Hi, I don't know what this is supposed to do, but I get pretty bad migraines and loading the page made me feel extremely strange almost immediately so I closed it.
I would check to make sure this can't trigger migraines or seizures. Maybe it's just me, but also, please double check.
Interesting, I wonder.. have you ever tried a VR headset? Does that cause you migraines as well? or maybe any other discomfort that'd prevent you from using it?
I don't usually have headache migraines but do have strong visual auras from time to time.
Looking at this it first looked fun: "whoa, that's cool, this fovea thing is really smaller than I imagined"
After a minute or so playing around I closed the window and then I noticed a form
of retina persistence that looked eerily similar to an onset of a visual
aura, as well as some faint but clear ear ringing, both typical symptoms of the migraines I experience.
I immediately walked away from the computer and although dwindling it's still in effect 10min out.
Yes, immediately felt weird and a bit uncomfortable. I can almost see, or kind of sense, all those parts moving in the image even though I can only see the movement clearly in the center. I can easily imagine getting a headache from watching that for a longer time.
You can see everything in your field of vision, but the area DIRECTLY in the centre has the highest level of detail. This image has high frequency animated details that are not cognisized equally by your entire FOV. The animated bit right in the middle at any given time is where your brain processes the most detail and also where you are looking.
Most of what you think you are seeing at any moment is only imagined.
The retina is not uniform. Most photosensitive cells (cones) are near the centre of vision. Peripheral vision has little resolving power. Can't make out fine details. The reality of this is much more extreme than it subjectively feels like. The eye doesn't actually have pixels but if it did they'd all be focused at the centre. Like an image where 10% of the area in the middle had 80% of the pixels.
At the centre of vision the eye has enough resolving power to make out the tiny star shapes and see that they are rotating. Outside of that narrow zone in the peripheral vision they're perceived as coloured blobs, at best. Normally your brain would make this transparent to you. But this is an unusual pattern. Your visual cortex doesn't realize all the stars should be rotating. So only the ones you can actually see at any one instant seem to rotate.
Try to look at an object in the room with you, such as a lamp, without looking at it directly. Observe it out of the corner of your eye. The more you try, the less sharply defined it will seem. At the very edge of your vision you're only getting a handful of pixels worth of colour information. But because you know it is a lamp, it has the sharpness of a lamp's definition even though you cannot actually see that definition without directly looking at it. That's a related illusion.
This is why the eye scans constantly in those micro-jerking motions known as saccades. If a face were to pop up on your display, it would feel like a single instant recognition of a person. But before you experience that the eye would scan over the eyes, mouth, nose and so on, several times, in sharp flicking motions, over about 100 milliseconds, and these dozen or so little snapshots, as it were, would be stitched together into the whole image of a face. Even though only a tiny slice of the eye, or the nose, etc. can actually be seen at any one time, you perceive the whole face.
This illusion hacks that and reveals how narrow our high-resolution vision really is. The whole visual field feels rather high resolution. But only that tiny spot where they rotate actually is.
TL;DR it helps you identify the true diameter of your visual focus, which is said to shrink with old age (mine shrinks more in terms of _time_ dimension but that's a different issue!)
For best results, use it _fullscreen_, change the #define `90` values to a higher value if you're on a high dpi screen.
Stare at a few places on the screen and you'll get the effect of appearing to rotate only where you stare.
on my phone at typical distance and 90 scale i only see about an asprin tablet size area spinning. but at 180 scale i see almost everything spinning at same distance.
i think peripheral vision is quite sensitive to movement/contrast changes, but the moving shapes have to be large enough to trigger those receptors?
Shadertoy got hugged to death by this shader a few years ago and it had a custom "please go away" banner for a little while. Funny seeing it show up again on HN front page.
I have nystagmus (rapid, uncontrollable, rhythmic eye movements), so I couldn't see anything at first, just lots of small dots.
I had to zoom in (Mac accessibility tool) but then I could see the effect briefly. My eyes go everywhere, but I could see patches of moving shapes with stationary shapes further away, only that the patch moved around a lot!
I can't see any movement, at any distance. How likely is it something weird with my vision vs. something weird with my monitor/computer? I'm on a 360hz monitor at 2k.
At the default scale of 90, I can't see anything spinning at all even with the video full screen. If I set the scale to 250 or larger I can see the stars spinning, but I just see the whole field spinning. Even if I get so close to the screen it almost fills my field of vision.
So for me either the stars are too small to see any motion, or I can see them all spinning no matter what.
Awesome. You'll see the little stars rotating only in the area they reach your fovea, the most sensible part of the retina. All the rest will not be able to perceive any motion.
This is quite cool, rocked back and forth from and to my screen and got a (bit inconsistent, but consistently visible) "shape" of the fovea. maybe 30% larger than I thought it'd be!
Right after though, I felt like my vision was clouded, like there was a grey overlay on it or something for a few minutes. Don't recommend having this open for too long. Visual cortex doesn't like running against its limits I guess
Oh wow, this made me realize something I've had for 20 years: When I look too close for a few seconds, I get blurriness at the center of my vision. It goes away after a while, but this made me realize that the blurry region is actually my fovea!
I have no idea why my fovea blurs when I look close up at something, and doctors haven't been able to figure it out, but at least now I can google it better.
Fascinating. I get very different results depending on which glasses I use.
I'm far-sighted with a relatively weak prescription.
Without glasses I have a tiny bit of lazy eye, it's not really perceptible for the most part looking at me, but for stuff like this I get a sort of figure-eight shaped blob of motion that skips around a fair bit which I guess is because my eyes fail to track correctly and can't find anything to focus on. Can't perceive the motion outside of this area.
With my regular glasses this there's still some of this effect, but much less pronounced. Can't see any motion outside of the center of my field of view.
With my reading/screen glasses, which technically makes me myopic, I get a large perfect circle, and can still detect a lot of motion outside of the circle, even if it's "low FPS".
woah its incredible how quickly i can spot the fuzzy spot around where i can clearly see the rotation, and when i unfocus can see fuzzy movement all around.
This is really cool. So this is the theory beind foveated rendering/streaming
51 comments
[ 2.9 ms ] story [ 63.8 ms ] threadI would check to make sure this can't trigger migraines or seizures. Maybe it's just me, but also, please double check.
Looking at this it first looked fun: "whoa, that's cool, this fovea thing is really smaller than I imagined"
After a minute or so playing around I closed the window and then I noticed a form of retina persistence that looked eerily similar to an onset of a visual aura, as well as some faint but clear ear ringing, both typical symptoms of the migraines I experience.
I immediately walked away from the computer and although dwindling it's still in effect 10min out.
The retina is not uniform. Most photosensitive cells (cones) are near the centre of vision. Peripheral vision has little resolving power. Can't make out fine details. The reality of this is much more extreme than it subjectively feels like. The eye doesn't actually have pixels but if it did they'd all be focused at the centre. Like an image where 10% of the area in the middle had 80% of the pixels.
At the centre of vision the eye has enough resolving power to make out the tiny star shapes and see that they are rotating. Outside of that narrow zone in the peripheral vision they're perceived as coloured blobs, at best. Normally your brain would make this transparent to you. But this is an unusual pattern. Your visual cortex doesn't realize all the stars should be rotating. So only the ones you can actually see at any one instant seem to rotate.
Try to look at an object in the room with you, such as a lamp, without looking at it directly. Observe it out of the corner of your eye. The more you try, the less sharply defined it will seem. At the very edge of your vision you're only getting a handful of pixels worth of colour information. But because you know it is a lamp, it has the sharpness of a lamp's definition even though you cannot actually see that definition without directly looking at it. That's a related illusion.
This is why the eye scans constantly in those micro-jerking motions known as saccades. If a face were to pop up on your display, it would feel like a single instant recognition of a person. But before you experience that the eye would scan over the eyes, mouth, nose and so on, several times, in sharp flicking motions, over about 100 milliseconds, and these dozen or so little snapshots, as it were, would be stitched together into the whole image of a face. Even though only a tiny slice of the eye, or the nose, etc. can actually be seen at any one time, you perceive the whole face.
This illusion hacks that and reveals how narrow our high-resolution vision really is. The whole visual field feels rather high resolution. But only that tiny spot where they rotate actually is.
For best results, use it _fullscreen_, change the #define `90` values to a higher value if you're on a high dpi screen.
Stare at a few places on the screen and you'll get the effect of appearing to rotate only where you stare.
It's pretty neat.
on my phone at typical distance and 90 scale i only see about an asprin tablet size area spinning. but at 180 scale i see almost everything spinning at same distance.
i think peripheral vision is quite sensitive to movement/contrast changes, but the moving shapes have to be large enough to trigger those receptors?
not sure what to conclude from this.
"Bad request"
am I missing the joke?
https://web.archive.org/web/20210430091013/https://www.shade...
I had to zoom in (Mac accessibility tool) but then I could see the effect briefly. My eyes go everywhere, but I could see patches of moving shapes with stationary shapes further away, only that the patch moved around a lot!
So for me either the stars are too small to see any motion, or I can see them all spinning no matter what.
What effect am I supposed to see?
Right after though, I felt like my vision was clouded, like there was a grey overlay on it or something for a few minutes. Don't recommend having this open for too long. Visual cortex doesn't like running against its limits I guess
I have no idea why my fovea blurs when I look close up at something, and doctors haven't been able to figure it out, but at least now I can google it better.
https://www.paulkeeble.co.uk/posts/cff/
I'm far-sighted with a relatively weak prescription.
Without glasses I have a tiny bit of lazy eye, it's not really perceptible for the most part looking at me, but for stuff like this I get a sort of figure-eight shaped blob of motion that skips around a fair bit which I guess is because my eyes fail to track correctly and can't find anything to focus on. Can't perceive the motion outside of this area.
With my regular glasses this there's still some of this effect, but much less pronounced. Can't see any motion outside of the center of my field of view.
With my reading/screen glasses, which technically makes me myopic, I get a large perfect circle, and can still detect a lot of motion outside of the circle, even if it's "low FPS".
[1] https://en.wikipedia.org/wiki/Chromostereopsis