1 // fgwind.cxx -- routines to create variable winds
3 // Written by Torsten Dreyer
5 // Copyright (C) 2009 Torsten Dreyer - Torsten _at_ t3r*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.
26 FGWindModulator::FGWindModulator() :
27 direction_offset_norm(0.0),
28 magnitude_factor_norm(1.0)
32 FGWindModulator::~FGWindModulator()
36 FGBasicWindModulator::FGBasicWindModulator() :
43 FGBasicWindModulator::~FGBasicWindModulator()
47 void FGBasicWindModulator::update( double dt)
50 double t = elapsed/direction_period;
52 direction_offset_norm = (sin(t)*sin(2*t)+sin(t/3)) / 1.75;
54 t = elapsed/speed_period;
55 magnitude_factor_norm = sin(t)* sin(5*direction_offset_norm*direction_offset_norm);;
56 magnitude_factor_norm = magnitude_factor_norm < 0 ? 0 : magnitude_factor_norm;