Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!maverick.ksu.ksu.edu!unmvax!uservx.afwl.af.mil!galetti
From: galetti@uservx.afwl.af.mil
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Fast 3d Graphics
Message-ID: <1991Apr9.164038.21673@uservx.afwl.af.mil>
Date: 9 Apr 91 16:40:38 GMT
References: <9529@star.cs.vu.nl> <1047@cbmger.UUCP> <20338@cbmvax.commodore.com>
Organization: Phillips Laboratory - Kirtland AFB
Lines: 26

In article <20338@cbmvax.commodore.com>, chrisg@cbmvax.commodore.com (Chris Green) writes:
> 
> 	Doing a quick cycle count on my routine, it looks like 485 worst case.
> 60% is really high to spend on rotation. 10% is more likely for an amiga.
> You ARE using a 3x3 matrix and not 3 separate axis rotations, right?
> 

Does your routine rotate about an arbitrary axis or about one of the principle
axes?  If it rotates about an arbitrary axis, do you assume the axis is fixed
or do you allow it to vary?  If you allow it to vary, there are a few
additional multiplications you have to perform to set up the rotation matrix,
not to mention a few additional trig. functions.  For an arbitrary axis, 485
cycles sounds awfully low.

> -- 
> *-------------------------------------------*---------------------------*
> |Chris Green - Graphics Software Engineer   - chrisg@commodore.COM      f
> |                  Commodore-Amiga          - uunet!cbmvax!chrisg       n
> |My opinions are my own, and do not         - killyouridolssonicdeath   o
> |necessarily represent those of my employer.- itstheendoftheworld       r
> *-------------------------------------------*---------------------------d
  ___________________________________________________________________________
 /   Ralph Galetti                  Internet:   galetti@uservx.afwl.af.mil   \
|    PL/LITT                        Interests:  computers, music, computers   |
|    Kirtland AFB, NM 87117-6008                and music, golf, sleep.       |
 \__"No, they couldn't actually prove that it was HIS vomit" - Nigel Tufnel__/