src/common/fvect.c

/* Copyright (c) 1986 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  fvect.c - routines for float vector calculations
 *
 *     8/14/85
 */

#include  "fvect.h"


double
fdot(v1, v2)                    /* return the dot product of two vectors */
register FVECT  v1, v2;
{
        return(DOT(v1,v2));
}


double
dist2(p1, p2)                   /* return square of distance between points */
register FVECT  p1, p2;
{
        static FVECT  delta;

        delta[0] = p2[0] - p1[0];
        delta[1] = p2[1] - p1[1];
        delta[2] = p2[2] - p1[2];
        return(DOT(delta, delta));
}


double
dist2line(p, ep1, ep2)          /* return square of distance to line */
FVECT  p;               /* the point */
FVECT  ep1, ep2;        /* points on the line */
{
        static double  d, d1, d2;

        d = dist2(ep1, ep2);
        d1 = dist2(ep1, p);
        d2 = dist2(ep2, p);

        return(d1 - (d+d1-d2)*(d+d1-d2)/d/4);
}


double
dist2lseg(p, ep1, ep2)          /* return square of distance to line segment */
FVECT  p;               /* the point */
FVECT  ep1, ep2;        /* the end points */
{
        static double  d, d1, d2;

        d = dist2(ep1, ep2);
        d1 = dist2(ep1, p);
        d2 = dist2(ep2, p);

        if (d2 > d1) {                  /* check if past endpoints */
                if (d2 - d1 > d)
                        return(d1);
        } else {
                if (d1 - d2 > d)
                        return(d2);
        }

        return(d1 - (d+d1-d2)*(d+d1-d2)/d/4);   /* distance to line */
}


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];
}


fvsum(vres, v0, v1, f)          /* vres = v0 + f*v1 */
FVECT  vres, v0, v1;
double  f;
{
        vres[0] = v0[0] + f*v1[0];
        vres[1] = v0[1] + f*v1[1];
        vres[2] = v0[2] + f*v1[2];
}


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);
        
        /****** problematic
        if (len >= (1.0-FTINY)*(1.0-FTINY) &&
                        len <= (1.0+FTINY)*(1.0+FTINY))
                return(1.0);
        ******/

        len = sqrt(len);
        v[0] /= len;
        v[1] /= len;
        v[2] /= len;
        return(len);
}


spinvector(vres, vorig, vnorm, theta)   /* rotate vector around normal */
FVECT  vres, vorig, vnorm;
double  theta;
{
        extern double  cos(), sin();
        double  sint, cost, normprod;
        FVECT  vperp;
        register int  i;
        
        if (theta == 0.0) {
                if (vres != vorig)
                        VCOPY(vres, vorig);
                return;
        }
        cost = cos(theta);
        sint = sin(theta);
        normprod = DOT(vorig, vnorm)*(1.-cost);
        fcross(vperp, vnorm, vorig);
        for (i = 0; i < 3; i++)
                vres[i] = vorig[i]*cost + vnorm[i]*normprod + vperp[i]*sint;
}
Revision:	1.7
Committed:	Wed Oct 23 13:43:15 1991 UTC (32 years, 6 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.6:	+0 -2 lines
Log Message:	added FLOAT definition to better control size of structures
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1986 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* fvect.c - routines for float vector calculations
9			*
10			* 8/14/85
11			*/
12
13			#include "fvect.h"
14
15
16			double
17			fdot(v1, v2) /* return the dot product of two vectors */
18			register FVECT v1, v2;
19			{
20			return(DOT(v1,v2));
21			}
22
23
24			double
25			dist2(p1, p2) /* return square of distance between points */
26			register FVECT p1, p2;
27			{
28			static FVECT delta;
29
30			delta[0] = p2[0] - p1[0];
31			delta[1] = p2[1] - p1[1];
32			delta[2] = p2[2] - p1[2];
33			return(DOT(delta, delta));
34			}
35
36
37			double
38			dist2line(p, ep1, ep2) /* return square of distance to line */
39			FVECT p; /* the point */
40			FVECT ep1, ep2; /* points on the line */
41			{
42			static double d, d1, d2;
43
44			d = dist2(ep1, ep2);
45			d1 = dist2(ep1, p);
46			d2 = dist2(ep2, p);
47
48			return(d1 - (d+d1-d2)*(d+d1-d2)/d/4);
49			}
50
51
52			double
53			dist2lseg(p, ep1, ep2) /* return square of distance to line segment */
54			FVECT p; /* the point */
55			FVECT ep1, ep2; /* the end points */
56			{
57			static double d, d1, d2;
58
59			d = dist2(ep1, ep2);
60			d1 = dist2(ep1, p);
61			d2 = dist2(ep2, p);
62
63			if (d2 > d1) { /* check if past endpoints */
64			if (d2 - d1 > d)
65			return(d1);
66			} else {
67			if (d1 - d2 > d)
68			return(d2);
69			}
70
71			return(d1 - (d+d1-d2)(d+d1-d2)/d/4); / distance to line */
72			}
73
74
75			fcross(vres, v1, v2) /* vres = v1 X v2 */
76			register FVECT vres, v1, v2;
77			{
78			vres[0] = v1[1]v2[2] - v1[2]v2[1];
79			vres[1] = v1[2]v2[0] - v1[0]v2[2];
80			vres[2] = v1[0]v2[1] - v1[1]v2[0];
81			}
82
83
84	greg	1.4	fvsum(vres, v0, v1, f) /* vres = v0 + fv1 /
85			FVECT vres, v0, v1;
86			double f;
87			{
88			vres[0] = v0[0] + f*v1[0];
89			vres[1] = v0[1] + f*v1[1];
90			vres[2] = v0[2] + f*v1[2];
91			}
92
93
94	greg	1.1	double
95			normalize(v) /* normalize a vector, return old magnitude */
96			register FVECT v;
97			{
98			static double len;
99
100			len = DOT(v, v);
101
102	greg	1.3	if (len <= 0.0)
103	greg	1.1	return(0.0);
104
105	greg	1.2	/****** problematic
106	greg	1.1	if (len >= (1.0-FTINY)*(1.0-FTINY) &&
107			len <= (1.0+FTINY)*(1.0+FTINY))
108			return(1.0);
109	greg	1.2	******/
110	greg	1.1
111			len = sqrt(len);
112			v[0] /= len;
113			v[1] /= len;
114			v[2] /= len;
115			return(len);
116			}
117	greg	1.5
118
119			spinvector(vres, vorig, vnorm, theta) /* rotate vector around normal */
120			FVECT vres, vorig, vnorm;
121			double theta;
122			{
123	greg	1.6	extern double cos(), sin();
124			double sint, cost, normprod;
125	greg	1.5	FVECT vperp;
126			register int i;
127
128			if (theta == 0.0) {
129	greg	1.6	if (vres != vorig)
130			VCOPY(vres, vorig);
131	greg	1.5	return;
132			}
133	greg	1.6	cost = cos(theta);
134	greg	1.5	sint = sin(theta);
135	greg	1.6	normprod = DOT(vorig, vnorm)*(1.-cost);
136	greg	1.5	fcross(vperp, vnorm, vorig);
137			for (i = 0; i < 3; i++)
138	greg	1.6	vres[i] = vorig[i]cost + vnorm[i]normprod + vperp[i]*sint;
139	greg	1.5	}