1 // gravity.hxx -- interface for earth gravitational model
3 // Written by Torsten Dreyer, June 2011
5 // Copyright (C) 2011 Torsten Dreyer - torsten (at) t3r _dot_ de
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 #include <simgear/math/SGMath.hxx>
27 namespace Environment {
33 virtual double getGravity( const SGGeod & position ) const = 0;
35 const static Gravity * instance();
38 static Gravity * _instance;
43 #endif // __GRAVITY_HXX