Pre-emption for VR on nvidia now working correctly

andybird123 · 25 Mar 2016 at 18:35

https://developer.oculus.com/blog/asynchronous-timewarp-on-oculus-rift/

that big hoo har about NVidia pre-emption being "potentially catastrophic" - now fixed, and even better timewarp is built in to Oculus SDK 1.3 alongside both NVidia and AMD drivers, so doesn't even need any input from game devs for both vendors

BS Dave · 30 Mar 2016 at 09:21

Andy could you quickly explain what both things do, for those of that don't know?

Rilot · 30 Mar 2016 at 09:32

My understanding is that it's a process that displays an interpolated frame in the goggles if the graphics card has had to drop a frame for whatever reason. This keeps the refresh at 90fps even if the GPU can't keep up. It only works with head movement data though, not animation within the scene.
So, if you were turning your head without this tech and the GPU dropped a frame you would get a judder which can induce nausea. With this tech the driver guesses what to display based on the data from the movement sensors.

BS Dave · 30 Mar 2016 at 10:15

Thanks Rilot. Interesting. It would be kind cool if we could have the same for normal monitors, might make good 'ol v-sync smoother for those that don't wanna buy into freesync/g-sync

Rilot · 30 Mar 2016 at 10:51

I don't see any reason why it couldn't apply to mouse movements in an FPS.

Jarrastafari · 30 Mar 2016 at 11:27

Because the frames are warped (not interpolated) using the latest tracking data it doesn't produce additional frames (i.e. performance boost) that you'd like to see in your normal monitor.

drunkenmaster · 30 Mar 2016 at 11:28

andybird123 said:
https://developer.oculus.com/blog/asynchronous-timewarp-on-oculus-rift/

that big hoo har about NVidia pre-emption being "potentially catastrophic" - now fixed, and even better timewarp is built in to Oculus SDK 1.3 alongside both NVidia and AMD drivers, so doesn't even need any input from game devs for both vendors

Does it somewhere within the link say that it works perfectly on Nvidia drivers or works as well as it does on AMD? It doesn't say it works better on AMD either, but no where does it say it's 'now fixed', it just says they've worked with everyone involved to release the SDK. They know how the code should work, it now works, it's in final SDK form... that isn't proof it works well(on any cards) nor works specifically well on Nvidia. It just means they got what they believe to be good enough code to add it to the SDK.

Nvidia keeps saying Fermi will get Dx12, they keep saying Maxwell supports async, maybe they say they'll support timewarp too.... doesn't actually mean it does though.

andybird123 · 30 Mar 2016 at 12:15

Read their previous blog on ATW and then read this one, its pretty obvious what they are saying unless youre just looking to argue for arguments sake

olivier renault · 30 Mar 2016 at 20:23

PS4 VR also does frame interpolation with their magic VR box, to boost the FPS from 60hz (or lower?) to 120Hz display refresh rate. Not as complicated as Carmack time warping though, but seems to be 'good enough'.