     {
28.         if (currentSceneIndex < maxSceneIndex - 2)
29.         {
30.             //SceneManager.UnloadSceneAsync(currentSceneIndex + 1);
31.             //SceneManager.LoadScene(currentSceneIndex + 2, LoadSceneMode.Additive);
32.             //SceneManager.SetActiveScene(SceneManager.GetSceneByBuildIndex(currentSceneIndex + 2));
33.             StartCoroutine(SetActiveScene());
34.             print("loading next level");
35.         }
36.         else
37.         {
38.             print("No more levels yet!");
39.         }
40.     }
41.  
42.     public void RetryLevel()
43.     {
44.         SceneManager.UnloadSceneAsync(currentSceneIndex);
45.         SceneManager.LoadScene(currentSceneIndex, LoadSceneMode.Additive);
46.         print("Restarting level");
47.     }
48.  
49.     public void QuitToMainMenu()
50.     {
51.         SceneManager.LoadScene(0, LoadSceneMode.Single);
52.         print("Loading Main Menu");
53.     }
54.  
55.     private IEnumerator SetActiveScene()
56.     {
57.         SceneManager.LoadScene(currentSceneIndex + 2, LoadSceneMode.Additive);
58.         yield return new WaitForSeconds(0.01f);
59.         SceneManager.UnloadSceneAsync(currentSceneIndex + 1);
60.         SceneManager.SetActiveScene(SceneManager.GetSceneByBuildIndex(currentSceneIndex + 2));
61.         Time.timeScale = 1;
62.         yield return new WaitForSeconds(0.01f);
63.  
64.  
65.         //SceneManager.UnloadSceneAsync(currentSceneIndex + 1);
66.         //SceneManager.LoadScene(currentSceneIndex + 2, LoadSceneMode.Additive);
67.         //yield return new WaitForFixedUpdate();
68.         //SceneManager.SetActiveScene(SceneManager.GetSceneByName(nextLevelName));
69.         //yield return new WaitForFixedUpdate();
70.     }
71. }
72.  

 

Scenes don't load until the end of the current frame, so you cannot both load it and set it active. I know, annoying af, but what can you do?

What you need is a handy little "do something later" construct, such as my CallAfterDelay class:

https://gist.github.com/kurtdekker/0da9a9721c15bd3af1d2ced0a367e24e

And that class is what I use in my SceneHelper static class, which I use in all my games:

https://gist.github.com/kurtdekker/862da3bc22ee13aff61a7606ece6fdd3

 

Right okay, I shall try this tonight and report back!

Thank you!

 

an other way of doing this as well is using LoadSceneAsync, since when you call it it will return a AsyncOperation. With this you can either yield it in a coroutine or subscribe to its Completed event to execute logic once the scene is fully loaded and ready.