Question by unity_sq26Sg98wIfncw · Mar 27, 2020 at 07:25 PM · scene-loading scene-switching load scene scene load loadlevelasync

Order of SceneManager.LoadSceneAsync and UnloadSceneAsync.

I wrote some codes using SceneManager.LoadSceneAsync()

 IEnumerator LoadTest()
 {
 //load persistent scene(some managers are placed here)
 yield return SceneManager.LoadSceneAsync("persistentScene", LoadSceneMode.Single);

 //load first scene
 yield return SceneManager.LoadSceneAsync("firstScene", LoadSceneMode.Additive);
 
 //preload second scene
 var secondScene= SceneManager.LoadSceneAsync("secondScene", LoadSceneMode.Additive);
 
 //dont activate immediately
 secondScene.allowSceneActivation = false;
 
 //instead of fadeout
 yield return new WaitForSeconds(1.0f);
 
 //Unload first scene
 SceneManager.UnloadSceneAsync("firstScene");
 
 //activate second scene
 secondScene.allowSceneActivation = true;
 }

It works like
construct "persistentScene"
↓
construct "firstScene"
↓
construct "secondScene"
↓
destruct "firstScene"

How can i destruct "firstScene" before construct "secondScene"?

0 Show 3

Kastenfrosch2 · Jun 21, 2020 at 09:12 AM 0

Did you solve or find a workaround for your problem? I'm currently facing the same issue and don't see any way to achieve my goal. The Unloading always waits for the loaded scene to be activated :(.

unity_sq26Sg98wIfncw Kastenfrosch2 · Jun 21, 2020 at 09:24 AM 0

Yes.

 //Get current scene instance 
 var currentScene = SceneManager.GetSceneByName(currentSceneName);
 
 //preload 
 var loadAsync = SceneManager.LoadSceneAsync(_nextScene, LoadSceneMode.Additive); 
 loadAsync.allowSceneActivation = false;

 //wait for complete loading and fadeout
 while(loadAsync.progress < 0.9f || !Fade.IsFadeoutCompleted)
     yield return null;
 
 //Destroy GameObjects in CurrentScene 
 foreach (GameObject go in currentScene.GetRootGameObjects()) Destroy(go);

 //or like this
 //GameObject[] gameObjects = currentScene.GetRootGameObjects();
 //int maxDestroyPerFrame = 128;
 //for(int i = 0, int cnt = 0; i<gameObjects.length; ++i,++cnt)
 //{
 //    Destroy(gameObjects[i]);
 //    if(cnt > maxDestroyPerFrame) 
 //    cnt  = 0; yield return null;
 //}

 loadAsync.allowSceneActivation = true;
 yield return loadAsync;
 yield return SceneManager.UnloadSceneAsync(currentScene);

Kastenfrosch2 unity_sq26Sg98wIfncw · Jun 21, 2020 at 01:27 PM 0

Hey, thanks for your answer. Its seems a bit hacky, because i don't get a sceneUnloaded-callback this way and I need special handling whenever someone asks "IsSceneLoaded", but I guess it's better than nothing :).

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