From: T DOT Harte_ AT _btinternet DOT com (Thomas Harte)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: ALLEGRO - 256 shades of grey?? How?
Date: Sat, 18 Oct 1997 23:03:00 GMT
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>: i.e., a palette consisting of values like:
>: 0,0,0
>: 1,1,1
>: 2,2,2
>: ..
>: 255,255,255
>: and then set it.  I believe the 6 bits per color is only applicable when 
>: converting a palette value to it's equivalent DAC register value.  I may 
>: not have the details right, but I believe the DAC is limited to a 6-bit 
>: digital to analog conversion per color(2^6 = 64).
>
>Yes, but Allegro uses DAC format, i.e. all colour strengths go from 0 to
>63. This is why the original poster had a problem.

	And just to reiterate, when you load a 256 colour pcx (pcx's use
8bit colour lookup tables), it simply quarters all the values, it
doesn't do anything more complex than that, so loading an image which
really has 256 shades to use the palette wouldn't work.

		-Thomas