****EDIT: There’s apparently an issue for people running the Vive and WMR where they’re seeing reduced resolution. We’re looking into it and will post an update as soon as possible.
****EDIT2: We’ve found the issue affecting Vive and WMR. We’re testing a fix internally and will release an update hopefully in the next 24 hours. Please do not submit any more bug reports about Vive/WMR resolution.
11.20 VR4 is Live on the servers. Aside from the usability fixes that Ben already mentioned, the major ‘feature’ in VR4 is…Oculus users will no longer need SteamVR. If you downloaded it just for X-Plane, go ahead and remove it. It will no longer be necessary.
As we said we would do from the very beginning, we investigated the relative performance of X-Plane through the native Oculus SDK versus SteamVR and what we found, through data collection, is that the overall experience for Oculus users was better by going through the Oculus SDK directly. I know many of you are thinking “Duh! I told you that a month ago ya big dummy!” and yes…yes you did. Fortunately/Unfortunately, we try not to make engineering decisions based on gut feelings and anecdotal evidence when we have a way to collect actual numbers. We wanted to tackle a majority of the usability issues affecting everyone before we looked into performance.
In the various A/B tests that we performed, we found that going to the Oculus SDK directly got us about 25% improvement in frame rate. This does not necessarily indicate that there’s anything wrong with SteamVR itself. There are several factors influencing the performance in VR. First, Oculus has their “home”, that little bachelor pad where you hang out while waiting for games to load. SteamVR has their “home” as well. When you use SteamVR, BOTH are running on your machine. Those houses are not free and X-Plane is already CPU bottlenecked so anything consuming CPU resources is going to directly affect performance. (I noticed an Autodesk updater in my task manager that was stealing 5% of my CPU consistently. That too was decreasing my performance….every bit matters!). Going directly to the Oculus SDK removes the SteamVR house from the equation.
Sure, getting 25% improvement is a huge win, but that’s NOT the biggest win. The biggest win, in my opinion, is that Asynchronous Space Warp (ASW) works MUCH better even at very low frames rates down to about 22.5fps. It appears as though the timing of the frames is critical for ASW to work properly. Being at 22.5, 30, 45, 90fps feels smooth! Being in between those frame timings seems to make ASW lose its mind creating an annoying judder; the opposite of what ASW is supposed to be doing for us. Oculus seems to be V-Syncing us to hit those intervals, allowing their algorithms to make reliable timing decisions and predictions. It’s my suspicion that SteamVR was just not hitting those intervals, causing ASW to flip out.
TLDR; Performance for Oculus will be on par with what Vive users have been seeing all along. The smoothness of the rendering seems consistent even down to 22.5fps. If you’re a Vive user, you will still, of course, need SteamVR as that IS your native SDK. If you’re a WMR user, you will still need SteamVR. I have not seen any reprojection issues with WMR like we have with Oculus. Supposedly the upcoming versions of SteamVR have some performance improvements coming for WMR users as well so we’ll be sticking with SteamVR for all headsets other than Oculus. That can always change in the future…based on data.