1 // MagicCarpet.cxx -- interface to the "Magic Carpet" flight model
3 // Written by Curtis Olson, started October 1999.
5 // Copyright (C) 1999 Curtis L. Olson - http://www.flightgear.org/~curt
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., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include <simgear/math/sg_geodesy.hxx>
29 #include <simgear/math/point3d.hxx>
30 #include <simgear/math/polar3d.hxx>
32 #include <Aircraft/controls.hxx>
33 #include <Main/globals.hxx>
34 #include <Main/fg_props.hxx>
36 #include "MagicCarpet.hxx"
39 FGMagicCarpet::FGMagicCarpet( double dt ) {
44 FGMagicCarpet::~FGMagicCarpet() {
48 // Initialize the Magic Carpet flight model, dt is the time increment
49 // for each subsequent iteration through the EOM
50 void FGMagicCarpet::init() {
55 // Run an iteration of the EOM (equations of motion)
56 void FGMagicCarpet::update( double dt ) {
57 // cout << "FGLaRCsim::update()" << endl;
62 // int multiloop = _calc_multiloop(dt);
64 double time_step = dt;
66 // speed and distance traveled
67 double speed = globals->get_controls()->get_throttle( 0 ) * 2000; // meters/sec
68 if ( globals->get_controls()->get_brake_left() > 0.0
69 || globals->get_controls()->get_brake_right() > 0.0 )
74 double dist = speed * time_step;
75 double kts = speed * SG_METER_TO_NM * 3600.0;
76 _set_V_equiv_kts( kts );
77 _set_V_calibrated_kts( kts );
78 _set_V_ground_speed( kts );
81 double turn_rate = globals->get_controls()->get_aileron() * SGD_PI_4; // radians/sec
82 double turn = turn_rate * time_step;
84 // update euler angles
85 _set_Euler_Angles( get_Phi(), get_Theta(),
86 fmod(get_Psi() + turn, SGD_2PI) );
87 _set_Euler_Rates(0,0,0);
89 // update (lon/lat) position
90 double lat2, lon2, az2;
91 if ( fabs( speed ) > SG_EPSILON ) {
92 geo_direct_wgs_84 ( get_Altitude(),
93 get_Latitude() * SGD_RADIANS_TO_DEGREES,
94 get_Longitude() * SGD_RADIANS_TO_DEGREES,
95 get_Psi() * SGD_RADIANS_TO_DEGREES,
96 dist, &lat2, &lon2, &az2 );
98 _set_Longitude( lon2 * SGD_DEGREES_TO_RADIANS );
99 _set_Latitude( lat2 * SGD_DEGREES_TO_RADIANS );
102 // cout << "lon error = " << fabs(end.x()*SGD_RADIANS_TO_DEGREES - lon2)
103 // << " lat error = " << fabs(end.y()*SGD_RADIANS_TO_DEGREES - lat2)
106 double sl_radius, lat_geoc;
107 sgGeodToGeoc( get_Latitude(), get_Altitude(), &sl_radius, &lat_geoc );
110 double real_climb_rate = -globals->get_controls()->get_elevator() * 5000; // feet/sec
111 _set_Climb_Rate( real_climb_rate / 500.0 );
112 double climb = real_climb_rate * time_step;
114 _set_Geocentric_Position( lat_geoc, get_Longitude(),
115 sl_radius + get_Altitude() + climb );
116 // cout << "sea level radius (ft) = " << sl_radius << endl;
117 // cout << "(setto) sea level radius (ft) = " << get_Sea_level_radius() << endl;
118 _update_ground_elev_at_pos();
119 _set_Sea_level_radius( sl_radius * SG_METER_TO_FEET);
120 _set_Altitude( get_Altitude() + climb );