129 lines
3.7 KiB
C++
129 lines
3.7 KiB
C++
// vector.cxx -- additional vector routines
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//
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// Written by Curtis Olson, started December 1997.
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//
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// Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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//
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// $Id$
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#include <math.h>
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#include <stdio.h>
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// #include <Include/fg_types.h>
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#include "vector.hxx"
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#include "mat3.h"
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#if !defined( USE_XTRA_MAT3_INLINES )
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// Map a vector onto the plane specified by normal
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void map_vec_onto_cur_surface_plane(MAT3vec normal, MAT3vec v0, MAT3vec vec,
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MAT3vec result)
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{
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MAT3vec u1, v, tmp;
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// calculate a vector "u1" representing the shortest distance from
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// the plane specified by normal and v0 to a point specified by
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// "vec". "u1" represents both the direction and magnitude of
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// this desired distance.
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// u1 = ( (normal <dot> vec) / (normal <dot> normal) ) * normal
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MAT3_SCALE_VEC( u1,
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normal,
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( MAT3_DOT_PRODUCT(normal, vec) /
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MAT3_DOT_PRODUCT(normal, normal)
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)
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);
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// printf(" vec = %.2f, %.2f, %.2f\n", vec[0], vec[1], vec[2]);
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// printf(" v0 = %.2f, %.2f, %.2f\n", v0[0], v0[1], v0[2]);
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// printf(" u1 = %.2f, %.2f, %.2f\n", u1[0], u1[1], u1[2]);
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// calculate the vector "v" which is the vector "vec" mapped onto
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// the plane specified by "normal" and "v0".
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// v = v0 + vec - u1
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MAT3_ADD_VEC(tmp, v0, vec);
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MAT3_SUB_VEC(v, tmp, u1);
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// printf(" v = %.2f, %.2f, %.2f\n", v[0], v[1], v[2]);
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// Calculate the vector "result" which is "v" - "v0" which is a
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// directional vector pointing from v0 towards v
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// result = v - v0
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MAT3_SUB_VEC(result, v, v0);
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// printf(" result = %.2f, %.2f, %.2f\n",
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// result[0], result[1], result[2]);
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}
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#endif // !defined( USE_XTRA_MAT3_INLINES )
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// Given a point p, and a line through p0 with direction vector d,
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// find the shortest distance from the point to the line
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double fgPointLine(MAT3vec p, MAT3vec p0, MAT3vec d) {
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MAT3vec u, u1, v;
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double ud, dd, tmp;
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// u = p - p0
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MAT3_SUB_VEC(u, p, p0);
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// calculate the projection, u1, of u along d.
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// u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
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ud = MAT3_DOT_PRODUCT(u, d);
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dd = MAT3_DOT_PRODUCT(d, d);
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tmp = ud / dd;
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MAT3_SCALE_VEC(u1, d, tmp);;
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// v = u - u1 = vector from closest point on line, p1, to the
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// original point, p.
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MAT3_SUB_VEC(v, u, u1);
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return sqrt(MAT3_DOT_PRODUCT(v, v));
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}
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// Given a point p, and a line through p0 with direction vector d,
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// find the shortest distance (squared) from the point to the line
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double fgPointLineSquared(MAT3vec p, MAT3vec p0, MAT3vec d) {
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MAT3vec u, u1, v;
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double ud, dd, tmp;
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// u = p - p0
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MAT3_SUB_VEC(u, p, p0);
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// calculate the projection, u1, of u along d.
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// u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
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ud = MAT3_DOT_PRODUCT(u, d);
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dd = MAT3_DOT_PRODUCT(d, d);
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tmp = ud / dd;
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MAT3_SCALE_VEC(u1, d, tmp);;
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// v = u - u1 = vector from closest point on line, p1, to the
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// original point, p.
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MAT3_SUB_VEC(v, u, u1);
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return ( MAT3_DOT_PRODUCT(v, v) );
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}
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