1 // vector.cxx -- additional vector routines
3 // Written by Curtis Olson, started December 1997.
5 // Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 // #include <Include/fg_types.h>
34 // Map a vector onto the plane specified by normal
35 void map_vec_onto_cur_surface_plane(MAT3vec normal, MAT3vec v0, MAT3vec vec,
40 // calculate a vector "u1" representing the shortest distance from
41 // the plane specified by normal and v0 to a point specified by
42 // "vec". "u1" represents both the direction and magnitude of
43 // this desired distance.
45 // u1 = ( (normal <dot> vec) / (normal <dot> normal) ) * normal
49 ( MAT3_DOT_PRODUCT(normal, vec) /
50 MAT3_DOT_PRODUCT(normal, normal)
54 // printf(" vec = %.2f, %.2f, %.2f\n", vec[0], vec[1], vec[2]);
55 // printf(" v0 = %.2f, %.2f, %.2f\n", v0[0], v0[1], v0[2]);
56 // printf(" u1 = %.2f, %.2f, %.2f\n", u1[0], u1[1], u1[2]);
58 // calculate the vector "v" which is the vector "vec" mapped onto
59 // the plane specified by "normal" and "v0".
63 MAT3_ADD_VEC(tmp, v0, vec);
64 MAT3_SUB_VEC(v, tmp, u1);
65 // printf(" v = %.2f, %.2f, %.2f\n", v[0], v[1], v[2]);
67 // Calculate the vector "result" which is "v" - "v0" which is a
68 // directional vector pointing from v0 towards v
72 MAT3_SUB_VEC(result, v, v0);
73 // printf(" result = %.2f, %.2f, %.2f\n",
74 // result[0], result[1], result[2]);
78 // Given a point p, and a line through p0 with direction vector d,
79 // find the shortest distance from the point to the line
80 double fgPointLine(MAT3vec p, MAT3vec p0, MAT3vec d) {
85 MAT3_SUB_VEC(u, p, p0);
87 // calculate the projection, u1, of u along d.
88 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
89 ud = MAT3_DOT_PRODUCT(u, d);
90 dd = MAT3_DOT_PRODUCT(d, d);
93 MAT3_SCALE_VEC(u1, d, tmp);;
95 // v = u - u1 = vector from closest point on line, p1, to the
97 MAT3_SUB_VEC(v, u, u1);
99 return sqrt(MAT3_DOT_PRODUCT(v, v));
103 // Given a point p, and a line through p0 with direction vector d,
104 // find the shortest distance (squared) from the point to the line
105 double fgPointLineSquared(MAT3vec p, MAT3vec p0, MAT3vec d) {
110 MAT3_SUB_VEC(u, p, p0);
112 // calculate the projection, u1, of u along d.
113 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
114 ud = MAT3_DOT_PRODUCT(u, d);
115 dd = MAT3_DOT_PRODUCT(d, d);
118 MAT3_SCALE_VEC(u1, d, tmp);;
120 // v = u - u1 = vector from closest point on line, p1, to the
121 // original point, p.
122 MAT3_SUB_VEC(v, u, u1);
124 return ( MAT3_DOT_PRODUCT(v, v) );
128 // Given a point p, and a line through p0 with direction vector d,
129 // find the shortest distance (squared) from the point to the line
130 double sgPointLineDistSquared( const sgVec3 p, const sgVec3 p0,
139 // calculate the projection, u1, of u along d.
140 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
141 ud = sgScalarProductVec3(u, d);
142 dd = sgScalarProductVec3(d, d);
145 sgScaleVec3(u1, d, tmp);;
147 // v = u - u1 = vector from closest point on line, p1, to the
148 // original point, p.
151 return ( sgScalarProductVec3(v, v) );
155 // Given a point p, and a line through p0 with direction vector d,
156 // find the shortest distance (squared) from the point to the line
157 double sgdPointLineDistSquared( const sgdVec3 p, const sgdVec3 p0,
164 sgdSubVec3(u, p, p0);
166 // calculate the projection, u1, of u along d.
167 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
168 ud = sgdScalarProductVec3(u, d);
169 dd = sgdScalarProductVec3(d, d);
172 sgdScaleVec3(u1, d, tmp);;
174 // v = u - u1 = vector from closest point on line, p1, to the
175 // original point, p.
176 sgdSubVec3(v, u, u1);
178 return ( sgdScalarProductVec3(v, v) );