From:	"Tony O'Bryan" <aho450s AT nic DOT smsu DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: allegro scrolling limitation?
Date:	Tue, 11 Nov 1997 18:10:21 -0600
Organization:	Southwest Missouri State University
Lines:	19
Message-ID:	<3468F3ED.6D3A@nic.smsu.edu>
References:	<01bcee43$9495dc40$0c2331ce AT pentium> <EuZr3EA0gMa0Mwqf AT pulsedesign DOT demon DOT co DOT uk>
Reply-To:	aho450s AT nic DOT smsu DOT edu
NNTP-Posting-Host:	marie.a14.smsu.edu
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Alistair Bain wrote:
> 
> In article <01bcee43$9495dc40$0c2331ce AT pentium>, RL <jate AT ionsys DOT com>
> writes
> >Does anyone know any tricks to get allegro/djgpp to create smooth
> >screen scroll (ie. not skipping by 4 pixels) in high resolution?
> >In other words, not using modex.

	My game Mythos smoothly scrolls a 640x480x256 screen using compiled
sprite tiles.  Using compiled sprites was the fastest way I could think
of to scroll such a large screen.  The only speed drain is that although
the compiled sprites are drawn quickly to an invisible screen, the
invisible screen has to be blit()ed to the video screen.  All the
drawing and scrolling is done through software, but the frame rate is
still very good on a fast computer (my system is 120Mhz Pentium).  The
blit of a 640x480x256 regular Allegro bitmap is the only slow part of
the entire algorithm.
	E-Mail me if you want to try the executable on your system for a speed
trial.

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