[osg-users] Oculus+OSG

[Jan Ciger]

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On 08/09/15 19:48, Björn Blissing wrote:
> I concur with your conclusion that it is highly likely that Oculus 
> are in fact using the asynchronous solution in the SDK0.6 and 0.7, 
> BUT they have not stated officially that the are using this. In 
> theory positional re-projection could be done in synchronous 
> rendering (although unlikely).

Positional reprojection could certainly be done synchronously (modulo
artifacts, etc), but the Reddit video you have posted explictly shows
framerate "smoothing".

That wouldn't happen if you do the warping at the end of each frame
(as before), regardless whether only rotational warp is done or both
positional and rotational. The framerate will be the same or even a
bit worse than before because more calculation has to be done per
frame. However, the tracking latency will be perceived as lower,
because the time between the movement and the change making it to the
screen will be shorter.

That's why I have concluded that the video is showing the new
asynchronous timewarping technique - that one actually permits to
fill-in for the missing frames and allows to smooth over framerate
jitter and occasional missed vsync deadline. The "old style"
timewarping doesn't do that (and was not advertised as a tool for that
neither).

J.



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