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Unity 5 bug? DontDestroyOnLoad with AudioSource failing on Windows standalone build

Discussion in 'Scripting' started by daterre, Jul 30, 2015.

  1. daterre

    daterre

    Joined:
    Jul 30, 2012
    Posts:
    41
    My game includes a UI that loads upon startup, sets itself with DontDestroyOnLoad on Awake and persists between level loads. The structure is as follows:
    • UI (in scene root, no parent) - has multiple scripts attached
      • Canvas (with children)
      • Audio - has a single Component, AudioSource

    In the Editor, the system works perfectly - the UI object, along with all its components and child objects, maintain their state. In a Windows build, however, after 3 or 4 level loads, the following message appears in the player log:

    Unloading 3 Unused Serialized files (Serialized files now loaded: 0)
    UnloadTime: 1.104330 ms

    Unloading 214 unused Assets to reduce memory usage. Loaded Objects now: 1062.
    Total: 0.683746 ms (FindLiveObjects: 0.046304 ms CreateObjectMapping: 0.033523 ms MarkObjects: 0.281600 ms DeleteObjects: 0.317847 ms)​

    After this message is generted, the UI objects, its scripts, and the child Canvas all stay alive correctly, but the Audio object gets destroyed. This doesn't seem like intended engine behavior, any thoughts on the matter?

    [EDIT]
    I moved the AudioSource component to the UI object, and now it is being preserved. So something to do with the fact that the Audio game object is a standalone object with no scene references to it (it is being accessed by GetComponentInChildren) is causing it to be destroyed regardless of the DontDestroyOnLoad on its hierarchy. Bug?
     
    Last edited: Jul 30, 2015
  2. Chris-Trueman

    Chris-Trueman

    Joined:
    Oct 10, 2014
    Posts:
    1,233
    Each object in the hierarchy has to be registered to not be destroyed. I don't think its a bug. I would have to say that its probably better to not have all children stay on a scene load unless explicitly told to not be destroyed.
     
  3. daterre

    daterre

    Joined:
    Jul 30, 2012
    Posts:
    41
    That's not true - see DontDestroyOnLoad documentation:
    "If the object is a component or game object then its entire transform hierarchy will not be destroyed either."

    In any case, I tried it and it didn't help. If this behavior is by design I would expect it to occur in the editor, and after every level load - not only when the engine is doing cleanup.
     
  4. Chris-Trueman

    Chris-Trueman

    Joined:
    Oct 10, 2014
    Posts:
    1,233
    Then it is a bug, not by design. Should be filed as a bug, I don't see it on the tracker.