-#include "mat3.h"
-
-
-// Map a vector onto the plane specified by normal
-void map_vec_onto_cur_surface_plane(MAT3vec normal, MAT3vec v0, MAT3vec vec,
- MAT3vec result)
-{
- MAT3vec u1, v, tmp;
-
- // calculate a vector "u1" representing the shortest distance from
- // the plane specified by normal and v0 to a point specified by
- // "vec". "u1" represents both the direction and magnitude of
- // this desired distance.
-
- // u1 = ( (normal <dot> vec) / (normal <dot> normal) ) * normal
-
- MAT3_SCALE_VEC( u1,
- normal,
- ( MAT3_DOT_PRODUCT(normal, vec) /
- MAT3_DOT_PRODUCT(normal, normal)
- )
- );
-
- // printf(" vec = %.2f, %.2f, %.2f\n", vec[0], vec[1], vec[2]);
- // printf(" v0 = %.2f, %.2f, %.2f\n", v0[0], v0[1], v0[2]);
- // printf(" u1 = %.2f, %.2f, %.2f\n", u1[0], u1[1], u1[2]);
-
- // calculate the vector "v" which is the vector "vec" mapped onto
- // the plane specified by "normal" and "v0".
-
- // v = v0 + vec - u1
-
- MAT3_ADD_VEC(tmp, v0, vec);
- MAT3_SUB_VEC(v, tmp, u1);
- // printf(" v = %.2f, %.2f, %.2f\n", v[0], v[1], v[2]);
-
- // Calculate the vector "result" which is "v" - "v0" which is a
- // directional vector pointing from v0 towards v
-
- // result = v - v0
-
- MAT3_SUB_VEC(result, v, v0);
- // printf(" result = %.2f, %.2f, %.2f\n",
- // result[0], result[1], result[2]);
-}
-
-
-// Given a point p, and a line through p0 with direction vector d,
-// find the shortest distance from the point to the line
-double fgPointLine(MAT3vec p, MAT3vec p0, MAT3vec d) {
- MAT3vec u, u1, v;
- double ud, dd, tmp;
-
- // u = p - p0
- MAT3_SUB_VEC(u, p, p0);
-
- // calculate the projection, u1, of u along d.
- // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
- ud = MAT3_DOT_PRODUCT(u, d);
- dd = MAT3_DOT_PRODUCT(d, d);
- tmp = ud / dd;
-
- MAT3_SCALE_VEC(u1, d, tmp);;
-
- // v = u - u1 = vector from closest point on line, p1, to the
- // original point, p.
- MAT3_SUB_VEC(v, u, u1);
-
- return sqrt(MAT3_DOT_PRODUCT(v, v));
-}
-
-
-// Given a point p, and a line through p0 with direction vector d,
-// find the shortest distance (squared) from the point to the line
-double fgPointLineSquared(MAT3vec p, MAT3vec p0, MAT3vec d) {
- MAT3vec u, u1, v;
- double ud, dd, tmp;
-
- // u = p - p0
- MAT3_SUB_VEC(u, p, p0);
-
- // calculate the projection, u1, of u along d.
- // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
- ud = MAT3_DOT_PRODUCT(u, d);
- dd = MAT3_DOT_PRODUCT(d, d);
- tmp = ud / dd;
-
- MAT3_SCALE_VEC(u1, d, tmp);;
-
- // v = u - u1 = vector from closest point on line, p1, to the
- // original point, p.
- MAT3_SUB_VEC(v, u, u1);
-
- return ( MAT3_DOT_PRODUCT(v, v) );
-}
-