From: shoguntim AT aol DOT com (ShogunTim)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: ALLEGRO - 256 shades of grey?? How?
Date: 17 Oct 1997 10:13:11 GMT
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>In 800*600*256 mode, GRX20 lets you set up 256 shades of gray. >ALLEGRO in 
>the same mode only lets you set up 64 (then you get them >repeated 3 times 
>as the routine uses 6 bits per colour).
>
>How do I get the full 256 shades of grey. HELP!!!
>

Since its 18 bit color depth 6 bits per color you can't have 256 shades of true
 gray no matter what.  So GRX20 isn't doing what you think it is.   But you can
 have 256 fake shades by setting it up something like this

0,0,0 - 1,0, 0 - 1, 0, 1 - 1, 1, 0...        
   This may work but would 1,1,0 look brigther than 1,0,1?
0,0,0 - 1, 0, 0 - 1, 0, 1 - 1, 1, 1 ...    
    Really this is only 192 shades
   Or the easiest way is to just fake it
0,0,0 - 0,0,0  - 0, 0, 0 -  0, 0, 0...

--------l- Shogun