]> git.mxchange.org Git - flightgear.git/blobdiff - src/Environment/environment_ctrl.cxx
Merge branch 'next' into durk-atc
[flightgear.git] / src / Environment / environment_ctrl.cxx
index 6e6f350c99296bb644c3674fdc1a162bf2304982..c182f06250cf250e62993e3b77f726c02e9b3992 100644 (file)
@@ -1,6 +1,7 @@
 // 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
 //
 //
 // 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.
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
-// $Id$
 
-#include <simgear/debug/logstream.hxx>
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
 
-#include <stdlib.h>
 #include <algorithm>
 
-#include <simgear/structure/exception.hxx>
-
 #include <Main/fg_props.hxx>
-
-#include "environment_mgr.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);
+    }
+};
 
-SG_USING_STD(sort);
-
-// FIXME, from options.cxx
-extern void fgSetupWind (double min_hdg, double max_hdg, double speed, double gust);
-
-
-\f
-////////////////////////////////////////////////////////////////////////
-// Implementation of FGEnvironmentCtrl abstract base class.
-////////////////////////////////////////////////////////////////////////
-
-FGEnvironmentCtrl::FGEnvironmentCtrl ()
-  : _environment(0),
-    _lon_deg(0),
-    _lat_deg(0),
-    _elev_ft(0)
-{
-}
-
-FGEnvironmentCtrl::~FGEnvironmentCtrl ()
-{
-}
-
-void
-FGEnvironmentCtrl::setEnvironment (FGEnvironment * environment)
-{
-  _environment = environment;
-}
-
-void
-FGEnvironmentCtrl::setLongitudeDeg (double lon_deg)
-{
-  _lon_deg = lon_deg;
-}
-
-void
-FGEnvironmentCtrl::setLatitudeDeg (double lat_deg)
-{
-  _lat_deg = lat_deg;
-}
-
-void
-FGEnvironmentCtrl::setElevationFt (double elev_ft)
-{
-  _elev_ft = elev_ft;
-}
+//////////////////////////////////////////////////////////////////////////////
 
-void
-FGEnvironmentCtrl::setPosition (double lon_deg, double lat_deg, double elev_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
 {
-  _lon_deg = lon_deg;
-  _lat_deg = lat_deg;
-  _elev_ft = elev_ft;
-}
-
-
-\f
-////////////////////////////////////////////////////////////////////////
-// Implementation of FGUserDefEnvironmentCtrl.
-////////////////////////////////////////////////////////////////////////
-
-FGUserDefEnvironmentCtrl::FGUserDefEnvironmentCtrl ()
-  : _base_wind_speed_node(0),
-    _gust_wind_speed_node(0),
-    _current_wind_speed_kt(0),
-    _delta_wind_speed_kt(0)
+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
 {
-}
-
-FGUserDefEnvironmentCtrl::~FGUserDefEnvironmentCtrl ()
+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
-FGUserDefEnvironmentCtrl::init ()
+void LayerTable::read(FGEnvironment * parent )
 {
-                               // Fill in some defaults.
-  if (!fgHasNode("/environment/params/base-wind-speed-kt"))
-    fgSetDouble("/environment/params/base-wind-speed-kt",
-               fgGetDouble("/environment/wind-speed-kt"));
-  if (!fgHasNode("/environment/params/gust-wind-speed-kt"))
-    fgSetDouble("/environment/params/gust-wind-speed-kt",
-               fgGetDouble("/environment/params/base-wind-speed-kt"));
-
-  _base_wind_speed_node =
-    fgGetNode("/environment/params/base-wind-speed-kt", true);
-  _gust_wind_speed_node =
-    fgGetNode("/environment/params/gust-wind-speed-kt", true);
-
-  _current_wind_speed_kt = _base_wind_speed_node->getDoubleValue();
-  _delta_wind_speed_kt = 0.1;
-}
+    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();
 
-void
-FGUserDefEnvironmentCtrl::update (double dt)
-{
-  double base_wind_speed = _base_wind_speed_node->getDoubleValue();
-  double gust_wind_speed = _gust_wind_speed_node->getDoubleValue();
-
-  if (gust_wind_speed < base_wind_speed) {
-      gust_wind_speed = base_wind_speed;
-      _gust_wind_speed_node->setDoubleValue(gust_wind_speed);
-  }
-
-  if (base_wind_speed == gust_wind_speed) {
-    _current_wind_speed_kt = base_wind_speed;
-  } else {
-    int rn = rand() % 128;
-    int sign = (_delta_wind_speed_kt < 0 ? -1 : 1);
-    double gust = _current_wind_speed_kt - base_wind_speed;
-    double incr = gust / 50;
-
-    if (rn == 0)
-      _delta_wind_speed_kt = - _delta_wind_speed_kt;
-    else if (rn < 4)
-      _delta_wind_speed_kt -= incr * sign;
-    else if (rn < 16)
-      _delta_wind_speed_kt += incr * sign;
-
-    _current_wind_speed_kt += _delta_wind_speed_kt;
-
-    if (_current_wind_speed_kt < base_wind_speed) {
-      _current_wind_speed_kt = base_wind_speed;
-      _delta_wind_speed_kt = 0.01;
-    } else if (_current_wind_speed_kt > gust_wind_speed) {
-      _current_wind_speed_kt = gust_wind_speed;
-      _delta_wind_speed_kt = -0.01;
+            // 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 (_environment != 0)
-    _environment->set_wind_speed_kt(_current_wind_speed_kt);
-}
-
-
-\f
-////////////////////////////////////////////////////////////////////////
-// Implementation of FGInterpolateEnvironmentCtrl.
-////////////////////////////////////////////////////////////////////////
-
-FGInterpolateEnvironmentCtrl::FGInterpolateEnvironmentCtrl ()
-{
-}
-
-FGInterpolateEnvironmentCtrl::~FGInterpolateEnvironmentCtrl ()
-{
-    unsigned int i;
-    for (i = 0; i < _boundary_table.size(); i++)
-        delete _boundary_table[i];
-    for (i = 0; i < _aloft_table.size(); i++)
-        delete _aloft_table[i];
-}
-
 
+    if( sort_required )
+        sort(begin(), end(), LayerTableBucket::lessThan);
 
-void
-FGInterpolateEnvironmentCtrl::init ()
-{
-    read_table(fgGetNode("/environment/config/boundary", true),
-               _boundary_table);
-    read_table(fgGetNode("/environment/config/aloft", true),
-               _aloft_table);
+    // 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_GENERAL, SG_ALERT, "Removing duplicate altitude entry in environment config for altitude " << at(n)->altitude_ft );
+            erase( begin() + n );
+        }
+    }
 }
 
-void
-FGInterpolateEnvironmentCtrl::reinit ()
+void LayerTable::Bind()
 {
-    unsigned int i;
-    for (i = 0; i < _boundary_table.size(); i++)
-        delete _boundary_table[i];
-    for (i = 0; i < _aloft_table.size(); i++)
-        delete _aloft_table[i];
-    _boundary_table.clear();
-    _aloft_table.clear();
-    init();
+    // 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
-FGInterpolateEnvironmentCtrl::read_table (const SGPropertyNode * node,
-                                          vector<bucket *> &table)
+void LayerTable::Unbind()
 {
-    for (int i = 0; i < node->nChildren(); i++) {
-        const SGPropertyNode * child = node->getChild(i);
-        if ( strcmp(child->getName(), "entry") == 0
-            && child->getStringValue("elevation-ft", "")[0] != '\0'
-            && ( child->getDoubleValue("elevation-ft") > 0.1 || i == 0 ) )
-       {
-            bucket * b = new bucket;
-            if (i > 0)
-                b->environment.copy(table[i-1]->environment);
-            b->environment.read(child);
-            b->altitude_ft = b->environment.get_elevation_ft();
-            table.push_back(b);
-        }
+    // 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 );
     }
-    sort(table.begin(), table.end());
 }
 
-void
-FGInterpolateEnvironmentCtrl::update (double delta_time_sec)
+void LayerTable::valueChanged( SGPropertyNode * node ) 
 {
-                                // FIXME
-    double altitude_ft = fgGetDouble("/position/altitude-ft");
-    double altitude_agl_ft = fgGetDouble("/position/altitude-agl-ft");
-    double boundary_transition =
-        fgGetDouble("/environment/config/boundary-transition-ft", 500);
-
-    // double ground_elevation_ft = altitude_ft - altitude_agl_ft;
-
-    int length = _boundary_table.size();
-
-    if (length > 0) {
-                                // boundary table
-        double boundary_limit = _boundary_table[length-1]->altitude_ft;
-        if (boundary_limit >= altitude_agl_ft) {
-            do_interpolate(_boundary_table, altitude_agl_ft,
-                           _environment);
-            return;
-        } else if ((boundary_limit + boundary_transition) >= altitude_agl_ft) {
-                                // both tables
-            do_interpolate(_boundary_table, altitude_agl_ft, &env1);
-            do_interpolate(_aloft_table, altitude_ft, &env2);
-            double fraction =
-                (altitude_agl_ft - boundary_limit) / boundary_transition;
-            interpolate(&env1, &env2, fraction, _environment);
-            return;
-        }
-    }
-
-                                // aloft table
-    do_interpolate(_aloft_table, altitude_ft, _environment);
+    // 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
-FGInterpolateEnvironmentCtrl::do_interpolate (vector<bucket *> &table,
-                                              double altitude_ft,
-                                              FGEnvironment * environment)
+
+void LayerTable::interpolate( double altitude_ft, FGEnvironment * result )
 {
-    int length = table.size();
+    int length = size();
     if (length == 0)
         return;
 
-                                // Boundary conditions
-    if ((length == 1) || (table[0]->altitude_ft >= altitude_ft)) {
-        environment->copy(table[0]->environment);
+    // Boundary conditions
+    if ((length == 1) || (at(0)->altitude_ft >= altitude_ft)) {
+        *result = at(0)->environment; // below bottom of table
         return;
-    } else if (table[length-1]->altitude_ft <= altitude_ft) {
-        environment->copy(table[length-1]->environment);
+    } else if (at(length-1)->altitude_ft <= altitude_ft) {
+        *result = at(length-1)->environment; // above top of table
         return;
-    }
-        
-                                // Search the interpolation table
-    for (int i = 0; i < length - 1; i++) {
-        if ((i == length - 1) || (table[i]->altitude_ft <= altitude_ft)) {
-                FGEnvironment * env1 = &(table[i]->environment);
-                FGEnvironment * env2 = &(table[i+1]->environment);
-                double fraction;
-                if (table[i]->altitude_ft == table[i+1]->altitude_ft)
-                    fraction = 1.0;
-                else
-                    fraction =
-                        ((altitude_ft - table[i]->altitude_ft) /
-                         (table[i+1]->altitude_ft - table[i]->altitude_ft));
-                interpolate(env1, env2, fraction, environment);
-
-                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);
 }
 
-bool
-FGInterpolateEnvironmentCtrl::bucket::operator< (const bucket &b) const
-{
-    return (altitude_ft < b.altitude_ft);
-}
-
-
-\f
-////////////////////////////////////////////////////////////////////////
-// Implementation of FGMetarEnvironmentCtrl.
-////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////
 
-FGMetarEnvironmentCtrl::FGMetarEnvironmentCtrl ()
-    : env( new FGInterpolateEnvironmentCtrl ),
-      _icao( strdup( fgGetString("/sim/presets/airport-id") ) )
+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 ) )
 {
 }
 
-FGMetarEnvironmentCtrl::~FGMetarEnvironmentCtrl ()
+void LayerInterpolateControllerImplementation::init ()
 {
-    if (_icao) {
-      free(_icao);
-      _icao = NULL;
-    }
-
-   delete env;
-   env = NULL;
+    _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
-FGMetarEnvironmentCtrl::init ()
+void LayerInterpolateControllerImplementation::reinit ()
 {
-    if (_icao != NULL) {
-        free(_icao);
-        _icao = NULL;
-    }
-
-    fetch_data(_icao);
-    fgSetupWind( fgGetDouble("/environment/metar/base-wind-range-from"),
-                 fgGetDouble("/environment/metar/base-wind-range-to"),
-                 fgGetDouble("/environment/metar/base-wind-speed-kt"),
-                 fgGetDouble("/environment/metar/gust-wind-speed-kt") );
-
-    fgSetDouble("/environment/visibility-m",
-        fgGetDouble("/environment/metar/min-visibility-m"));
-    fgSetDouble("/environment/temperature-degc",
-        fgGetDouble("/environment/metar/temperature-degc"));
-    fgSetDouble("/environment/dewpoint-degc",
-        fgGetDouble("/environment/metar/dewpoint-degc"));
-    fgSetDouble("/environment/pressure-inhg",
-        fgGetDouble("/environment/metar/pressure-inhg"));
-
-    env->init();
+    _boundary_table.Unbind();
+    _aloft_table.Unbind();
+    init();
+    postinit();
 }
 
-void
-FGMetarEnvironmentCtrl::reinit ()
+void LayerInterpolateControllerImplementation::postinit()
 {
-#if 0
-    if (_icao != NULL) {
-        free(_icao);
-        _icao = NULL;
-    }
-
-    fetch_data(_icao);
-    fgSetupWind( fgGetDouble("/environment/metar/base-wind-range-from"),
-                 fgGetDouble("/environment/metar/base-wind-range-to"),
-                 fgGetDouble("/environment/metar/base-wind-speed-kt"),
-                 fgGetDouble("/environment/metar/gust-wind-speed-kt") );
-
-    fgSetDouble("/environment/visibility-m",
-        fgGetDouble("/environment/metar/min-visibility-m"));
-    fgSetDouble("/environment/pressure-inhg",
-        fgGetDouble("/environment/metar/pressure-inhg"));
-
-    // FIXME: The following seem to egt overriden?
-    fgSetDouble("/environment/temperature-degc",
-        fgGetDouble("/environment/metar/temperature-degc"));
-    fgSetDouble("/environment/dewpoint-degc",
-        fgGetDouble("/environment/metar/dewpoint-degc"));
-#endif
-
-    env->reinit();
+    // we get here after 1. bind() and 2. init() was called by fg_init
+    _boundary_table.Bind();
+    _aloft_table.Bind();
 }
 
-void
-FGMetarEnvironmentCtrl::update(double delta_time_sec)
+void LayerInterpolateControllerImplementation::bind()
 {
-    env->update(delta_time_sec);
+    // 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
-FGMetarEnvironmentCtrl::setEnvironment (FGEnvironment * environment)
+void LayerInterpolateControllerImplementation::unbind()
 {
-    env->setEnvironment(environment);
+    _boundary_table.Unbind();
+    _aloft_table.Unbind();
+    _tiedProperties.Untie();
+    _environment.Untie();
 }
 
-void
-FGMetarEnvironmentCtrl::fetch_data (const char *icao)
+void LayerInterpolateControllerImplementation::update (double delta_time_sec)
 {
-    char s[128];
-    double d, dt;
-    int i;
-
-    if ((icao == NULL) && (_icao == NULL)) {
-        _icao = strdup( fgGetString("/sim/presets/airport-id") );
-
-    } else if (icao != NULL) {
-        if (_icao != NULL)
-            free(_icao);
-
-        _icao = strdup(icao);
-    }
-
-    SGMetar *m;
-    try {
-        m = new SGMetar(_icao);
-    } catch (const sg_io_exception& e) {
-        SG_LOG( SG_GENERAL, SG_WARN, "Error fetching live weather data: "
-                                      << e.getFormattedMessage().c_str() );
+    if( !_enabled || delta_time_sec <= SGLimitsd::min() )
         return;
-    }
-
-    d = m->getMinVisibility().getVisibility_m();
-    d = (d != SGMetarNaN) ? d : 10000;
-    fgSetDouble("/environment/metar/min-visibility-m", d);
 
-    dt =  m->getMaxVisibility().getVisibility_m();
-    d = (dt != SGMetarNaN) ? dt : d;
-    fgSetDouble("/environment/metar/max-visibility-m", d);
+    double altitude_ft = _altitude_n->getDoubleValue();
+    double altitude_agl_ft = _altitude_agl_n->getDoubleValue();
 
-    SGMetarVisibility *dirvis = m->getDirVisibility();
-    for (i = 0; i < 8; i++, dirvis++) {
-        const char *min = "/environment/metar/visibility[%d]/min-m";
-        const char *max = "/environment/metar/visibility[%d]/max-m";
-        char s[128];
+    // avoid div by zero later on and init with a default value if not given
+    if( _boundary_transition <= SGLimitsd::min() )
+        _boundary_transition = 500;
 
-        d = dirvis->getVisibility_m();
-        d = (d != SGMetarNaN) ? d : 10000;
+    int length = _boundary_table.size();
 
-        snprintf(s, 128, min, i);
-        fgSetDouble(s, d);
-        snprintf(s, 128, max, i);
-        fgSetDouble(s, d);
-    }
+    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);
+}
 
-    i = m->getWindDir();
-    if ( i == -1 ) {
-        fgSetInt("/environment/metar/base-wind-range-from",
-                    m->getWindRangeFrom() );
-        fgSetInt("/environment/metar/base-wind-range-to",
-                    m->getWindRangeTo() );
-    } else {
-        fgSetInt("/environment/metar/base-wind-range-from", i);
-        fgSetInt("/environment/metar/base-wind-range-to", i);
-    }
-    fgSetDouble("/environment/metar/base-wind-speed-kt",
-                m->getWindSpeed_kt() );
-
-    d = m->getGustSpeed_kt();
-    d = (d != SGMetarNaN) ? d : 0.0;
-    fgSetDouble("/environment/metar/gust-wind-speed-kt", d);
-
-    d = m->getTemperature_C();
-    if (d != SGMetarNaN) {
-        dt = m->getDewpoint_C();
-        dt = (dt != SGMetarNaN) ? dt : 0.0;
-        fgSetDouble("/environment/metar/dewpoint-degc", dt);
-        fgSetDouble("/environment/metar/rel-humidity-norm",
-                    m->getRelHumidity() );
-    }   
-    d = (d != SGMetarNaN) ? d : 15.0;
-    fgSetDouble("/environment/metar/temperature-degc", d);
-
-    d = m->getPressure_inHg();
-    d = (d != SGMetarNaN) ? d : 30.0;
-    fgSetDouble("/environment/metar/pressure-inhg", d);
-
-    vector<SGMetarCloud> cv = m->getClouds();
-    vector<SGMetarCloud>::iterator cloud;
-
-    const char *cl = "/environment/clouds/layer[%i]";
-    for (i = 0, cloud = cv.begin(); cloud != cv.end(); cloud++, i++) {
-        const char *coverage_string[5] = 
-            { "clear", "few", "scattered", "broken", "overcast" };
-        const double thickness[5] = { 0, 65, 600,750, 1000};
-        int q;
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/coverage", 128);
-        q = cloud->getCoverage();
-        q = (q != -1 ) ? q : 0;
-        fgSetString(s, coverage_string[q] );
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/elevation-ft", 128);
-        d = cloud->getAltitude_ft();
-        d = (d != SGMetarNaN) ? d : -9999;
-        fgSetDouble(s, d);
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/thickness-ft", 128);
-        fgSetDouble(s, thickness[q]);
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/span-m", 128);
-        fgSetDouble(s, 40000.0);
-    }
-    for (; i < FGEnvironmentMgr::MAX_CLOUD_LAYERS; i++) {
-        snprintf(s, 128, cl, i);
-        strncat(s, "/coverage", 128);
-        fgSetString(s, "clear");
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/elevation-ft", 128);
-        fgSetDouble(s, -9999);
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/thickness-ft", 128);
-        fgSetDouble(s, 0);
-
-        snprintf(s, 128, cl, i);
-        strncat(s, "/span-m", 128);
-        fgSetDouble(s, 40000.0);
-    }
+//////////////////////////////////////////////////////////////////////////////
 
-    delete m;
+LayerInterpolateController * LayerInterpolateController::createInstance( SGPropertyNode_ptr rootNode )
+{
+    return new LayerInterpolateControllerImplementation( rootNode );
 }
 
+//////////////////////////////////////////////////////////////////////////////
 
-// end of environment_ctrl.cxx
+} // namespace