Path: chuka.playstation.co.uk!news
From: "Michael Enoch" <100413.2514@compuserve.com>
Newsgroups: scee.yaroze.programming.libraries
Subject: Re: Rotation Matrix Functions : The Solution?
Date: 10 Apr 1997 01:00:20 GMT
Organization: PlayStation Net Yaroze (SCEE)
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> Take the rows (or columns) one at a time calculate the length
> sqrt(x*x+y*y+z*z)
> and divide the x,y,z by the length
> 
> The problem is that 4096 is one and sqrt is slow.
> All this means is that before the divide you have to multiply by 4096,
> and for the sqrt, only doing one row in a frame and not every frame.
> 
> Stuart

Thanks for the explanation, I made this from it and tried it within my
code:

length=sqrt(Matrix->m[i][0]*Matrix->m[i][0]+
        Matrix->m[i][1]*Matrix->m[i][1]+
        Matrix->m[i][2]*Matrix->m[i][2]);
Matrix->m[i][0]=(Matrix->m[i][0]*ONE)/length;
Matrix->m[i][1]=(Matrix->m[i][1]*ONE)/length;
Matrix->m[i][2]=(Matrix->m[i][2]*ONE)/length;

I repeated it 3 times changing i to equal 0,1,or 2 for the rows, I wasn't
too bothered about speed at the moment so I just did all 3 rows every
frame.  What I was wondering is whether I got it right? The reason I ask is
that the object still changes shape/whatever slightly. Am I just being
picky or have I done something wrong?  It doesn't seem as bad as before but
I thought I'd ask anyway to make sure.

	Thanks for your trouble,
		Mike.