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flightgear/src/Environment/environment_ctrl.cxx
2012-05-05 00:56:29 +02:00

350 lines
12 KiB
C++

// environment_ctrl.cxx -- manager for natural environment information.
//
// Written by David Megginson, started February 2002.
// Partly rewritten by Torsten Dreyer, August 2010.
//
// Copyright (C) 2002 David Megginson - david@megginson.com
//
// 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.
//
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <algorithm>
#include <simgear/math/SGMath.hxx>
#include <Main/fg_props.hxx>
#include "environment_ctrl.hxx"
#include "environment.hxx"
namespace Environment {
/**
* @brief Describes an element of a LayerTable. A defined environment at a given altitude.
*/
struct LayerTableBucket {
double altitude_ft;
FGEnvironment environment;
inline bool operator< (const LayerTableBucket &b) const {
return (altitude_ft < b.altitude_ft);
}
/**
* @brief LessThan predicate for bucket pointers.
*/
static bool lessThan(LayerTableBucket *a, LayerTableBucket *b) {
return (a->altitude_ft) < (b->altitude_ft);
}
};
//////////////////////////////////////////////////////////////////////////////
/**
* @brief Models a column of our atmosphere by stacking a number of environments above
* each other
*/
class LayerTable : public std::vector<LayerTableBucket *>, public SGPropertyChangeListener
{
public:
LayerTable( SGPropertyNode_ptr rootNode ) :
_rootNode(rootNode) {}
~LayerTable();
/**
* @brief Read the environment column from properties relative to the given root node
* @param environment A template environment to copy values from, not given in the configuration
*/
void read( FGEnvironment * parent = NULL );
/**
*@brief Interpolate and write environment values for a given altitude
*@param altitude_ft The altitude for the desired environment
*@environment the destination to write the resulting environment properties to
*/
void interpolate(double altitude_ft, FGEnvironment * environment);
/**
*@brief Bind all environments properties to property nodes and initialize the listeners
*/
void Bind();
/**
*@brief Unbind all environments properties from property nodes and deregister listeners
*/
void Unbind();
private:
/**
* @brief Implementation of SGProertyChangeListener::valueChanged()
* Takes care of consitent sea level pressure for the entire column
*/
void valueChanged( SGPropertyNode * node );
SGPropertyNode_ptr _rootNode;
};
//////////////////////////////////////////////////////////////////////////////
/**
*@brief Implementation of the LayerIterpolateController
*/
class LayerInterpolateControllerImplementation : public LayerInterpolateController
{
public:
LayerInterpolateControllerImplementation( SGPropertyNode_ptr rootNode );
virtual void init ();
virtual void reinit ();
virtual void postinit();
virtual void bind();
virtual void unbind();
virtual void update (double delta_time_sec);
private:
SGPropertyNode_ptr _rootNode;
bool _enabled;
double _boundary_transition;
SGPropertyNode_ptr _altitude_n;
SGPropertyNode_ptr _altitude_agl_n;
LayerTable _boundary_table;
LayerTable _aloft_table;
FGEnvironment _environment;
simgear::TiedPropertyList _tiedProperties;
};
//////////////////////////////////////////////////////////////////////////////
LayerTable::~LayerTable()
{
for( iterator it = begin(); it != end(); it++ )
delete (*it);
}
void LayerTable::read(FGEnvironment * parent )
{
double last_altitude_ft = 0.0;
double sort_required = false;
size_t i;
for (i = 0; i < (size_t)_rootNode->nChildren(); i++) {
const SGPropertyNode * child = _rootNode->getChild(i);
if ( child->getNameString() == "entry"
&& child->getStringValue("elevation-ft", "")[0] != '\0'
&& ( child->getDoubleValue("elevation-ft") > 0.1 || i == 0 ) )
{
LayerTableBucket * b;
if( i < size() ) {
// recycle existing bucket
b = at(i);
} else {
// more nodes than buckets in table, add a new one
b = new LayerTableBucket;
push_back(b);
}
if (i == 0 && parent != NULL )
b->environment = *parent;
if (i > 0)
b->environment = at(i-1)->environment;
b->environment.read(child);
b->altitude_ft = b->environment.get_elevation_ft();
// check, if altitudes are in ascending order
if( b->altitude_ft < last_altitude_ft )
sort_required = true;
last_altitude_ft = b->altitude_ft;
}
}
// remove leftover buckets
while( size() > i ) {
LayerTableBucket * b = *(end() - 1);
delete b;
pop_back();
}
if( sort_required )
sort(begin(), end(), LayerTableBucket::lessThan);
// cleanup entries with (almost)same altitude
for( size_type n = 1; n < size(); n++ ) {
if( fabs(at(n)->altitude_ft - at(n-1)->altitude_ft ) < 1 ) {
SG_LOG( SG_ENVIRONMENT, SG_ALERT, "Removing duplicate altitude entry in environment config for altitude " << at(n)->altitude_ft );
erase( begin() + n );
}
}
}
void LayerTable::Bind()
{
// tie all environments to ~/entry[n]/xxx
// register this as a changelistener of ~/entry[n]/pressure-sea-level-inhg
for( unsigned i = 0; i < size(); i++ ) {
SGPropertyNode_ptr baseNode = _rootNode->getChild("entry", i, true );
at(i)->environment.Tie( baseNode );
baseNode->getNode( "pressure-sea-level-inhg", true )->addChangeListener( this );
}
}
void LayerTable::Unbind()
{
// untie all environments to ~/entry[n]/xxx
// deregister this as a changelistener of ~/entry[n]/pressure-sea-level-inhg
for( unsigned i = 0; i < size(); i++ ) {
SGPropertyNode_ptr baseNode = _rootNode->getChild("entry", i, true );
at(i)->environment.Untie();
baseNode->getNode( "pressure-sea-level-inhg", true )->removeChangeListener( this );
}
}
void LayerTable::valueChanged( SGPropertyNode * node )
{
// Make sure all environments in our column use the same sea level pressure
double value = node->getDoubleValue();
for( iterator it = begin(); it != end(); it++ )
(*it)->environment.set_pressure_sea_level_inhg( value );
}
void LayerTable::interpolate( double altitude_ft, FGEnvironment * result )
{
int length = size();
if (length == 0)
return;
// Boundary conditions
if ((length == 1) || (at(0)->altitude_ft >= altitude_ft)) {
*result = at(0)->environment; // below bottom of table
return;
} else if (at(length-1)->altitude_ft <= altitude_ft) {
*result = at(length-1)->environment; // above top of table
return;
}
// Search the interpolation table
int layer;
for ( layer = 1; // can't be below bottom layer, handled above
layer < length && at(layer)->altitude_ft <= altitude_ft;
layer++);
FGEnvironment & env1 = (at(layer-1)->environment);
FGEnvironment & env2 = (at(layer)->environment);
// two layers of same altitude were sorted out in read_table
double fraction = ((altitude_ft - at(layer-1)->altitude_ft) /
(at(layer)->altitude_ft - at(layer-1)->altitude_ft));
env1.interpolate(env2, fraction, result);
}
//////////////////////////////////////////////////////////////////////////////
LayerInterpolateControllerImplementation::LayerInterpolateControllerImplementation( SGPropertyNode_ptr rootNode ) :
_rootNode( rootNode ),
_enabled(true),
_boundary_transition(0.0),
_altitude_n( fgGetNode("/position/altitude-ft", true)),
_altitude_agl_n( fgGetNode("/position/altitude-agl-ft", true)),
_boundary_table( rootNode->getNode("boundary", true ) ),
_aloft_table( rootNode->getNode("aloft", true ) )
{
}
void LayerInterpolateControllerImplementation::init ()
{
_boundary_table.read();
// pass in a pointer to the environment of the last bondary layer as
// a starting point
_aloft_table.read(&(*(_boundary_table.end()-1))->environment);
}
void LayerInterpolateControllerImplementation::reinit ()
{
_boundary_table.Unbind();
_aloft_table.Unbind();
init();
postinit();
}
void LayerInterpolateControllerImplementation::postinit()
{
// we get here after 1. bind() and 2. init() was called by fg_init
_boundary_table.Bind();
_aloft_table.Bind();
}
void LayerInterpolateControllerImplementation::bind()
{
// don't bind the layer tables here, because they have not been read in yet.
_environment.Tie( _rootNode->getNode( "interpolated", true ) );
_tiedProperties.Tie( _rootNode->getNode("enabled", true), &_enabled );
_tiedProperties.Tie( _rootNode->getNode("boundary-transition-ft", true ), &_boundary_transition );
}
void LayerInterpolateControllerImplementation::unbind()
{
_boundary_table.Unbind();
_aloft_table.Unbind();
_tiedProperties.Untie();
_environment.Untie();
}
void LayerInterpolateControllerImplementation::update (double delta_time_sec)
{
if( !_enabled || delta_time_sec <= SGLimitsd::min() )
return;
double altitude_ft = _altitude_n->getDoubleValue();
double altitude_agl_ft = _altitude_agl_n->getDoubleValue();
// avoid div by zero later on and init with a default value if not given
if( _boundary_transition <= SGLimitsd::min() )
_boundary_transition = 500;
int length = _boundary_table.size();
if (length > 0) {
// If a boundary table is defined, get the top of the boundary layer
double boundary_limit = _boundary_table[length-1]->altitude_ft;
if (boundary_limit >= altitude_agl_ft) {
// If current altitude is below top of boundary layer, interpolate
// only in boundary layer
_boundary_table.interpolate(altitude_agl_ft, &_environment);
return;
} else if ((boundary_limit + _boundary_transition) >= altitude_agl_ft) {
// If current altitude is above top of boundary layer and within the
// transition altitude, interpolate boundary and aloft layers
FGEnvironment env1, env2;
_boundary_table.interpolate( altitude_agl_ft, &env1);
_aloft_table.interpolate(altitude_ft, &env2);
double fraction = (altitude_agl_ft - boundary_limit) / _boundary_transition;
env1.interpolate(env2, fraction, &_environment);
return;
}
}
// If no boundary layer is defined or altitude is above top boundary-layer plus boundary-transition
// altitude, use only the aloft table
_aloft_table.interpolate( altitude_ft, &_environment);
}
//////////////////////////////////////////////////////////////////////////////
LayerInterpolateController * LayerInterpolateController::createInstance( SGPropertyNode_ptr rootNode )
{
return new LayerInterpolateControllerImplementation( rootNode );
}
//////////////////////////////////////////////////////////////////////////////
} // namespace