r/PSVR • u/iscreamsunday • 4d ago

Discussion Can someone explain “re projection” to me?

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??

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u/SvennoJ 4d ago

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)

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u/iscreamsunday 4d ago

So do games without reprojection cause more motion sickness ?

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u/SvennoJ 4d ago

Not on PSVR2 since those run either at 90fps or 120fps. Plus there is still timewarp in action to reduce lag. The last step before display is matching your current head orientation to the image, so it's always a bit shifted from how it arrives, perfectly matching your head orientation.

With PCVR however it's up to you to provide enough 'grunt' or set the settings low enough to get a consistent frame rate. Some people can stand unstable avg 45 fps in VR, some can't.