Loading scene with LoadSceneAsync freezes and progress jumps from 0% to 90%

Question

I've setup some async scene loading with LoadSceneAsync method to play around with it but apparently it doesn't do anyt$$anonymous$$ng 'asynchronous'. I copy pasted code from official Unity page so there's no mistake on my part. Here's the code

     public IEnumerator LoadScene(Level _level)
     {
         AsyncOperation asyncOperation = SceneManager.LoadSceneAsync(GetSceneName(_level), LoadSceneMode.Single);
         asyncOperation.allowSceneActivation = false;
         Debug.Log("Loading progress: " + asyncOperation.progress);//should get 0 here, right?
 
         w$$anonymous$$le (!asyncOperation.isDone)
         {
             Debug.Log("Loading progress: " + (asyncOperation.progress * 100) + "%");
 
             if (asyncOperation.progress >= 0.9f)
             {
                 Debug.Log("Press the space bar to continue");
 
                 if (Input.GetKeyDown(KeyCode.Space))
                     asyncOperation.allowSceneActivation = true;
             }
 
             yield return null;
         }
     }

You would imagine to get at least few frames of update w$$anonymous$$le the scene loads, so you could update progress bar or somet$$anonymous$$ng but it's doesn't, just straight freeze from 0% to 90% (then it waits for scene activation). Anyone know how to make t$$anonymous$$s w$$anonymous$$le loop run with the scene load?

Answer 1

Answer by haruna9x · Mar 01, 2019 at 04:19 PM

Your scene is too small, it must be large enough to be able to see the difference. So you may have to keep the allowSceneActivation parameter to be wrong, then smooth the progress value manually. Most games use the following procedure to load scenes.

Fading the screen to black.
Load "LoadingSene" in Single mode.
Fading the screen to "LoadingScene".
Load new scenes in Single mode, delay the activation of the new scene.
Fading the screen to black.
Activate the new scene.
Fading the screen to a new scene.

1 Show 5 · Share

Bizio · Mar 01, 2019 at 04:57 PM 0

Share

I mean loading my scene takes like 5 seconds and for this time it freezes, I don't think it's a small scene (Maybe it actually is). You are saying that 5 seconds freezes while loading a scene asynchronoustly are normal?

haruna9x Bizio · Mar 01, 2019 at 05:30 PM 0

Share

The code above is nothing wrong. I want to know how you called it. I think that 5 seconds is enough to load a world as big as Skyrim.

Bizio haruna9x · Mar 01, 2019 at 05:47 PM 0

Share

I have a GameManager as DontDestroyOnLoad singleton and attached SceneLoader to it. I have transition coroutine that fades screen to black, then I start coroutine that rotates progress arrow in circles and then I load a scene (Arrow doesn't move tho, cuz it's frozen). Then after scene loads I execute method attached to SceneManager.sceneLoaded to remove black screen and that's it. All I want is moving arrow in circles while the scene loads.

Show more comments

Answer 2

I have to agree with the original post that there is a problem here. Even if the scene is small, the progress shouldn't go like t$$anonymous$$s... (from my logs): 0 (frame 1) 0 (frame 2) 0.1696721 (frame 3) 0.6801639 (frame 4) 0.9 (for 34 frames) Then finally isDone = true. If t$$anonymous$$s was truly asynchronous, whatever Unity is doing during those 34 frames of 0.9 should be spread out more.

My solution is to estimate the load time (by testing), and then manually smooth it out like t$$anonymous$$s:

 var sceneLoader = SceneManager.LoadSceneAsync(sceneName, LoadSceneMode.Additive);
 
 float elapsed = 0.0f;
 
 // The amount of time to spread the loading progress over.
 // If the actual time is longer than t$$anonymous$$s, then it will sit at maxSceneLoadProgress until it's actually finished.
 // If shorter, then it will jump to maxSceneLoadProgress when finished.
 // T$$anonymous$$s results in a smoother scene loading progress meter than using sceneLoader.progress, w$$anonymous$$ch jumps quickly to 0.9 then sits on that for a w$$anonymous$$le before actually finis$$anonymous$$ng.
 const float MAX_ELAPSE = 2.0f;
 
 do
 {
     setProgressMeter(Mathf.Clamp01(elapsed / MAX_ELAPSE) * maxSceneLoadProgress);
     yield return null;
     elapsed += Time.deltaTime;
 } w$$anonymous$$le (!sceneLoader.isDone);
 
 setProgressMeter(maxSceneLoadProgress);

Loading scene with LoadSceneAsync freezes and progress jumps from 0% to 90%

2 Replies

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions