From: "Larry Patton" <pattonl AT worldnet DOT att DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: ALLEGRO   RLE Sprites not quite doing the compression
Date: 20 Jul 1997 21:34:27 GMT
Organization: AT&T WorldNet Services
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
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I am making a program, where the datafiles will be transferred accross
modem, so one program will use different dat files.  My problem is space, I
decided on using RLE sprites to decrease the size of the DAT file, and so
that it will draw the sprite very fast.  I loaded a PCX file which is
640x960, and I have a I had the "background" be white (color 15), and black
letters ( color 16), that way I could draw the sprite multiple times,
without having to clear the screen, or any other CPU consuming routines. 
My problem is uncompressed, the RLE sprite takes up 600,000 bytes, and when
I convert it to a Bitmap instead, it takes up the same space.  I'm taking
it that the RLE is not compressing it whatsoever, however when I do the
background as color 0, uncompressed it is about 64,000 bytes.  Does the RLE
routine in Allegro only compress color 0's?  I know that compressing the
DATA file using global or individual will get me compression, but if the
sprite is 64,000 in the first place, it will compress even more than if it
were 600,000.  Is there something I'm doing wrong?  I don't want to use
color 0 as the background, because the sprite functions will skip that
color, and leave whatever is behind it, which for what I'm using it for, is
an undesired effect.  Anyone have any ideas?  Please e-mail me at
cytric AT kktv DOT com