Date:	Fri, 31 Jan 1997 05:42:29 +0800 (GMT)
From:	Orlando Andico <orly AT gibson DOT eee DOT upd DOT edu DOT ph>
To:	Tudor <tudor AT cam DOT org>
cc:	djgpp AT delorie DOT com
Subject:	Allegro and Mesa (off-topic, warning)
In-Reply-To:	<32F13459.110E@cam.org>
Message-ID:	<Pine.SGI.3.93.970131045951.3205A-100000@gibson.eee.upd.edu.ph>
MIME-Version:	1.0

On Thu, 30 Jan 1997, Tudor wrote:

[...]
> Ok,maybe I exageratted a little. :)
> What is Mesa ? Is it a general graphics lib or is it 3d oriented?

Mesa is an OpenGL clone. There is support in the basic package for Watcom
(ick) and SVGA modes. It would be a nice exercise to port it to DJGPP
(I'll find time one of these days, if no one has..)

OpenGL supports oodles of graphics functions like the usual 3D rendering
stuff (wireframes, polygons, hidden-line and -surface removal), lighting,
(emitted, ambient, diffuse, specular), shading, multiple light sources,
blending, antialiasing, fog, drawing bitmaps, it has support for
reading/writing bitmaps (SGI RGB format though, really big on size),
texture mapping, scene antialiasing, motion blur, depth of field, soft
shadows, motion jitter, translucency.. 

One big problem if you're using DOS -- the Mesa libraries are HUGE, the
smallest executables you'll have would be in the 1-MB range (ack..) of
course, I use Linux, so I have shared libraries (hint, hint!) and typical
binaries are in the 10K-30K range :)  One disadvantage of Mesa is that it
doesn't take advantage of 3D rendering hardware except the Cirrus 547x
Mondello (but who has it?) So Mesa is SLOW. VERRRY slow. And for "mere" 
games, overkill.

Here are some timings I did (using the `speed' program from
Mesa-2.1/examples/): 

	i486-66MHz		5400 triangles/second
	P5-100MHz		18400 triangles/second
	R5000SC-180MHz		250000 triangles/second

As you can see, the SGI (using native OpenGL) really beats the crap out of
the PC's (which were running Linux). Note that this SGI is the _rock
bottom low end_ model (Indy R5000SC, not sold anymore), it's only about
70% faster than a P5-100 on integer ops (it also costs US$20000+ :(

Mesa doesn't implement the full OpenGL API (yet). Missing is antialiased
lines, shaded NURBS (Bezier surfaces), and some other stuff. Anyway the
plan is to integrate it into XFree86. Can't wait for that, so finally
Linux/X will get GLX support in the server.

Anyway the Mesa home page is at
	http://www.ssec.wisc.edu/~brianp/Mesa.html

.. and I think it's under the GPL, in any case you can get it from
	ftp://ftp.simtel.net/pub/gnu/Mesa-2.1.tar.gz

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