Quest 3 FFR implementation

[milesrotaru]

On previous headsets, when fixed foveated rendering is enabled, the low-res regions are distributed all around the edges of the screen, with regions of varying levels, being strongest in the corners, as shown by the images below.

On the Quest 3 however, I've noticed that on medium and low settings the FFR region is just a uniform strip covering the top of the display but not the sides or bottom. And on medium it comes down pretty far, apparently covering the entire top third of the visual field. Is this really the intended behavior or just a bug some people are having? It seems like a weird decision not to spread the FFR around more evenly.

Here's a screenshot of Pop One demonstrating the issue. A very large region at the top of the screen is degraded while the sides and bottom are barely touched.

[TheLegend27]

Hey @milesrotaru!

It was hard to notice at first, but I can definitely tell what you're talking about now with the FFR banner strip at the top. With foveated rendering being controlled by the app developer, I'm wondering if you see this specific case present in games other than Population: One. I noticed a handful of other users were having this same issue on r/populationonevr—specifically with the top banner. It may be worth reaching out to BigBox directly to see if this is a known issue they're working on improving for Quest 3 users.

Hope this helps!

[milesrotaru]

That was the only screenshot readily available on Google but the issue isn't exclusive to Pop One. Any game that uses FFR medium or higher has the same very large foveated region at the top and very little on the sides and bottom. Other applications that don't use FFR by default all exhibit similar behaviour if you force FFR medium using ADB commands. Low foveation setting is okay, the top region is small enough not to be distracting.

[TheLegend27]

With the way rendering works with Quest devices, what you're describing (for the top layer) sounds like normal FFR behavior. 

When we look at the fragment density map for the Quest 3:

The top region can be quite large, especially for the high and medium settings. This doesn't really explain the mapping not being present for the bottom and sides, as those regions should be larger than the top portion. It's also worth noting that position and sizes of tiles will depend on your headset and render settings. Other factors to consider are how a developer controls their shading quality through variable rate shading, along with localized resolution control.

• What other games have you noticed this in?
  • Are any of them PCVR titles? 
  • Do you have examples comparing Low to Medium and High FFR for those games that you can post? (This one is important)
• Has there been anything else that seems off about your display?
  • Off center menus, character reticles being slightly off, etc.?
• Can you confirm which headset version your Quest 3 is currently running? You can check in Quick Settings > Settings > Software Update under the Current Version Details section. The formatting should be 62.#.#.###.###.######### or 63.#.#.###.###.#########.
  • If you're testing on any PCVR titles, what version is your Meta Quest Link App running?
• Are you enrolled in the V63 PTC?
  • If so, are you still on the PTC's V63, or the live V63 update?

I can't rely too heavily on the Population: One example, as that one seems to be a separate issue.