Message-ID:	<378C896D.BA341D0@ameritech.net>
From:	S Prasad <aangels AT ameritech DOT net>
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Allegro shading, once again I'm lost
Lines:	25
Date:	Wed, 14 Jul 1999 08:58:21 -0400
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

First of all, sorry to be posting the (almost) same question, but I'm
still lost...

Lets say I have a 256-color BMP in 8 bit color mode.  So something like
this:

BMP->line[y][x]

will return a value between 0-255.  So, if I needed, I could use this
value as the subscript for an array, like this:


Color = ShadePalette[  BMP->line[y][x]  ] [ 0 ] 
		       ^^^^^^^^^^^^^^^      ^
                         Color Index    Shading Index

Now for the question... In 16-bit color mode, the BMP->line[y][x]
returns a 16-bit number, which ranges from 0 to 65535.  Now, its pretty
hard to have an array that is like this: ShadePalette[65535][255]   Its
a little too big!  So using it as an array subscript is out of the
question.  So, how do I use a LUT for shading in 16-bit color mode?  Or
is there another way?


Thanx in advance!!

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