VOGONS


Reply 20 of 24, by Scali

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Great Hierophant wrote:

I think my blog entry http://nerdlypleasures.blogspot.com/2013/10/t … patibility.html dispels the idea that few games used mode 4 composite color graphics or that many games supported Tandy/PCjr composite color.

You could be right. I recall quite a few games having Tandy/PCjr support back in the day, but that's probably just for the 16-colour RGBI mode.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 21 of 24, by bjt

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Great Hierophant wrote:

I think that most clone manufacturers made sure that the direct colors would look OK and left it at that because increasingly fewer people were using composite color graphics.

I guess that also means that adjusting the hue to correct won't work with 320x200 modes, as it'll throw the direct colours out.
Should be OK in 640x200 though.

Reply 22 of 24, by Great Hierophant

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bjt wrote:
Great Hierophant wrote:

I think that most clone manufacturers made sure that the direct colors would look OK and left it at that because increasingly fewer people were using composite color graphics.

I guess that also means that adjusting the hue to correct won't work with 320x200 modes, as it'll throw the direct colours out.
Should be OK in 640x200 though.

That is a good point, the hue control does work better in 640x200 because you are really only adjusting the artifact colors. The direct colors are almost always white and black, which really are not affected by the hue control. (One version of Pitstop 2 uses green and black in the 640x200 for the composite color graphics)

When you have 320x200 composite color graphics, you are dealing with a mixture of direct and artifact colors. Almost invariably the cyan/magenta/white palette is used because the red/green/brown palette tends to look very garish on TVs (Shamus is an exception). Hue control applies to every color on the screen, so both direct and artifact colors get changed.

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog

Reply 23 of 24, by Scali

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Yes, I guess the fix should be in the circuit itself, to adjust the phase of the colorburst relative to the pixeldata/direct colours.
I wonder if this can be reconstructed after the fact... that is, the colorburst should just be a carrier wave...
So would it be possible to extract that carrier wave from the signal (feed an inverted carrier of the exact same wavelength, so they cancel out), and then add a new carrier wave, where you can adjust the phase?

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 24 of 24, by konc

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I was researching why an ATI Small Wonder delivers wrong colors when connected through composite and I couldn't believe I found the exact thread with answers here 😀

I don't have (or it's likely to find) a color RGBI monitor, so my intention was to just use the composite connection to a LCD TV monitor.
First of all, is it normally that bad? (I've never seen CGA composite live before but it's way worse than using RGBI).

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Are clones known to have problems displaying the correct colors in general when using the composite connection? I mean even in 16-color text mode. For example this is how the standard colors look like (hue untouched, adjusting it can bring it pretty close to the correct colors):

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Of course magenta being blue causes Dave Dangerous to appear like this (the game doesn't have any special composite color mode, just uses one 4-color palette).

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I'm mostly trying to figure out if there's something wrong with my card, since even standard palette colors are off. I don't mind if this ATI displays things like that when connected through composite, as long as it's the normal behavior of the card. I'll call it a feature 🤣