RelativePath="..\..\..\src\Environment\presets.hxx"\r
>\r
</File>\r
+ <File\r
+ RelativePath="..\..\..\src\Environment\gravity.cxx"\r
+ >\r
+ </File>\r
+ <File\r
+ RelativePath="..\..\..\src\Environment\gravity.hxx"\r
+ >\r
+ </File>\r
</Filter>\r
<Filter\r
Name="Lib_Model"\r
ridge_lift.cxx
terrainsampler.cxx
presets.cxx
+ gravity.cxx
)
flightgear_component(Environment "${SOURCES}")
ridge_lift.cxx ridge_lift.hxx \
ephemeris.cxx ephemeris.hxx \
terrainsampler.cxx terrainsampler.cxx \
- presets.cxx presets.hxx
+ presets.cxx presets.hxx \
+ gravity.cxx gravity.hxx
INCLUDES = -I$(top_srcdir) -I$(top_srcdir)/src
#include "ridge_lift.hxx"
#include "terrainsampler.hxx"
#include "Airports/simple.hxx"
+#include "gravity.hxx"
class SGSky;
extern SGSky *thesky;
_environment(new FGEnvironment()),
fgClouds(new FGClouds()),
_cloudLayersDirty(true),
- _altitudeNode(fgGetNode("/position/altitude-ft", true)),
+ _altitude_n(fgGetNode("/position/altitude-ft", true)),
_longitude_n(fgGetNode( "/position/longitude-deg", true )),
_latitude_n( fgGetNode( "/position/latitude-deg", true )),
_positionTimeToLive(0.0)
SGSubsystemGroup::init();
fgClouds->Init();
+ // FIXME: is this really part of the environment_mgr?
// Initialize the longitude, latitude and altitude to the initial position
// of the aircraft so that the atmospheric properties (pressure, temperature
// and density) can be initialized accordingly.
- _altitudeNode->setDoubleValue(fgGetDouble("/sim/presets/altitude-ft"));
+ _altitude_n->setDoubleValue(fgGetDouble("/sim/presets/altitude-ft"));
_longitude_n->setDoubleValue(fgGetDouble("/sim/presets/longitude-deg"));
_latitude_n->setDoubleValue(fgGetDouble("/sim/presets/latitude-deg"));
}
{
SGSubsystemGroup::update(dt);
- _environment->set_elevation_ft( _altitudeNode->getDoubleValue() );
+ _environment->set_elevation_ft( _altitude_n->getDoubleValue() );
simgear::Particles::setWindFrom( _environment->get_wind_from_heading_deg(),
_environment->get_wind_speed_kt() );
fgClouds->set_update_event( fgClouds->get_update_event()+1 );
}
+
+ fgSetDouble( "/environment/gravitational-acceleration-mps2",
+ Environment::Gravity::instance()->getGravity(SGGeod::fromDegFt(
+ _longitude_n->getDoubleValue(),
+ _latitude_n->getDoubleValue(),
+ _altitude_n->getDoubleValue()
+ )));
+
_positionTimeToLive -= dt;
if( _positionTimeToLive <= 0.0 )
{
FGEnvironment * _environment; // always the same, for now
FGClouds *fgClouds;
bool _cloudLayersDirty;
- SGPropertyNode_ptr _altitudeNode;
+ SGPropertyNode_ptr _altitude_n;
SGPropertyNode_ptr _longitude_n;
SGPropertyNode_ptr _latitude_n;
double _positionTimeToLive;
--- /dev/null
+// gravity.cxx -- interface for earth gravitational model
+//
+// Written by Torsten Dreyer, June 2011
+//
+// Copyright (C) 2011 Torsten Dreyer - torsten (at) t3r _dot_ de
+//
+// 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.
+//
+
+#include "gravity.hxx"
+
+#include <simgear/structure/exception.hxx>
+
+namespace Environment {
+
+/*
+http://de.wikipedia.org/wiki/Normalschwereformel
+*/
+class Somigliana : public Gravity {
+public:
+ Somigliana();
+ virtual ~Somigliana();
+ virtual double getGravity( const SGGeod & position ) const;
+};
+
+Somigliana::Somigliana()
+{
+}
+
+Somigliana::~Somigliana()
+{
+}
+#include <stdio.h>
+
+double Somigliana::getGravity( const SGGeod & position ) const
+{
+// Geodetic Reference System 1980 parameter
+#define A 6378137.0 // equatorial radius of earth
+#define B 6356752.3141 // semiminor axis
+#define AGA (A*9.7803267715) // A times normal gravity at equator
+#define BGB (B*9.8321863685) // B times normal gravity at pole
+ // forumla of Somigliana
+ double cosphi = ::cos(position.getLatitudeRad());
+ double cos2phi = cosphi*cosphi;
+ double sinphi = ::sin(position.getLatitudeRad());
+ double sin2phi = sinphi*sinphi;
+ double g0 = (AGA * cos2phi + BGB * sin2phi) / sqrt( A*A*cos2phi+B*B*sin2phi );
+
+ static const double k1 = 3.15704e-7;
+ static const double k2 = 2.10269e-9;
+ static const double k3 = 7.37452e-14;
+
+ double h = position.getElevationM();
+
+ return g0*(1-(k1-k2*sin2phi)*h+k3*h*h);
+}
+
+static Somigliana _somigliana;
+
+/* --------------------- Gravity implementation --------------------- */
+Gravity * Gravity::_instance = NULL;
+
+Gravity::~Gravity()
+{
+}
+
+//double Gravity::getGravity( const SGGeoc & position ) = 0;
+
+const Gravity * Gravity::instance()
+{
+ if( _instance == NULL )
+ _instance = &_somigliana;
+
+ return _instance;
+}
+
+} // namespace
--- /dev/null
+// gravity.hxx -- interface for earth gravitational model
+//
+// Written by Torsten Dreyer, June 2011
+//
+// Copyright (C) 2011 Torsten Dreyer - torsten (at) t3r _dot_ de
+//
+// 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.
+//
+
+#ifndef __GRAVITY_HXX
+#define __GRAVITY_HXX
+
+#include <simgear/math/SGMath.hxx>
+
+namespace Environment {
+
+class Gravity
+{
+public:
+ virtual ~Gravity();
+ virtual double getGravity( const SGGeod & position ) const = 0;
+
+ const static Gravity * instance();
+
+private:
+ static Gravity * _instance;
+
+};
+
+} // namespace
+#endif // __GRAVITY_HXX
projects / flightgear.git / commitdiff