Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!e260-3f.berkeley.edu!labc-3dc
From: labc-3dc@e260-3f.berkeley.edu (Andy McFadden)
Newsgroups: comp.sys.apple
Subject: Re:  3-D vector graphics in assembly
Summary: okay...
Message-ID: <23551@agate.BERKELEY.EDU>
Date: 25 Apr 89 02:33:32 GMT
References: <8904220157.AA04218@amethyst>
Sender: usenet@agate.BERKELEY.EDU
Organization: University of California, Berkeley
Lines: 23

In article <8904220157.AA04218@amethyst> hentosh@amethyst.bucknell.EDU writes:
[chop chop]
>I don't know what routines applesoft uses to draw a line, but a fast one I
>know is to take the end point and subtract the other end point from it.
[description of algorithm]

I tried this once.  It wound up being slightly slower than Applesoft, because
I was using lookup tables... the fastest way to go about it seems to be this
algorithm, doing some fancy calculations to get the next bit/line position.
Probably the fastest way is to have 8 subroutines, one for movement in any
given direction.

Woz's routines (source can be found in the Programmer's Assitant #1 manual,
along with the code relocator source, etc) manage to pull this off on an
8-bit computer, but bear a strong resemblance to spaghetti.  Since the hires
screen is non-linear, the computations involved are a little weird.

>-- InterNet: hentosh@amethyst.bucknell.edu | 'Ever have deja vu and amnesia

-- 
fadden@cory.berkeley.edu (Andy McFadden)
...!ucbvax!cory!fadden
labc-3dc@widow.berkeley.edu