cv/mgflib/fvect.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 * Routines for 3-d vectors
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "parser.h"


double
normalize(v)                    /* normalize a vector, return old magnitude */
register FVECT  v;
{
        static double  len;
        
        len = DOT(v, v);
        
        if (len <= 0.0)
                return(0.0);
        
        if (len <= 1.0+FTINY && len >= 1.0-FTINY)
                len = 0.5 + 0.5*len;    /* first order approximation */
        else
                len = sqrt(len);

        v[0] /= len;
        v[1] /= len;
        v[2] /= len;

        return(len);
}


void
fcross(vres, v1, v2)            /* vres = v1 X v2 */
register FVECT  vres, v1, v2;
{
        vres[0] = v1[1]*v2[2] - v1[2]*v2[1];
        vres[1] = v1[2]*v2[0] - v1[0]*v2[2];
        vres[2] = v1[0]*v2[1] - v1[1]*v2[0];
}
Revision:	1.4
Committed:	Fri Feb 28 20:11:29 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P1, rad4R0, rad3R5, rad3R6, rad3R6P1, rad3R8, rad3R9, rad3R7P2
Changes since 1.3:	+2 -4 lines
Log Message:	Updates for 3.5 release
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	1.4	static const char RCSid[] = "$Id$";
3	greg	1.1	#endif
4			/*
5			* Routines for 3-d vectors
6			*/
7
8			#include <stdio.h>
9	greg	1.4	#include <stdlib.h>
10	greg	1.1	#include <math.h>
11			#include "parser.h"
12
13
14			double
15			normalize(v) /* normalize a vector, return old magnitude */
16			register FVECT v;
17			{
18			static double len;
19
20	greg	1.2	len = DOT(v, v);
21	greg	1.1
22			if (len <= 0.0)
23			return(0.0);
24
25	greg	1.2	if (len <= 1.0+FTINY && len >= 1.0-FTINY)
26			len = 0.5 + 0.5len; / first order approximation */
27			else
28			len = sqrt(len);
29	greg	1.1
30			v[0] /= len;
31			v[1] /= len;
32			v[2] /= len;
33
34			return(len);
35			}
36
37
38	greg	1.3	void
39	greg	1.1	fcross(vres, v1, v2) /* vres = v1 X v2 */
40			register FVECT vres, v1, v2;
41			{
42			vres[0] = v1[1]v2[2] - v1[2]v2[1];
43			vres[1] = v1[2]v2[0] - v1[0]v2[2];
44			vres[2] = v1[0]v2[1] - v1[1]v2[0];
45			}