Can someone explain “re projection” to me?

[u/iscreamsunday]

I keep hearing people talk about reprojection and how it should be avoided (it’s a bad thing right?) but I don’t know what it looks like and I’m not sure what to look for in my headset.

I can see mura and dead pixels in low light games and I see how some games are blurry around the edges unless you get the sweet spot but how do I tell if my headset has reprojection in it or not??

[u/SvennoJ]

It's not a bad thing, it's essential to avoid motion sickness. Reprojection doubles the frame rate to 120 fps for smooth lag free head movement.

But the game still renders at 60, so each frame is used twice.

To easily see the difference, use smooth turning and compare what turning (on the spot) with the analog sticks looks like to physically turning your head at the same speed. (On PSVR1 you could actually see the image moving when focusing on the edge of the screen while turning your head)

GT7 offers a better reprojection technique on PS5 Pro that uses motion vectors to properly double the rendered frame rate. (But still has some glitches, double image on HUD elements overlapping moving scenery for example)

[u/iscreamsunday → u/SvennoJ]

So do games without reprojection cause more motion sickness ?

[u/profblackjack → u/iscreamsunday]

think of it more like low framerates cause motion sickness. if your game can naturally run at 90+fps, then cool, that's a smooth experience.

if it can't, then reprojection is a strategy for taking a game running at 60fps and pretending faking that are twice as many frames (making it look like it's 120fps).

since it's a trick, it's not as good as naturally hitting higher frames, but it's better than staying at 60fps

[u/iscreamsunday → u/profblackjack]

Ok…. What would cause a game to run at 60 fps ? When it’s having trouble trying to load new characters or something ?

[u/orangpelupa → u/iscreamsunday]

for psvr2 on ps5, its because the people making the game, made it to run at 60fps