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Unity Physics BlobAsset Deallocation questions

Discussion in 'Entity Component System' started by recursive, May 26, 2019.

  1. recursive

    recursive

    Joined:
    Jul 12, 2012
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    669
    Hello.

    I'm writing my own non-physics related code to convert ScriptableObject data to BlobAssetReference<T> and I'm wondering how Unity Physics Releases the memory. As far as I can tell, the Release() function is called anywhere in the sample demos and there doesn't seem to be any other magic.

    Do persistent allocations made by BlobAllocator/BlobReference go into a special pool that's released for domain reloads? Is there a memory leak? Is there some other cleanup code I've overlooked?

    More "Best practices"/documentation with Blob Assets would be appreciated.
     
    recursive, May 26, 2019
    #1
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  2. Joachim_Ante

    Joachim_Ante

    Unity Technologies

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    Mar 16, 2005
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    Blobs are grouped together into one mega blob per scene at conversion time. Each scene references the pointer of the single allocation of all blobs from the converted scene. This is referenced by a shared component, when the last entity using that shared component / scene gets unloaded then the memory is unloaded.

    The result of it is that the cost of memory management for lots of small blobs is practically zero. This is great for streaming massive amounts of content without any perf impact. Also it means that specific code doesn't have to think about allocating / deallocation of blob data. Hence physics has no code that does it explicitly.
     
    Joachim_Ante, May 26, 2019
    #2
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  3. SamOld

    SamOld

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    Aug 17, 2018
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    Does all of this only apply to the conversion workflow? If I make a custom blob (for example by using the factory methods to create a collider) does the engine at some point take on responsibility for destroying that or does that still need manual release? Are you saying that any blob assigned to a shared component is released alongside the component?

    I agree with @recursive that we need more documentation on blobs.
     
    SamOld, May 26, 2019
    #3
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  4. recursive

    recursive

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    Jul 12, 2012
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    To add to what @SamOld put. I'd like to setup something akin to ScriptableObject's scope for certain types of blob data: A shared pointer that's alive as long as something in *any* scene references it and is deleted when the last reference is changed or deleted.
     
    recursive, May 28, 2019
    #4