The online racing simulator
Severe Lack of Smoothness in VR
(15 posts, started )
#1 - AndyG
Severe Lack of Smoothness in VR
I have a high spec PC and the game easily runs at 90fps all the time (I use a Rift), yet the world itself doesn't move smoothly. This is most obviously seen when cornering, the objects on the horizon passing across in small steps, rather than smoothly. On straights too, if you look to the side at passing fence posts etc, you see the same effect. In 2D it doesn't happen, the game is smooth at all times.

Any ideas please? It makes the game unplayable for me because it creates a very uncomfortable feeling, very close to motion sickness.
LFS runs best at 100fps on 100Hz refresh rate. It's going to be difficult to get that when you're limited to 90Hz, since anything besides 100fps @ 100Hz is results in judder.
#3 - AndyG
Thanks, yes I've read that before but I'm not convinced it's the case here. In 2D mode if I turn VSYNC on (which is 60fps for my screen), it runs perfectly smoothly. Similarly, 300fps with VSYNC off is smooth. I think this is something different, something VR specific, and different to the minor jitter some see due to the 100Hz physics.
If its something that is present for all using VR then it must be something i had not noticed. Il do a check and see if i notice it
To be honest when i am racing i focus on so many things that if i could miss it if its not really bad
#5 - AndyG
Scawen any thoughts on this please? LFS does a lot of things brilliantly, so it's a real shame we have this fundamental issue in VR.
Scawen said that he knows about it and he is working on it, but it turns out its more complicated than it seems and its going to take some time after the graphic/physics update.
#7 - AndyG
Ok thanks for that - is there by any chance a thread here with more information on that process please? I did find one other thread on the issue, but no developer input there either.
Quote from Scawen :If I can get the graphics ready to a condition that is suitable for this release and could then get back on the physics so that is suitable in time for Eric to have finished the tracks, then this opens the possibility of working on separate physics and graphics threads. That would be a great help and the plan would be to combine this with some means of producing visual frames at the correct visual frequency for the monitor. That would either be by using a high frequency physics update that can be interrupted at any point for a graphical frame, or by using a lower frequency physics update that can be interpolated to produce graphical frames.

Obviously the graphics needs to be done then that would make it releasable, even with the current physics and it's possible this may happen. But I really hope I can sort out the new physics so we can move on.

Quote from AndyG :Ok thanks for that - is there by any chance a thread here with more information on that process please? I did find one other thread on the issue, but no developer input there either.

Here - https://www.lfs.net/news Big grin
#9 - AndyG
Ah thanks, but that's actually a different issue (see my post 3 above).
What is your VR setup? I mean HTC Vive or Oculus or?
Rift (as per my first post).
Quote from AndyG :I'm not convinced it's the case here. In 2D mode if I turn VSYNC on (which is 60fps for my screen), it runs perfectly smoothly. Similarly, 300fps with VSYNC off is smooth.

I still think it may be the same issue. It just depends what you call severe. The 100Hz physics displayed at 90Hz issue can be quite bad when you look sideways. A definite problem.

You can see the same effect with 60Hz VSync on a monitor, it just doesn't look as bad as it does in VR. To try it, select a low FOV then drive along beside something big and nearby, e.g. pit garages, looking sideways. You can see the edges seem to be jittering along.

Trouble is it's a major graphics and physics engine redesign to avoid this, there's no quick solution and for sure it's not something I can do in the current public version, I would only do it in the new development version. It's too big a job to code up twice in the two separate diverged code bases.
Understood thanks, and I really appreciate the reply. The only thing I'd add, is that the problem for me is not just when looking sideways, but also when cornering, and looking ahead normally, it is quite severe.

Anyway, I will try and be patient and look forward one day to it being sorted!
BTW, and you must get this all the time - but if you ever need a beta tester for this, I'm happy to oblige. I work in game development myself, so know what's required - although couldn't commit the time to test much generally, beyond this specific issue. I fully expect to be ignored on this though, so no worries!

Severe Lack of Smoothness in VR
(15 posts, started )
FGED GREDG RDFGDR GSFDG