1 /**************************************************************************
2 * vector.c -- additional vector routines
4 * Written by Curtis Olson, started December 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
30 // #include <Include/fg_types.h>
37 #if !defined( USE_XTRA_MAT3_INLINES )
38 /* Map a vector onto the plane specified by normal */
39 void map_vec_onto_cur_surface_plane(MAT3vec normal, MAT3vec v0, MAT3vec vec,
44 /* calculate a vector "u1" representing the shortest distance from
45 * the plane specified by normal and v0 to a point specified by
46 * "vec". "u1" represents both the direction and magnitude of
47 * this desired distance. */
49 /* u1 = ( (normal <dot> vec) / (normal <dot> normal) ) * normal */
53 ( MAT3_DOT_PRODUCT(normal, vec) /
54 MAT3_DOT_PRODUCT(normal, normal)
59 printf(" vec = %.2f, %.2f, %.2f\n", vec[0], vec[1], vec[2]);
60 printf(" v0 = %.2f, %.2f, %.2f\n", v0[0], v0[1], v0[2]);
61 printf(" u1 = %.2f, %.2f, %.2f\n", u1[0], u1[1], u1[2]);
64 /* calculate the vector "v" which is the vector "vec" mapped onto
65 the plane specified by "normal" and "v0". */
67 /* v = v0 + vec - u1 */
69 MAT3_ADD_VEC(tmp, v0, vec);
70 MAT3_SUB_VEC(v, tmp, u1);
71 /* printf(" v = %.2f, %.2f, %.2f\n", v[0], v[1], v[2]); */
73 /* Calculate the vector "result" which is "v" - "v0" which is a
74 * directional vector pointing from v0 towards v */
78 MAT3_SUB_VEC(result, v, v0);
79 /* printf(" result = %.2f, %.2f, %.2f\n",
80 result[0], result[1], result[2]); */
82 #endif // !defined( USE_XTRA_MAT3_INLINES )
85 // Given a point p, and a line through p0 with direction vector d,
86 // find the shortest distance from the point to the line
87 double fgPointLine(MAT3vec p, MAT3vec p0, MAT3vec d) {
89 double ud, dd, tmp, dist;
92 MAT3_SUB_VEC(u, p, p0);
94 // calculate the projection, u1, of u along d.
95 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
96 ud = MAT3_DOT_PRODUCT(u, d);
97 dd = MAT3_DOT_PRODUCT(d, d);
100 MAT3_SCALE_VEC(u1, d, tmp);;
102 // v = u - u1 = vector from closest point on line, p1, to the
103 // original point, p.
104 MAT3_SUB_VEC(v, u, u1);
106 dist = sqrt(MAT3_DOT_PRODUCT(v, v));
112 // Given a point p, and a line through p0 with direction vector d,
113 // find the shortest distance (squared) from the point to the line
114 double fgPointLineSquared(MAT3vec p, MAT3vec p0, MAT3vec d) {
119 MAT3_SUB_VEC(u, p, p0);
121 // calculate the projection, u1, of u along d.
122 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
123 ud = MAT3_DOT_PRODUCT(u, d);
124 dd = MAT3_DOT_PRODUCT(d, d);
127 MAT3_SCALE_VEC(u1, d, tmp);;
129 // v = u - u1 = vector from closest point on line, p1, to the
130 // original point, p.
131 MAT3_SUB_VEC(v, u, u1);
133 return ( MAT3_DOT_PRODUCT(v, v) );
138 /* Revision 1.4 1998/10/16 00:50:31 curt
139 /* Added point3d.hxx to replace cheezy fgPoint3d struct.
141 * Revision 1.3 1998/08/24 20:04:12 curt
142 * Various "inline" code optimizations contributed by Norman Vine.
144 * Revision 1.2 1998/07/24 21:34:38 curt
145 * fgPointLine() rewritten into fgPointLineSquared() ... this ultimately saves
146 * us from doing a sqrt().
148 * Revision 1.1 1998/07/08 14:40:10 curt
149 * polar3d.[ch] renamed to polar3d.[ch]xx, vector.[ch] renamed to vector.[ch]xx
150 * Updated fg_geodesy comments to reflect that routines expect and produce
153 * Revision 1.3 1998/05/07 23:04:28 curt
154 * Added a blank formating line!
156 * Revision 1.2 1998/01/19 19:27:13 curt
157 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
158 * This should simplify things tremendously.
160 * Revision 1.1 1997/12/22 04:13:17 curt