Path: chuka.playstation.co.uk!news
From: "Craig Graham" <c_graham@hinge.mistral.co.uk>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: What is a normal?
Date: 15 Aug 1998 08:54:35 GMT
Organization: PlayStation Net Yaroze (SCEE)
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Robert Swan <rs108@mdx.ac.uk> wrote in article <35D435D7.3A82@mdx.ac.uk>...
> Alex Herbert wrote:
> > 
> > normals are stored in the TMD.  Yes they should be normalised to ONE
(4096).  You
> > don't need to get hold of them unless you are greating/modifyinf TMDs
dynaically.
> > Check out the File Formats PDF on this site.  Ignore the TMD file
format HTMD doc > 'cos
> 
> its precisely cos you need to calculate the normals yourself when
> creating tmds dynamically that I er, dont include those primitive types
> :) seeing as I only ever wanted primitives without light calculations

// Cross Product==Normal Vector
void CrossProduct(SVECTOR *a, SVECTOR *b, SVECTOR *c, SVECTOR *out)
{
	SVECTOR ab,ac;

	ab.vx=b.vx-a.vx; ab.vy=b.vy-a.vy; ab.vz=b.vz-a.vz;
	ac.vx=c.vx-a.vx; ac.vy=c.vy-a.vy; ac.vz=c.vz-a.vz;

	out->vx=ab.vy*ac.vz - ab.vz*ac.vy;
	out->vy=ab.vz*ac.vx - ab.vx*ac.v.z;
	out->vz=ab.vx*ac.vy - ab.vy*ac.vx;
}

Then unify to length 4096 using the usual methods.

> Robert Swan

Craig.