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 **************************************************************************/
32 #include "../Math/mat3.h"
35 /* Map a vector onto the plane specified by normal */
36 void map_vec_onto_cur_surface_plane(MAT3vec normal, MAT3vec v0, MAT3vec vec,
41 /* calculate a vector "u1" representing the shortest distance from
42 * the plane specified by normal and v0 to a point specified by
43 * "vec". "u1" represents both the direction and magnitude of
44 * this desired distance. */
46 /* u1 = ( (normal <dot> vec) / (normal <dot> normal) ) * normal */
50 ( MAT3_DOT_PRODUCT(normal, vec) /
51 MAT3_DOT_PRODUCT(normal, normal)
56 printf(" vec = %.2f, %.2f, %.2f\n", vec[0], vec[1], vec[2]);
57 printf(" v0 = %.2f, %.2f, %.2f\n", v0[0], v0[1], v0[2]);
58 printf(" u1 = %.2f, %.2f, %.2f\n", u1[0], u1[1], u1[2]);
61 /* calculate the vector "v" which is the vector "vec" mapped onto
62 the plane specified by "normal" and "v0". */
64 /* v = v0 + vec - u1 */
66 MAT3_ADD_VEC(tmp, v0, vec);
67 MAT3_SUB_VEC(v, tmp, u1);
68 /* printf(" v = %.2f, %.2f, %.2f\n", v[0], v[1], v[2]); */
70 /* Calculate the vector "result" which is "v" - "v0" which is a
71 * directional vector pointing from v0 towards v */
75 MAT3_SUB_VEC(result, v, v0);
76 /* printf(" result = %.2f, %.2f, %.2f\n",
77 result[0], result[1], result[2]); */
81 /* Revision 1.1 1997/12/22 04:13:17 curt