The raster problem is (another reason) why they're going to low persistence using a strobe flash rather than continuous illumination.
If you look at how television systems worked before CCD cameras and LCD screens, and look at a still from such a camera, you see that the recording and the playback were "distorted" in harmony, so the flash of light from each individual pixel as it was scanned out in raster (and interlaced) order was perfectly timed such that it did not apper warped as one might otherwise expect from what was effectively a rolling shutter camera.
That's the sort of dynamically-reoriented raytracing I had in mind.
Of course we're not likely to see CRT displays on a headset but I think you can get the same effect from other technologies.
Dio wrote:Colour me unconvinced on both practicality and effectiveness grounds .
Well it used to work in the old days. Things went a bit shit with bad mixtures of new and old displays and cameras until both became standard (kind of).
Also, it was an obvious but well tolerated problem that LED signs would turn text italic as it scrolled. I always marvelled at how well phase error could render sub-pixel positioned text like that, and even had the good fortune to get paid to experiment with more elaborate effects in the same line.
However, it looks like its a gross overoptimisation, anyway. Abrash's figure is 20ms, and with latency room like that there's really no point bothering.
If the system knows which ways the user's eyes are pointing, surely the biggest not-done-yet optimisation is to modulate the render quality from highest at the spot that projects onto the fovea to lower in the peripheral regions. Has to be a definition reduction rather than latency for obvious reasons. Also a dynamic scheme such that scenes too complex to render completely in one frame period result in a degraded image rather than a lower frame rate.
One attempt to hit both birds with one stone might be a ray-tracing style where most rays are traced for pixels nearer the high definition area and inter-tracepoint pixels are interpolated; could maybe have a hybrid polygon/ray-trace system to fake hard edges between objects. The system could render until its allotted frame-time is up resulting in a rock-steady frame-rate.
Barney wrote:I used to play games with LCD shutter glasses back in the day - and the effect was awesome. Quake 2 was especially good. There was no head tracking then and it's only a small step to go up to fully immersive stereo from there - and still no head tracking needed.
If they got that out on the market now, a lot of games would be able to take advantage of it (disregarding things like HUDs that are 3D flat objects that ruin the effect!) without needing API code to enable them. There's plenty of support for 3D drivers out there, and they'd be picked up again pretty quickly.
Uh, that already happened. List of stereoscopic 3d PS3 games. It got a huge push from sony a couple of years ago, but died when no-one wants to fork out £1000+ for a tv that can do a 120hz refresh.
To be honest, stereoscopic 3d (both 90s PC glasses or 2010 tvs) for me was always a bit rubbish. It was great for the first ten minutes, but colour bleeding was always too annoying and you only get depth 'into' the display, rather than the proper immersive 3d that a head-mounted unit can give you.
Orangy Tang wrote:
Uh, that already happened. List of stereoscopic 3d PS3 games. It got a huge push from sony a couple of years ago, but died when no-one wants to fork out £1000+ for a tv that can do a 120hz refresh.
To be honest, stereoscopic 3d (both 90s PC glasses or 2010 tvs) for me was always a bit rubbish. It was great for the first ten minutes, but colour bleeding was always too annoying and you only get depth 'into' the display, rather than the proper immersive 3d that a head-mounted unit can give you.
The PS4 is supporting it too. One of the pinball games has it and it's surprisingly effective on my TV.
Tried a couple of things on the PS3, but didn't get on with them as well as they suffered from being lower resolution. Saying that I probably should have tried Uncharted 3 on the TV rather than the projector, the resolution issue would have been less apparent!
venusian wrote:If the system knows which ways the user's eyes are pointing, surely the biggest not-done-yet optimisation is to modulate the render quality from highest at the spot that projects onto the fovea to lower in the peripheral regions.
Has been done already, apparently. A workmate was telling me about it, but I was totally unprepared to hear about fovea tracking in what I had assumed must have been fairly old and clunky technology.
Dio wrote:It gets pretty interesting as the refresh rate pushes up and latency goes down.
I believe it was a mechanical system (really it was so left-field I had trouble visualising what he was describing), so there was latency by the truckload, but that's OK because human brains aren't all that snappy anyway.
The constraints can be kind of ridiculous in both directions. Getting resolution over the fovea after saccade appears to be one of the relaxed ones.
gumboot wrote:Getting resolution over the fovea after saccade appears to be one of the relaxed ones.
Ooh, saccades I haven't thought about them much since graduating. Is it not possible/probable that they are to get motion detectors involved in feature detection, by making the image move across the eye, thus making features move relative to the retina?
"My way is the way of not fighting":- the book of Enter the Dragon.
Barney wrote:I used to play games with LCD shutter glasses back in the day - and the effect was awesome. Quake 2 was especially good. There was no head tracking then and it's only a small step to go up to fully immersive stereo from there - and still no head tracking needed.
If they got that out on the market now, a lot of games would be able to take advantage of it (disregarding things like HUDs that are 3D flat objects that ruin the effect!) without needing API code to enable them. There's plenty of support for 3D drivers out there, and they'd be picked up again pretty quickly.
Uh, that already happened. List of stereoscopic 3d PS3 games. It got a huge push from sony a couple of years ago, but died when no-one wants to fork out £1000+ for a tv that can do a 120hz refresh.
To be honest, stereoscopic 3d (both 90s PC glasses or 2010 tvs) for me was always a bit rubbish. It was great for the first ten minutes, but colour bleeding was always too annoying and you only get depth 'into' the display, rather than the proper immersive 3d that a head-mounted unit can give you.
Well, yes, I already said I had played games in stereoscopic 3D - what I always wanted was full 3D, ie filling the field of view.
Head tracking can go hang for all I care - I just want the next logical step up from the glasses.
"Oh dear lord, I slightly soiled myself. Oxfam won’t be pleased."
gumboot wrote:The constraints can be kind of ridiculous in both directions. Getting resolution over the fovea after saccade appears to be one of the relaxed ones.
Co-incidently, I was thinking about this whilst cycling home. I was thinking you'd need to track not only position but movement direction and acceleration in order to predict its eventual resting place and have an image waiting, Then I was trying to figure out what kind of resolution and scanning speed you'd need for that kind of measurement and decided a 60Hz camera simply wouldn't cut it. The I got to some traffic lights and had to think about something else.
zip accident wrote:Ooh, saccades I haven't thought about them much since graduating. Is it not possible/probable that they are to get motion detectors involved in feature detection, by making the image move across the eye, thus making features move relative to the retina?
There's no lightweight, low-latency, cheap eye tracking technology at present. I would not be remotely surprised if Oculus and / or Valve are working on that one. It would be a big thing for gameplay, analysis... and, yes, advertising... as well as allowing rendering tricks.
VR, Carmack, Abrash... feels like it's, what? '95 again and I can't wait for Abrash's next column in Dr. Dobb's, explaining id's current experiments and thoughts on their new engine leading to something never seen before.
>take off sunglasses
Seamen and fishermen alike swear to have heard voices in the rising tide. Inhuman screams, some of them say.
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