VOGONS


Art of CGA

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First post, by reenigne

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In the course of making 8088 MPH, I wrote a program for converting arbitrary sRGB images to data for displaying on an IBM CGA card in various different modes and palettes. I have continued to develop this program (on and off) ever since. It's still not finished (there are a bunch of controls which don't do anything yet) but in the modes that are working I think it does a pretty nice job of showing off just what CGA is capable of. Here are some of the best results that I've come up with, in the course of development/testing.

scarlet_macaw_640x200_out.png
fish_640x200_out.png
sunset_640x200_out.png
rr2_640x200a_out.png
oak_cropped_out.png
treefrog_cropped_out.png
clown_cropped_out.png
sonic_out3.png
glass-sphere-640x200_out.png
stonehenge2_out.png
gems2_out.png
swirl_out.png
landscape_640x200_out.png
Grier_out.png
pink-purple-flowers-hd_out.png

I believe that all of these can be displayed (and will look pretty much as shown here) on a IBM PC 5150 with 4.77MHz i8088 and IBM CGA card, but some require more sophisticated code than others to display.

Please feel free to add your own favourite CGA images to the thread, whether they were created with CGAArt or some other way.

Reply 1 of 106, by Jo22

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Just beautiful. Thank you very much for sharing! ^_^

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 6 of 106, by Moogle!

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reenigne wrote:
Just for you, Moogle: […]
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Moogle! wrote:

>no hooves

A waste of vintage hardware.

Just for you, Moogle:

hooves.png

I think you're trying to troll me.

Why is the Sonic one so clear? Is it because the source image was a lower color count to begin with?

Reply 7 of 106, by reenigne

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TheGouldFish wrote:

Amazing work, was always impressed by 8088mph.

Thanks!

TheGouldFish wrote:

Was so hoping that it would run on my PPC640 but it got to the first major bit and didn't continue.

Yeah, unfortunately the PPC640 uses a custom video chip which disables reprogramming of most of the CRTC registers, so most of our tricks have no hope of working on these machines.

Reply 8 of 106, by reenigne

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Moogle! wrote:

Why is the Sonic one so clear? Is it because the source image was a lower color count to begin with?

It definitely helped that the source image didn't have much in the way of gradients, so I was able to turn off dither without causing a lot of banding. I also got very lucky with the colours - there weren't too many places where there were two adjacent colours in the source image that mapped to the same colour on CGA. It's still a significant decrease in colour depth, though (38 in the original to 15 solid colours on CGA composite).

Reply 9 of 106, by chartreuse

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reenigne wrote:

It definitely helped that the source image didn't have much in the way of gradients, so I was able to turn off dither without causing a lot of banding. I also got very lucky with the colours - there weren't too many places where there were two adjacent colours in the source image that mapped to the same colour on CGA. It's still a significant decrease in colour depth, though (38 in the original to 15 solid colours on CGA composite).

It's also likely to do with the colours lining up quite nicely to the artifact colours, since the Genesis would be outputting NTSC colours in the first place, though not a perfect match since the Genesis can get more phases that is possible with artifact colouring on CGA

Reply 10 of 106, by Ozzuneoj

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Wow, looks awesome!

When I finally get an old tube TV in the same room as my IBM 5150 I'm going to drop the CGA card back in it and run 8088MPH for sure... I've been wanting to do it since I saw the demo, I just have nowhere to put the TV. 🤣

Just to clarify, do the images converted with your program display correctly on a standard IBM 5153 monitor or only when using the CGA card's composite video output?

Now for some blitting from the back buffer.

Reply 11 of 106, by reenigne

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Ozzuneoj wrote:

Just to clarify, do the images converted with your program display correctly on a standard IBM 5153 monitor or only when using the CGA card's composite video output?

The program has modes for both connectors (and, for the composite connector, both new and old style CGA cards). Of the images above, Rainbow Rocks, Clown, Glass Sphere, Gems, Swirl and Grier are for the RGBI output and the others are for the composite output.

Reply 12 of 106, by TheGouldFish

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reenigne wrote:
Thanks! […]
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TheGouldFish wrote:

Amazing work, was always impressed by 8088mph.

Thanks!

TheGouldFish wrote:

Was so hoping that it would run on my PPC640 but it got to the first major bit and didn't continue.

Yeah, unfortunately the PPC640 uses a custom video chip which disables reprogramming of most of the CRTC registers, so most of our tricks have no hope of working on these machines.

Figured as much, Amstrad always made odd choices 😀

Reply 14 of 106, by reenigne

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leileilol wrote:

All i've got is this. Bad aspect I know

Lovely, but unfortunately black, white and yellow is not a combination that exists in any of the possible CGA 4-colour palettes. Maybe if we make her hair green?

cgaluluco_out.png

Reply 15 of 106, by keropi

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nice tool I'll play with it once I setup my cga xt again 😀
thanks for sharing reengine!

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Reply 16 of 106, by VileR

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As I'm just back from vacation, and just saw this thread, here are some of my trip photos in CGA:

01_out.png

04_out.png

06_out.png

07_out.png

07_out1.png

09_out.png

10_out.png

11_out.png

12_out.png

And since "miscellaneous favorite CGA images" is on-topic, I'll just throw this one here from an old disk magazine named PC Life, circa 1986/87. They had a section for reader-submitted graphics, which had some good stuff like this one:

cgashow_000.png
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Very cool, especially considering the sort of graphic programs/editor they had back then!

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Reply 17 of 106, by dr.zeissler

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That is really god! Can you please give us a link for these cga-slideshows.

Retro-Gamer 😀PowerMac 6100-66/Houdini 486/66 - G4 Cube 450/Rage128pro OS9.0.1 - Macintosh LC/Apple IIe Card OS6.0.8 - Acorn A4000 Archimedes - Unisys CWD 486/66 + Aztech Washington

Reply 18 of 106, by reenigne

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dr.zeissler wrote:

That is really god! Can you please give us a link for these cga-slideshows.

I haven't actually put them into executable form yet. I will at some point, though, and I'll be sure to put a link here when I do.

Reply 19 of 106, by dr.zeissler

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Thx, other nice VGA stuff.
http://michaelnoland.com/cga-post-processing-in-ue4/

The colors do match with the miami-vice-logo, but I have not found a real CGA image.

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Retro-Gamer 😀PowerMac 6100-66/Houdini 486/66 - G4 Cube 450/Rage128pro OS9.0.1 - Macintosh LC/Apple IIe Card OS6.0.8 - Acorn A4000 Archimedes - Unisys CWD 486/66 + Aztech Washington