SSR in our project, takes around 1ms, and when in VR it takes 3-4ms. In my naive mind, it should take around twice as much in VR, it it takes 3-4 times as much.
Anyone?
Hi,
Can you give more details about the resolution used in both cases ?
What really matters is the total amount of pixels rendered but VR devices are configured to display a very large resolution by default (both SteamVR and Oculus will pre-apply super-sampling resolution with about 150% increase from actual display resolution and often end up with a total resolution equivalent to 4K or more if you account for both eyes).
Fabien
@fabien-unity We use standard setup with Unity XR and Oculus integration packages, without adjusting anything related to resolution.
I understand your point with 1.5 x higher resolution and raymarching in framebuffer…
Ok what I mean to ask is :
- without VR, what resolution are you using?
- with VR, what resolution are you using ?
For Oculus, can you check your settings here for the resolution ?
Ok, I think this setting will end up returning a resolution of 1648x1776 per eye (you can confirm by querying the display resolution from Unity or by using RenderDoc, or by using the Oculus debug tool).
Quick math on this :
1648x1776 x 2 = about 5.85 MP
versus
1920x1080 (non-VR standard HD resolution) = 2.07 MP
With these values, we can expect the VR render times to be almost 3 times more, entirely due to the increased resolution.
This could explain the perf numbers you’re seeing.
Does that match your setup ?
Yes, it matches our setup. So this all makes sense, nice to understand and know. Thank you very much for quick response, and taking the time!
You’re welcome 
It can be tricky.
I’ll look into making this information more broadly available !
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