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Optimise NavCache airport query
[flightgear.git] / src / AIModel / AIAircraft.cxx
index 69c519f63d9824231fd4d33998b48bec2a980467..5e803ef5e159b81e6c3934a73c060f13ab96a16a 100644 (file)
 #  include <config.h>
 #endif
 
-#include <simgear/route/waypoint.hxx>
 #include <Main/fg_props.hxx>
 #include <Main/globals.hxx>
-#include <Main/viewer.hxx>
 #include <Scenery/scenery.hxx>
 #include <Scenery/tilemgr.hxx>
 #include <Airports/dynamics.hxx>
-#include <Airports/simple.hxx>
+#include <Airports/airport.hxx>
+#include <Main/util.hxx>
+
+#include <simgear/structure/exception.hxx>
 
 #include <string>
-#include <math.h>
-#include <time.h>
-
-#ifdef _MSC_VER
-#  include <float.h>
-#  define finite _finite
-#elif defined(__sun) || defined(sgi)
-#  include <ieeefp.h>
-#endif
+#include <cmath>
+#include <ctime>
 
-using std::string;
+// defined in AIShip.cxx
+extern double fgIsFinite(double x);
 
 #include "AIAircraft.hxx"
 #include "performancedata.hxx"
 #include "performancedb.hxx"
 #include <signal.h>
 
+using std::string;
+using std::cerr;
+using std::endl;
+
 //#include <Airports/trafficcontroller.hxx>
 
 FGAIAircraft::FGAIAircraft(FGAISchedule *ref) :
@@ -85,6 +84,7 @@ FGAIAircraft::FGAIAircraft(FGAISchedule *ref) :
     headingError = 0;
     minBearing = 360;
     speedFraction =1.0;
+    prev_dist_to_go = 0.0;
 
     holdPos = false;
     needsTaxiClearance = false;
@@ -93,6 +93,9 @@ FGAIAircraft::FGAIAircraft(FGAISchedule *ref) :
     _performance = 0; //TODO initialize to JET_TRANSPORT from PerformanceDB
     dt = 0;
     takeOffStatus = 0;
+
+    trackCache.remainingLength = 0;
+    trackCache.startWptName = "-";
 }
 
 
@@ -109,7 +112,7 @@ void FGAIAircraft::readFromScenario(SGPropertyNode* scFileNode) {
 
     FGAIBase::readFromScenario(scFileNode);
 
-    setPerformance(scFileNode->getStringValue("class", "jet_transport"));
+    setPerformance("", scFileNode->getStringValue("class", "jet_transport"));
     setFlightPlan(scFileNode->getStringValue("flightplan"),
                   scFileNode->getBoolValue("repeat", false));
     setCallSign(scFileNode->getStringValue("callsign"));
@@ -119,39 +122,28 @@ void FGAIAircraft::readFromScenario(SGPropertyNode* scFileNode) {
 void FGAIAircraft::bind() {
     FGAIBase::bind();
 
-    props->tie("controls/gear/gear-down",
-               SGRawValueMethods<FGAIAircraft,bool>(*this,
-                                                    &FGAIAircraft::_getGearDown));
-    props->tie("transponder-id",
-               SGRawValueMethods<FGAIAircraft,const char*>(*this,
-                                                    &FGAIAircraft::_getTransponderCode));
-}
-
-
-void FGAIAircraft::unbind() {
-    FGAIBase::unbind();
-
-    props->untie("controls/gear/gear-down");
-    props->untie("transponder-id");
+    tie("transponder-id",
+        SGRawValueMethods<FGAIAircraft,const char*>(*this,
+                &FGAIAircraft::_getTransponderCode));
 }
 
-
 void FGAIAircraft::update(double dt) {
     FGAIBase::update(dt);
     Run(dt);
     Transform();
 }
 
-void FGAIAircraft::setPerformance(const std::string& acclass) {
-     static PerformanceDB perfdb; //TODO make it a global service
-     setPerformance(perfdb.getDataFor(acclass));
-  }
-
+void FGAIAircraft::setPerformance(const std::string& acType, const std::string& acclass)
+{
+  static PerformanceDB perfdb; //TODO make it a global service
+  _performance = perfdb.getDataFor(acType, acclass);
+}
 
+#if 0
  void FGAIAircraft::setPerformance(PerformanceData *ps) {
      _performance = ps;
   }
-
+#endif
 
  void FGAIAircraft::Run(double dt) {
       FGAIAircraft::dt = dt;
@@ -169,24 +161,23 @@ void FGAIAircraft::setPerformance(const std::string& acclass) {
 
      handleATCRequests(); // ATC also has a word to say
      updateSecondaryTargetValues(); // target roll, vertical speed, pitch
-     updateActualState(); 
-    // We currently have one situation in which an AIAircraft object is used that is not attached to the 
+     updateActualState();
+#if 0
+   // 25/11/12 - added but disabled, since setting properties isn't
+   // affecting the AI-model as expected.
+     updateModelProperties(dt);
+#endif
+   
+    // We currently have one situation in which an AIAircraft object is used that is not attached to the
     // AI manager. In this particular case, the AIAircraft is used to shadow the user's aircraft's behavior in the AI world.
     // Since we perhaps don't want a radar entry of our own aircraft, the following conditional should probably be adequate
     // enough
-     if (manager)
+     if (manager){
         UpdateRadar(manager);
-     checkVisibility();
+       invisible = !manager->isVisible(pos);
+     }
   }
 
-void FGAIAircraft::checkVisibility() 
-{
-  double visibility_meters = fgGetDouble("/environment/visibility-m");
-  FGViewer* vw = globals->get_current_view();
-  invisible = (SGGeodesy::distanceM(vw->getPosition(), pos) > visibility_meters);
-}
-
-
 
 void FGAIAircraft::AccelTo(double speed) {
     tgt_speed = speed;
@@ -233,16 +224,26 @@ double FGAIAircraft::sign(double x) {
 }
 
 
-void FGAIAircraft::setFlightPlan(const std::string& flightplan, bool repeat) {
-    if (!flightplan.empty()) {
-        FGAIFlightPlan* fp = new FGAIFlightPlan(flightplan);
+void FGAIAircraft::setFlightPlan(const std::string& flightplan, bool repeat)
+{
+    if (flightplan.empty()) {
+        // this is the case for Nasal-scripted aircraft
+        return;
+    }
+    
+    FGAIFlightPlan* fp = new FGAIFlightPlan(flightplan);
+    if (fp->isValidPlan()) {
         fp->setRepeat(repeat);
         SetFlightPlan(fp);
+    } else {
+        SG_LOG(SG_AI, SG_WARN, "setFlightPlan: invalid flightplan specified:" << flightplan);
+        delete fp;
     }
 }
 
 
-void FGAIAircraft::SetFlightPlan(FGAIFlightPlan *f) {
+void FGAIAircraft::SetFlightPlan(FGAIFlightPlan *f)
+{
     delete fp;
     fp = f;
 }
@@ -284,6 +285,12 @@ void FGAIAircraft::ProcessFlightPlan( double dt, time_t now ) {
         curr = fp->getCurrentWaypoint();
         next = fp->getNextWaypoint();
     }
+    if (!curr)
+    {
+        // Oops! FIXME
+        return;
+    }
+
     if (! leadPointReached(curr)) {
         controlHeading(curr);
         controlSpeed(curr, next);
@@ -379,7 +386,7 @@ double FGAIAircraft::calcVerticalSpeed(double vert_ft, double dist_m, double spe
 {
     // err is negative when we passed too high
     double vert_m = vert_ft * SG_FEET_TO_METER;
-    double err_m  = err     * SG_FEET_TO_METER;
+    //double err_m  = err     * SG_FEET_TO_METER;
     //double angle = atan2(vert_m, dist_m);
     double speedMs = (speed * SG_NM_TO_METER) / 3600;
     //double vs = cos(angle) * speedMs; // Now in m/s
@@ -448,12 +455,6 @@ void FGAIAircraft::checkTcas(void)
 void FGAIAircraft::initializeFlightPlan() {
 }
 
-
-bool FGAIAircraft::_getGearDown() const {
-    return _performance->gearExtensible(this);
-}
-
-
 const char * FGAIAircraft::_getTransponderCode() const {
   return transponderCode.c_str();
 }
@@ -520,10 +521,8 @@ void FGAIAircraft::getGroundElev(double dt) {
 
     // Only do the proper hitlist stuff if we are within visible range of the viewer.
     if (!invisible) {
-        double visibility_meters = fgGetDouble("/environment/visibility-m");
-        FGViewer* vw = globals->get_current_view();
-        
-        if (SGGeodesy::distanceM(vw->getPosition(), pos) > visibility_meters) {
+        double visibility_meters = fgGetDouble("/environment/visibility-m");        
+        if (SGGeodesy::distanceM(globals->get_view_position(), pos) > visibility_meters) {
             return;
         }
 
@@ -560,54 +559,61 @@ void FGAIAircraft::doGroundAltitude() {
 
 
 void FGAIAircraft::announcePositionToController() {
-    if (trafficRef) {
-        int leg = fp->getLeg();
-
-        // Note that leg has been incremented after creating the current leg, so we should use
-        // leg numbers here that are one higher than the number that is used to create the leg
-        // NOTE: As of July, 30, 2011, the post-creation leg updating is no longer happening. 
-        // Leg numbers are updated only once the aircraft passes the last waypoint created for that legm so I should probably just use
-        // the original leg numbers here!
-        switch (leg) {
-          case 1:              // Startup and Push back
-            if (trafficRef->getDepartureAirport()->getDynamics())
-                controller = trafficRef->getDepartureAirport()->getDynamics()->getStartupController();
-            break;
-        case 2:              // Taxiing to runway
-            if (trafficRef->getDepartureAirport()->getDynamics()->getGroundNetwork()->exists())
-                controller = trafficRef->getDepartureAirport()->getDynamics()->getGroundNetwork();
-            break;
-        case 3:              //Take off tower controller
-            if (trafficRef->getDepartureAirport()->getDynamics()) {
-                controller = trafficRef->getDepartureAirport()->getDynamics()->getTowerController();
-                towerController = 0;
-            } else {
-                cerr << "Error: Could not find Dynamics at airport : " << trafficRef->getDepartureAirport()->getId() << endl;
-            }
-            break;
-        case 6:
-             if (trafficRef->getDepartureAirport()->getDynamics()) {
-                 controller = trafficRef->getArrivalAirport()->getDynamics()->getApproachController();
-              }
-              break;
-        case 8:              // Taxiing for parking
-            if (trafficRef->getArrivalAirport()->getDynamics()->getGroundNetwork()->exists())
-                controller = trafficRef->getArrivalAirport()->getDynamics()->getGroundNetwork();
-            break;
-        default:
-            controller = 0;
-            break;
+    if (!trafficRef) {
+        return;
+    }
+    
+    int leg = fp->getLeg();
+    if (!fp->getCurrentWaypoint()) {
+        // http://code.google.com/p/flightgear-bugs/issues/detail?id=1153
+        // throw an exception so this aircraft gets killed by the AIManager.
+        throw sg_exception("bad AI flight plan");
+    }
+    
+    // Note that leg has been incremented after creating the current leg, so we should use
+    // leg numbers here that are one higher than the number that is used to create the leg
+    // NOTE: As of July, 30, 2011, the post-creation leg updating is no longer happening. 
+    // Leg numbers are updated only once the aircraft passes the last waypoint created for that legm so I should probably just use
+    // the original leg numbers here!
+    switch (leg) {
+      case 1:              // Startup and Push back
+        if (trafficRef->getDepartureAirport()->getDynamics())
+            controller = trafficRef->getDepartureAirport()->getDynamics()->getStartupController();
+        break;
+    case 2:              // Taxiing to runway
+        if (trafficRef->getDepartureAirport()->getDynamics()->getGroundNetwork()->exists())
+            controller = trafficRef->getDepartureAirport()->getDynamics()->getGroundNetwork();
+        break;
+    case 3:              //Take off tower controller
+        if (trafficRef->getDepartureAirport()->getDynamics()) {
+            controller = trafficRef->getDepartureAirport()->getDynamics()->getTowerController();
+            towerController = 0;
+        } else {
+            cerr << "Error: Could not find Dynamics at airport : " << trafficRef->getDepartureAirport()->getId() << endl;
         }
+        break;
+    case 6:
+         if (trafficRef->getDepartureAirport()->getDynamics()) {
+             controller = trafficRef->getArrivalAirport()->getDynamics()->getApproachController();
+          }
+          break;
+    case 8:              // Taxiing for parking
+        if (trafficRef->getArrivalAirport()->getDynamics()->getGroundNetwork()->exists())
+            controller = trafficRef->getArrivalAirport()->getDynamics()->getGroundNetwork();
+        break;
+    default:
+        controller = 0;
+        break;
+    }
 
-        if ((controller != prevController) && (prevController != 0)) {
-            prevController->signOff(getID());
-        }
-        prevController = controller;
-        if (controller) {
-            controller->announcePosition(getID(), fp, fp->getCurrentWaypoint()->getRouteIndex(),
-                                         _getLatitude(), _getLongitude(), hdg, speed, altitude_ft,
-                                         trafficRef->getRadius(), leg, this);
-        }
+    if ((controller != prevController) && (prevController != 0)) {
+        prevController->signOff(getID());
+    }
+    prevController = controller;
+    if (controller) {
+        controller->announcePosition(getID(), fp, fp->getCurrentWaypoint()->getRouteIndex(),
+                                     _getLatitude(), _getLongitude(), hdg, speed, altitude_ft,
+                                     trafficRef->getRadius(), leg, this);
     }
 }
 
@@ -633,7 +639,7 @@ void FGAIAircraft::scheduleForATCTowerDepartureControl(int state) {
 
 // Process ATC instructions and report back
 
-void FGAIAircraft::processATC(FGATCInstruction instruction) {
+void FGAIAircraft::processATC(const FGATCInstruction& instruction) {
     if (instruction.getCheckForCircularWait()) {
         // This is not exactly an elegant solution, 
         // but at least it gives me a chance to check
@@ -716,9 +722,9 @@ void FGAIAircraft::handleFirstWaypoint() {
     setAltitude(prev->getAltitude());
 
     if (prev->getSpeed() > 0.0)
-        setHeading(fp->getBearing(prev->getLatitude(), prev->getLongitude(), curr));
+        setHeading(fp->getBearing(prev, curr));
     else
-        setHeading(fp->getBearing(curr->getLatitude(), curr->getLongitude(), prev));
+        setHeading(fp->getBearing(curr, prev));
 
     // If next doesn't exist, as in incrementally created flightplans for
     // AI/Trafficmanager created plans,
@@ -806,7 +812,7 @@ bool FGAIAircraft::leadPointReached(FGAIWaypoint* curr) {
     //          << " Ground target speed " << groundTargetSpeed << endl;
     double bearing = 0;
      // don't do bearing calculations for ground traffic
-       bearing = getBearing(fp->getBearing(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr));
+       bearing = getBearing(fp->getBearing(pos, curr));
        if (bearing < minBearing) {
             minBearing = bearing;
             if (minBearing < 10) {
@@ -843,7 +849,7 @@ bool FGAIAircraft::aiTrafficVisible()
     SGVec3d cartPos = SGVec3d::fromGeod(pos);
     const double d2 = (TRAFFICTOAIDISTTODIE * SG_NM_TO_METER) *
         (TRAFFICTOAIDISTTODIE * SG_NM_TO_METER);
-    return (distSqr(cartPos, globals->get_aircraft_positon_cart()) < d2);
+    return (distSqr(cartPos, globals->get_aircraft_position_cart()) < d2);
 }
 
 
@@ -869,7 +875,8 @@ bool FGAIAircraft::handleAirportEndPoints(FGAIWaypoint* prev, time_t now) {
     //cerr << trafficRef->getCallSign() << " has passed waypoint " << prev->name << " at speed " << speed << endl;
     //cerr << "Passing waypoint : " << prev->getName() << endl;
     if (prev->contains("PushBackPoint")) {
-        dep->getDynamics()->releaseParking(fp->getGate());
+      // clearing the parking assignment will release the gate
+        fp->setGate(ParkingAssignment());
         AccelTo(0.0);
         //setTaxiClearanceRequest(true);
     }
@@ -920,15 +927,14 @@ bool FGAIAircraft::handleAirportEndPoints(FGAIWaypoint* prev, time_t now) {
  * @param curr
  */
 void FGAIAircraft::controlHeading(FGAIWaypoint* curr) {
-    double calc_bearing = fp->getBearing(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr);
+    double calc_bearing = fp->getBearing(pos, curr);
     //cerr << "Bearing = " << calc_bearing << endl;
     if (speed < 0) {
         calc_bearing +=180;
-        if (calc_bearing > 360)
-            calc_bearing -= 360;
+        SG_NORMALIZE_RANGE(calc_bearing, 0.0, 360.0);
     }
 
-    if (finite(calc_bearing)) {
+    if (fgIsFinite(calc_bearing)) {
         double hdg_error = calc_bearing - tgt_heading;
         if (fabs(hdg_error) > 0.01) {
             TurnTo( calc_bearing );
@@ -938,9 +944,9 @@ void FGAIAircraft::controlHeading(FGAIWaypoint* curr) {
         cerr << "calc_bearing is not a finite number : "
         << "Speed " << speed
         << "pos : " << pos.getLatitudeDeg() << ", " << pos.getLongitudeDeg()
-        << "waypoint " << curr->getLatitude() << ", " << curr->getLongitude() << endl;
-        cerr << "waypoint name " << curr->getName();
-        exit(1);                 // FIXME
+        << ", waypoint: " << curr->getLatitude() << ", " << curr->getLongitude() << endl;
+        cerr << "waypoint name: '" << curr->getName() << "'" << endl;
+        //exit(1);                 // FIXME
     }
 }
 
@@ -1004,7 +1010,7 @@ void FGAIAircraft::updatePrimaryTargetValues(bool& flightplanActive, bool& aiOut
         // from control properties.  These default to the initial
         // settings in the config file, but can be changed "on the
         // fly".
-        string lat_mode = props->getStringValue("controls/flight/lateral-mode");
+        const string& lat_mode = props->getStringValue("controls/flight/lateral-mode");
         if ( lat_mode == "roll" ) {
             double angle
             = props->getDoubleValue("controls/flight/target-roll" );
@@ -1030,19 +1036,6 @@ void FGAIAircraft::updatePrimaryTargetValues(bool& flightplanActive, bool& aiOut
     }
 }
 
-void FGAIAircraft::updatePosition() {
-    // convert speed to degrees per second
-    double speed_north_deg_sec = cos( hdg * SGD_DEGREES_TO_RADIANS )
-                                 * speed * 1.686 / ft_per_deg_lat;
-    double speed_east_deg_sec  = sin( hdg * SGD_DEGREES_TO_RADIANS )
-                                 * speed * 1.686 / ft_per_deg_lon;
-
-    // set new position
-    pos.setLatitudeDeg( pos.getLatitudeDeg() + speed_north_deg_sec * dt);
-    pos.setLongitudeDeg( pos.getLongitudeDeg() + speed_east_deg_sec * dt);
-}
-
-
 void FGAIAircraft::updateHeading() {
     // adjust heading based on current bank angle
     if (roll == 0.0)
@@ -1057,7 +1050,7 @@ void FGAIAircraft::updateHeading() {
         // If on ground, calculate heading change directly
         if (onGround()) {
             double headingDiff = fabs(hdg-tgt_heading);
-            double bank_sense = 0.0;
+//            double bank_sense = 0.0;
         /*
         double diff = fabs(hdg - tgt_heading);
         if (diff > 180)
@@ -1077,9 +1070,9 @@ void FGAIAircraft::updateHeading() {
             if (sum > 360.0) 
                 sum -= 360.0;
             if (fabs(sum - tgt_heading) > 0.0001) {
-                bank_sense = -1.0;
+//                bank_sense = -1.0;
             } else {
-                bank_sense = 1.0;
+//                bank_sense = 1.0;
             }
             //if (trafficRef)
             // cerr << trafficRef->getCallSign() << " Heading " 
@@ -1117,10 +1110,8 @@ void FGAIAircraft::updateHeading() {
                     }
                 }
             }
-            if (trafficRef)
-               //cerr << trafficRef->getCallSign() << " Heading " 
-                //     << hdg << ". Target " << tgt_heading <<  ". Diff " << fabs(sum - tgt_heading) << ". Speed " << speed << "Heading change rate : " << headingChangeRate << " bacnk sence " << bank_sense << endl;
-           hdg += headingChangeRate * dt * sqrt(fabs(speed) / 15);
+
+            hdg += headingChangeRate * dt * sqrt(fabs(speed) / 15);
             headingError = headingDiff;
             if (fabs(headingError) < 1.0) {
                 hdg = tgt_heading;
@@ -1188,13 +1179,9 @@ void FGAIAircraft::updateVerticalSpeedTarget() {
         // find target vertical speed
         if (use_perf_vs) {
             if (altitude_ft < tgt_altitude_ft) {
-                tgt_vs = tgt_altitude_ft - altitude_ft;
-                if (tgt_vs > _performance->climbRate())
-                    tgt_vs = _performance->climbRate();
+                tgt_vs = std::min(tgt_altitude_ft - altitude_ft, _performance->climbRate());
             } else {
-                tgt_vs = tgt_altitude_ft - altitude_ft;
-                if (tgt_vs  < (-_performance->descentRate()))
-                    tgt_vs = -_performance->descentRate();
+                tgt_vs = std::max(tgt_altitude_ft - altitude_ft, -_performance->descentRate());
             }
         } else {
             double vert_dist_ft = fp->getCurrentWaypoint()->getCrossat() - altitude_ft;
@@ -1234,18 +1221,16 @@ void FGAIAircraft::updatePitchAngleTarget() {
     }
 }
 
-string FGAIAircraft::atGate() {
-     string tmp("");
-     if (fp->getLeg() < 3) {
-         if (trafficRef) {
-             if (fp->getGate() > 0) {
-                 FGParking *park =
-                     trafficRef->getDepartureAirport()->getDynamics()->getParking(fp->getGate());
-                 tmp = park->getName();
-             }
-         }
+const string& FGAIAircraft::atGate()
+{
+     if ((fp->getLeg() < 3) && trafficRef) {
+       if (fp->getParkingGate()) {
+         return fp->getParkingGate()->ident();
+       }
      }
-     return tmp;
+       
+     static const string empty;
+     return empty;
 }
 
 void FGAIAircraft::handleATCRequests() {
@@ -1272,7 +1257,9 @@ void FGAIAircraft::handleATCRequests() {
 void FGAIAircraft::updateActualState() {
     //update current state
     //TODO have a single tgt_speed and check speed limit on ground on setting tgt_speed
-    updatePosition();
+    double distance = speed * SG_KT_TO_MPS * dt;
+    pos = SGGeodesy::direct(pos, hdg, distance);
+
 
     if (onGround())
         speed = _performance->actualSpeed(this, groundTargetSpeed, dt, holdPos);
@@ -1364,11 +1351,20 @@ double FGAIAircraft::getBearing(double crse)
   return hdgDiff;
 }
 
-time_t FGAIAircraft::checkForArrivalTime(string wptName) {
+time_t FGAIAircraft::checkForArrivalTime(const string& wptName) {
      FGAIWaypoint* curr = 0;
      curr = fp->getCurrentWaypoint();
 
-     double tracklength = fp->checkTrackLength(wptName);
+     // don't recalculate tracklength unless the start/stop waypoint has changed
+     if (curr &&
+         ((curr->getName() != trackCache.startWptName)||
+          (wptName != trackCache.finalWptName)))
+     {
+         trackCache.remainingLength = fp->checkTrackLength(wptName);
+         trackCache.startWptName = curr->getName();
+         trackCache.finalWptName = wptName;
+     }
+     double tracklength = trackCache.remainingLength;
      if (tracklength > 0.1) {
           tracklength += fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr);
      } else {
@@ -1384,3 +1380,44 @@ time_t FGAIAircraft::checkForArrivalTime(string wptName) {
      }
      return (ete - secondsToGo); // Positive when we're too slow...
 }
+
+double limitRateOfChange(double cur, double target, double maxDeltaSec, double dt)
+{
+  double delta = target - cur;
+  double maxDelta = maxDeltaSec * dt;
+  
+// if delta is > maxDelta, use maxDelta, but with the sign of delta.
+  return (fabs(delta) < maxDelta) ? delta : copysign(maxDelta, delta);
+}
+
+// drive various properties in a semi-realistic fashion.
+void FGAIAircraft::updateModelProperties(double dt)
+{
+  if (!props) {
+    return;
+  }
+  
+  SGPropertyNode* gear = props->getChild("gear", 0, true);
+  double targetGearPos = fp->getCurrentWaypoint()->getGear_down() ? 1.0 : 0.0;
+  if (!gear->hasValue("gear/position-norm")) {
+    gear->setDoubleValue("gear/position-norm", targetGearPos);
+  }
+  
+  double gearPosNorm = gear->getDoubleValue("gear/position-norm");
+  if (gearPosNorm != targetGearPos) {
+    gearPosNorm += limitRateOfChange(gearPosNorm, targetGearPos, 0.1, dt);
+    if (gearPosNorm < 0.001) {
+      gearPosNorm = 0.0;
+    } else if (gearPosNorm > 0.999) {
+      gearPosNorm = 1.0;
+    }
+    
+    for (int i=0; i<6; ++i) {
+      SGPropertyNode* g = gear->getChild("gear", i, true);
+      g->setDoubleValue("position-norm", gearPosNorm);
+    } // of gear setting loop      
+  } // of gear in-transit
+  
+//  double flapPosNorm = props->getDoubleValue();
+}
+