src/FDM/JSBSim/JSBSim.cxx

   1 // JSBsim.cxx -- interface to the JSBsim flight model
   2 //
   3 // Written by Curtis Olson, started February 1999.
   4 //
   5 // Copyright (C) 1999  Curtis L. Olson  - curt@flightgear.org
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU Lesser General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // Lesser General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU Lesser General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
  20 //
  21 // $Id: FlightGear.cxx,v 1.15 2014/01/28 09:42:20 ehofman Exp $
  22
  23
  24 #ifdef HAVE_CONFIG_H
  25 #  include <config.h>
  26 #endif
  27
  28 #include <simgear/compiler.h>
  29 #include <simgear/sg_inlines.h>
  30
  31 #include <stdio.h>    //    size_t
  32 #include <string>
  33
  34 #include <simgear/constants.h>
  35 #include <simgear/debug/logstream.hxx>
  36 #include <simgear/math/sg_geodesy.hxx>
  37 #include <simgear/misc/sg_path.hxx>
  38 #include <simgear/structure/commands.hxx>
  39 #include <simgear/bvh/BVHMaterial.hxx>
  40
  41 #include <FDM/flight.hxx>
  42
  43 #include <Aircraft/controls.hxx>
  44 #include <Main/globals.hxx>
  45 #include <Main/fg_props.hxx>
  46
  47 #include "JSBSim.hxx"
  48 #include <FDM/JSBSim/FGFDMExec.h>
  49 #include <FDM/JSBSim/FGJSBBase.h>
  50 #include <FDM/JSBSim/initialization/FGInitialCondition.h>
  51 #include <FDM/JSBSim/initialization/FGTrim.h>
  52 #include <FDM/JSBSim/models/FGModel.h>
  53 #include <FDM/JSBSim/models/FGAircraft.h>
  54 #include <FDM/JSBSim/models/FGFCS.h>
  55 #include <FDM/JSBSim/models/FGPropagate.h>
  56 #include <FDM/JSBSim/models/FGAuxiliary.h>
  57 #include <FDM/JSBSim/models/FGInertial.h>
  58 #include <FDM/JSBSim/models/FGAtmosphere.h>
  59 #include <FDM/JSBSim/models/FGMassBalance.h>
  60 #include <FDM/JSBSim/models/FGAerodynamics.h>
  61 #include <FDM/JSBSim/models/FGLGear.h>
  62 #include <FDM/JSBSim/models/FGGroundReactions.h>
  63 #include <FDM/JSBSim/models/FGPropulsion.h>
  64 #include <FDM/JSBSim/models/FGAccelerations.h>
  65 #include <FDM/JSBSim/models/atmosphere/FGWinds.h>
  66 #include <FDM/JSBSim/models/propulsion/FGEngine.h>
  67 #include <FDM/JSBSim/models/propulsion/FGPiston.h>
  68 #include <FDM/JSBSim/models/propulsion/FGTurbine.h>
  69 #include <FDM/JSBSim/models/propulsion/FGTurboProp.h>
  70 #include <FDM/JSBSim/models/propulsion/FGRocket.h>
  71 #include <FDM/JSBSim/models/propulsion/FGElectric.h>
  72 #include <FDM/JSBSim/models/propulsion/FGNozzle.h>
  73 #include <FDM/JSBSim/models/propulsion/FGPropeller.h>
  74 #include <FDM/JSBSim/models/propulsion/FGRotor.h>
  75 #include <FDM/JSBSim/models/propulsion/FGTank.h>
  76 #include <FDM/JSBSim/input_output/FGPropertyManager.h>
  77 #include <FDM/JSBSim/input_output/FGGroundCallback.h>
  78
  79 using namespace JSBSim;
  80
  81 static inline double
  82 FMAX (double a, double b)
  83 {
  84   return a > b ? a : b;
  85 }
  86
  87 class FGFSGroundCallback : public FGGroundCallback {
  88 public:
  89   FGFSGroundCallback(FGJSBsim* ifc) : mInterface(ifc) {}
  90   virtual ~FGFSGroundCallback() {}
  91
  92   /** Get the altitude above sea level dependent on the location. */
  93   virtual double GetAltitude(const FGLocation& l) const {
  94     double pt[3] = { SG_FEET_TO_METER*l(FGJSBBase::eX),
  95                      SG_FEET_TO_METER*l(FGJSBBase::eY),
  96                      SG_FEET_TO_METER*l(FGJSBBase::eZ) };
  97     double lat, lon, alt;
  98     sgCartToGeod( pt, &lat, &lon, &alt);
  99     return alt * SG_METER_TO_FEET;
 100   }
 101
 102   /** Compute the altitude above ground. */
 103   virtual double GetAGLevel(double t, const FGLocation& l,
 104                             FGLocation& cont, FGColumnVector3& n,
 105                             FGColumnVector3& v, FGColumnVector3& w) const {
 106     double loc_cart[3] = { l(FGJSBBase::eX), l(FGJSBBase::eY), l(FGJSBBase::eZ) };
 107     double contact[3], normal[3], vel[3], angularVel[3], agl = 0;
 108     mInterface->get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, normal,
 109                            vel, angularVel, &agl);
 110     n = FGColumnVector3( normal[0], normal[1], normal[2] );
 111     v = FGColumnVector3( vel[0], vel[1], vel[2] );
 112     w = FGColumnVector3( angularVel[0], angularVel[1], angularVel[2] );
 113     cont = FGColumnVector3( contact[0], contact[1], contact[2] );
 114     return agl;
 115   }
 116
 117   virtual double GetTerrainGeoCentRadius(double t, const FGLocation& l) const {
 118     double loc_cart[3] = { l(FGJSBBase::eX), l(FGJSBBase::eY), l(FGJSBBase::eZ) };
 119     double contact[3], normal[3], vel[3], angularVel[3], agl = 0;
 120     mInterface->get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, normal,
 121                            vel, angularVel, &agl);
 122     return sqrt(contact[0]*contact[0]+contact[1]*contact[1]+contact[2]*contact[2]);
 123   }
 124
 125   virtual double GetSeaLevelRadius(const FGLocation& l) const {
 126     double seaLevelRadius, latGeoc;
 127
 128     sgGeodToGeoc(l.GetGeodLatitudeRad(), l.GetGeodAltitude(),
 129                  &seaLevelRadius, &latGeoc);
 130
 131     return seaLevelRadius * SG_METER_TO_FEET;
 132   }
 133
 134   virtual void SetTerrainGeoCentRadius(double radius) {}
 135   virtual void SetSeaLevelRadius(double radius) {}
 136 private:
 137   FGJSBsim* mInterface;
 138 };
 139
 140 // FG uses a squared normalized magnitude for turbulence
 141 // this lookup table maps fg's severity levels
 142 // none(0), light(1/3), moderate(2/3) and severe(3/3)
 143 // to the POE table indexes 0, 3, 4 and 7
 144 class FGTurbulenceSeverityTable : public FGTable {
 145 public:
 146   FGTurbulenceSeverityTable() : FGTable(4) {
 147     *this << (0.0/9.0) << 0.0;
 148     *this << (1.0/9.0) << 3.0;
 149     *this << (4.0/9.0) << 4.0;
 150     *this << (9.0/9.0) << 7.0;
 151   }
 152 };
 153
 154 /******************************************************************************/
 155 std::map<std::string,int> FGJSBsim::TURBULENCE_TYPE_NAMES;
 156
 157 static FGTurbulenceSeverityTable TurbulenceSeverityTable;
 158
 159 FGJSBsim::FGJSBsim( double dt )
 160   : FGInterface(dt), got_wire(false)
 161 {
 162     bool result;
 163     if( TURBULENCE_TYPE_NAMES.empty() ) {
 164         TURBULENCE_TYPE_NAMES["ttNone"]     = FGWinds::ttNone;
 165         TURBULENCE_TYPE_NAMES["ttStandard"] = FGWinds::ttStandard;
 166         TURBULENCE_TYPE_NAMES["ttCulp"]     = FGWinds::ttCulp;
 167         TURBULENCE_TYPE_NAMES["ttMilspec"]  = FGWinds::ttMilspec;
 168         TURBULENCE_TYPE_NAMES["ttTustin"]   = FGWinds::ttTustin;
 169     }
 170
 171     // Set up the debugging level
 172     // FIXME: this will not respond to
 173     // runtime changes
 174
 175                                 // if flight is excluded, don't bother
 176     if ((sglog().get_log_classes() & SG_FLIGHT) != 0) {
 177
 178                                 // do a rough-and-ready mapping to
 179                                 // the levels documented in FGFDMExec.h
 180         switch (sglog().get_log_priority()) {
 181         case SG_BULK:
 182             FGJSBBase::debug_lvl = 0x1f;
 183             break;
 184         case SG_DEBUG:
 185             FGJSBBase::debug_lvl = 0x1f;
 186         case SG_INFO:
 187         case SG_WARN:
 188         case SG_ALERT:
 189             FGJSBBase::debug_lvl = 0x00;
 190             break;
 191         }
 192     }
 193
 194     PropertyManager = new FGPropertyManager( (FGPropertyNode*)globals->get_props() );
 195     fdmex = new FGFDMExec( PropertyManager );
 196
 197     // Register ground callback.
 198     fdmex->SetGroundCallback( new FGFSGroundCallback(this) );
 199
 200     Atmosphere      = fdmex->GetAtmosphere();
 201     Winds           = fdmex->GetWinds();
 202     FCS             = fdmex->GetFCS();
 203     MassBalance     = fdmex->GetMassBalance();
 204     Propulsion      = fdmex->GetPropulsion();
 205     Aircraft        = fdmex->GetAircraft();
 206     Propagate       = fdmex->GetPropagate();
 207     Auxiliary       = fdmex->GetAuxiliary();
 208     Inertial        = fdmex->GetInertial();
 209     Aerodynamics    = fdmex->GetAerodynamics();
 210     GroundReactions = fdmex->GetGroundReactions();
 211     Accelerations   = fdmex->GetAccelerations();
 212
 213     fgic=fdmex->GetIC();
 214     needTrim=true;
 215
 216     SGPath aircraft_path( fgGetString("/sim/aircraft-dir") );
 217
 218     SGPath engine_path( fgGetString("/sim/aircraft-dir") );
 219     engine_path.append( "Engine" );
 220
 221     SGPath systems_path( fgGetString("/sim/aircraft-dir") );
 222     systems_path.append( "Systems" );
 223
 224 // deprecate sim-time-sec for simulation/sim-time-sec
 225 // remove alias with increased configuration file version number (2.1 or later)
 226     SGPropertyNode * node = fgGetNode("/fdm/jsbsim/simulation/sim-time-sec");
 227     fgGetNode("/fdm/jsbsim/sim-time-sec", true)->alias( node );
 228 // end of sim-time-sec deprecation patch
 229
 230     fdmex->Setdt( dt );
 231
 232     result = fdmex->LoadModel( aircraft_path.str(),
 233                                engine_path.str(),
 234                                systems_path.str(),
 235                                fgGetString("/sim/aero"), false );
 236
 237     if (result) {
 238       SG_LOG( SG_FLIGHT, SG_INFO, "  loaded aero.");
 239     } else {
 240       SG_LOG( SG_FLIGHT, SG_INFO,
 241               "  aero does not exist (you may have mis-typed the name).");
 242       throw(-1);
 243     }
 244
 245     SG_LOG( SG_FLIGHT, SG_INFO, "" );
 246     SG_LOG( SG_FLIGHT, SG_INFO, "" );
 247     SG_LOG( SG_FLIGHT, SG_INFO, "After loading aero definition file ..." );
 248
 249     int Neng = Propulsion->GetNumEngines();
 250     SG_LOG( SG_FLIGHT, SG_INFO, "num engines = " << Neng );
 251
 252     if ( GroundReactions->GetNumGearUnits() <= 0 ) {
 253         SG_LOG( SG_FLIGHT, SG_ALERT, "num gear units = "
 254                 << GroundReactions->GetNumGearUnits() );
 255         SG_LOG( SG_FLIGHT, SG_ALERT, "This is a very bad thing because with 0 gear units, the ground trimming");
 256         SG_LOG( SG_FLIGHT, SG_ALERT, "routine (coming up later in the code) will core dump.");
 257         SG_LOG( SG_FLIGHT, SG_ALERT, "Halting the sim now, and hoping a solution will present itself soon!");
 258         exit(-1);
 259     }
 260
 261     init_gear();
 262
 263     // Set initial fuel levels if provided.
 264     for (unsigned int i = 0; i < Propulsion->GetNumTanks(); i++) {
 265       double d;
 266       SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 267       FGTank* tank = Propulsion->GetTank(i);
 268
 269       d = node->getNode( "density-ppg", true )->getDoubleValue();
 270       if( d > 0.0 ) {
 271         tank->SetDensity( d );
 272       } else {
 273         node->getNode( "density-ppg", true )->setDoubleValue( SG_MAX2<double>(tank->GetDensity(), 0.1) );
 274       }
 275
 276       d = node->getNode( "level-lbs", true )->getDoubleValue();
 277       if( d > 0.0 ) {
 278         tank->SetContents( d );
 279       } else {
 280         node->getNode( "level-lbs", true )->setDoubleValue( tank->GetContents() );
 281       }
 282       /* Capacity is read-only in FGTank and can't be overwritten from FlightGear */
 283       node->getNode("capacity-gal_us", true )->setDoubleValue( tank->GetCapacityGallons() );
 284     }
 285     Propulsion->SetFuelFreeze((fgGetNode("/sim/freeze/fuel",true))->getBoolValue());
 286
 287     fgSetDouble("/fdm/trim/pitch-trim", FCS->GetPitchTrimCmd());
 288     fgSetDouble("/fdm/trim/throttle",   FCS->GetThrottleCmd(0));
 289     fgSetDouble("/fdm/trim/aileron",    FCS->GetDaCmd());
 290     fgSetDouble("/fdm/trim/rudder",     FCS->GetDrCmd());
 291
 292     startup_trim = fgGetNode("/sim/presets/trim", true);
 293
 294     trimmed = fgGetNode("/fdm/trim/trimmed", true);
 295     trimmed->setBoolValue(false);
 296
 297     pitch_trim = fgGetNode("/fdm/trim/pitch-trim", true );
 298     throttle_trim = fgGetNode("/fdm/trim/throttle", true );
 299     aileron_trim = fgGetNode("/fdm/trim/aileron", true );
 300     rudder_trim = fgGetNode("/fdm/trim/rudder", true );
 301
 302     stall_warning = fgGetNode("/sim/alarms/stall-warning",true);
 303     stall_warning->setDoubleValue(0);
 304
 305
 306     flap_pos_pct=fgGetNode("/surface-positions/flap-pos-norm",true);
 307     elevator_pos_pct=fgGetNode("/surface-positions/elevator-pos-norm",true);
 308     left_aileron_pos_pct
 309         =fgGetNode("/surface-positions/left-aileron-pos-norm",true);
 310     right_aileron_pos_pct
 311         =fgGetNode("/surface-positions/right-aileron-pos-norm",true);
 312     rudder_pos_pct=fgGetNode("/surface-positions/rudder-pos-norm",true);
 313     speedbrake_pos_pct
 314         =fgGetNode("/surface-positions/speedbrake-pos-norm",true);
 315     spoilers_pos_pct=fgGetNode("/surface-positions/spoilers-pos-norm",true);
 316     tailhook_pos_pct=fgGetNode("/gear/tailhook/position-norm",true);
 317     wing_fold_pos_pct=fgGetNode("surface-positions/wing-fold-pos-norm",true);
 318
 319     elevator_pos_pct->setDoubleValue(0);
 320     left_aileron_pos_pct->setDoubleValue(0);
 321     right_aileron_pos_pct->setDoubleValue(0);
 322     rudder_pos_pct->setDoubleValue(0);
 323     flap_pos_pct->setDoubleValue(0);
 324     speedbrake_pos_pct->setDoubleValue(0);
 325     spoilers_pos_pct->setDoubleValue(0);
 326
 327     ab_brake_engaged = fgGetNode("/autopilot/autobrake/engaged", true);
 328     ab_brake_left_pct = fgGetNode("/autopilot/autobrake/brake-left-output", true);
 329     ab_brake_right_pct = fgGetNode("/autopilot/autobrake/brake-right-output", true);
 330
 331     altitude = fgGetNode("/position/altitude-ft");
 332     temperature = fgGetNode("/environment/temperature-degc",true);
 333     pressure = fgGetNode("/environment/pressure-inhg",true);
 334     pressureSL = fgGetNode("/environment/pressure-sea-level-inhg",true);
 335     ground_wind = fgGetNode("/environment/config/boundary/entry[0]/wind-speed-kt",true);
 336     turbulence_gain = fgGetNode("/environment/turbulence/magnitude-norm",true);
 337     turbulence_rate = fgGetNode("/environment/turbulence/rate-hz",true);
 338     turbulence_model = fgGetNode("/environment/params/jsbsim-turbulence-model",true);
 339
 340     wind_from_north= fgGetNode("/environment/wind-from-north-fps",true);
 341     wind_from_east = fgGetNode("/environment/wind-from-east-fps" ,true);
 342     wind_from_down = fgGetNode("/environment/wind-from-down-fps" ,true);
 343
 344     slaved = fgGetNode("/sim/slaved/enabled", true);
 345
 346     for (unsigned int i = 0; i < Propulsion->GetNumEngines(); i++) {
 347       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 348       Propulsion->GetEngine(i)->GetThruster()->SetRPM(node->getDoubleValue("rpm") /
 349                      Propulsion->GetEngine(i)->GetThruster()->GetGearRatio());
 350     }
 351
 352     hook_root_struct = FGColumnVector3(
 353         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-x-in", 196),
 354         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-y-in", 0),
 355         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-z-in", -16));
 356     last_hook_tip[0] = 0; last_hook_tip[1] = 0; last_hook_tip[2] = 0;
 357     last_hook_root[0] = 0; last_hook_root[1] = 0; last_hook_root[2] = 0;
 358
 359     crashed = false;
 360 }
 361
 362 /******************************************************************************/
 363 FGJSBsim::~FGJSBsim(void)
 364 {
 365   delete fdmex;
 366   delete PropertyManager;
 367 }
 368
 369 /******************************************************************************/
 370
 371 // Initialize the JSBsim flight model, dt is the time increment for
 372 // each subsequent iteration through the EOM
 373
 374 void FGJSBsim::init()
 375 {
 376     SG_LOG( SG_FLIGHT, SG_INFO, "Starting and initializing JSBsim" );
 377
 378     // Explicitly call the superclass's
 379     // init method first.
 380
 381     if (fgGetBool("/environment/params/control-fdm-atmosphere")) {
 382       Atmosphere->SetTemperature(temperature->getDoubleValue(), get_Altitude(), FGAtmosphere::eCelsius);
 383       Atmosphere->SetPressureSL(FGAtmosphere::eInchesHg, pressureSL->getDoubleValue());
 384       // initialize to no turbulence, these values get set in the update loop
 385       Winds->SetTurbType(FGWinds::ttNone);
 386       Winds->SetTurbGain(0.0);
 387       Winds->SetTurbRate(0.0);
 388       Winds->SetWindspeed20ft(0.0);
 389       Winds->SetProbabilityOfExceedence(0.0);
 390     }
 391
 392     fgic->SetWindNEDFpsIC( -wind_from_north->getDoubleValue(),
 393                            -wind_from_east->getDoubleValue(),
 394                            -wind_from_down->getDoubleValue() );
 395
 396     SG_LOG(SG_FLIGHT,SG_INFO,"T,p,rho: " << Atmosphere->GetTemperature()
 397      << ", " << Atmosphere->GetPressure()
 398      << ", " << Atmosphere->GetDensity() );
 399
 400     FCS->SetDfPos( ofNorm, globals->get_controls()->get_flaps() );
 401
 402     needTrim = startup_trim->getBoolValue();
 403     common_init();
 404
 405     copy_to_JSBsim();
 406     fdmex->RunIC();     //loop JSBSim once w/o integrating
 407     if (fgGetBool("/sim/presets/running")) {
 408       Propulsion->InitRunning(-1);
 409       for (unsigned int i = 0; i < Propulsion->GetNumEngines(); i++) {
 410         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 411         globals->get_controls()->set_magnetos(i, eng->GetMagnetos());
 412         globals->get_controls()->set_mixture(i, FCS->GetMixtureCmd(i));
 413       }
 414     }
 415
 416     if ( needTrim ) {
 417       FGLocation cart(fgic->GetLongitudeRadIC(), fgic->GetLatitudeRadIC(),
 418                       get_Sea_level_radius() + fgic->GetAltitudeASLFtIC());
 419       double cart_pos[3], contact[3], d[3], vel[3], agl;
 420       update_ground_cache(cart, cart_pos, 0.01);
 421
 422       get_agl_ft(fdmex->GetSimTime(), cart_pos, SG_METER_TO_FEET*2, contact,
 423                  d, vel, d, &agl);
 424       double terrain_alt = sqrt(contact[0]*contact[0] + contact[1]*contact[1]
 425            + contact[2]*contact[2]) - get_Sea_level_radius();
 426
 427       SG_LOG(SG_FLIGHT, SG_INFO, "Ready to trim, terrain elevation is: "
 428                                  << terrain_alt * SG_METER_TO_FEET );
 429
 430       if (fgGetBool("/sim/presets/onground")) {
 431         FGColumnVector3 gndVelNED = cart.GetTec2l()
 432                                   * FGColumnVector3(vel[0], vel[1], vel[2]);
 433         fgic->SetVNorthFpsIC(gndVelNED(1));
 434         fgic->SetVEastFpsIC(gndVelNED(2));
 435         fgic->SetVDownFpsIC(gndVelNED(3));
 436       }
 437       fgic->SetTerrainElevationFtIC( terrain_alt );
 438       do_trim();
 439       needTrim = false;
 440     }
 441
 442     copy_from_JSBsim(); //update the bus
 443
 444     SG_LOG( SG_FLIGHT, SG_INFO, "  Initialized JSBSim with:" );
 445
 446     switch(fgic->GetSpeedSet()) {
 447     case setned:
 448         SG_LOG(SG_FLIGHT,SG_INFO, "  Vn,Ve,Vd= "
 449                << Propagate->GetVel(FGJSBBase::eNorth) << ", "
 450                << Propagate->GetVel(FGJSBBase::eEast) << ", "
 451                << Propagate->GetVel(FGJSBBase::eDown) << " ft/s");
 452     break;
 453     case setuvw:
 454         SG_LOG(SG_FLIGHT,SG_INFO, "  U,V,W= "
 455                << Propagate->GetUVW(1) << ", "
 456                << Propagate->GetUVW(2) << ", "
 457                << Propagate->GetUVW(3) << " ft/s");
 458     break;
 459     case setmach:
 460         SG_LOG(SG_FLIGHT,SG_INFO, "  Mach: "
 461                << Auxiliary->GetMach() );
 462     break;
 463     case setvc:
 464     default:
 465         SG_LOG(SG_FLIGHT,SG_INFO, "  Indicated Airspeed: "
 466                << Auxiliary->GetVcalibratedKTS() << " knots" );
 467     break;
 468     }
 469
 470     stall_warning->setDoubleValue(0);
 471
 472     SG_LOG( SG_FLIGHT, SG_INFO, "  Bank Angle: "
 473             << Propagate->GetEuler(FGJSBBase::ePhi)*RADTODEG << " deg" );
 474     SG_LOG( SG_FLIGHT, SG_INFO, "  Pitch Angle: "
 475             << Propagate->GetEuler(FGJSBBase::eTht)*RADTODEG << " deg" );
 476     SG_LOG( SG_FLIGHT, SG_INFO, "  True Heading: "
 477             << Propagate->GetEuler(FGJSBBase::ePsi)*RADTODEG << " deg" );
 478     SG_LOG( SG_FLIGHT, SG_INFO, "  Latitude: "
 479             << Propagate->GetLocation().GetLatitudeDeg() << " deg" );
 480     SG_LOG( SG_FLIGHT, SG_INFO, "  Longitude: "
 481             << Propagate->GetLocation().GetLongitudeDeg() << " deg" );
 482     SG_LOG( SG_FLIGHT, SG_INFO, "  Altitude: "
 483             << Propagate->GetAltitudeASL() << " feet" );
 484     SG_LOG( SG_FLIGHT, SG_INFO, "  loaded initial conditions" );
 485
 486     SG_LOG( SG_FLIGHT, SG_INFO, "  set dt" );
 487
 488     SG_LOG( SG_FLIGHT, SG_INFO, "Finished initializing JSBSim" );
 489
 490     SG_LOG( SG_FLIGHT, SG_INFO, "FGControls::get_gear_down()= " <<
 491                                   globals->get_controls()->get_gear_down() );
 492 }
 493
 494 /******************************************************************************/
 495
 496 void FGJSBsim::unbind()
 497 {
 498   fdmex->Unbind();
 499   FGInterface::unbind();
 500 }
 501
 502 /******************************************************************************/
 503
 504 // Run an iteration of the EOM (equations of motion)
 505
 506 void FGJSBsim::update( double dt )
 507 {
 508     if(crashed) {
 509       if(!fgGetBool("/sim/crashed"))
 510         fgSetBool("/sim/crashed", true);
 511       return;
 512     }
 513
 514     if (is_suspended())
 515       return;
 516
 517     int multiloop = _calc_multiloop(dt);
 518     FGLocation cart = Auxiliary->GetLocationVRP();
 519     double cart_pos[3];
 520
 521     update_ground_cache(cart, cart_pos, dt);
 522
 523     copy_to_JSBsim();
 524
 525     trimmed->setBoolValue(false);
 526
 527     for ( int i=0; i < multiloop; i++ ) {
 528       fdmex->Run();
 529       update_external_forces(fdmex->GetSimTime() + i * fdmex->GetDeltaT());
 530     }
 531
 532     FGJSBBase::Message* msg;
 533     while ((msg = fdmex->ProcessNextMessage()) != NULL) {
 534 //      msg = fdmex->ProcessNextMessage();
 535       switch (msg->type) {
 536       case FGJSBBase::Message::eText:
 537         if (msg->text == "Crash Detected: Simulation FREEZE.")
 538           crashed = true;
 539         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text );
 540         break;
 541       case FGJSBBase::Message::eBool:
 542         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->bVal );
 543         break;
 544       case FGJSBBase::Message::eInteger:
 545         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->iVal );
 546         break;
 547       case FGJSBBase::Message::eDouble:
 548         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->dVal );
 549         break;
 550       default:
 551         SG_LOG( SG_FLIGHT, SG_INFO, "Unrecognized message type." );
 552         break;
 553       }
 554     }
 555
 556     // translate JSBsim back to FG structure so that the
 557     // autopilot (and the rest of the sim can use the updated values
 558     copy_from_JSBsim();
 559 }
 560
 561 /******************************************************************************/
 562
 563 void FGJSBsim::suspend()
 564 {
 565   fdmex->Hold();
 566   SGSubsystem::suspend();
 567 }
 568
 569 /******************************************************************************/
 570
 571 void FGJSBsim::resume()
 572 {
 573   fdmex->Resume();
 574   SGSubsystem::resume();
 575 }
 576
 577 /******************************************************************************/
 578
 579 // Convert from the FGInterface struct to the JSBsim generic_ struct
 580
 581 bool FGJSBsim::copy_to_JSBsim()
 582 {
 583     unsigned int i;
 584
 585     // copy control positions into the JSBsim structure
 586
 587     FCS->SetDaCmd( globals->get_controls()->get_aileron());
 588     FCS->SetRollTrimCmd( globals->get_controls()->get_aileron_trim() );
 589     FCS->SetDeCmd( globals->get_controls()->get_elevator());
 590     FCS->SetPitchTrimCmd( globals->get_controls()->get_elevator_trim() );
 591     FCS->SetDrCmd( -globals->get_controls()->get_rudder() );
 592     FCS->SetYawTrimCmd( -globals->get_controls()->get_rudder_trim() );
 593     FCS->SetDsCmd( globals->get_controls()->get_rudder() );
 594     FCS->SetDfCmd( globals->get_controls()->get_flaps() );
 595     FCS->SetDsbCmd( globals->get_controls()->get_speedbrake() );
 596     FCS->SetDspCmd( globals->get_controls()->get_spoilers() );
 597
 598         // Parking brake sets minimum braking
 599         // level for mains.
 600     double parking_brake = globals->get_controls()->get_brake_parking();
 601     double left_brake = globals->get_controls()->get_brake_left();
 602     double right_brake = globals->get_controls()->get_brake_right();
 603
 604     if (ab_brake_engaged->getBoolValue()) {
 605       left_brake = ab_brake_left_pct->getDoubleValue();
 606       right_brake = ab_brake_right_pct->getDoubleValue();
 607     }
 608
 609     FCS->SetLBrake(FMAX(left_brake, parking_brake));
 610     FCS->SetRBrake(FMAX(right_brake, parking_brake));
 611
 612
 613     FCS->SetCBrake( 0.0 );
 614     // FCS->SetCBrake( globals->get_controls()->get_brake(2) );
 615
 616     FCS->SetGearCmd( globals->get_controls()->get_gear_down());
 617     for (i = 0; i < Propulsion->GetNumEngines(); i++) {
 618       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 619
 620       FCS->SetThrottleCmd(i, globals->get_controls()->get_throttle(i));
 621       FCS->SetMixtureCmd(i, globals->get_controls()->get_mixture(i));
 622       FCS->SetPropAdvanceCmd(i, globals->get_controls()->get_prop_advance(i));
 623       FCS->SetFeatherCmd(i, globals->get_controls()->get_feather(i));
 624
 625       switch (Propulsion->GetEngine(i)->GetType()) {
 626       case FGEngine::etPiston:
 627         { // FGPiston code block
 628         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 629         eng->SetMagnetos( globals->get_controls()->get_magnetos(i) );
 630         break;
 631         } // end FGPiston code block
 632       case FGEngine::etTurbine:
 633         { // FGTurbine code block
 634         FGTurbine* eng = (FGTurbine*)Propulsion->GetEngine(i);
 635         eng->SetAugmentation( globals->get_controls()->get_augmentation(i) );
 636         eng->SetReverse( globals->get_controls()->get_reverser(i) );
 637         //eng->SetInjection( globals->get_controls()->get_water_injection(i) );
 638         eng->SetCutoff( globals->get_controls()->get_cutoff(i) );
 639         eng->SetIgnition( globals->get_controls()->get_ignition(i) );
 640         break;
 641         } // end FGTurbine code block
 642       case FGEngine::etRocket:
 643         { // FGRocket code block
 644 //        FGRocket* eng = (FGRocket*)Propulsion->GetEngine(i);
 645         break;
 646         } // end FGRocket code block
 647       case FGEngine::etTurboprop:
 648         { // FGTurboProp code block
 649         FGTurboProp* eng = (FGTurboProp*)Propulsion->GetEngine(i);
 650         eng->SetReverse( globals->get_controls()->get_reverser(i) );
 651         eng->SetCutoff( globals->get_controls()->get_cutoff(i) );
 652         eng->SetIgnition( globals->get_controls()->get_ignition(i) );
 653
 654         eng->SetGeneratorPower( globals->get_controls()->get_generator_breaker(i) );
 655         eng->SetCondition( globals->get_controls()->get_condition(i) );
 656         break;
 657         } // end FGTurboProp code block
 658       default:
 659         break;
 660       }
 661
 662       { // FGEngine code block
 663       FGEngine* eng = Propulsion->GetEngine(i);
 664
 665       eng->SetStarter( globals->get_controls()->get_starter(i) );
 666       eng->SetRunning( node->getBoolValue("running") );
 667       } // end FGEngine code block
 668     }
 669
 670     Atmosphere->SetTemperature(temperature->getDoubleValue(), get_Altitude(), FGAtmosphere::eCelsius);
 671     Atmosphere->SetPressureSL(FGAtmosphere::eInchesHg, pressureSL->getDoubleValue());
 672
 673     Winds->SetTurbType((FGWinds::tType)TURBULENCE_TYPE_NAMES[turbulence_model->getStringValue()]);
 674     switch( Winds->GetTurbType() ) {
 675         case FGWinds::ttStandard:
 676         case FGWinds::ttCulp: {
 677             double tmp = turbulence_gain->getDoubleValue();
 678             Winds->SetTurbGain(tmp * tmp * 100.0);
 679             Winds->SetTurbRate(turbulence_rate->getDoubleValue());
 680             break;
 681         }
 682         case FGWinds::ttMilspec:
 683         case FGWinds::ttTustin: {
 684             // milspec turbulence: 3=light, 4=moderate, 6=severe turbulence
 685             // turbulence_gain normalized: 0: none, 1/3: light, 2/3: moderate, 3/3: severe
 686             double tmp = turbulence_gain->getDoubleValue();
 687             Winds->SetProbabilityOfExceedence(
 688               SGMiscd::roundToInt(TurbulenceSeverityTable.GetValue( tmp ) )
 689             );
 690             Winds->SetWindspeed20ft(ground_wind->getDoubleValue());
 691             break;
 692         }
 693
 694         default:
 695             break;
 696     }
 697
 698     Winds->SetWindNED( -wind_from_north->getDoubleValue(),
 699                        -wind_from_east->getDoubleValue(),
 700                        -wind_from_down->getDoubleValue() );
 701 //    SG_LOG(SG_FLIGHT,SG_INFO, "Wind NED: "
 702 //                  << get_V_north_airmass() << ", "
 703 //                  << get_V_east_airmass()  << ", "
 704 //                  << get_V_down_airmass() );
 705
 706     for (i = 0; i < Propulsion->GetNumTanks(); i++) {
 707       SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 708       FGTank * tank = Propulsion->GetTank(i);
 709       double fuelDensity = node->getDoubleValue("density-ppg");
 710
 711       if (fuelDensity < 0.1)
 712         fuelDensity = 6.0; // Use average fuel value
 713
 714       tank->SetDensity(fuelDensity);
 715       tank->SetContents(node->getDoubleValue("level-lbs"));
 716     }
 717
 718     Propulsion->SetFuelFreeze((fgGetNode("/sim/freeze/fuel",true))->getBoolValue());
 719     fdmex->SetChild(slaved->getBoolValue());
 720
 721     return true;
 722 }
 723
 724 /******************************************************************************/
 725
 726 // Convert from the JSBsim generic_ struct to the FGInterface struct
 727
 728 bool FGJSBsim::copy_from_JSBsim()
 729 {
 730     unsigned int i, j;
 731 /*
 732     _set_Inertias( MassBalance->GetMass(),
 733                    MassBalance->GetIxx(),
 734                    MassBalance->GetIyy(),
 735                    MassBalance->GetIzz(),
 736                    MassBalance->GetIxz() );
 737 */
 738     _set_CG_Position( MassBalance->GetXYZcg(1),
 739                       MassBalance->GetXYZcg(2),
 740                       MassBalance->GetXYZcg(3) );
 741
 742     _set_Accels_Body( Accelerations->GetBodyAccel(1),
 743                       Accelerations->GetBodyAccel(2),
 744                       Accelerations->GetBodyAccel(3) );
 745
 746     _set_Accels_CG_Body_N ( Auxiliary->GetNcg(1),
 747                             Auxiliary->GetNcg(2),
 748                             Auxiliary->GetNcg(3) );
 749
 750     _set_Accels_Pilot_Body( Auxiliary->GetPilotAccel(1),
 751                             Auxiliary->GetPilotAccel(2),
 752                             Auxiliary->GetPilotAccel(3) );
 753
 754     _set_Nlf( Auxiliary->GetNlf() );
 755
 756     // Velocities
 757
 758     _set_Velocities_Local( Propagate->GetVel(FGJSBBase::eNorth),
 759                            Propagate->GetVel(FGJSBBase::eEast),
 760                            Propagate->GetVel(FGJSBBase::eDown) );
 761
 762     _set_Velocities_Body( Propagate->GetUVW(1),
 763                           Propagate->GetUVW(2),
 764                           Propagate->GetUVW(3) );
 765
 766     // Make the HUD work ...
 767     _set_Velocities_Ground( Propagate->GetVel(FGJSBBase::eNorth),
 768                             Propagate->GetVel(FGJSBBase::eEast),
 769                             -Propagate->GetVel(FGJSBBase::eDown) );
 770
 771     _set_V_rel_wind( Auxiliary->GetVt() );
 772
 773     _set_V_equiv_kts( Auxiliary->GetVequivalentKTS() );
 774
 775     _set_V_calibrated_kts( Auxiliary->GetVcalibratedKTS() );
 776
 777     _set_V_ground_speed( Auxiliary->GetVground() );
 778
 779     _set_Omega_Body( Propagate->GetPQR(FGJSBBase::eP),
 780                      Propagate->GetPQR(FGJSBBase::eQ),
 781                      Propagate->GetPQR(FGJSBBase::eR) );
 782
 783     _set_Euler_Rates( Auxiliary->GetEulerRates(FGJSBBase::ePhi),
 784                       Auxiliary->GetEulerRates(FGJSBBase::eTht),
 785                       Auxiliary->GetEulerRates(FGJSBBase::ePsi) );
 786
 787     _set_Mach_number( Auxiliary->GetMach() );
 788
 789     // Positions of Visual Reference Point
 790     FGLocation l = Auxiliary->GetLocationVRP();
 791     _updatePosition(SGGeoc::fromRadFt( l.GetLongitude(), l.GetLatitude(),
 792                                        l.GetRadius() ));
 793
 794     _set_Altitude_AGL( Propagate->GetDistanceAGL() );
 795     {
 796       double loc_cart[3] = { l(FGJSBBase::eX), l(FGJSBBase::eY), l(FGJSBBase::eZ) };
 797       double contact[3], d[3], sd, t;
 798       is_valid_m(&t, d, &sd);
 799       get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, d, d, d, &sd);
 800       double rwrad
 801         = FGColumnVector3( contact[0], contact[1], contact[2] ).Magnitude();
 802       _set_Runway_altitude( rwrad - get_Sea_level_radius() );
 803     }
 804
 805     _set_Euler_Angles( Propagate->GetEuler(FGJSBBase::ePhi),
 806                        Propagate->GetEuler(FGJSBBase::eTht),
 807                        Propagate->GetEuler(FGJSBBase::ePsi) );
 808
 809     _set_Alpha( Auxiliary->Getalpha() );
 810     _set_Beta( Auxiliary->Getbeta() );
 811
 812
 813     _set_Gamma_vert_rad( Auxiliary->GetGamma() );
 814
 815     _set_Earth_position_angle( Propagate->GetEarthPositionAngle() );
 816
 817     _set_Climb_Rate( Propagate->Gethdot() );
 818
 819     const FGMatrix33& Tl2b = Propagate->GetTl2b();
 820     for ( i = 1; i <= 3; i++ ) {
 821         for ( j = 1; j <= 3; j++ ) {
 822             _set_T_Local_to_Body( i, j, Tl2b(i,j) );
 823         }
 824     }
 825
 826     // Copy the engine values from JSBSim.
 827     for ( i=0; i < Propulsion->GetNumEngines(); i++ ) {
 828       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 829       SGPropertyNode * tnode = node->getChild("thruster", 0, true);
 830       FGThruster * thruster = Propulsion->GetEngine(i)->GetThruster();
 831
 832       switch (Propulsion->GetEngine(i)->GetType()) {
 833       case FGEngine::etPiston:
 834         { // FGPiston code block
 835         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 836         node->setDoubleValue("egt-degf", eng->getExhaustGasTemp_degF());
 837         node->setDoubleValue("oil-temperature-degf", eng->getOilTemp_degF());
 838         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 839         node->setDoubleValue("mp-osi", eng->getManifoldPressure_inHg());
 840         // NOTE: mp-osi is not in ounces per square inch.
 841         // This error is left for reasons of backwards compatibility with
 842         // existing FlightGear sound and instrument configurations.
 843         node->setDoubleValue("mp-inhg", eng->getManifoldPressure_inHg());
 844         node->setDoubleValue("cht-degf", eng->getCylinderHeadTemp_degF());
 845         node->setDoubleValue("rpm", eng->getRPM());
 846         } // end FGPiston code block
 847         break;
 848       case FGEngine::etRocket:
 849         { // FGRocket code block
 850 //        FGRocket* eng = (FGRocket*)Propulsion->GetEngine(i);
 851         } // end FGRocket code block
 852         break;
 853       case FGEngine::etTurbine:
 854         { // FGTurbine code block
 855         FGTurbine* eng = (FGTurbine*)Propulsion->GetEngine(i);
 856         node->setDoubleValue("n1", eng->GetN1());
 857         node->setDoubleValue("n2", eng->GetN2());
 858         node->setDoubleValue("egt-degf", 32 + eng->GetEGT()*9/5);
 859         node->setBoolValue("augmentation", eng->GetAugmentation());
 860         node->setBoolValue("water-injection", eng->GetInjection());
 861         node->setBoolValue("ignition", eng->GetIgnition() != 0);
 862         node->setDoubleValue("nozzle-pos-norm", eng->GetNozzle());
 863         node->setDoubleValue("inlet-pos-norm", eng->GetInlet());
 864         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 865         node->setBoolValue("reversed", eng->GetReversed());
 866         node->setBoolValue("cutoff", eng->GetCutoff());
 867         node->setDoubleValue("epr", eng->GetEPR());
 868         globals->get_controls()->set_reverser(i, eng->GetReversed() );
 869         globals->get_controls()->set_cutoff(i, eng->GetCutoff() );
 870         globals->get_controls()->set_water_injection(i, eng->GetInjection() );
 871         globals->get_controls()->set_augmentation(i, eng->GetAugmentation() );
 872         } // end FGTurbine code block
 873         break;
 874       case FGEngine::etTurboprop:
 875         { // FGTurboProp code block
 876         FGTurboProp* eng = (FGTurboProp*)Propulsion->GetEngine(i);
 877         node->setDoubleValue("n1", eng->GetN1());
 878         //node->setDoubleValue("n2", eng->GetN2());
 879         node->setDoubleValue("itt_degf", 32 + eng->GetITT()*9/5);
 880         node->setBoolValue("ignition", eng->GetIgnition() != 0);
 881         node->setDoubleValue("nozzle-pos-norm", eng->GetNozzle());
 882         node->setDoubleValue("inlet-pos-norm", eng->GetInlet());
 883         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 884         node->setBoolValue("reversed", eng->GetReversed());
 885         node->setBoolValue("cutoff", eng->GetCutoff());
 886         node->setBoolValue("starting", eng->GetEngStarting());
 887         node->setBoolValue("generator-power", eng->GetGeneratorPower());
 888         node->setBoolValue("damaged", eng->GetCondition() != 0);
 889         node->setBoolValue("ielu-intervent", eng->GetIeluIntervent());
 890         node->setDoubleValue("oil-temperature-degf", eng->getOilTemp_degF());
 891 //        node->setBoolValue("onfire", eng->GetFire());
 892         globals->get_controls()->set_reverser(i, eng->GetReversed() );
 893         globals->get_controls()->set_cutoff(i, eng->GetCutoff() );
 894         } // end FGTurboProp code block
 895         break;
 896       case FGEngine::etElectric:
 897         { // FGElectric code block
 898         FGElectric* eng = (FGElectric*)Propulsion->GetEngine(i);
 899         node->setDoubleValue("rpm", eng->getRPM());
 900         } // end FGElectric code block
 901         break;
 902       case FGEngine::etUnknown:
 903         break;
 904       }
 905
 906       { // FGEngine code block
 907       FGEngine* eng = Propulsion->GetEngine(i);
 908       node->setDoubleValue("fuel-flow-gph", eng->getFuelFlow_gph());
 909       node->setDoubleValue("thrust_lb", thruster->GetThrust());
 910       node->setDoubleValue("fuel-flow_pph", eng->getFuelFlow_pph());
 911       node->setBoolValue("running", eng->GetRunning());
 912       node->setBoolValue("starter", eng->GetStarter());
 913       node->setBoolValue("cranking", eng->GetCranking());
 914       globals->get_controls()->set_starter(i, eng->GetStarter() );
 915       } // end FGEngine code block
 916
 917       switch (thruster->GetType()) {
 918       case FGThruster::ttNozzle:
 919         { // FGNozzle code block
 920 //        FGNozzle* noz = (FGNozzle*)thruster;
 921         } // end FGNozzle code block
 922         break;
 923       case FGThruster::ttPropeller:
 924         { // FGPropeller code block
 925         FGPropeller* prop = (FGPropeller*)thruster;
 926         tnode->setDoubleValue("rpm", thruster->GetRPM());
 927         tnode->setDoubleValue("pitch", prop->GetPitch());
 928         tnode->setDoubleValue("torque", prop->GetTorque());
 929         tnode->setBoolValue("feathered", prop->GetFeather());
 930         } // end FGPropeller code block
 931         break;
 932       case FGThruster::ttRotor:
 933         { // FGRotor code block
 934 //        FGRotor* rotor = (FGRotor*)thruster;
 935         } // end FGRotor code block
 936         break;
 937       case FGThruster::ttDirect:
 938         { // Direct code block
 939         } // end Direct code block
 940         break;
 941       }
 942
 943     }
 944
 945     // Copy the fuel levels from JSBSim if fuel
 946     // freeze not enabled.
 947     if ( ! Propulsion->GetFuelFreeze() ) {
 948       for (i = 0; i < Propulsion->GetNumTanks(); i++) {
 949         SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 950         FGTank* tank = Propulsion->GetTank(i);
 951         double contents = tank->GetContents();
 952         double temp = tank->GetTemperature_degC();
 953         double fuelDensity = tank->GetDensity();
 954
 955         if (fuelDensity < 0.1)
 956           fuelDensity = 6.0; // Use average fuel value
 957
 958         node->setDoubleValue("density-ppg" , fuelDensity);
 959         node->setDoubleValue("level-lbs", contents);
 960         if (temp != -9999.0) node->setDoubleValue("temperature_degC", temp);
 961       }
 962     }
 963
 964     update_gear();
 965
 966     stall_warning->setDoubleValue( Aerodynamics->GetStallWarn() );
 967
 968     elevator_pos_pct->setDoubleValue( FCS->GetDePos(ofNorm) );
 969     left_aileron_pos_pct->setDoubleValue( FCS->GetDaLPos(ofNorm) );
 970     right_aileron_pos_pct->setDoubleValue( FCS->GetDaRPos(ofNorm) );
 971     rudder_pos_pct->setDoubleValue( -1*FCS->GetDrPos(ofNorm) );
 972     flap_pos_pct->setDoubleValue( FCS->GetDfPos(ofNorm) );
 973     speedbrake_pos_pct->setDoubleValue( FCS->GetDsbPos(ofNorm) );
 974     spoilers_pos_pct->setDoubleValue( FCS->GetDspPos(ofNorm) );
 975     tailhook_pos_pct->setDoubleValue( FCS->GetTailhookPos() );
 976     wing_fold_pos_pct->setDoubleValue( FCS->GetWingFoldPos() );
 977
 978     // force a sim crashed if crashed (altitude AGL < 0)
 979     if (get_Altitude_AGL() < -100.0) {
 980          fdmex->SuspendIntegration();
 981          crashed = true;
 982     }
 983
 984     return true;
 985 }
 986
 987
 988 bool FGJSBsim::ToggleDataLogging(void)
 989 {
 990   // ToDo: handle this properly
 991   fdmex->DisableOutput();
 992   return false;
 993 }
 994
 995
 996 bool FGJSBsim::ToggleDataLogging(bool state)
 997 {
 998     if (state) {
 999       fdmex->EnableOutput();
1000       return true;
1001     } else {
1002       fdmex->DisableOutput();
1003       return false;
1004     }
1005 }
1006
1007
1008 //Positions
1009 void FGJSBsim::set_Latitude(double lat)
1010 {
1011   double alt = altitude->getDoubleValue();
1012   double sea_level_radius_meters, lat_geoc;
1013
1014   if ( alt < -9990 ) alt = 0.0;
1015
1016   SG_LOG(SG_FLIGHT,SG_INFO,"FGJSBsim::set_Latitude: " << lat );
1017   SG_LOG(SG_FLIGHT,SG_INFO," cur alt (ft) =  " << alt );
1018
1019   sgGeodToGeoc( lat, alt * SG_FEET_TO_METER,
1020                     &sea_level_radius_meters, &lat_geoc );
1021
1022   double sea_level_radius_ft = sea_level_radius_meters * SG_METER_TO_FEET;
1023   _set_Sea_level_radius( sea_level_radius_ft );
1024
1025   if (needTrim) {
1026     fgic->SetSeaLevelRadiusFtIC( sea_level_radius_ft );
1027     fgic->SetLatitudeRadIC( lat_geoc );
1028   }
1029   else
1030     Propagate->SetLatitude(lat_geoc);
1031
1032   FGInterface::set_Latitude(lat);
1033 }
1034
1035
1036 void FGJSBsim::set_Longitude(double lon)
1037 {
1038   SG_LOG(SG_FLIGHT,SG_INFO,"FGJSBsim::set_Longitude: " << lon );
1039
1040   if (needTrim)
1041     fgic->SetLongitudeRadIC(lon);
1042   else
1043     Propagate->SetLongitude(lon);
1044
1045   FGInterface::set_Longitude(lon);
1046 }
1047
1048 // Sets the altitude above sea level.
1049 void FGJSBsim::set_Altitude(double alt)
1050 {
1051   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Altitude: " << alt );
1052
1053   if (needTrim)
1054     fgic->SetAltitudeASLFtIC(alt);
1055   else
1056     Propagate->SetAltitudeASL(alt);
1057
1058   FGInterface::set_Altitude(alt);
1059 }
1060
1061 void FGJSBsim::set_V_calibrated_kts(double vc)
1062 {
1063     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_V_calibrated_kts: " <<  vc );
1064
1065   if (needTrim)
1066     fgic->SetVcalibratedKtsIC(vc);
1067   else {
1068     double p=pressure->getDoubleValue();
1069     double psl=fdmex->GetAtmosphere()->GetPressureSL();
1070     double rhosl=fdmex->GetAtmosphere()->GetDensitySL();
1071     double mach = FGJSBBase::MachFromVcalibrated(vc, p, psl, rhosl);
1072     double temp = 1.8*(temperature->getDoubleValue()+273.15);
1073     double soundSpeed = sqrt(1.4*1716.0*temp);
1074     FGColumnVector3 vUVW = Propagate->GetUVW();
1075     vUVW.Normalize();
1076     vUVW *= mach * soundSpeed;
1077     Propagate->SetUVW(1, vUVW(1));
1078     Propagate->SetUVW(2, vUVW(2));
1079     Propagate->SetUVW(3, vUVW(3));
1080   }
1081
1082   FGInterface::set_V_calibrated_kts(vc);
1083 }
1084
1085 void FGJSBsim::set_Mach_number(double mach)
1086 {
1087   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Mach_number: " <<  mach );
1088
1089   if (needTrim)
1090     fgic->SetMachIC(mach);
1091   else {
1092     double temp = 1.8*(temperature->getDoubleValue()+273.15);
1093     double soundSpeed = sqrt(1.4*1716.0*temp);
1094     FGColumnVector3 vUVW = Propagate->GetUVW();
1095     vUVW.Normalize();
1096     vUVW *= mach * soundSpeed;
1097     Propagate->SetUVW(1, vUVW(1));
1098     Propagate->SetUVW(2, vUVW(2));
1099     Propagate->SetUVW(3, vUVW(3));
1100   }
1101
1102   FGInterface::set_Mach_number(mach);
1103 }
1104
1105 void FGJSBsim::set_Velocities_Local( double north, double east, double down )
1106 {
1107   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Velocities_Local: "
1108      << north << ", " <<  east << ", " << down );
1109
1110   if (needTrim) {
1111     fgic->SetVNorthFpsIC(north);
1112     fgic->SetVEastFpsIC(east);
1113     fgic->SetVDownFpsIC(down);
1114   }
1115   else {
1116     FGColumnVector3 vNED(north, east, down);
1117     FGColumnVector3 vUVW = Propagate->GetTl2b() * vNED;
1118     Propagate->SetUVW(1, vUVW(1));
1119     Propagate->SetUVW(2, vUVW(2));
1120     Propagate->SetUVW(3, vUVW(3));
1121   }
1122
1123   FGInterface::set_Velocities_Local(north, east, down);
1124 }
1125
1126 void FGJSBsim::set_Velocities_Body( double u, double v, double w)
1127 {
1128   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Velocities_Body: "
1129      << u << ", " <<  v << ", " <<  w );
1130
1131   if (needTrim) {
1132     fgic->SetUBodyFpsIC(u);
1133     fgic->SetVBodyFpsIC(v);
1134     fgic->SetWBodyFpsIC(w);
1135   }
1136   else {
1137     Propagate->SetUVW(1, u);
1138     Propagate->SetUVW(2, v);
1139     Propagate->SetUVW(3, w);
1140   }
1141
1142   FGInterface::set_Velocities_Body(u, v, w);
1143 }
1144
1145 //Euler angles
1146 void FGJSBsim::set_Euler_Angles( double phi, double theta, double psi )
1147 {
1148   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Euler_Angles: "
1149      << phi << ", " << theta << ", " << psi );
1150
1151   if (needTrim) {
1152     fgic->SetThetaRadIC(theta);
1153     fgic->SetPhiRadIC(phi);
1154     fgic->SetPsiRadIC(psi);
1155   }
1156   else {
1157     FGQuaternion quat(phi, theta, psi);
1158     FGMatrix33 Tl2b = quat.GetT();
1159     FGMatrix33 Ti2b = Tl2b*Propagate->GetTi2l();
1160     FGQuaternion Qi = Ti2b.GetQuaternion();
1161     Propagate->SetInertialOrientation(Qi);
1162   }
1163
1164   FGInterface::set_Euler_Angles(phi, theta, psi);
1165 }
1166
1167 //Flight Path
1168 void FGJSBsim::set_Climb_Rate( double roc)
1169 {
1170   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Climb_Rate: " << roc );
1171
1172   //since both climb rate and flight path angle are set in the FG
1173   //startup sequence, something is needed to keep one from cancelling
1174   //out the other.
1175   if( fabs(roc) > 1 && fabs(fgic->GetFlightPathAngleRadIC()) < 0.01 ) {
1176     if (needTrim)
1177       fgic->SetClimbRateFpsIC(roc);
1178     else {
1179       FGColumnVector3 vNED = Propagate->GetVel();
1180       vNED(FGJSBBase::eDown) = -roc;
1181       FGColumnVector3 vUVW = Propagate->GetTl2b() * vNED;
1182       Propagate->SetUVW(1, vUVW(1));
1183       Propagate->SetUVW(2, vUVW(2));
1184       Propagate->SetUVW(3, vUVW(3));
1185     }
1186
1187     FGInterface::set_Climb_Rate(roc);
1188   }
1189 }
1190
1191 void FGJSBsim::set_Gamma_vert_rad( double gamma)
1192 {
1193   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Gamma_vert_rad: " << gamma );
1194
1195   if( !(fabs(gamma) < 0.01 && fabs(fgic->GetClimbRateFpsIC()) > 1) ) {
1196     if (needTrim)
1197       fgic->SetFlightPathAngleRadIC(gamma);
1198     else {
1199       FGColumnVector3 vNED = Propagate->GetVel();
1200       double vt = vNED.Magnitude();
1201       vNED(FGJSBBase::eDown) = -vt * sin(gamma);
1202       FGColumnVector3 vUVW = Propagate->GetTl2b() * vNED;
1203       Propagate->SetUVW(1, vUVW(1));
1204       Propagate->SetUVW(2, vUVW(2));
1205       Propagate->SetUVW(3, vUVW(3));
1206     }
1207
1208     FGInterface::set_Gamma_vert_rad(gamma);
1209   }
1210 }
1211
1212 void FGJSBsim::init_gear(void )
1213 {
1214     FGGroundReactions* gr=fdmex->GetGroundReactions();
1215     int Ngear=GroundReactions->GetNumGearUnits();
1216     for (int i=0;i<Ngear;i++) {
1217       FGLGear *gear = gr->GetGearUnit(i);
1218       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
1219       node->setDoubleValue("xoffset-in", gear->GetBodyLocation()(1) * 12);
1220       node->setDoubleValue("yoffset-in", gear->GetBodyLocation()(2) * 12);
1221       node->setDoubleValue("zoffset-in", gear->GetBodyLocation()(3) * 12);
1222       node->setBoolValue("wow", gear->GetWOW());
1223       node->setDoubleValue("rollspeed-ms", gear->GetWheelRollVel()*0.3043);
1224       node->setBoolValue("has-brake", gear->GetBrakeGroup() > 0);
1225       node->setDoubleValue("position-norm", gear->GetGearUnitPos());
1226 //    node->setDoubleValue("tire-pressure-norm", gear->GetTirePressure());
1227       node->setDoubleValue("compression-norm", gear->GetCompLen());
1228       node->setDoubleValue("compression-ft", gear->GetCompLen());
1229       if ( gear->GetSteerable() )
1230         node->setDoubleValue("steering-norm", gear->GetSteerNorm());
1231     }
1232 }
1233
1234 void FGJSBsim::update_gear(void)
1235 {
1236     FGGroundReactions* gr=fdmex->GetGroundReactions();
1237     int Ngear=GroundReactions->GetNumGearUnits();
1238     for (int i=0;i<Ngear;i++) {
1239       FGLGear *gear = gr->GetGearUnit(i);
1240       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
1241       node->getChild("wow", 0, true)->setBoolValue( gear->GetWOW());
1242       node->getChild("rollspeed-ms", 0, true)->setDoubleValue(gear->GetWheelRollVel()*0.3043);
1243       node->getChild("position-norm", 0, true)->setDoubleValue(gear->GetGearUnitPos());
1244 //    gear->SetTirePressure(node->getDoubleValue("tire-pressure-norm"));
1245       node->setDoubleValue("compression-norm", gear->GetCompLen());
1246       node->setDoubleValue("compression-ft", gear->GetCompLen());
1247       if ( gear->GetSteerable() )
1248         node->setDoubleValue("steering-norm", gear->GetSteerNorm());
1249     }
1250 }
1251
1252 void FGJSBsim::do_trim(void)
1253 {
1254   FGTrim *fgtrim;
1255
1256   if ( fgGetBool("/sim/presets/onground") )
1257   {
1258     fgtrim = new FGTrim(fdmex,tGround);
1259   } else {
1260     fgtrim = new FGTrim(fdmex,tFull);
1261   }
1262
1263   if ( !fgtrim->DoTrim() ) {
1264     fgtrim->Report();
1265     fgtrim->TrimStats();
1266   } else {
1267     trimmed->setBoolValue(true);
1268   }
1269   delete fgtrim;
1270
1271   pitch_trim->setDoubleValue( FCS->GetPitchTrimCmd() );
1272   throttle_trim->setDoubleValue( FCS->GetThrottleCmd(0) );
1273   aileron_trim->setDoubleValue( FCS->GetDaCmd() );
1274   rudder_trim->setDoubleValue( -FCS->GetDrCmd() );
1275
1276   globals->get_controls()->set_elevator_trim(FCS->GetPitchTrimCmd());
1277   globals->get_controls()->set_elevator(FCS->GetDeCmd());
1278   for( unsigned i = 0; i < Propulsion->GetNumEngines(); i++ )
1279     globals->get_controls()->set_throttle(i, FCS->GetThrottleCmd(i));
1280
1281   globals->get_controls()->set_aileron(FCS->GetDaCmd());
1282   globals->get_controls()->set_rudder( -FCS->GetDrCmd());
1283
1284   SG_LOG( SG_FLIGHT, SG_INFO, "  Trim complete" );
1285 }
1286
1287 bool FGJSBsim::update_ground_cache(FGLocation cart, double* cart_pos, double dt)
1288 {
1289   // Compute the radius of the aircraft. That is the radius of a ball
1290   // where all gear units are in. At the moment it is at least 10ft ...
1291   double acrad = 10.0;
1292   int n_gears = GroundReactions->GetNumGearUnits();
1293   for (int i=0; i<n_gears; ++i) {
1294     FGColumnVector3 bl = GroundReactions->GetGearUnit(i)->GetBodyLocation();
1295     double r = bl.Magnitude();
1296     if (acrad < r)
1297       acrad = r;
1298   }
1299
1300   // Compute the potential movement of this aircraft and query for the
1301   // ground in this area.
1302   double groundCacheRadius = acrad + 2*dt*Propagate->GetUVW().Magnitude();
1303   cart_pos[0] = cart(1);
1304   cart_pos[1] = cart(2);
1305   cart_pos[2] = cart(3);
1306   double t0 = fdmex->GetSimTime();
1307   bool cache_ok = prepare_ground_cache_ft( t0, t0 + dt, cart_pos,
1308                                            groundCacheRadius );
1309   if (!cache_ok) {
1310     SG_LOG(SG_FLIGHT, SG_WARN,
1311            "FGInterface is being called without scenery below the aircraft!");
1312
1313     SG_LOG(SG_FLIGHT, SG_WARN, "altitude         = "
1314                       << fgic->GetAltitudeASLFtIC());
1315
1316     SG_LOG(SG_FLIGHT, SG_WARN, "sea level radius = "
1317                       << get_Sea_level_radius());
1318
1319     SG_LOG(SG_FLIGHT, SG_WARN, "latitude         = "
1320                       << fgic->GetLatitudeRadIC());
1321
1322     SG_LOG(SG_FLIGHT, SG_WARN, "longitude        = "
1323                       << fgic->GetLongitudeRadIC());
1324   }
1325
1326   return cache_ok;
1327 }
1328
1329 bool
1330 FGJSBsim::get_agl_ft(double t, const double pt[3], double alt_off,
1331                      double contact[3], double normal[3], double vel[3],
1332                      double angularVel[3], double *agl)
1333 {
1334   const simgear::BVHMaterial* material;
1335   simgear::BVHNode::Id id;
1336   if (!FGInterface::get_agl_ft(t, pt, alt_off, contact, normal, vel,
1337                                angularVel, material, id))
1338     return false;
1339
1340   SGGeod geodPt = SGGeod::fromCart(SG_FEET_TO_METER*SGVec3d(pt));
1341   SGQuatd hlToEc = SGQuatd::fromLonLat(geodPt);
1342   *agl = dot(hlToEc.rotate(SGVec3d(0, 0, 1)), SGVec3d(contact) - SGVec3d(pt));
1343
1344   static SGPropertyNode_ptr terrain = fgGetNode("/sim/fdm/surface", true);
1345
1346 #ifdef JSBSIM_USE_GROUNDREACTIONS
1347   bool terrain_active = (terrain->getIntValue("override-level", -1) > 0) ? false : true;
1348   terrain->setBoolValue("active", terrain_active);
1349   terrain->setBoolValue("valid", (material && terrain_active) ? true : false);
1350   if (terrain_active)
1351   {
1352     static bool material_valid = false;
1353     if (material) {
1354       GroundReactions->SetStaticFFactor((*material).get_friction_factor());
1355       GroundReactions->SetRollingFFactor((*material).get_rolling_friction()/0.02);
1356       // 1 Pascal = 0.00014503773800721815 lbs/in^2
1357       double pressure = (*material).get_load_resistance(); // N/m^2 (or Pascal)
1358       GroundReactions->SetMaximumForce(pressure*0.00014503773800721815);
1359
1360       GroundReactions->SetBumpiness((*material).get_bumpiness());
1361       GroundReactions->SetSolid((*material).get_solid());
1362       GroundReactions->SetPosition(pt);
1363       material_valid = true;
1364     } else {
1365        if (material_valid) {
1366          GroundReactions->resetValues();
1367          material_valid = false;
1368       }
1369     }
1370   }
1371 #else
1372   terrain->setBoolValue("valid", false);
1373 #endif
1374   return true;
1375 }
1376
1377 inline static double sqr(double x)
1378 {
1379     return x * x;
1380 }
1381
1382 static double angle_diff(double a, double b)
1383 {
1384     double diff = fabs(a - b);
1385     if (diff > 180) diff = 360 - diff;
1386
1387     return diff;
1388 }
1389
1390 static void check_hook_solution(const FGColumnVector3& ground_normal_body, double E, double hook_length, double sin_fi_guess, double cos_fi_guess, double* sin_fis, double* cos_fis, double* fis, int* points)
1391 {
1392     FGColumnVector3 tip(-hook_length * cos_fi_guess, 0, hook_length * sin_fi_guess);
1393     double dist = DotProduct(tip, ground_normal_body);
1394     if (fabs(dist + E) < 0.0001) {
1395         sin_fis[*points] = sin_fi_guess;
1396         cos_fis[*points] = cos_fi_guess;
1397         fis[*points] = atan2(sin_fi_guess, cos_fi_guess) * SG_RADIANS_TO_DEGREES;
1398         (*points)++;
1399     }
1400 }
1401
1402
1403 static void check_hook_solution(const FGColumnVector3& ground_normal_body, double E, double hook_length, double sin_fi_guess, double* sin_fis, double* cos_fis, double* fis, int* points)
1404 {
1405     if (sin_fi_guess >= -1 && sin_fi_guess <= 1) {
1406         double cos_fi_guess = sqrt(1 - sqr(sin_fi_guess));
1407         check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, cos_fi_guess, sin_fis, cos_fis, fis, points);
1408         if (fabs(cos_fi_guess) > SG_EPSILON) {
1409             check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, -cos_fi_guess, sin_fis, cos_fis, fis, points);
1410         }
1411     }
1412 }
1413
1414 void FGJSBsim::update_external_forces(double t_off)
1415 {
1416     const FGMatrix33& Tb2l = Propagate->GetTb2l();
1417     const FGMatrix33& Tl2b = Propagate->GetTl2b();
1418     const FGLocation& Location = Propagate->GetLocation();
1419     const FGMatrix33& Tec2l = Location.GetTec2l();
1420
1421     double hook_area[4][3];
1422
1423     FGColumnVector3 hook_root_body = MassBalance->StructuralToBody(hook_root_struct);
1424     FGColumnVector3 hook_root = Location.LocalToLocation(Tb2l *   hook_root_body);
1425     hook_area[1][0] = hook_root(1);
1426     hook_area[1][1] = hook_root(2);
1427     hook_area[1][2] = hook_root(3);
1428
1429     hook_length = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-length-ft", 6.75);
1430     double fi_min = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-min-deg", -18);
1431     double fi_max = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-max-deg", 30);
1432     double fi = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-norm") * (fi_max - fi_min) + fi_min;
1433     double cos_fi = cos(fi * SG_DEGREES_TO_RADIANS);
1434     double sin_fi = sin(fi * SG_DEGREES_TO_RADIANS);
1435
1436     FGColumnVector3 hook_tip_body = hook_root_body;
1437     hook_tip_body(1) -= hook_length * cos_fi;
1438     hook_tip_body(3) += hook_length * sin_fi;
1439
1440     double contact[3];
1441     double ground_normal[3];
1442     double ground_vel[3];
1443     double ground_angular_vel[3];
1444     double root_agl_ft;
1445
1446     if (!got_wire) {
1447         bool got = get_agl_ft(t_off, hook_area[1], 0, contact, ground_normal,
1448                               ground_vel, ground_angular_vel, &root_agl_ft);
1449         if (got && root_agl_ft > 0 && root_agl_ft < hook_length) {
1450             FGColumnVector3 ground_normal_body = Tl2b * (Tec2l * FGColumnVector3(ground_normal[0], ground_normal[1], ground_normal[2]));
1451             FGColumnVector3 contact_body = Tl2b * Location.LocationToLocal(FGColumnVector3(contact[0], contact[1], contact[2]));
1452             double D = -DotProduct(contact_body, ground_normal_body);
1453
1454             // check hook tip agl against same ground plane
1455             double hook_tip_agl_ft = DotProduct(hook_tip_body, ground_normal_body) + D;
1456             if (hook_tip_agl_ft < 0) {
1457
1458                 // hook tip: hx - l cos, hy, hz + l sin
1459                 // on ground:  - n0 l cos + n2 l sin + E = 0
1460
1461                 double E = D + DotProduct(hook_root_body, ground_normal_body);
1462
1463                 // substitue x = sin fi, cos fi = sqrt(1 - x * x)
1464                 // and rearrange to get a quadratic with coeffs:
1465                 double a = sqr(hook_length) * (sqr(ground_normal_body(1)) + sqr(ground_normal_body(3)));
1466                 double b = 2 * E * ground_normal_body(3) * hook_length;
1467                 double c = sqr(E) - sqr(ground_normal_body(1) * hook_length);
1468
1469                 double disc = sqr(b) - 4 * a * c;
1470                 if (disc >= 0) {
1471                     double delta = sqrt(disc) / (2 * a);
1472
1473                     // allow 4 solutions for safety, should never happen
1474                     double sin_fis[4];
1475                     double cos_fis[4];
1476                     double fis[4];
1477                     int points = 0;
1478
1479                     double sin_fi_guess = -b / (2 * a) - delta;
1480                     check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, sin_fis, cos_fis, fis, &points);
1481                     check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess + 2 * delta, sin_fis, cos_fis, fis, &points);
1482
1483                     if (points == 2) {
1484                         double diff1 = angle_diff(fi, fis[0]);
1485                         double diff2 = angle_diff(fi, fis[1]);
1486                         int point = diff1 < diff2 ? 0 : 1;
1487                         fi = fis[point];
1488                         sin_fi = sin_fis[point];
1489                         cos_fi = cos_fis[point];
1490                         hook_tip_body(1) = hook_root_body(1) - hook_length * cos_fi;
1491                         hook_tip_body(3) = hook_root_body(3) + hook_length * sin_fi;
1492                     }
1493                 }
1494             }
1495         }
1496     } else {
1497         FGColumnVector3 hook_root_vel = Propagate->GetVel() + (Tb2l * (Propagate->GetPQR() *  hook_root_body));
1498         double wire_ends_ec[2][3];
1499         double wire_vel_ec[2][3];
1500         get_wire_ends_ft(t_off, wire_ends_ec, wire_vel_ec);
1501         FGColumnVector3 wire_vel_1 = Tec2l * FGColumnVector3(wire_vel_ec[0][0], wire_vel_ec[0][1], wire_vel_ec[0][2]);
1502         FGColumnVector3 wire_vel_2 = Tec2l * FGColumnVector3(wire_vel_ec[1][0], wire_vel_ec[1][1], wire_vel_ec[1][2]);
1503         FGColumnVector3 rel_vel = hook_root_vel - (wire_vel_1 + wire_vel_2) / 2;
1504         if (rel_vel.Magnitude() < 3) {
1505             got_wire = false;
1506             release_wire();
1507             fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", 0.0);
1508         } else {
1509             FGColumnVector3 wire_end1_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[0][0], wire_ends_ec[0][1], wire_ends_ec[0][2])) - hook_root_body;
1510             FGColumnVector3 wire_end2_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[1][0], wire_ends_ec[1][1], wire_ends_ec[1][2])) - hook_root_body;
1511             FGColumnVector3 force_plane_normal = wire_end1_body * wire_end2_body;
1512             force_plane_normal.Normalize();
1513             cos_fi = DotProduct(force_plane_normal, FGColumnVector3(0, 0, 1));
1514             if (cos_fi < 0) cos_fi = -cos_fi;
1515             sin_fi = sqrt(1 - sqr(cos_fi));
1516             fi = atan2(sin_fi, cos_fi) * SG_RADIANS_TO_DEGREES;
1517
1518             fgSetDouble("/fdm/jsbsim/external_reactions/hook/x", -cos_fi);
1519             fgSetDouble("/fdm/jsbsim/external_reactions/hook/y", 0);
1520             fgSetDouble("/fdm/jsbsim/external_reactions/hook/z", sin_fi);
1521             fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", fgGetDouble("/fdm/jsbsim/systems/hook/force"));
1522         }
1523     }
1524
1525     FGColumnVector3 hook_tip = Location.LocalToLocation(Tb2l * hook_tip_body);
1526
1527     hook_area[0][0] = hook_tip(1);
1528     hook_area[0][1] = hook_tip(2);
1529     hook_area[0][2] = hook_tip(3);
1530
1531     if (!got_wire) {
1532         // The previous positions.
1533         hook_area[2][0] = last_hook_root[0];
1534         hook_area[2][1] = last_hook_root[1];
1535         hook_area[2][2] = last_hook_root[2];
1536         hook_area[3][0] = last_hook_tip[0];
1537         hook_area[3][1] = last_hook_tip[1];
1538         hook_area[3][2] = last_hook_tip[2];
1539
1540         // Check if we caught a wire.
1541         // Returns true if we caught one.
1542         if (caught_wire_ft(t_off, hook_area)) {
1543                 got_wire = true;
1544         }
1545     }
1546
1547     // save actual position as old position ...
1548     last_hook_tip[0] = hook_area[0][0];
1549     last_hook_tip[1] = hook_area[0][1];
1550     last_hook_tip[2] = hook_area[0][2];
1551     last_hook_root[0] = hook_area[1][0];
1552     last_hook_root[1] = hook_area[1][1];
1553     last_hook_root[2] = hook_area[1][2];
1554
1555     fgSetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-deg", fi);
1556 }
1557