gtkradiant/libs/picomodel/lwo/vecmath.c
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git-svn-id: svn://svn.icculus.org/gtkradiant/GtkRadiant/branches/ZeroRadiant@183 8a3a26a2-13c4-0310-b231-cf6edde360e5
2007-11-04 03:34:51 +00:00

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C

/*
======================================================================
vecmath.c
Basic vector and matrix functions.
Ernie Wright 17 Sep 00
====================================================================== */
#include <math.h>
float dot( float a[], float b[] )
{
return a[ 0 ] * b[ 0 ] + a[ 1 ] * b[ 1 ] + a[ 2 ] * b[ 2 ];
}
void cross( float a[], float b[], float c[] )
{
c[ 0 ] = a[ 1 ] * b[ 2 ] - a[ 2 ] * b[ 1 ];
c[ 1 ] = a[ 2 ] * b[ 0 ] - a[ 0 ] * b[ 2 ];
c[ 2 ] = a[ 0 ] * b[ 1 ] - a[ 1 ] * b[ 0 ];
}
void normalize( float v[] )
{
float r;
r = ( float ) sqrt( dot( v, v ));
if ( r > 0 ) {
v[ 0 ] /= r;
v[ 1 ] /= r;
v[ 2 ] /= r;
}
}