Anyone know what can freeze rendering but look around?

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One of our customers is seeing this kind of freeze, where the VR image stops updating but you can still look around and past the edges of the last render. The app itself isn't reporting a crash, so I'm wondering how to begin to debug this. Could the app itself be in an infinite loop, with Oculus async reprojection allowing them to look around without the app itself cycling? Or must the app still be cycling for them to be able to look around, with perhaps the renderer having crashed somehow?

This build uses Unity 2020.3.35, but I posted here thinking it was more relevent to Quest than Unity behavior.

advice

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emalafeewAnswer

Inspiring

We finally caught it in Android Studio...

So it's a job thread that's barfing on a particle system, which somehow is killing the renderer while the main thread continues to run. Btw this crash has only been reported and reproed on the new firmware v55.

Moving from Unity 2020.3.35f1 to 2020.3.47f1 seems to have fixed it for customers. I didn't specifically see such a crash fix in the release notes between then but there were several others related to particle systems.

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TheDaddis

Up and Coming

It does look like the app has stopped responding. I would make a Development Build with Script Debugging enabled and try to attach Visual Studio, or at least open up the Meta Quest Developer Hub (or Android Studio) and monitor the debug output for exceptions.

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emalafeewAuthor

Inspiring

We haven't gotten a repro ourselves, and doesn't appear to be an unhandled exception since nothing is in our crash logs. Since the customer can keep looking around their space, it would seem our app thread has hung rather than crashed, while the rendering thread is continuing to draw that last rendered frame from new head perspectives.

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emalafeewAuthor

Inspiring

We've now gotten a repro but there's nothing in the adb logs. The app behaves exactly as if you connect the debugger and break execution. Which we did, but we're using IL2CPP and VS can't load native Android symbol files, so now we're trying to catch the hang in Android Studio and break there.

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emalafeewAuthorAnswer

Inspiring

We finally caught it in Android Studio...

So it's a job thread that's barfing on a particle system, which somehow is killing the renderer while the main thread continues to run. Btw this crash has only been reported and reproed on the new firmware v55.

Moving from Unity 2020.3.35f1 to 2020.3.47f1 seems to have fixed it for customers. I didn't specifically see such a crash fix in the release notes between then but there were several others related to particle systems.

Z

zojoi

New Participant

We're seeing this as well.

Since v55 came out, our game is crashing sporadically. It looks like the crash is happening during the particle update function due to a bad pointer of some kind (referencing an unknown memory address). Our crash logs suggest that a worker thread might be ending prematurely. We're using the particle system is built into Unity and are looking at upgrading now. Thanks for the info!