Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!jarthur!nntp-server.caltech.edu!nyet
From: nyet@nntp-server.caltech.edu (prof. n liu)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Need a good line drawing function for VGA
Message-ID: <1991Mar14.182134.1368@nntp-server.caltech.edu>
Date: 14 Mar 91 18:21:34 GMT
References: <1991Mar14.020823.5530@cc.helsinki.fi> <1991Mar14.152927.25350@ux1.cso.uiuc.edu>
Organization: California Institute of Technology, Pasadena
Lines: 24

mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes:


>You do what you want by noting that one bit plane controls red and another
>one blue. You simply instruct the VGA (or EGA) controller to write 
>to ONLY the red plane when doing red and ONLY the blue plane when doning
>blue - then you can use either XOR or OR mode quite well.

This should certainly work... and guess what? MSC does in fact have an OR mode
for all graphics, if you are lazy (and, of course, assuming you have MSC
around :). Which brings me to another point.. is there an equivalent "driver"
standard like .bgi for msc and code to load them, or do you have to do
everything yourself - like writing svga routines from scratch (and, of course
coding line drawing algorithms like Bresenham's manually). What a drag.

Also, (speaking of RB 3d), i wrote up an animation program that will spin
and move various figures in 3d with glasses. Its in MSC 6.00, but the source
is REAL long considering i cannabalized some graphics 3d rendering code
from a CS class. If there's suitable interest i could post, ul, or email it.
Actually, it runs pretty slow unless you have a 387 (lots of floating point
stuff). I haven't gotten around to redoing it with integer math. But on a
25MHz machine with a 20+MHz 387 it hauls pretty fast.

nyet