The GtkRadiant sources as originally released under the GPL license.

libs/picomodel/lwo/vecmath.c

@@ -0,0 +1,37 @@
+/*
+======================================================================
+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;
+   }
+}