flightgear/Lib/Math/vector.hxx

// vector.hxx -- additional vector routines
//
// Written by Curtis Olson, started December 1997.
//
// Copyright (C) 1997  Curtis L. Olson  - curt@infoplane.com
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$


#ifndef _VECTOR_HXX
#define _VECTOR_HXX


#ifndef __cplusplus                                                          
# error This library requires C++
#endif                                   


#include "mat3.h"


// Map a vector onto the plane specified by normal
#if defined( USE_XTRA_MAT3_INLINES )
#  define map_vec_onto_cur_surface_plane(normal, v0, vec, result) { \
	double scale = ((normal[0]*vec[0]+normal[1]*vec[1]+normal[2]*vec[2]) / \
	       (normal[0]*normal[0]+normal[1]*normal[1]+normal[2]*normal[2])); \
	result[0] = vec[0]-normal[0]*scale; \
	result[1] = vec[1]-normal[1]*scale; \
	result[2] = vec[2]-normal[2]*scale; \
  }
#else
  void map_vec_onto_cur_surface_plane(MAT3vec normal, MAT3vec v0, MAT3vec vec,
				    MAT3vec result);
#endif //defined( USE_XTRA_MAT3_INLINES )


// 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);


// 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);


#endif // _VECTOR_HXX