LookSee 3 person meeting disconnects when model closed

[Tom Goddard]

In testing 3-person LookSee (version 6) meetings at SLAC on September 13, 2023 with Mike Schmid and JJ we found that closing a model would often drop the last participant. Mike started a meeting, JJ joined, I joined, Mike opened a model, worked, Mike closed the model and my connection to the meeting dropped. We tried this about 3 times and if failed in similar ways. But later we had a 3-person meeting where we opened and closed many models and it did not fail. So it is not entirely reproducible. The earlier cases were 900K triangle tomogram surface models colored by z that were slow to transfer to participant headsets (20-30 seconds), and maybe the size of the gltf and some timing issue was responsible for the disconnections.

I think when I rejoined the meeting after being dropped it continued not to work. Maybe it also didn't work for the first participant who joined (not sure). It appeared that the problem was perhaps on the headset that started the meeting.

[Tom Goddard]

Fixed in LookSee v8.

The send_newly_closed_models() routine was modifying the meeting_models dictionary as it iterated over it and generated an InvalidOperationException. Fixing that fixed the 3-person meeting model closing. I tested extensively with every participant opening and closing a model and it all worked fine.

I used

adb logcat >& quest_logcat.out

on the meeting host headset which was connected by USB cable. This writes 100,000 lines in just 5 minutes and it is useful to search it for "Exception:" and "Unity" to find errors.