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I had an experience with an HTC Vive a couple of years ago, and I'm now considering getting the hardware required to do proper VR.
Obviously, I'd like to play games, but I'm also interested in visualising data (in particular I see that VTK supports OpenVR).
So I was wondering whether anyone in the community here has succeeded in getting this to work under linux, and if they can comment on the hardware required.
I'd be grateful for any insights.
As I understand it, it's best to get 120FPS, otherwise the brain doesn't like it.
I see that system76 has a "thelio major" desktop that can handle a range of NVIDIA cards, but I honestly don't know which would be the minimum that still gets me reasonable performance.
Is it important to have a lot of memory, a lot of cores?
Will I be able to change the level of detail in games to gain in FPS?
Right now it looks to me like I'd need more than 3000 euros for the whole thing (computer+htc vive).
My wife may not approve.
In any case, with the possibility of a second wave of coronavirus in the winter, I'm under the impression a working VR system would be a reasonable addition to the "don't go crazy" activities around the house.
(Score: 4, Interesting) by Rich on Friday July 17 2020, @09:08AM (12 children)
On a related topic: Is there any simple solution to having a primitive shutter glass (or even just a passive) setup for Linux? Preferably with the Raspi and RK3399 class of SBCs, explicitly excluded is anything involving NVidia,
E.g. I have a scissor mechanism on my tripod to move my camera 65mm sideways to make one photo for the left eye, and one for the right. I put on my shutter glasses and type "view3d left.jpg right.jpg" (or similar) and get a 3D-view of my photos? It is acceptable if I have to write that "view3d" program, but I would need the information how it can be achieved. I could also build a fitting transmitter for one of the weird glass signalings off a GPIO, if that was needed (mind you, HDMI has no easily tappable vsync).
There used to be the LG D2342P-PN for a passive solution, but this has become a lucky ebay find now. (There is also minimal information how these would be made to work, but from two words at some "pymol" wiki, i deduce it is polarization by row).
(Score: 2, Informative) by Anonymous Coward on Friday July 17 2020, @11:27AM (4 children)
Well, I only have stupid or weird solutions to offer you :
(I was interested in that topic some time ago)
- Use vintage hardware on Windows 98 or XP. The H3D glasses came out in 1998 and were still sold a decade later sometimes under another name. Supports nvidia and 3DFX. Needs a CRT monitor that does 120Hz at 800x600 or 1024x768 (no res limitation other than practical?). The glasses run on two coin batteries, aren't great and feel like using blueish sunglasses too. I tried it!
Nvidia supported every such old 3D things (and anaglyph) until geforce 6 or 7, then pulled support when they released "Nvidia 3D vision" when 120Hz LCD came out. They were open until then and said a big fuck you to 3D Stereo users!
- hacky solution? these fairly common H3D glasses came with a VGA dongle (power from PS/2 keyboard interface). It trivially synced from there. IR LED on a wire plugged in there. HDMI to VGA adapter would possibly work with this but I don't know if they do low res at 120 and 144Hz etc. Still need some iiyama or other CRT.
- Cut some cardboard and attach it to a monitor such that each eye can only see half the screen ; display side by side.
- Use a Nintendo 3DS. Was made for children, no other hardware needed! Low res. Might want it run "homebrew" software.
- Use two projectors. Raspi 4 makes this really easy I guess! (two outputs). The minimum setup would be two pico projectors I guess, as long as they accept hdmi and not just composite. Polarize them, now you can use those $1 plastic glasses from TVs and theaters!
I don't know how easy it is to line them up using calibration pictures.
what do ya think?
(Score: 3, Insightful) by Marand on Friday July 17 2020, @12:22PM (3 children)
This is basically the premise of "Google Cardboard" and works surprisingly well. You could probably rig something similar with a Pi, a cardboard box, and a small LCD display at the end. Stick your face in the box and see 3d pictures by displaying left/right eye images on the corresponding halves of the display.
(Score: 2) by Freeman on Friday July 17 2020, @03:42PM (2 children)
You'd want to use the most powerful Pi available, at this moment, the Raspberry Pi 4. Still, that would be a lot of work, for what I would call very little reward. Since, you'd likely get a better experience doing the google cardboard thing, but just using a cheap phone you grabbed off e-bay for it.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 2) by Marand on Saturday July 18 2020, @02:06AM (1 child)
The original question seemed to be about viewing photos with depth (via left/right eye stills) so I don't think you'd need particularly powerful hardware for that; anything that can drive a small display should work. You're right that repurposing an old phone or small tablet to do the same thing with a small android app would do it as well or better though. And help avoid electronic waste as well.
(Score: 2) by Rich on Saturday July 18 2020, @06:59AM
Indeed. Thanks to everyone who replied here. In the meantime, I had another look for one of the old passive LG monitors (in FHD), found a good offer and ordered it, together with some glasses. We'll see how it works. As I understand, they use circular polarization and are Real3D compatible, i.e. you can even use the good glasses in cinemas.
It's a pity they are not made anymore. If I wanted to reproduce my experiment, I'd still have to look for active glasses. Fortunately there is a paper on the confusion with all the possible signaling methods, the hardest part is probably to get the images past the Linux compositors and a precise frame sync whenever this happens. I'd also look away from the Raspi and towards the RK3399 if I had to try.
One might start to believe in conspiracy theories about this sector, after getting an overview of the huge mess it is.
(Score: 2) by hubie on Friday July 17 2020, @11:46AM (3 children)
Writing your own software should be pretty straightforward. All the tools you'd need are in OpenCV and there seems to be a lot of tutorials on how to do them (search "anaglyph opencv stereo" for instance). You probably know this already, but your results will improve, depending upon what kind of lens you're using, if you remove lens distortion. I used to code this kind of stuff up many years ago before most of the OpenCV tools were available, but poking around online it looks like a lot of the hard work is now packaged into very nice libraries. I'm feeling more than a little inspired now to mess around with this again. There is a lot of interesting things you can do by playing with the camera focal length as well as the baseline separation.
(Score: 2) by Rich on Friday July 17 2020, @12:42PM (2 children)
I wasn't aware of any of this, and just spent some time searching for most possible combinations of "opencv" with "stereo", "display", and whatever and didn't find anything. Note that "anaglyph" isn't what I want here, this is about providing one colour picture for each eye from a single monitor. There's boatloads of stuff related to stereo cameras, and computing depth fields from those, but I found nothing about displays. You don't happen to have a better lead?
(Score: 2) by hubie on Friday July 17 2020, @02:14PM (1 child)
No, I'm afraid I'm not of much use on the display side. You might want to check out the site for the stereopi [stereopi.com] project. They've implemented a stereo camera on a little pi and their website has a blog section [stereopi.com] where they go into interesting projects. Perhaps there are display options/ideas to be mined from there.
I did see this arXiv paper [arxiv.org], which might be in the direction of what you're looking for on the code side of things.
(Score: 2) by Rich on Friday July 17 2020, @03:27PM
Thanks for the leads, at least I learned something new
- The arXiv paper uses a display from lookingglassfactory. it's a passive no-glasses 3D display with a 50 degree FOV; the 15 inch model for three grand, the 9 incher start at 600$. Looking at the specs, these probably must be seen to be believed. The "how it works" vaguely mentions 45 separate views in a lightfield, so it might be a bit resolution challenged, or, I fear, worse for my plan, it can't directly work from stereo images (however they seem to have tools to convert stereo images to what they need). Absolutely nothing about active shutters, though.
- The raspi foundation are asshats wrt the cameras, including a dongle chip, but because they couldn't get away with that with industrial customers, their locked-up driver doesn't check the dongle on compute modules, and there's a nice stereo camera setup with a fitting CM3 carrier from a shop called "waveshare".
(Score: 0) by Anonymous Coward on Friday July 17 2020, @12:10PM
Is the 3D Imager for the Vectrex game system primitive enough? :D
https://en.wikipedia.org/wiki/Vectrex#Peripherals [wikipedia.org]
https://old.madtronix.com/html/3d_imager.html [madtronix.com]
CYA
(Score: 0) by Anonymous Coward on Friday July 17 2020, @12:23PM
I was actually impressed with remote desktop viewer for phone + google glass.
I didn't bother pursuing this for other reasons, but I got to a point where my problem was setting up VTK cameras at appropriate angles to get the stereoscopy right.
for photos it should work perfectly fine.
(Score: 2) by acid andy on Friday July 17 2020, @01:32PM
I tried some shutter glasses very briefly but they never went fully opaque so each eye could see a ghost of the other eye's image, which I found quite distracting and ugly, so I stopped using them. It's a nice concept though.
If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?