Path: utzoo!attcan!uunet!wuarchive!psuvax1!rutgers!att!cbnewsd!jmdavis
From: jmdavis@cbnewsd.ATT.COM (j.michael.davis)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 3D-graphics
Message-ID: <3379@cbnewsd.ATT.COM>
Date: 29 Nov 89 04:02:20 GMT
References: <734@crash.cts.com>
Reply-To: jmdavis@cbnewsd.ATT.COM (j.michael.davis,ix,)
Organization: AT&T Bell Laboratories
Lines: 36

In article <734@crash.cts.com> wade@pnet01.cts.com (Wade Bickel) writes:
>PKONTKANEN@cc.helsinki.fi writes:
>>
>>		I am going to make a program, which uses filled 3D vector
>>	graphics with hidden-surface removal. Normal methods - transform and
>>        rotation matrices - aren't fast enough for my purposes. I have planned
>          No can do!  If you want to move in arbitrary 3-Space your going to
                                                                ^^^^^
                                    ACK ACK!!! you're not your!

>have to do the algebra.  If nothing in your 3-D world moves you can cut some
>          Try developing a fixed point integer system if you want to strive


Good idea, but also try pre-computing the sines and cosines, an array
of 100 for each will provide less than 1 degree accuracy if you keep
track of the signs of the numbers and degrees. With this table and the
above mentioned fixed point, or even better, total integer but scaled
you should be able to do a sine by just doing a table look-up.

I have seen this technique used on the APPLE II (gawd that is a long
time ago) and it works quite fast there. I suspect that ELITE for the
Apple also uses this technique.

After you get the math part solved how do you plan to solve hidden
surfaces? This is your next big time hurdle. The math is linear in
the number of polygons, but the scale factor is large. Simple polygon
sorting methods are nlog(n) but the scale factor is lower. However there
are tricks for simple camera movements that is linear, and of course
there is the zbuffer method.

-- 
----------------------------------------------------------------------------
        I am just about fed up  |       Mike Davis
        and I will only take it |       ..!att!ihlpm!jmdavis
        a few more times.       |