A&A palette bug

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leilei
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A&A palette bug

Post by leilei »

In Amulets & Armor (any version) the brighter colors of the palette get malformed into being even brighter and oversaturated as if it were posterized to a lower bpp. There's occasional blips of intact frames during screen changes where the palette is intact. The game's built-in gamma correction (Alt-F10) and fading routines also affects these new malformed colors.

Seems to happen on anything with VGA. Occurs on interpreter too.
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omarsis81
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Re: A&A palette bug

Post by omarsis81 »

Is this how it looks to you?
Rather than oversaturated, it looks as if it was EGA, but of course a game from 1996 it doesn't even support that card

DOSbox vs PCem latest commit
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aa_pcem.png
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leilei
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Re: A&A palette bug

Post by leilei »

Yep.

And since the game's been open sourced, this file might provide a clue.
Battler
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Re: A&A palette bug

Post by Battler »

Looks to me like the palette indexes might be off by 1 - look at the red blocky cursor under "Character Name".
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omarsis81
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Re: A&A palette bug

Post by omarsis81 »

Battler wrote:Looks to me like the palette indexes might be off by 1 - look at the red blocky cursor under "Character Name".
The big question would be: why only happens in this game?
Battler
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Re: A&A palette bug

Post by Battler »

I remember that on the MAME forum, someone once wrote a (S)VGA sequencer test, that on real hardware, would under some conditions, sequence the colors off by one. I tested it in PCem, and it didn't do that. If this game sets up the sequencer mode that way, it could explain why this happens.
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SarahWalker
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Re: A&A palette bug

Post by SarahWalker »

Fixed in rev 831.
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omarsis81
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Re: A&A palette bug

Post by omarsis81 »

leilei: you owe me one for resurrecting this thread ;)
StefanDD
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Re: A&A palette bug

Post by StefanDD »

Hello all, I just joined the forum today to post about the subsequent issue, and it may, by coincidence, be related to the one discussed here. In both Weltenschmiede text adventures "Die Kathedrale" and "Hexuma", the palette looks corrupt. This does not at all depend on the choice of main board, CPU speed, video bus speed, or video card. Here it is shown for a more modern configuration but also happens on an old IBM AT with VGA adapter.
VGA palette bug.png
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omarsis81
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Re: A&A palette bug

Post by omarsis81 »

StefanDD wrote:Hello all, I just joined the forum today to post about the subsequent issue, and it may, by coincidence, be related to the one discussed here. In both Weltenschmiede text adventures "Die Kathedrale" and "Hexuma", the palette looks corrupt. This does not at all depend on the choice of main board, CPU speed, video bus speed, or video card. Here it is shown for a more modern configuration but also happens on an old IBM AT with VGA adapter.

VGA palette bug.png
Did you test PCem with the latest commit? or stock version 12?
StefanDD
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Re: A&A palette bug

Post by StefanDD »

omarsis81 wrote:Did you test PCem with the latest commit? or stock version 12?
I have unfortunately not set up a build system for the Windows version, so I am just using the v12 stock from February.
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omarsis81
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Re: A&A palette bug

Post by omarsis81 »

StefanDD wrote:
omarsis81 wrote:Did you test PCem with the latest commit? or stock version 12?
I have unfortunately not set up a build system for the Windows version, so I am just using the v12 stock from February.
Because the bu from A&A was fixed, but of course was much after February. I test the game with the latest commit if the recent fix also applies to these games
StefanDD
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Re: A&A palette bug

Post by StefanDD »

omarsis81 wrote:Because the bu from A&A was fixed, but of course was much after February. I test the game with the latest commit if the recent fix also applies to these games
I'd appreciate that!
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leilei
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Re: A&A palette bug

Post by leilei »

Battler wrote:Looks to me like the palette indexes might be off by 1 - look at the red blocky cursor under "Character Name".
FTR this is incorrect and wrongly interpreted from two different frames of palette ramp cycling.
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omarsis81
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Re: A&A palette bug

Post by omarsis81 »

I confirm Hexuma works fine with the latest commit
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StefanDD
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Re: A&A palette bug

Post by StefanDD »

Fantastic - Thanks for testing this!
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