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Article #2383Re: VGA palette "blues"
From: mr r vanschyndel
Date: Wed, 26 Sep 1990 13:22
Date: Wed, 26 Sep 1990 13:22
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bg0v+@andrew.cmu.edu (Brian M. Gottier) writes:
>What's wrong?... For example, I try to set color 14 to black. I enter the
>value of 0x3f for each of rgb for color 14. (only the lower six bits are
>significant) I then read the values of rgb for color 14 and, sure enough,
>they are all 0x3f. However the areas of the screen that have values of 14
>are not black at all. By the way, if I set the color by just setting color
>14 to 0 (with the setpalette function in Turbo C or the equivalent BIOS call)
>the areas which have color 14 do indeed display in black.
Your VGA values are being translated by the EGA palette -- so set them to
a one-to-one mapping (eg pal[1] = 1, pal[2] = 2, etc).
It was set up this way to maintain compatability (i think).
In short:
Pixel value -----> EGA XLAT ----> VGA DAC XLAT ---> RGB to monitor
ron
--
Ron van Schyndel rdt155r@monu6.cc.monash.edu.au
Physics Department, Monash University rdt155r%monu6.cc.monash.oz@uunet.UU.NET
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!munnari.oz.au!goanna!minyos!monu6!rdt155r From: rdt155r@monu6.cc.monash.edu.au (mr r vanschyndel) Newsgroups: comp.os.msdos.programmer Subject: Re: VGA palette "blues" Message-ID: <1990Sep26.132234.15739@monu6.cc.monash.edu.au> Date: 26 Sep 90 13:22:34 GMT References: <Yazhz3600WB78JnUMU@andrew.cmu.edu> Organization: Caulfield Campus, Monash University, Melb., Australia. Lines: 26