From:	Damian Yerrick <Bullcr_pd_yerrick AT hotmail DOT comRemoveBullcr_p>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Allegro: Grayscale creation
Organization:	Pin Eight Software http://pineight.8m.com/
Message-ID:	<ed9ohsc41b9t1g5frhv564qvlcd8l5bpov@4ax.com>
References:	<391C097E DOT 74720B9C AT tiscalinet DOT it>
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NNTP-Posting-Date:	Fri, 12 May 2000 15:58:31 GMT
Distribution:	world
Date:	Fri, 12 May 2000 15:58:31 GMT
To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

On Fri, 12 May 2000 15:39:10 +0200, night DOT walker AT tiscalinet DOT it wrote:

>I want to set a 256-color grayscale on a 8bit screen, so i wrote:

[snip: gives four palettes of 64 grays each]

>How can I fix this? (i need more than 64 grays!)

The VGA specification only supports 64 levels of each component;
there is no standard extension to make cards support 256 levels.
Try this (untested) snippet, which adds a bit of color noise to
the grays to get them to look a little better:

int x;
PALETTE pal;

for(x = 0; x < 256; x++)
{
  pal[x].r = (x + rand() % 4) * 63 / 255;
  pal[x].g = (x + rand() % 4) * 63 / 255;
  pal[x].b = (x + rand() % 4) * 63 / 255;
}
set_palette(pal);

-- 
Damian Yerrick
"I refuse to listen to those who refuse to listen to reason."
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