Some Lag On Some 2D Graphics

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cjflnyc
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Some Lag On Some 2D Graphics

Post by cjflnyc » Sat 05 Jan, 2019 2:33 pm

I'm trying to figure out why some windows graphics (2D) get so choppy like this Youtube video example I recorded running the "Maze" screen saver from Windows running on this emulator. I can't seem to figure out why? I have tried emulating all graphic cards with more or less the same results. I have installed the various corresponding emulated video card drivers for Win9x . I keep a note at my emulation speed, stays mostly at 100% or above. No dips below 100. So I don't know what would be lagging it. It does this with some 2d high action windows games as well. As far as 3dFX graphics, It does a good job and most games I tried are well playable but then there is this bug? Any hints or help comments? Besides this little issue. PCem is a fun great emulator. Thank you for this.
https://youtu.be/IYrsu1FW13Y

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leilei
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Re: Some Lag On Some 2D Graphics

Post by leilei » Sun 06 Jan, 2019 12:06 am

3D Maze is performing as intended. Note that all of the Windows 95B+ OpenGL screensavers are ALL software rasterized and render in true color. You cannot accelerate them. If you recall it being faster on a computer of that spec, it's likely the low-res mode.


(later down the line, XP did accelerate those 3D savers (but they dropped Maze :( ). also PCem doesn't emulate a good primary 3d card suitable for that yet either)

cjflnyc
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Re: Some Lag On Some 2D Graphics

Post by cjflnyc » Sun 06 Jan, 2019 2:12 am

Hmmm Strange. I got many real computers to try it with and I got the same setup going just fine on old Pentium PC with no 3D video card. I also noticed the lag varies with versions of PCem.
Software Open GL mode and Direct Draw on emulated 200 MHZ running at 100% should give me the same smoothness as the real thing running at 200 mhz? or very close or am I not understanding PCem properly? Any config hints? Video card configs to use etc?


Thanks all!

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leilei
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Re: Some Lag On Some 2D Graphics

Post by leilei » Sun 06 Jan, 2019 6:27 am

There's also the particular textures you have picked. The color cycled ones likely involves a per-frame texture process + upload.

cjflnyc
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Re: Some Lag On Some 2D Graphics

Post by cjflnyc » Sun 06 Jan, 2019 10:38 am

Yes, That is what I figured. It does very depending on textures and how busy the screen is animating. Even in Direct Draw mode. I just figured the performance should be equal or very near the real thing if my PCem emulated CPU speeds stay at 100%. Should this lag not get worst when the CPU drops among with sound lags etc. I don't seem to be getting any of this while running these graphics running on emulated 9x, stress (software mode) of Direct Draw and Open GL does not seem to drop the emulated CPU speed to give me some sort of indication that PCem is having some sort of a hard time. So All I can think of is some setting perhaps?
Thanks.

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leilei
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Re: Some Lag On Some 2D Graphics

Post by leilei » Sun 06 Jan, 2019 2:19 pm

The software rasterizer in Microsoft's OpenGL32.dll was always slow though. it's kind of a miracle they squeezed that performance - while being perspective correct - out of 3d maze on a Pentium at all! The video backend you choose shouldn't matter for the screensaver as it's going to through to GDI on the guest anyway.

Also it's typical for a screensaver to not exploit the most out of the hardware as it's meant to be a low processing priority with one task only - to prevent burn-in. I don't see slow 3D Maze as a PCem problem...

cjflnyc
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Re: Some Lag On Some 2D Graphics

Post by cjflnyc » Sun 06 Jan, 2019 4:35 pm

The Maze was one of many examples.

More or less anything high action does this even the 2D stuff. And yes textures do affect it for this maze screen saver, But I have the real system to compare it with and with those same settings and it does nothing like this. I thought at first that perhaps this is normal behavior for a non accelerated pentium200 system. But comparing it with my own non accelerated P200 system and a few others I have here. I found that there was a difference worth the mention. I even tried many interactive media CD's the stuff that worked with Microsoft Video and QuickTime. They all do the same thing if the graphics are busy.But if they are simple. No problem. Very speedy and smooth. I can provide more recordings if you like? I also noticed that with 3DFX titles this does not seem to be an issue. But is well noticeable for me playing around the Windows desktop for office and media apps about %10 of the time. I'm sorry if mentioning this small issue. Offended anyone. I was just looking for possible configuration hints to make this work better.But its far from the end of the world. All in all the emulator runs good. I run a very good Host system. An i7 4GHZ system with 32GB of Ram and Geforce GTX 1060 6GB. And my HD is SSD. So I don't think it is my host system specs that are low and dragging it down but who knows? and as I mentioned before, When I notice these lags in Pcem, I don't notice my CPU speed drop below 100% so it's difficult to tell if PCem is having a hard time processing certain emulated functions and I should choose/avoid some setting in PCem as a result?

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leilei
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Re: Some Lag On Some 2D Graphics

Post by leilei » Mon 07 Jan, 2019 3:24 am

The currently released recompiler does hiccup with the Windows desktop a lot, you're best waiting for the major rewrite to be finished.

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