Xref:	news2.mv.net comp.os.msdos.djgpp:5198
From:	richard725 AT denver DOT email DOT com (Richard Adams)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Two really stupid questions re: graphics.
Date:	Thu, 20 Jun 1996 11:36:14 GMT
Organization:	Netcom
Lines:	38
Message-ID:	<4qb9kg$i7b@sjx-ixn6.ix.netcom.com>
NNTP-Posting-Host:	den-co12-09.ix.netcom.com
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

I'm brand new to djgpp, and still a beginner in C, so I have two
questions I'd like to ask--I apologize if they're faqs. Yes, I have
read the FAQ. And no, I didn't understand it.

Ok. I am writing a raytracer similar to POV-Ray except mine can do
some things POV can't. I have the source code for POV-Ray 2.2, but
apparently, it was written for djgpp v1.0 and doesn't work under the
version of djgpp I have, v2.0. It generates general protection faults
when writing to the video display. Since the graphics code in POV-Ray
is rather labyrinthine, I want to write my own graphics routine, both
to get my raytracer working, and as an excercise in learning more
about C and djgpp. 

I've looked at the code for GRX2.0 and Allegro, but both are gross
overkill for what I need, and I can't figure those programs out
either. All I need is a routine to set up a graphics display, and a
routine to plot a pixel.  So here are my two questions:

1) Does anyone know of a SIMPLE way to set up VGA mode 13h, and how to
set up a VESA 1.2 truecolor video mode? (and of course how to get back
to text). I know how to do this in Forth and assembly language in real
mode, but djgpp and it's protected mode has me stumped (wonderful as
protected mode is...:).
 
2) Does anyone know of a simple way to plot a pixel in the VESA 1.2
and VGA's mode 13h? Again, I could do this in assembly language and
forth in real mode, but not in djgpp/protected mode. I know that for
Vesa modes there's stuff like bank switching involved.
 
Again, I apologize if these are really easy questions. After being
expert in Forth and Assembly language programming in real mode for so
long, being a raw beginner in C, djgpp, and protected mode
programming, is a rather discomforting feeling...:)
 
Thank you all very much! :)
--Richard
richard725 AT denver DOT email DOT net

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