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flightgear/src/FDM/MagicCarpet.cxx
1999-10-15 05:35:50 +00:00

93 lines
3.1 KiB
C++

// MagicCarpet.cxx -- interface to the "Magic Carpet" flight model
//
// Written by Curtis Olson, started October 1999.
//
// Copyright (C) 1999 Curtis L. Olson - curt@flightgear.org
//
// 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.
//
// $Id$
#include <Controls/controls.hxx>
#include <Main/options.hxx>
#include <Math/fg_geodesy.hxx>
#include <Math/point3d.hxx>
#include <Math/polar3d.hxx>
#include "MagicCarpet.hxx"
// Initialize the Magic Carpet flight model, dt is the time increment
// for each subsequent iteration through the EOM
int FGMagicCarpet::init( double dt ) {
// set valid time for this record
stamp_time();
return 1;
}
// Run an iteration of the EOM (equations of motion)
int FGMagicCarpet::update( int multiloop ) {
// cout << "FGLaRCsim::update()" << endl;
double time_step = (1.0 / current_options.get_model_hz()) * multiloop;
// speed and distance traveled
double speed = controls.get_throttle( 0 ) * 2000; // meters/sec
double dist = speed * time_step;
double kts = speed * METER_TO_NM * 3600.0;
set_V_equiv_kts( kts );
set_V_ground_speed( kts );
// angle of turn
double turn_rate = controls.get_aileron() * FG_PI_4; // radians/sec
double turn = turn_rate * time_step;
// update euler angles
set_Euler_Angles( get_Phi(), get_Theta(), fmod(get_Psi() + turn, FG_2PI) );
// update (lon/lat) position
double lat2, lon2, az2;
geo_direct_wgs_84 ( get_Altitude(),
get_Latitude() * RAD_TO_DEG,
get_Longitude() * RAD_TO_DEG,
get_Psi() * RAD_TO_DEG,
dist, &lat2, &lon2, &az2 );
set_Longitude( lon2 * DEG_TO_RAD );
set_Latitude( lat2 * DEG_TO_RAD );
// cout << "lon error = " << fabs(end.x()*RAD_TO_DEG - lon2)
// << " lat error = " << fabs(end.y()*RAD_TO_DEG - lat2)
// << endl;
double sl_radius, lat_geoc;
fgGeodToGeoc( get_Latitude(), get_Altitude(), &sl_radius, &lat_geoc );
// update altitude
double real_climb_rate = -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;
set_Sea_level_radius( sl_radius * METER_TO_FEET);
set_Altitude( get_Altitude() + climb );
return 1;
}