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flightgear/src/FDM/MagicCarpet.cxx
2006-02-21 01:16:04 +00:00

121 lines
3.7 KiB
C++

// MagicCarpet.cxx -- interface to the "Magic Carpet" flight model
//
// Written by Curtis Olson, started October 1999.
//
// Copyright (C) 1999 Curtis L. Olson - http://www.flightgear.org/~curt
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/math/point3d.hxx>
#include <simgear/math/polar3d.hxx>
#include <Aircraft/controls.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include "MagicCarpet.hxx"
FGMagicCarpet::FGMagicCarpet( double dt ) {
// set_delta_t( dt );
}
FGMagicCarpet::~FGMagicCarpet() {
}
// Initialize the Magic Carpet flight model, dt is the time increment
// for each subsequent iteration through the EOM
void FGMagicCarpet::init() {
common_init();
}
// Run an iteration of the EOM (equations of motion)
void FGMagicCarpet::update( double dt ) {
// cout << "FGLaRCsim::update()" << endl;
if (is_suspended())
return;
// int multiloop = _calc_multiloop(dt);
double time_step = dt;
// speed and distance traveled
double speed = globals->get_controls()->get_throttle( 0 ) * 2000; // meters/sec
if ( globals->get_controls()->get_brake_left() > 0.0
|| globals->get_controls()->get_brake_right() > 0.0 )
{
speed = -speed;
}
double dist = speed * time_step;
double kts = speed * SG_METER_TO_NM * 3600.0;
_set_V_equiv_kts( kts );
_set_V_calibrated_kts( kts );
_set_V_ground_speed( kts );
// angle of turn
double turn_rate = globals->get_controls()->get_aileron() * SGD_PI_4; // radians/sec
double turn = turn_rate * time_step;
// update euler angles
_set_Euler_Angles( get_Phi(), get_Theta(),
fmod(get_Psi() + turn, SGD_2PI) );
_set_Euler_Rates(0,0,0);
// update (lon/lat) position
double lat2, lon2, az2;
if ( fabs( speed ) > SG_EPSILON ) {
geo_direct_wgs_84 ( get_Altitude(),
get_Latitude() * SGD_RADIANS_TO_DEGREES,
get_Longitude() * SGD_RADIANS_TO_DEGREES,
get_Psi() * SGD_RADIANS_TO_DEGREES,
dist, &lat2, &lon2, &az2 );
_set_Longitude( lon2 * SGD_DEGREES_TO_RADIANS );
_set_Latitude( lat2 * SGD_DEGREES_TO_RADIANS );
}
// cout << "lon error = " << fabs(end.x()*SGD_RADIANS_TO_DEGREES - lon2)
// << " lat error = " << fabs(end.y()*SGD_RADIANS_TO_DEGREES - lat2)
// << endl;
double sl_radius, lat_geoc;
sgGeodToGeoc( get_Latitude(), get_Altitude(), &sl_radius, &lat_geoc );
// update altitude
double real_climb_rate = -globals->get_controls()->get_elevator() * 5000; // feet/sec
_set_Climb_Rate( real_climb_rate / 500.0 );
double climb = real_climb_rate * time_step;
_set_Geocentric_Position( lat_geoc, get_Longitude(),
sl_radius + get_Altitude() + climb );
// cout << "sea level radius (ft) = " << sl_radius << endl;
// cout << "(setto) sea level radius (ft) = " << get_Sea_level_radius() << endl;
_update_ground_elev_at_pos();
_set_Sea_level_radius( sl_radius * SG_METER_TO_FEET);
_set_Altitude( get_Altitude() + climb );
}