From:	Bussi Andrea <bta AT cicladi DOT unial DOT it>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: How to program compiled sprites?
Date:	Thu, 23 Jan 1997 16:22:04 +0100
Organization:	University Of Alessandria, Italy
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Message-ID:	<32E7821C.67B5@cicladi.unial.it>
References:	<32e54b6d DOT 501326 AT news DOT prestel DOT co DOT uk>
NNTP-Posting-Host:	aldebaran.unial.it
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Luke Steele wrote:
> One of the test programs that comes with it demonstrates
> certain methods of sprite putting, including one called compiled
> sprites.  How does this work?  According to the documentation, the
> routine performs a number of immediate 'mov's, but I am unable to see
> how this could make things faster.  Surely, the time for an immediate
> 'mov' is 1 cycle, as is the time for each mov in a 'rep movsd'?  What
> is it that I'm not getting?

This is true when you do a blit block transfer, but when you use a
sprite, you want to skip some trasparent pixel, and you're used to
give 'em 0 value, test each pixel and draw it if not zero, skip 
otherwise. So you haven't a single 'mov' every pixel, but you have
also a test. You can reduce the tests with the RLE metod, or cut
them with a compiled sprite.

> Thanks in advance for any explanations!
 
I hope this help (my English is not so good...)

				Bussi Andrea
				bta AT cicladi DOT unial DOT it

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