Every second time or so, the VR preview in 4.8 simply doesn’t work. Instead of a mirrored VR view it just opens a normal window, the VR display stays back. HMD is on and connected, works with 4.7.6:
Restarting the editor didn’t change anything, sometimes it just works, sometimes not
Launching as standalone seems to work (HMD gets a image)
PS: GPU load is just about 50-66% in VR mode while often not keeping the target framerate, shouldn’t this upate have late-latching implemented (CPU and GPU aren’t forced to work in sync anymore)?
Unfortunately not, I just load up the project and try to activate VR mode, will report back if I can narrow it down
EDIT: After restarting windows, it seems to work reliable first (started several VR preview sessions without problems). After 3-4 minutes and multiple non-VR-PIE sessions the problem came back.
Standalone works, but performance is even worse then 4.7 (maybe, because of the new SDK and no late-latching).
Could you please answer the question about late latching and UE 4.8? I am eagerly awaiting this feature but can’t find any infos about it in the release notes. It was mentioned in the Twitch stream when first talking about 4.8 and VR. Are GPU and CPU still forced in sync? This would explain the bad GPU utilisation. If yes, will late-latching be patched-in later then or did you kill this feature internally?
I was able to reproduce this issue on our end. I have written up a report (UE-17053) and I have submitted it to the developers for further consideration. I will provide updates with any pertinent information as it becomes available.
As for the information you have requested. I have reached out to some developers for more information on late latching. I will provide any relevant information provided. Thank you for your time and information.
30-50% GPU stall is fantastic, exactly what I need for a demanding-as-hell VR project.
There is a trello card for this stuff since last October (!), with over 500 votes from the community. I was really, really hopeing that this would improve in 4.8, especially after the twitch broadcast where this was announced. Instead, I got an update which broke VR completely.
And now I’ve to read, that there isn’t even a timeframe for late-latching, ah that feels so great.
Man, so glad, I went UE4.
Sorry for this, but developing VR apps is really no fun in UE4 ATM, forgive me. Thanks for the clarification anyway, even though these are really bad news.
UPDATE: Now even standalone mode for PIE sessions don’t work anymore. Just get a black image. Restarting the editor gives me one single shot for standalone mode, than its broken again.
The issue that you mentioned at the end of your last post has already been reported. Thank you for the heads up. I will be sure to bump the community interest for that issue.
I just tried a VR project in 4.8 now and had the same issue (black screen or non-vr preview window).
One workaround that seems to work for me so far is to make sure that only the main editor window is open. Having any tabs or other “separate” windows open when I click the vr-preview or standalone launch button will give me the same issues you describe.
Many thanks, I can confirm this sometimes really works. But it’s not enough to just have one single window open, in my case I often really have to close all open tabs, too.
Please let them know that this is wasting VR developers a lot of time. Having to close all tabs before testing a change in VR is really slowing development down
