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danknugz
Inspiring
September 2, 2014

VR performance disparity between devs

Some games/demos seem to implement head/positional tracking better than others; that is to say, some suffer from great amounts of judder while others don't, with respect to how the non-VR version of the game performs. A good example is Live for Speed vs. Euro Truck Simulator 2. Both run fine in non-VR mode on my laptop, and Live for Speed runs great with no judder or lag in the headtracking or positional tracking. However ETS2 runs horribly in VR-mode, the framerate drops by at least 50% and considerable judder.

I haven't started developing yet so I can't speak much to this technically, but when I do start, this is going to be priority for me. We have also seen that the Cyberspace demo pretty much works for everyone with flawless tracking, and that was made with Unity. So what is it exactly that is causing this disparity? Are demos/games made with Unity easier to implement head tracking, or do they just run better in VR? Is it an AMD/Nvidia thing with issues with the runtime? Or is it solely up to the dev in how they implement timewarp/lookahead algorithms.

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    cybereality
    Inspiring
    September 3, 2014
    I've experienced judder on a few demos, and I'm pretty sure my machine is capable of handling it performance-wise.
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    kojack
    kojack
    Honored Contributor
    September 3, 2014
    "cybereality" wrote:
    I've experienced judder on a few demos, and I'm pretty sure my machine is capable of handling it performance-wise.

    Just on a hunch, could you (or anyone else in here) try running one of them again, go to the task manager and set the process affinity to a single cpu core and see if that changes anything?
    Author: Oculus Monitor , Auto Oculus Touch , Forum Dark Mode , Phantom Touch Remover , X-Plane Fixer Hardware: Threadripper 1950x, MSI Gaming Trio 2080TI, Asrock X399 Taich Headsets: Wrap 1200VR, DK1, DK2, CV1, Rift-S, GearVR, Go, Quest, Quest 2, Reverb G2, Quest 3
    Itsinthemind
    Inspiring
    September 3, 2014
    "Fredz" wrote:
    I think you may have some expensive shaders somewhere, maybe related to shadows which seems quite costly in Unity.

    It would be nice if someone was able to pinpoint the culprit in these jittering demos. The author of SightLine: The Chair managed to remove judder in some scenes but not everywhere, no idea what he tried.

    I used the RTP shader in Unity https://www.assetstore.unity3d.com/en/#!/category/1000049/sortby/popularity, simply because it makes the terrain materials pop. I think as you walk around in VR your attention will be mostly on your immediate surrounding, having a smooth, 3d, non pixelating texture I think is essential. To find out whether that is the cause I am going to build a very simple terrain with simple textures and then use RTP, and test the cost on frame rate. I will gradually introduce other elements and see what effect they have on performance.

    I think there is probable still an unavoidable trade-off at the current state of the arts in VR between eye candy and performance. It's just so noticeable in VR, not so much on the monitor where even 30fps can look acceptable.
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