Chocolate DOOM: Scanlines

I'm pretty sure this request will be a no-go, but I'd REALLY like to see scanline features implemented in Chocolate DOOM.

Call me a weirdo, but I LOVE scanlines! They make 2D games and graphics so sharp and crispy. I understand that they look funny on LCD monitors when not set to maximum resolution, but when I DO set the monitor to max-res, OH MAN! :D :D :D It's one of the best features of DOSBox, and also one of the major reasons I still play Vanilla DOOM today.

Fraggle, if you can implement this, you'd make me a VERY happy man...

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Ah, just tested it on Chocodoom 1.7.0. Scanlines only work with a screen height of 1200, so if your monitor can cope, use -geometry 1600x1200 as well...

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All that effort to replicate an effect that was never there in the first place. I never saw a single scanline on a decently calibrated, 0.28 or better dot pitch SVGA monitor. SVGA monitors != arcade "generic" RGB CRTs.

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I remember scanlines on CBM 1084 monitor, but it was effectively just a high-quality TV (even ran at 15 KHz, with lots of flicker at higher resolutions).

Don't remember scanlines on my old 15-inch SVGA monitor from 1994. The pixels weren't as sharp as an LCD screen though. And the colors were more vivid (but this matte screen probably doesn't help with that...)

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-scanline is fairly stupidly named because it doesn't replicate scan lines.

Instead it tries to simulate the effect you'd get on old (especially large ones) monitors where the 320x200 display appears to be more like 320x400 and you can see small lines (about 400 of the time) in between rows of pixels. -scanline can only possibly replicate this with any shred of accuracy in 1200-pixel-high resolutions.

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I always got this effect in 320x200 and 640x400, on my AMD64 box.

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Should work in 1600x1200, though it just blanks out every 4th line.
'
if (M_CheckParm("-scanline") > 0)
{
screenp = (byte *) dest_buffer + 2 * dest_pitch;

for (y=0; y<1198; y += 3)
{
memset(screenp, 0, 1600);

screenp += dest_pitch * 3;
}
}
'

If adopting a solution I would look into the MAME/ePSX one - looks pretty good(overlay or tile). Requires fast cpu+sse or handling it via video card which defies the choco spirit.

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Quasar said:

I always got this effect in 320x200 and 640x400, on my AMD64 box.


Which probably means that you were using a monitor >17" in size, by that time. On a typical 14" or 15" SVGA monitor of the day (1993-1994), unless it really sucked, you would need a magnifying glass or force some weird tweaked video mode in order to see scanlines at all.

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I always got this effect in 320x200 and 640x400, on my 486SX box.

(Although I suspect the 14" monitor that I was using at the time was the culprit. I think I still have it somewhere, I should see if it still works...)

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My 14" that was supposedly 'something special' because it was capable of 1024x768 never showed any scanlines unless I forced it to.

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Belial said:

My 14" that was supposedly 'something special' because it was capable of 1024x768 never showed any scanlines unless I forced it to.


Well, SVGA != VGA. There was quite a bit of difference between a good multisync RGB monitor capable of handling SVGA and higher resolutions, and a bottom-feeder type of monitor that barely met VGA specs.

I even remember how screenshots from game magazines of the times looked: PC games never showed any scanlines (unless we're talking CGA or EGA games on a CGA or EGA monitor, not a VGA one), while Amiga/Atari ST/Amstrad CPC etc. did, but those "monitors" were little more than small TVs.

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On my old monitor, there were scanlines when using lower resolutions. The standard line would be bright, but the line below it would be a bit darker, but still use the correct colors.

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_bruce_ said:

Requires fast cpu+sse or handling it via video card which defies the choco spirit.

Nope, that's incorrect - I don't see hardware acceleration as against the project philosophy. In fact I'm looking at adding hardware accelerated scaling. Once it's added, supporting the scanlines hack at resolutions other than 1600x1200 should be trivial.

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