vb-fan wrote:
I was really disappointed the output wasn’t “3D”. I didn’t understand why he couldn’t do that…
Yeah, I was wondering about that too. He says: “The 3D separation is too pronounced to work with anaglyph glasses, let’s forget about that idea.”, though I’m not sure about that… I had no problem using red/blue on mine, and shutter glasses work too.
Without 3D, it’s not really playable… it’s only good for showing what someone is playing, or grabbing screenshots (though VGA capture isn’t very common, so it’s not too great for that). If you try playing using only one screen, everything will be shifted by the parallax, making everything seem awkward.
The technical reason for him not being able to do it, is because he went with the XuLA, rather than the XuLA2: “Luckily the anaglyph mode was a bad idea as it wouldn’t have been possible with this board either without heavy tearing in the output since it would require 2 separate framebuffers and so twice the amount of RAM.”
The XuLA (with the Spartan 3A) only has enough block RAM for one frame buffer. While it could be possible to use the SDRAM, that would complicate things quite a bit (especially since VB draws in the opposite direction of TVs), while using block RAM makes it really easy. But the XuLA2 is double the cost, so I guess that’s the tradeoff.
The FPGA I used didn’t quite have enough block RAM for two whole buffers, but I was able to make up the rest of it with distributed RAM. When I finally get my final version built, I’ll be using a newer FPGA with plenty of block RAM.
WoLfMaN wrote:
So is there some hope, that you continue working on your solution?
Yeah, I still put a couple hours into it every now and then… I just have a LOT of different projects going on. I really just need to get a PCB laid out for it, but figuring out the mechanicals of making it all fit nicely into a VB without hand-wiring a bunch of wires is time consuming.
DogP wrote:
Yeah, I was wondering about that too. He says: “The 3D separation is too pronounced to work with anaglyph glasses, let’s forget about that idea.”, though I’m not sure about that… I had no problem using red/blue on mine, and shutter glasses work too.
Without 3D, it’s not really playable… it’s only good for showing what someone is playing, or grabbing screenshots (though VGA capture isn’t very common, so it’s not too great for that). If you try playing using only one screen, everything will be shifted by the parallax, making everything seem awkward.
The technical reason for him not being able to do it, is because he went with the XuLA, rather than the XuLA2: “Luckily the anaglyph mode was a bad idea as it wouldn’t have been possible with this board either without heavy tearing in the output since it would require 2 separate framebuffers and so twice the amount of RAM.”
The XuLA (with the Spartan 3A) only has enough block RAM for one frame buffer. While it could be possible to use the SDRAM, that would complicate things quite a bit (especially since VB draws in the opposite direction of TVs), while using block RAM makes it really easy. But the XuLA2 is double the cost, so I guess that’s the tradeoff.
The FPGA I used didn’t quite have enough block RAM for two whole buffers, but I was able to make up the rest of it with distributed RAM. When I finally get my final version built, I’ll be using a newer FPGA with plenty of block RAM.
DogP
Will your module be able to output NTSC? I’m not sure how the analglyph would work — one image fully red, the other fully blue?
I’d love to try to make those Chinese glasses work; haven’t verified the “odd/even (interlaced) 3D”, but can’t imagine it would be anything else. Except maybe doing like the arcade 3D sets did, cutting the frame rate down to 15 (very bad flicker!).
The Chinese glasses have a “VGA” button; but doesn’t VGA need multiple connections, like separated red green and blue lines? A single composite line would be better…
DogP wrote:
Without 3D, it’s not really playable… it’s only good for showing what someone is playing, or grabbing screenshots (though VGA capture isn’t very common, so it’s not too great for that). If you try playing using only one screen, everything will be shifted by the parallax, making everything seem awkward.
This reminds me of something. The Video Boy made by Intelligent Systems, how does it display Virtual Boy games on a television? Does it simply display one of the two Virtual Boy screens, resulting in the shifted-by-parallax problem, or does it somehow correct for this?
I really just need to get a PCB laid out for it, but figuring out the mechanicals of making it all fit nicely into a VB without hand-wiring a bunch of wires is time consuming.
Who says it has to fit into a VB? 🙂
How about a prototype box that sits outside and connects into the needed places via some sort of cable? I’m sure any of us that love to tinker would gladly have an extra box connected into both our VB and TV and not give you any grief over it!
Feel free to save the internal mod for version 2 of the release once we’ve helped you get all the bugs out of it! 😀
vb-fan wrote:
Will your module be able to output NTSC? I’m not sure how the analglyph would work — one image fully red, the other fully blue?
I’d love to try to make those Chinese glasses work; haven’t verified the “odd/even (interlaced) 3D”, but can’t imagine it would be anything else. Except maybe doing like the arcade 3D sets did, cutting the frame rate down to 15 (very bad flicker!).
The Chinese glasses have a “VGA” button; but doesn’t VGA need multiple connections, like separated red green and blue lines? A single composite line would be better…
Yeah, it currently outputs NTSC (S-Video/Composite) and VGA. I don’t know anything about your specific glasses, though there are several pretty common 3D signals, and my board could probably do most of them (not saying that it will, since they take time for me to do.
Benjamin Stevens wrote:
This reminds me of something. The Video Boy made by Intelligent Systems, how does it display Virtual Boy games on a television? Does it simply display one of the two Virtual Boy screens, resulting in the shifted-by-parallax problem, or does it somehow correct for this?
It definitely doesn’t do any sort of correction. It does output at least just a single eye… I don’t remember if it does anaglyph or not.
Koohiisan wrote:
Who says it has to fit into a VB? 🙂
Me. 😉
Koohiisan wrote:
How about a prototype box that sits outside and connects into the needed places via some sort of cable? I’m sure any of us that love to tinker would gladly have an extra box connected into both our VB and TV and not give you any grief over it!
Feel free to save the internal mod for version 2 of the release once we’ve helped you get all the bugs out of it! 😀
I’ve pretty much already got that… just not in a box, or with a connector (just a board with wires connected directly to the VB). I definitely don’t want to solder individual wires to the displays for every board (it’s pretty fragile that way). And really… laying out my own PCB that does exactly what this needs to is the way to go, and if I’m gonna go to that length, I might as well just go for the gold and make it fit in the VB (size certainly isn’t the limiting factor… it’s more the specific form factor).
