vmap/libs/picomodel/vecmath.c

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2020-11-17 11:16:16 +00:00
/*
======================================================================
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;
}
}