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2xSaI Pixel Shader code maybe not compatible with all cards? Maybe ATI only?

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First post, by Nazo

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I ran across a site -- http://home.amis.net/lkslavi/dosbox.html -- a while ago purely by accident and got my hopes up, but, for some reason it doesn't work with my system. What I'm thinking is that it's designed for a Radeon (as I understand it, the original author designed it for some ATI contest or something -- I don't remember what specifically I read as it was a while ago, so that might be a bit off.)

For those who don't want to waste time looking up the model numbers, my video card, the LeadTek A400TDH is a Geforce FX 6800 (plain vanilla version.) It's MAYBE not 100% stable as I messed up something with the memory (nothing to do with the pipelines, this core could have just as easily been placed on an Ultra as it even makes it up to 433MHz stable if you supply 1.3V to it,) however, it's almost purely stable, and the only errors I ever get only happen when I've been using it for hours on end. Also, the nature of the bugs are minor annoyances. When I run DOSBox with 2xSaI enabled, my system simply reboots. And, yes, I have the automatic reboot disabled, so I can see the blue screens with the error message when something goes wrong. In other words, it's pretty bad. This has NEVER happened with anything else at all, including tougher things like Doom 3 that can actually push a card like this a bit (I run on maximum quality settings.)

The reason I blame the pixel shader code itself is because, out of curiosity, I looked up the program that the author apparently originally made with this on beyond3d or whatever that site was and tried it with the same results. I couldn't really figure out how to contact the author, and besides, this is the only project I know of actually using that code in any manner, so I'm thinking if anyone should take a look at it, it's probably the people trying to use it first in such a thing.

I can't wait for the day I can play some of my old DOS games with 2xSaI scaling done in hardware since my CPU isn't powerful enough to do some of the tougher emulation plus even bilinear scaling. Also, I can't wait until more people take on the idea of using the video card for video processing rather than the CP -- right now I only know of one other REAL project doing this, and it only does bilinear or bicubic (with only three settings) in hardware. I exclude technology demo type things that can't be used for any real purposes.

(BTW, sorry I accidentally posted this in the wrong forum at first if anyone saw that. Must have misclicked something somewhere.)

EDIT: Oh, and I'm sorry, I'd test this stuff out more, but, the only other systems I have access to are an old retro gaming system (this is why I want DOSBox for things like 2xSaI) which has an ancient (and not so great even at the time) rage pro 3D chip and a P4-2.4 (the slow kind) with a mere Radeon 9200SE, which lacks PS2.0.

Reply 1 of 2, by gulikoza

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I do all the testing on my R9800pro since I don't own a nvidia card but I occasionally let my friend with 6600gt test my builds as well. I don't know if I mentioned this already but he did report some problems with blue screens & nvidia beta drivers but it was supposed to run ok with latest stable drivers.
You didn't mention if d3d output works w/o 2xsai scaling or with scale2x for example. I think that scale2x looks better than 2xsai (it's less blurry). You should also check hardware hq2x scaling (openglhq mode) it looks really amazing 😁

Reply 2 of 2, by Nazo

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Oh, sorry. Yes, I did definitely test other codes. No crashes. I just mainly was really dissapointed that the 2xSaI wouldn't work as I wanted it for certain things that I couldn't help but think would look better with it. In fact, I will admit that OpenGLHQ is better for most things and is what I usually use.

And I like the blurriness of the normal 2xSaI. It's just exactly right to get it clear enough, yet get rid of ugly jagged edges. I've been using emulators for a long time and have definitely seen Super 2xSaI (this is what was later renamed to "Advanced Mame 2x" isn't it? Either way, it's actually called Super 2xSaI in ZSNES & co) and I've tried eagle, super eagle, and so on. I always found plain 2xSaI the best suited to older things like those for me at least.

I was using the latest "stable" nvidia drivers btw. Mind you, in their case "stable" means nothing. I've had occasions where I tried their stable drivers and they were 5x more buggy than their beta drivers despite being WHQL certified and all that crap (which theoretically means MS tested, but, apparently means MS stuck one nvidia card in there, installed the drivers, and declared it good when it started up.)

I can't really blame the tiny instability on my card because it's rock solid in everything else with no crashes or reboots and even the rare problems I do have only come after hours of gameplay. I can't even catch it by immediately switching to ATITool and running the artifact test right after one of those. I may have messed up the memory, but, we're talking about the sort of thing that won't show up from a simple resize code, period.

Anyway, at least we know it's not COMPLETELY ATI specific. Technically speaking, the 6600GT should be about the same as far as code like that is concerned, so I don't entirely know WHAT to think. I don't believe it's instability on my card, so I'm inclined to say something funky with my current setup maybe. I might try some newer beta drivers or something later maybe. It's just really annoying because it causes such a forceful reset that I have to run through the chkdsk and all that other junk and almost every time at least one file shows up as damaged. I know, I need to have EVERYTHING closed down, but, there's only so much I can close down.

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