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You don't look at all of a 3840x2160 screen, with a need for pixel-precision all over it. Doing a test right now, I'm focusing on the 13-inch computer screen w

You don't look at all of a 3840x2160 screen, with a need for pixel-precision all over it. Doing a test right now, I'm focusing on the 13-inch computer screen where I'm typing this and holding up a large container of cashews directly to the right of the display. It's literally less than 30 degrees to the right of my focus, and the word "cashews" is in half-inch-high letters, and I can't remotely read the word without moving my eyes over to it.

mcphage 3y ago
> I can't remotely read the word without moving my eyes over to it Plus the portion of your eye that sees in high resolution is ridiculously small—1% of your field of view. And your eye and brain just hide that fact by making your eye constantly jitter to see a larger area.
- saltcured 3y ago
  But, they aren't doing fovea tracking and shifting the display around in response to eye movements, are they? If not, you would only get more screen space if you articulate your neck and cause the head-tracking to update your viewing perspective. I've monitored how I use 4K screens in the 28" size range. I would not normally move my head at all to look at different parts of the screen. I would only move my eyes. With two such screens side-by-side, I would turn my head just a little bit to focus on one screen or the other. Or, I found I would often hold one head position that is neutral between the two, and then use approximately 2/3 of each screen, with the far outer edges neglected or used to banish less relevant communications and status apps that I only check once in a while. And, these screens are not filling my field of view by any means. So, I'd really need a far higher resolution headset if it is going to give me a good immersive field of view and be a reasonable monitor-replacement. I fear that fovea-tracking will remain scifi dreams in my lifetime, so the reality is we need to render full resolution throughout the field of view to be prepared for where the eye gaze might go in the next frame.
  - jakemoshenko 3y ago
    > I fear that fovea-tracking will remain scifi dreams in my lifetime, so the reality is we need to render full resolution throughout the field of view to be prepared for where the eye gaze might go in the next frame. This is not at all true. All of the AVP, the Quest Pro, and the PSVR2 do eye tracking based foveated rending. They lower the clarity of the things you're not looking at. And reviewers say it works perfectly, like magic. They are unable to "catch" the screen adjusting for what they're looking at.
    - saltcured 3y ago
      Hmm, interesting... Are they actually doing some kind of optical shifting of a limited pixel display? Or you just mean they do some kind of low-res rendering mode to populate most of the framebuffer outside a smaller zone where they do full quality rendering? In other words, are they just allocating rendering compute capacity or actual pixel storage and emission based on foveal tracking?
      - jakemoshenko 3y ago
        > Or you just mean they do some kind of low-res rendering mode to populate most of the framebuffer outside a smaller zone where they do full quality rendering? This exactly. They don't reduce the resolution too much, but it's visible to an outside observer watching on a monitor.
        vlovich123 3y ago
        That’s just to be about to have enough compute/bandwidth to drive the display. Other posters are correct that the DPI decreases away from the center and various optical aberrations increase. Foveated rendering won’t help with that.
  - gcanyon 3y ago
    Fovea-jitter is far from covering the width of your vision. They can overshoot by (maybe, I'm guessing) 2-3x the are of your precise vision and all jitter will be covered.
treis 3y ago
This isn't how any of this works. It doesn't matter how little of an area of the monitor your focusing on. You still need to generate an equivalent DPI over that area in the headset to match the monitor. Which you can't do since the headset has fewer physical pixels than the monitor does.
- cududa 3y ago
  No you don't. The headset uses eye-tracking to enable foveated rendering. You only need to generate a high-dpi segment of the screen, where the eyes are actually focussed
  - etchalon 3y ago
    You can't really "generate" a high-DPI segment. The display either has a sufficient pixel density or it doesn't. Foveated rendering let's you cheat the details you render outside the focal point, but since your eyes can move to any portion of the display, the entire display needs to have a high-enough DPI that, once your eye moves to focus on that section, the content rendered in that location will be sharp.
    - deleted 3y ago
      [deleted]
  - charcircuit 3y ago
    The limit on DPI is from the display system. Foveated rendering doesn't help.
    - cududa 3y ago
      3840 x 2160 resolution per eye. 23 million pixels per eye, or, nearly 3x the pixels of a 4k TV with the equivalent resolution. That's roughly 3 physical sub-pixels per 1x1 "virtual pixel". As well, given the oddities of human vision and how eyes focus, they can give more subpixels to the tiny area your eye is looking at to increase fidelity

mcphage 3y ago

> I can't remotely read the word without moving my eyes over to it Plus the portion of your eye that sees in high resolution is ridiculously small—1% of your field of view. And your eye and brain just hide that fact by making your eye constantly jitter to see a larger area.

saltcured 3y ago
But, they aren't doing fovea tracking and shifting the display around in response to eye movements, are they? If not, you would only get more screen space if you articulate your neck and cause the head-tracking to update your viewing perspective. I've monitored how I use 4K screens in the 28" size range. I would not normally move my head at all to look at different parts of the screen. I would only move my eyes. With two such screens side-by-side, I would turn my head just a little bit to focus on one screen or the other. Or, I found I would often hold one head position that is neutral between the two, and then use approximately 2/3 of each screen, with the far outer edges neglected or used to banish less relevant communications and status apps that I only check once in a while. And, these screens are not filling my field of view by any means. So, I'd really need a far higher resolution headset if it is going to give me a good immersive field of view and be a reasonable monitor-replacement. I fear that fovea-tracking will remain scifi dreams in my lifetime, so the reality is we need to render full resolution throughout the field of view to be prepared for where the eye gaze might go in the next frame.
- jakemoshenko 3y ago
  > I fear that fovea-tracking will remain scifi dreams in my lifetime, so the reality is we need to render full resolution throughout the field of view to be prepared for where the eye gaze might go in the next frame. This is not at all true. All of the AVP, the Quest Pro, and the PSVR2 do eye tracking based foveated rending. They lower the clarity of the things you're not looking at. And reviewers say it works perfectly, like magic. They are unable to "catch" the screen adjusting for what they're looking at.
  - saltcured 3y ago
    Hmm, interesting... Are they actually doing some kind of optical shifting of a limited pixel display? Or you just mean they do some kind of low-res rendering mode to populate most of the framebuffer outside a smaller zone where they do full quality rendering? In other words, are they just allocating rendering compute capacity or actual pixel storage and emission based on foveal tracking?
    - jakemoshenko 3y ago
      > Or you just mean they do some kind of low-res rendering mode to populate most of the framebuffer outside a smaller zone where they do full quality rendering? This exactly. They don't reduce the resolution too much, but it's visible to an outside observer watching on a monitor.
      - vlovich123 3y ago
        That’s just to be about to have enough compute/bandwidth to drive the display. Other posters are correct that the DPI decreases away from the center and various optical aberrations increase. Foveated rendering won’t help with that.
- gcanyon 3y ago
  Fovea-jitter is far from covering the width of your vision. They can overshoot by (maybe, I'm guessing) 2-3x the are of your precise vision and all jitter will be covered.

treis 3y ago

This isn't how any of this works. It doesn't matter how little of an area of the monitor your focusing on. You still need to generate an equivalent DPI over that area in the headset to match the monitor. Which you can't do since the headset has fewer physical pixels than the monitor does.

cududa 3y ago
No you don't. The headset uses eye-tracking to enable foveated rendering. You only need to generate a high-dpi segment of the screen, where the eyes are actually focussed
- etchalon 3y ago
  You can't really "generate" a high-DPI segment. The display either has a sufficient pixel density or it doesn't. Foveated rendering let's you cheat the details you render outside the focal point, but since your eyes can move to any portion of the display, the entire display needs to have a high-enough DPI that, once your eye moves to focus on that section, the content rendered in that location will be sharp.
  - deleted 3y ago
    [deleted]
- charcircuit 3y ago
  The limit on DPI is from the display system. Foveated rendering doesn't help.
  - cududa 3y ago
    3840 x 2160 resolution per eye. 23 million pixels per eye, or, nearly 3x the pixels of a 4k TV with the equivalent resolution. That's roughly 3 physical sub-pixels per 1x1 "virtual pixel". As well, given the oddities of human vision and how eyes focus, they can give more subpixels to the tiny area your eye is looking at to increase fidelity