src/AIModel/AIAircraft.cxx

   1 // // FGAIAircraft - FGAIBase-derived class creates an AI airplane
   2 //
   3 // Written by David Culp, started October 2003.
   4 //
   5 // Copyright (C) 2003  David P. Culp - davidculp2@comcast.net
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU 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 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20
  21 #ifdef HAVE_CONFIG_H
  22 #  include <config.h>
  23 #endif
  24
  25 #include <simgear/route/waypoint.hxx>
  26 #include <Main/fg_props.hxx>
  27 #include <Main/globals.hxx>
  28 #include <Main/viewer.hxx>
  29 #include <Scenery/scenery.hxx>
  30 #include <Scenery/tilemgr.hxx>
  31 #include <Airports/dynamics.hxx>
  32 #include <Airports/simple.hxx>
  33
  34 #include <string>
  35 #include <math.h>
  36 #include <time.h>
  37
  38 #ifdef _MSC_VER
  39 #  include <float.h>
  40 #  define finite _finite
  41 #elif defined(__sun) || defined(sgi)
  42 #  include <ieeefp.h>
  43 #endif
  44
  45 using std::string;
  46
  47 #include "AIAircraft.hxx"
  48 #include "performancedata.hxx"
  49 #include "performancedb.hxx"
  50
  51 //#include <Airports/trafficcontroller.hxx>
  52
  53 static string tempReg;
  54
  55 FGAIAircraft::FGAIAircraft(FGAISchedule *ref) :
  56      /* HOT must be disabled for AI Aircraft,
  57       * otherwise traffic detection isn't working as expected.*/
  58      FGAIBase(otAircraft, false)
  59 {
  60     trafficRef = ref;
  61     if (trafficRef) {
  62         groundOffset = trafficRef->getGroundOffset();
  63         setCallSign(trafficRef->getCallSign());
  64     }
  65     else
  66         groundOffset = 0;
  67
  68     fp = 0;
  69     controller = 0;
  70     prevController = 0;
  71     dt_count = 0;
  72     dt_elev_count = 0;
  73     use_perf_vs = true;
  74
  75     no_roll = false;
  76     tgt_speed = 0;
  77     speed = 0;
  78     groundTargetSpeed = 0;
  79
  80     // set heading and altitude locks
  81     hdg_lock = false;
  82     alt_lock = false;
  83     roll = 0;
  84     headingChangeRate = 0.0;
  85     headingError = 0;
  86     minBearing = 360;
  87     speedFraction =1.0;
  88
  89     holdPos = false;
  90     needsTaxiClearance = false;
  91     _needsGroundElevation = true;
  92
  93     _performance = 0; //TODO initialize to JET_TRANSPORT from PerformanceDB
  94     dt = 0;
  95 }
  96
  97
  98 FGAIAircraft::~FGAIAircraft() {
  99     //delete fp;
 100     if (controller)
 101         controller->signOff(getID());
 102 }
 103
 104
 105 void FGAIAircraft::readFromScenario(SGPropertyNode* scFileNode) {
 106     if (!scFileNode)
 107         return;
 108
 109     FGAIBase::readFromScenario(scFileNode);
 110
 111     setPerformance(scFileNode->getStringValue("class", "jet_transport"));
 112     setFlightPlan(scFileNode->getStringValue("flightplan"),
 113                   scFileNode->getBoolValue("repeat", false));
 114     setCallSign(scFileNode->getStringValue("callsign"));
 115 }
 116
 117
 118 void FGAIAircraft::bind() {
 119     FGAIBase::bind();
 120
 121     props->tie("controls/gear/gear-down",
 122                SGRawValueMethods<FGAIAircraft,bool>(*this,
 123                                                     &FGAIAircraft::_getGearDown));
 124     props->tie("transponder-id",
 125                SGRawValueMethods<FGAIAircraft,const char*>(*this,
 126                                                     &FGAIAircraft::_getTransponderCode));
 127 }
 128
 129
 130 void FGAIAircraft::unbind() {
 131     FGAIBase::unbind();
 132
 133     props->untie("controls/gear/gear-down");
 134     props->untie("transponder-id");
 135 }
 136
 137
 138 void FGAIAircraft::update(double dt) {
 139     FGAIBase::update(dt);
 140     Run(dt);
 141     Transform();
 142 }
 143
 144 void FGAIAircraft::setPerformance(const std::string& acclass) {
 145      static PerformanceDB perfdb; //TODO make it a global service
 146      setPerformance(perfdb.getDataFor(acclass));
 147   }
 148
 149
 150  void FGAIAircraft::setPerformance(PerformanceData *ps) {
 151      _performance = ps;
 152   }
 153
 154
 155  void FGAIAircraft::Run(double dt) {
 156       FGAIAircraft::dt = dt;
 157
 158      bool outOfSight = false,
 159         flightplanActive = true;
 160      updatePrimaryTargetValues(flightplanActive, outOfSight); // target hdg, alt, speed
 161      if (outOfSight) {
 162         return;
 163      }
 164
 165      if (!flightplanActive) {
 166         groundTargetSpeed = 0;
 167      }
 168
 169      handleATCRequests(); // ATC also has a word to say
 170      updateSecondaryTargetValues(); // target roll, vertical speed, pitch
 171      updateActualState();
 172     // We currently have one situation in which an AIAircraft object is used that is not attached to the
 173     // AI manager. In this particular case, the AIAircraft is used to shadow the user's aircraft's behavior in the AI world.
 174     // Since we perhaps don't want a radar entry of our own aircraft, the following conditional should probably be adequate
 175     // enough
 176      if (manager)
 177         UpdateRadar(manager);
 178      checkVisibility();
 179   }
 180
 181 void FGAIAircraft::checkVisibility()
 182 {
 183   double visibility_meters = fgGetDouble("/environment/visibility-m");
 184   FGViewer* vw = globals->get_current_view();
 185   invisible = (SGGeodesy::distanceM(vw->getPosition(), pos) > visibility_meters);
 186 }
 187
 188
 189
 190 void FGAIAircraft::AccelTo(double speed) {
 191     tgt_speed = speed;
 192     if (!isStationary())
 193         _needsGroundElevation = true;
 194 }
 195
 196
 197 void FGAIAircraft::PitchTo(double angle) {
 198     tgt_pitch = angle;
 199     alt_lock = false;
 200 }
 201
 202
 203 void FGAIAircraft::RollTo(double angle) {
 204     tgt_roll = angle;
 205     hdg_lock = false;
 206 }
 207
 208
 209 void FGAIAircraft::YawTo(double angle) {
 210     tgt_yaw = angle;
 211 }
 212
 213
 214 void FGAIAircraft::ClimbTo(double alt_ft ) {
 215     tgt_altitude_ft = alt_ft;
 216     alt_lock = true;
 217 }
 218
 219
 220 void FGAIAircraft::TurnTo(double heading) {
 221     tgt_heading = heading;
 222     hdg_lock = true;
 223 }
 224
 225
 226 double FGAIAircraft::sign(double x) {
 227     if (x == 0.0)
 228         return x;
 229     else
 230         return x/fabs(x);
 231 }
 232
 233
 234 void FGAIAircraft::setFlightPlan(const std::string& flightplan, bool repeat) {
 235     if (!flightplan.empty()) {
 236         FGAIFlightPlan* fp = new FGAIFlightPlan(flightplan);
 237         fp->setRepeat(repeat);
 238         SetFlightPlan(fp);
 239     }
 240 }
 241
 242
 243 void FGAIAircraft::SetFlightPlan(FGAIFlightPlan *f) {
 244     delete fp;
 245     fp = f;
 246 }
 247
 248
 249 void FGAIAircraft::ProcessFlightPlan( double dt, time_t now ) {
 250
 251     // the one behind you
 252     FGAIFlightPlan::waypoint* prev = 0;
 253     // the one ahead
 254     FGAIFlightPlan::waypoint* curr = 0;
 255     // the next plus 1
 256     FGAIFlightPlan::waypoint* next = 0;
 257
 258     prev = fp->getPreviousWaypoint();
 259     curr = fp->getCurrentWaypoint();
 260     next = fp->getNextWaypoint();
 261
 262     dt_count += dt;
 263
 264     ///////////////////////////////////////////////////////////////////////////
 265     // Initialize the flightplan
 266     //////////////////////////////////////////////////////////////////////////
 267     if (!prev) {
 268         handleFirstWaypoint();
 269         return;
 270     }                            // end of initialization
 271     if (! fpExecutable(now))
 272           return;
 273     dt_count = 0;
 274
 275     double distanceToDescent;
 276     if(reachedEndOfCruise(distanceToDescent)) {
 277         if (!loadNextLeg(distanceToDescent)) {
 278             setDie(true);
 279             return;
 280         }
 281         prev = fp->getPreviousWaypoint();
 282         curr = fp->getCurrentWaypoint();
 283         next = fp->getNextWaypoint();
 284     }
 285     if (! leadPointReached(curr)) {
 286         controlHeading(curr);
 287         controlSpeed(curr, next);
 288             /*
 289             if (speed < 0) {
 290                 cerr << getCallSign()
 291                      << ": verifying lead distance to waypoint : "
 292                      << fp->getCurrentWaypoint()->name << " "
 293                      << fp->getLeadDistance() << ". Distance to go "
 294                      << (fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr))
 295                      << ". Target speed = "
 296                      << tgt_speed
 297                      << ". Current speed = "
 298                      << speed
 299                      << ". Minimum Bearing " << minBearing
 300                      << endl;
 301             } */
 302     } else {
 303         if (curr->finished)      //end of the flight plan
 304         {
 305             if (fp->getRepeat())
 306                 fp->restart();
 307             else
 308                 setDie(true);
 309             return;
 310         }
 311
 312         if (next) {
 313             //TODO more intelligent method in AIFlightPlan, no need to send data it already has :-)
 314             tgt_heading = fp->getBearing(curr, next);
 315             spinCounter = 0;
 316         }
 317
 318         //TODO let the fp handle this (loading of next leg)
 319         fp->IncrementWaypoint( trafficRef != 0 );
 320         if  ( ((!(fp->getNextWaypoint()))) && (trafficRef != 0) )
 321             if (!loadNextLeg()) {
 322                 setDie(true);
 323                 return;
 324             }
 325
 326         prev = fp->getPreviousWaypoint();
 327         curr = fp->getCurrentWaypoint();
 328         next = fp->getNextWaypoint();
 329
 330         // Now that we have incremented the waypoints, excute some traffic manager specific code
 331         if (trafficRef) {
 332             //TODO isn't this best executed right at the beginning?
 333             if (! aiTrafficVisible()) {
 334                 setDie(true);
 335                 return;
 336             }
 337
 338             if (! handleAirportEndPoints(prev, now)) {
 339                 setDie(true);
 340                 return;
 341             }
 342
 343             announcePositionToController();
 344
 345         }
 346
 347         if (next) {
 348             fp->setLeadDistance(tgt_speed, tgt_heading, curr, next);
 349         }
 350
 351         if (!(prev->on_ground))  // only update the tgt altitude from flightplan if not on the ground
 352         {
 353             tgt_altitude_ft = prev->altitude;
 354             if (curr->crossat > -1000.0) {
 355                 use_perf_vs = false;
 356                 tgt_vs = (curr->crossat - altitude_ft) / (fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr)
 357                          / 6076.0 / speed*60.0);
 358                 checkTcas();
 359                 tgt_altitude_ft = curr->crossat;
 360             } else {
 361                 use_perf_vs = true;
 362             }
 363         }
 364         AccelTo(prev->speed);
 365         hdg_lock = alt_lock = true;
 366         no_roll = prev->on_ground;
 367     }
 368 }
 369
 370 void FGAIAircraft::checkTcas(void)
 371 {
 372     if (props->getIntValue("tcas/threat-level",0)==3)
 373     {
 374         int RASense = props->getIntValue("tcas/ra-sense",0);
 375         if ((RASense>0)&&(tgt_vs<4000))
 376             // upward RA: climb!
 377             tgt_vs = 4000;
 378         else
 379         if (RASense<0)
 380         {
 381             // downward RA: descend!
 382             if (altitude_ft < 1000)
 383             {
 384                 // too low: level off
 385                 if (tgt_vs>0)
 386                     tgt_vs = 0;
 387             }
 388             else
 389             {
 390                 if (tgt_vs >- 4000)
 391                     tgt_vs = -4000;
 392             }
 393         }
 394     }
 395 }
 396
 397 void FGAIAircraft::initializeFlightPlan() {
 398 }
 399
 400
 401 bool FGAIAircraft::_getGearDown() const {
 402     return _performance->gearExtensible(this);
 403 }
 404
 405
 406 const char * FGAIAircraft::_getTransponderCode() const {
 407   return transponderCode.c_str();
 408 }
 409
 410
 411 bool FGAIAircraft::loadNextLeg(double distance) {
 412
 413     int leg;
 414     if ((leg = fp->getLeg())  == 10) {
 415         if (!trafficRef->next()) {
 416             return false;
 417         }
 418         setCallSign(trafficRef->getCallSign());
 419         leg = 1;
 420         fp->setLeg(leg);
 421     }
 422
 423     FGAirport *dep = trafficRef->getDepartureAirport();
 424     FGAirport *arr = trafficRef->getArrivalAirport();
 425     if (!(dep && arr)) {
 426         setDie(true);
 427
 428     } else {
 429         double cruiseAlt = trafficRef->getCruiseAlt() * 100;
 430
 431         fp->create (this,
 432                     dep,
 433                     arr,
 434                     leg,
 435                     cruiseAlt,
 436                     trafficRef->getSpeed(),
 437                     _getLatitude(),
 438                     _getLongitude(),
 439                     false,
 440                     trafficRef->getRadius(),
 441                     trafficRef->getFlightType(),
 442                     acType,
 443                     company,
 444                     distance);
 445        //cerr << "created  leg " << leg << " for " << trafficRef->getCallSign() << endl;
 446     }
 447     return true;
 448 }
 449
 450
 451 // Note: This code is copied from David Luff's AILocalTraffic
 452 // Warning - ground elev determination is CPU intensive
 453 // Either this function or the logic of how often it is called
 454 // will almost certainly change.
 455
 456 void FGAIAircraft::getGroundElev(double dt) {
 457     dt_elev_count += dt;
 458
 459     if (!needGroundElevation())
 460         return;
 461     // Update minimally every three secs, but add some randomness
 462     // to prevent all AI objects doing this in synchrony
 463     if (dt_elev_count < (3.0) + (rand() % 10))
 464         return;
 465
 466     dt_elev_count = 0;
 467
 468     // Only do the proper hitlist stuff if we are within visible range of the viewer.
 469     if (!invisible) {
 470         double visibility_meters = fgGetDouble("/environment/visibility-m");
 471         FGViewer* vw = globals->get_current_view();
 472
 473         if (SGGeodesy::distanceM(vw->getPosition(), pos) > visibility_meters) {
 474             return;
 475         }
 476
 477         double range = 500.0;
 478         if (globals->get_tile_mgr()->schedule_scenery(pos, range, 5.0))
 479         {
 480             double alt;
 481             if (getGroundElevationM(SGGeod::fromGeodM(pos, 20000), alt, 0))
 482             {
 483                 tgt_altitude_ft = alt * SG_METER_TO_FEET;
 484                 if (isStationary())
 485                 {
 486                     // aircraft is stationary and we obtained altitude for this spot - we're done.
 487                     _needsGroundElevation = false;
 488                 }
 489             }
 490         }
 491     }
 492 }
 493
 494
 495 void FGAIAircraft::doGroundAltitude() {
 496     if ((fabs(altitude_ft - (tgt_altitude_ft+groundOffset)) > 1000.0)||
 497         (isStationary()))
 498         altitude_ft = (tgt_altitude_ft + groundOffset);
 499     else
 500         altitude_ft += 0.1 * ((tgt_altitude_ft+groundOffset) - altitude_ft);
 501     tgt_vs = 0;
 502 }
 503
 504
 505 void FGAIAircraft::announcePositionToController() {
 506     if (trafficRef) {
 507         int leg = fp->getLeg();
 508
 509         // Note that leg has been incremented after creating the current leg, so we should use
 510         // leg numbers here that are one higher than the number that is used to create the leg
 511         //
 512         switch (leg) {
 513           case 2:              // Startup and Push back
 514             if (trafficRef->getDepartureAirport()->getDynamics())
 515                 controller = trafficRef->getDepartureAirport()->getDynamics()->getStartupController();
 516             break;
 517         case 3:              // Taxiing to runway
 518             if (trafficRef->getDepartureAirport()->getDynamics()->getGroundNetwork()->exists())
 519                 controller = trafficRef->getDepartureAirport()->getDynamics()->getGroundNetwork();
 520             break;
 521         case 4:              //Take off tower controller
 522             if (trafficRef->getDepartureAirport()->getDynamics()) {
 523                 controller = trafficRef->getDepartureAirport()->getDynamics()->getTowerController();
 524             } else {
 525                 cerr << "Error: Could not find Dynamics at airport : " << trafficRef->getDepartureAirport()->getId() << endl;
 526             }
 527             break;
 528         case 7:
 529              if (trafficRef->getDepartureAirport()->getDynamics()) {
 530                  controller = trafficRef->getArrivalAirport()->getDynamics()->getApproachController();
 531               }
 532               break;
 533         case 9:              // Taxiing for parking
 534             if (trafficRef->getArrivalAirport()->getDynamics()->getGroundNetwork()->exists())
 535                 controller = trafficRef->getArrivalAirport()->getDynamics()->getGroundNetwork();
 536             break;
 537         default:
 538             controller = 0;
 539             break;
 540         }
 541
 542         if ((controller != prevController) && (prevController != 0)) {
 543             prevController->signOff(getID());
 544         }
 545         prevController = controller;
 546         if (controller) {
 547             controller->announcePosition(getID(), fp, fp->getCurrentWaypoint()->routeIndex,
 548                                          _getLatitude(), _getLongitude(), hdg, speed, altitude_ft,
 549                                          trafficRef->getRadius(), leg, this);
 550         }
 551     }
 552 }
 553
 554 // Process ATC instructions and report back
 555
 556 void FGAIAircraft::processATC(FGATCInstruction instruction) {
 557     if (instruction.getCheckForCircularWait()) {
 558         // This is not exactly an elegant solution,
 559         // but at least it gives me a chance to check
 560         // if circular waits are resolved.
 561         // For now, just take the offending aircraft
 562         // out of the scene
 563         setDie(true);
 564         // a more proper way should be - of course - to
 565         // let an offending aircraft take an evasive action
 566         // for instance taxi back a little bit.
 567     }
 568     //cerr << "Processing ATC instruction (not Implimented yet)" << endl;
 569     if (instruction.getHoldPattern   ()) {}
 570
 571     // Hold Position
 572     if (instruction.getHoldPosition  ()) {
 573         if (!holdPos) {
 574             holdPos = true;
 575         }
 576         AccelTo(0.0);
 577     } else {
 578         if (holdPos) {
 579             //if (trafficRef)
 580             //  cerr << trafficRef->getCallSign() << " Resuming Taxi." << endl;
 581             holdPos = false;
 582         }
 583         // Change speed Instruction. This can only be excecuted when there is no
 584         // Hold position instruction.
 585         if (instruction.getChangeSpeed   ()) {
 586             //  if (trafficRef)
 587             //cerr << trafficRef->getCallSign() << " Changing Speed " << endl;
 588             AccelTo(instruction.getSpeed());
 589         } else {
 590             if (fp) AccelTo(fp->getPreviousWaypoint()->speed);
 591         }
 592     }
 593     if (instruction.getChangeHeading ()) {
 594         hdg_lock = false;
 595         TurnTo(instruction.getHeading());
 596     } else {
 597         if (fp) {
 598             hdg_lock = true;
 599         }
 600     }
 601     if (instruction.getChangeAltitude()) {}
 602
 603 }
 604
 605
 606 void FGAIAircraft::handleFirstWaypoint() {
 607     bool eraseWaypoints;         //TODO YAGNI
 608     headingError = 0;
 609     if (trafficRef) {
 610         eraseWaypoints = true;
 611     } else {
 612         eraseWaypoints = false;
 613     }
 614
 615     FGAIFlightPlan::waypoint* prev = 0; // the one behind you
 616     FGAIFlightPlan::waypoint* curr = 0; // the one ahead
 617     FGAIFlightPlan::waypoint* next = 0;// the next plus 1
 618
 619     spinCounter = 0;
 620     tempReg = "";
 621
 622     //TODO fp should handle this
 623     fp->IncrementWaypoint(eraseWaypoints);
 624     if (!(fp->getNextWaypoint()) && trafficRef)
 625         if (!loadNextLeg()) {
 626             setDie(true);
 627             return;
 628         }
 629
 630     prev = fp->getPreviousWaypoint();   //first waypoint
 631     curr = fp->getCurrentWaypoint();    //second waypoint
 632     next = fp->getNextWaypoint();       //third waypoint (might not exist!)
 633
 634     setLatitude(prev->latitude);
 635     setLongitude(prev->longitude);
 636     setSpeed(prev->speed);
 637     setAltitude(prev->altitude);
 638
 639     if (prev->speed > 0.0)
 640         setHeading(fp->getBearing(prev->latitude, prev->longitude, curr));
 641     else
 642         setHeading(fp->getBearing(curr->latitude, curr->longitude, prev));
 643
 644     // If next doesn't exist, as in incrementally created flightplans for
 645     // AI/Trafficmanager created plans,
 646     // Make sure lead distance is initialized otherwise
 647     if (next)
 648         fp->setLeadDistance(speed, hdg, curr, next);
 649
 650     if (curr->crossat > -1000.0) //use a calculated descent/climb rate
 651     {
 652         use_perf_vs = false;
 653         tgt_vs = (curr->crossat - prev->altitude)
 654                  / (fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr)
 655                     / 6076.0 / prev->speed*60.0);
 656         checkTcas();
 657         tgt_altitude_ft = curr->crossat;
 658     } else {
 659         use_perf_vs = true;
 660         tgt_altitude_ft = prev->altitude;
 661     }
 662     alt_lock = hdg_lock = true;
 663     no_roll = prev->on_ground;
 664     if (no_roll) {
 665         Transform();             // make sure aip is initialized.
 666         getGroundElev(60.1);     // make sure it's executed first time around, so force a large dt value
 667         doGroundAltitude();
 668         _needsGroundElevation = true; // check ground elevation again (maybe scenery wasn't available yet)
 669     }
 670     // Make sure to announce the aircraft's position
 671     announcePositionToController();
 672     prevSpeed = 0;
 673 }
 674
 675
 676 /**
 677  * Check Execution time (currently once every 100 ms)
 678  * Add a bit of randomization to prevent the execution of all flight plans
 679  * in synchrony, which can add significant periodic framerate flutter.
 680  *
 681  * @param now
 682  * @return
 683  */
 684 bool FGAIAircraft::fpExecutable(time_t now) {
 685     double rand_exec_time = (rand() % 100) / 100;
 686     return (dt_count > (0.1+rand_exec_time)) && (fp->isActive(now));
 687 }
 688
 689
 690 /**
 691  * Check to see if we've reached the lead point for our next turn
 692  *
 693  * @param curr
 694  * @return
 695  */
 696 bool FGAIAircraft::leadPointReached(FGAIFlightPlan::waypoint* curr) {
 697     double dist_to_go = fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr);
 698
 699     //cerr << "2" << endl;
 700     double lead_dist = fp->getLeadDistance();
 701     // experimental: Use fabs, because speed can be negative (I hope) during push_back.
 702     if ((dist_to_go < fabs(10.0* speed)) && (speed < 0) && (tgt_speed < 0) && fp->getCurrentWaypoint()->name == string("PushBackPoint")) {
 703           tgt_speed = -(dist_to_go / 10.0);
 704           if (tgt_speed > -0.5) {
 705                 tgt_speed = -0.5;
 706           }
 707           if (fp->getPreviousWaypoint()->speed < tgt_speed) {
 708               fp->getPreviousWaypoint()->speed = tgt_speed;
 709           }
 710     }
 711     if (lead_dist < fabs(2*speed)) {
 712       //don't skip over the waypoint
 713       lead_dist = fabs(2*speed);
 714       //cerr << "Extending lead distance to " << lead_dist << endl;
 715     }
 716
 717     //prev_dist_to_go = dist_to_go;
 718     //if (dist_to_go < lead_dist)
 719     //     cerr << trafficRef->getCallSign() << " Distance : "
 720     //          << dist_to_go << ": Lead distance "
 721     //          << lead_dist << " " << curr->name
 722     //          << " Ground target speed " << groundTargetSpeed << endl;
 723     double bearing = 0;
 724     if (speed > 50) { // don't do bearing calculations for ground traffic
 725        bearing = getBearing(fp->getBearing(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr));
 726        if (bearing < minBearing) {
 727             minBearing = bearing;
 728             if (minBearing < 10) {
 729                  minBearing = 10;
 730             }
 731             if ((minBearing < 360.0) && (minBearing > 10.0)) {
 732                 speedFraction = cos(minBearing *SG_DEGREES_TO_RADIANS);
 733             } else {
 734                 speedFraction = 1.0;
 735             }
 736        }
 737     }
 738     if (trafficRef) {
 739          //cerr << "Tracking callsign : \"" << fgGetString("/ai/track-callsign") << "\"" << endl;
 740 /*         if (trafficRef->getCallSign() == fgGetString("/ai/track-callsign")) {
 741               cerr << trafficRef->getCallSign() << " " << tgt_altitude_ft << " " << _getSpeed() << " "
 742                    << _getAltitude() << " "<< _getLatitude() << " " << _getLongitude() << " " << dist_to_go << " " << lead_dist << " " << curr->name << " " << vs << " " << tgt_vs << " " << bearing << " " << minBearing << " " << speedFraction << endl;
 743          }*/
 744      }
 745     if ((dist_to_go < lead_dist) || (bearing > (minBearing * 1.1))) {
 746         minBearing = 360;
 747         return true;
 748     } else {
 749         return false;
 750     }
 751 }
 752
 753
 754 bool FGAIAircraft::aiTrafficVisible() {
 755   SGGeod userPos(SGGeod::fromDeg(fgGetDouble("/position/longitude-deg"),
 756     fgGetDouble("/position/latitude-deg")));
 757
 758   return (SGGeodesy::distanceNm(userPos, pos) <= TRAFFICTOAIDISTTODIE);
 759 }
 760
 761
 762 /**
 763  * Handle release of parking gate, once were taxiing. Also ensure service time at the gate
 764  * in the case of an arrival.
 765  *
 766  * @param prev
 767  * @return
 768  */
 769
 770 //TODO the trafficRef is the right place for the method
 771 bool FGAIAircraft::handleAirportEndPoints(FGAIFlightPlan::waypoint* prev, time_t now) {
 772     // prepare routing from one airport to another
 773     FGAirport * dep = trafficRef->getDepartureAirport();
 774     FGAirport * arr = trafficRef->getArrivalAirport();
 775
 776     if (!( dep && arr))
 777         return false;
 778
 779     // This waypoint marks the fact that the aircraft has passed the initial taxi
 780     // departure waypoint, so it can release the parking.
 781     //cerr << trafficRef->getCallSign() << " has passed waypoint " << prev->name << " at speed " << speed << endl;
 782     if (prev->name == "PushBackPoint") {
 783         dep->getDynamics()->releaseParking(fp->getGate());
 784         AccelTo(0.0);
 785         setTaxiClearanceRequest(true);
 786     }
 787
 788     // This is the last taxi waypoint, and marks the the end of the flight plan
 789     // so, the schedule should update and wait for the next departure time.
 790     if (prev->name == "END") {
 791         time_t nextDeparture = trafficRef->getDepartureTime();
 792         // make sure to wait at least 20 minutes at parking to prevent "nervous" taxi behavior
 793         if (nextDeparture < (now+1200)) {
 794             nextDeparture = now + 1200;
 795         }
 796         fp->setTime(nextDeparture); // should be "next departure"
 797     }
 798
 799     return true;
 800 }
 801
 802
 803 /**
 804  * Check difference between target bearing and current heading and correct if necessary.
 805  *
 806  * @param curr
 807  */
 808 void FGAIAircraft::controlHeading(FGAIFlightPlan::waypoint* curr) {
 809     double calc_bearing = fp->getBearing(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr);
 810     //cerr << "Bearing = " << calc_bearing << endl;
 811     if (speed < 0) {
 812         calc_bearing +=180;
 813         if (calc_bearing > 360)
 814             calc_bearing -= 360;
 815     }
 816
 817     if (finite(calc_bearing)) {
 818         double hdg_error = calc_bearing - tgt_heading;
 819         if (fabs(hdg_error) > 0.01) {
 820             TurnTo( calc_bearing );
 821         }
 822
 823     } else {
 824         cerr << "calc_bearing is not a finite number : "
 825         << "Speed " << speed
 826         << "pos : " << pos.getLatitudeDeg() << ", " << pos.getLongitudeDeg()
 827         << "waypoint " << curr->latitude << ", " << curr->longitude << endl;
 828         cerr << "waypoint name " << curr->name;
 829         exit(1);                 // FIXME
 830     }
 831 }
 832
 833
 834 /**
 835  * Update the lead distance calculation if speed has changed sufficiently
 836  * to prevent spinning (hopefully);
 837  *
 838  * @param curr
 839  * @param next
 840  */
 841 void FGAIAircraft::controlSpeed(FGAIFlightPlan::waypoint* curr, FGAIFlightPlan::waypoint* next) {
 842     double speed_diff = speed - prevSpeed;
 843
 844     if (fabs(speed_diff) > 10) {
 845         prevSpeed = speed;
 846         if (next) {
 847             fp->setLeadDistance(speed, tgt_heading, curr, next);
 848         }
 849     }
 850 }
 851
 852
 853 /**
 854  * Update target values (heading, alt, speed) depending on flight plan or control properties
 855  */
 856 void FGAIAircraft::updatePrimaryTargetValues(bool& flightplanActive, bool& aiOutOfSight) {
 857     if (fp)                      // AI object has a flightplan
 858     {
 859         //TODO make this a function of AIBase
 860         time_t now = time(NULL) + fgGetLong("/sim/time/warp");
 861         //cerr << "UpateTArgetValues() " << endl;
 862         ProcessFlightPlan(dt, now);
 863
 864         // Do execute Ground elev for inactive aircraft, so they
 865         // Are repositioned to the correct ground altitude when the user flies within visibility range.
 866         // In addition, check whether we are out of user range, so this aircraft
 867         // can be deleted.
 868         if (onGround()) {
 869                 Transform();     // make sure aip is initialized.
 870                 getGroundElev(dt);
 871                 doGroundAltitude();
 872                 // Transform();
 873                 pos.setElevationFt(altitude_ft);
 874         }
 875         if (trafficRef) {
 876            //cerr << trafficRef->getRegistration() << " Setting altitude to " << altitude_ft;
 877             aiOutOfSight = !aiTrafficVisible();
 878             if (aiOutOfSight) {
 879                 setDie(true);
 880                 //cerr << trafficRef->getRegistration() << " is set to die " << endl;
 881                 aiOutOfSight = true;
 882                 return;
 883             }
 884         }
 885         timeElapsed = now - fp->getStartTime();
 886         flightplanActive = fp->isActive(now);
 887     } else {
 888         // no flight plan, update target heading, speed, and altitude
 889         // from control properties.  These default to the initial
 890         // settings in the config file, but can be changed "on the
 891         // fly".
 892         string lat_mode = props->getStringValue("controls/flight/lateral-mode");
 893         if ( lat_mode == "roll" ) {
 894             double angle
 895             = props->getDoubleValue("controls/flight/target-roll" );
 896             RollTo( angle );
 897         } else {
 898             double angle
 899             = props->getDoubleValue("controls/flight/target-hdg" );
 900             TurnTo( angle );
 901         }
 902
 903         string lon_mode
 904         = props->getStringValue("controls/flight/longitude-mode");
 905         if ( lon_mode == "alt" ) {
 906             double alt = props->getDoubleValue("controls/flight/target-alt" );
 907             ClimbTo( alt );
 908         } else {
 909             double angle
 910             = props->getDoubleValue("controls/flight/target-pitch" );
 911             PitchTo( angle );
 912         }
 913
 914         AccelTo( props->getDoubleValue("controls/flight/target-spd" ) );
 915     }
 916 }
 917
 918 void FGAIAircraft::updatePosition() {
 919     // convert speed to degrees per second
 920     double speed_north_deg_sec = cos( hdg * SGD_DEGREES_TO_RADIANS )
 921                                  * speed * 1.686 / ft_per_deg_lat;
 922     double speed_east_deg_sec  = sin( hdg * SGD_DEGREES_TO_RADIANS )
 923                                  * speed * 1.686 / ft_per_deg_lon;
 924
 925     // set new position
 926     pos.setLatitudeDeg( pos.getLatitudeDeg() + speed_north_deg_sec * dt);
 927     pos.setLongitudeDeg( pos.getLongitudeDeg() + speed_east_deg_sec * dt);
 928 }
 929
 930
 931 void FGAIAircraft::updateHeading() {
 932     // adjust heading based on current bank angle
 933     if (roll == 0.0)
 934         roll = 0.01;
 935
 936     if (roll != 0.0) {
 937         // double turnConstant;
 938         //if (no_roll)
 939         //  turnConstant = 0.0088362;
 940         //else
 941         //  turnConstant = 0.088362;
 942         // If on ground, calculate heading change directly
 943         if (onGround()) {
 944             double headingDiff = fabs(hdg-tgt_heading);
 945             double bank_sense = 0.0;
 946         /*
 947         double diff = fabs(hdg - tgt_heading);
 948         if (diff > 180)
 949             diff = fabs(diff - 360);
 950
 951         double sum = hdg + diff;
 952         if (sum > 360.0)
 953             sum -= 360.0;
 954         if (fabs(sum - tgt_heading) < 1.0) {
 955             bank_sense = 1.0;    // right turn
 956         } else {
 957             bank_sense = -1.0;   // left turn
 958         }*/
 959             if (headingDiff > 180)
 960                 headingDiff = fabs(headingDiff - 360);
 961             double sum = hdg + headingDiff;
 962             if (sum > 360.0)
 963                 sum -= 360.0;
 964             if (fabs(sum - tgt_heading) > 0.0001) {
 965                 bank_sense = -1.0;
 966             } else {
 967                 bank_sense = 1.0;
 968             }
 969             //if (trafficRef)
 970             //  cerr << trafficRef->getCallSign() << " Heading "
 971             //         << hdg << ". Target " << tgt_heading <<  ". Diff " << fabs(sum - tgt_heading) << ". Speed " << speed << endl;
 972             //if (headingDiff > 60) {
 973             groundTargetSpeed = tgt_speed; // * cos(headingDiff * SG_DEGREES_TO_RADIANS);
 974                 //groundTargetSpeed = tgt_speed - tgt_speed * (headingDiff/180);
 975             //} else {
 976             //    groundTargetSpeed = tgt_speed;
 977             //}
 978             if (sign(groundTargetSpeed) != sign(tgt_speed))
 979                 groundTargetSpeed = 0.21 * sign(tgt_speed); // to prevent speed getting stuck in 'negative' mode
 980
 981             // Only update the target values when we're not moving because otherwise we might introduce an enormous target change rate while waiting a the gate, or holding.
 982             if (speed != 0) {
 983                 if (headingDiff > 30.0) {
 984                     // invert if pushed backward
 985                     headingChangeRate += 10.0 * dt * sign(roll);
 986
 987                     // Clamp the maximum steering rate to 30 degrees per second,
 988                     // But only do this when the heading error is decreasing.
 989                     if ((headingDiff < headingError)) {
 990                         if (headingChangeRate > 30)
 991                             headingChangeRate = 30;
 992                         else if (headingChangeRate < -30)
 993                             headingChangeRate = -30;
 994                     }
 995                 } else {
 996                     if (speed != 0) {
 997                         if (fabs(headingChangeRate) > headingDiff)
 998                             headingChangeRate = headingDiff*sign(roll);
 999                         else
1000                             headingChangeRate += dt * sign(roll);
1001                     }
1002                 }
1003             }
1004             if (trafficRef)
1005                 //cerr << trafficRef->getCallSign() << " Heading "
1006                 //     << hdg << ". Target " << tgt_heading <<  ". Diff " << fabs(sum - tgt_heading) << ". Speed " << speed << "Heading change rate : " << headingChangeRate << " bacnk sence " << bank_sense << endl;
1007             hdg += headingChangeRate * dt * sqrt(fabs(speed) / 15);
1008             headingError = headingDiff;
1009         } else {
1010             if (fabs(speed) > 1.0) {
1011                 turn_radius_ft = 0.088362 * speed * speed
1012                                  / tan( fabs(roll) / SG_RADIANS_TO_DEGREES );
1013             } else {
1014                 // Check if turn_radius_ft == 0; this might lead to a division by 0.
1015                 turn_radius_ft = 1.0;
1016             }
1017             double turn_circum_ft = SGD_2PI * turn_radius_ft;
1018             double dist_covered_ft = speed * 1.686 * dt;
1019             double alpha = dist_covered_ft / turn_circum_ft * 360.0;
1020             hdg += alpha * sign(roll);
1021         }
1022         while ( hdg > 360.0 ) {
1023             hdg -= 360.0;
1024             spinCounter++;
1025         }
1026         while ( hdg < 0.0) {
1027             hdg += 360.0;
1028             spinCounter--;
1029         }
1030     }
1031 }
1032
1033
1034 void FGAIAircraft::updateBankAngleTarget() {
1035     // adjust target bank angle if heading lock engaged
1036     if (hdg_lock) {
1037         double bank_sense = 0.0;
1038         double diff = fabs(hdg - tgt_heading);
1039         if (diff > 180)
1040             diff = fabs(diff - 360);
1041
1042         double sum = hdg + diff;
1043         if (sum > 360.0)
1044             sum -= 360.0;
1045         if (fabs(sum - tgt_heading) < 1.0) {
1046             bank_sense = 1.0;    // right turn
1047         } else {
1048             bank_sense = -1.0;   // left turn
1049         }
1050         if (diff < _performance->maximumBankAngle()) {
1051             tgt_roll = diff * bank_sense;
1052         } else {
1053             tgt_roll = _performance->maximumBankAngle() * bank_sense;
1054         }
1055         if ((fabs((double) spinCounter) > 1) && (diff > _performance->maximumBankAngle())) {
1056             tgt_speed *= 0.999;  // Ugly hack: If aircraft get stuck, they will continually spin around.
1057             // The only way to resolve this is to make them slow down.
1058         }
1059     }
1060 }
1061
1062
1063 void FGAIAircraft::updateVerticalSpeedTarget() {
1064     // adjust target Altitude, based on ground elevation when on ground
1065     if (onGround()) {
1066         getGroundElev(dt);
1067         doGroundAltitude();
1068     } else if (alt_lock) {
1069         // find target vertical speed
1070         if (use_perf_vs) {
1071             if (altitude_ft < tgt_altitude_ft) {
1072                 tgt_vs = tgt_altitude_ft - altitude_ft;
1073                 if (tgt_vs > _performance->climbRate())
1074                     tgt_vs = _performance->climbRate();
1075             } else {
1076                 tgt_vs = tgt_altitude_ft - altitude_ft;
1077                 if (tgt_vs  < (-_performance->descentRate()))
1078                     tgt_vs = -_performance->descentRate();
1079             }
1080         } else {
1081             double max_vs = 4*(tgt_altitude_ft - altitude_ft);
1082             double min_vs = 100;
1083             if (tgt_altitude_ft < altitude_ft)
1084                 min_vs = -100.0;
1085             if ((fabs(tgt_altitude_ft - altitude_ft) < 1500.0)
1086                     && (fabs(max_vs) < fabs(tgt_vs)))
1087                 tgt_vs = max_vs;
1088
1089             if (fabs(tgt_vs) < fabs(min_vs))
1090                 tgt_vs = min_vs;
1091         }
1092     } //else
1093     //    tgt_vs = 0.0;
1094     checkTcas();
1095 }
1096
1097 void FGAIAircraft::updatePitchAngleTarget() {
1098     // if on ground and above vRotate -> initial rotation
1099     if (onGround() && (speed > _performance->vRotate()))
1100         tgt_pitch = 8.0; // some rough B737 value
1101
1102     //TODO pitch angle on approach and landing
1103
1104     // match pitch angle to vertical speed
1105     else if (tgt_vs > 0) {
1106         tgt_pitch = tgt_vs * 0.005;
1107     } else {
1108         tgt_pitch = tgt_vs * 0.002;
1109     }
1110 }
1111
1112 string FGAIAircraft::atGate() {
1113      string tmp("");
1114      if (fp->getLeg() < 3) {
1115          if (trafficRef) {
1116              if (fp->getGate() > 0) {
1117                  FGParking *park =
1118                      trafficRef->getDepartureAirport()->getDynamics()->getParking(fp->getGate());
1119                  tmp = park->getName();
1120              }
1121          }
1122      }
1123      return tmp;
1124 }
1125
1126 void FGAIAircraft::handleATCRequests() {
1127     //TODO implement NullController for having no ATC to save the conditionals
1128     if (controller) {
1129         controller->updateAircraftInformation(getID(),
1130                                               pos.getLatitudeDeg(),
1131                                               pos.getLongitudeDeg(),
1132                                               hdg,
1133                                               speed,
1134                                               altitude_ft, dt);
1135         processATC(controller->getInstruction(getID()));
1136     }
1137 }
1138
1139 void FGAIAircraft::updateActualState() {
1140     //update current state
1141     //TODO have a single tgt_speed and check speed limit on ground on setting tgt_speed
1142     updatePosition();
1143
1144     if (onGround())
1145         speed = _performance->actualSpeed(this, groundTargetSpeed, dt);
1146     else
1147         speed = _performance->actualSpeed(this, (tgt_speed *speedFraction), dt);
1148
1149     updateHeading();
1150     roll = _performance->actualBankAngle(this, tgt_roll, dt);
1151
1152     // adjust altitude (meters) based on current vertical speed (fpm)
1153     altitude_ft += vs / 60.0 * dt;
1154     pos.setElevationFt(altitude_ft);
1155
1156     vs = _performance->actualVerticalSpeed(this, tgt_vs, dt);
1157     pitch = _performance->actualPitch(this, tgt_pitch, dt);
1158 }
1159
1160 void FGAIAircraft::updateSecondaryTargetValues() {
1161     // derived target state values
1162     updateBankAngleTarget();
1163     updateVerticalSpeedTarget();
1164     updatePitchAngleTarget();
1165
1166     //TODO calculate wind correction angle (tgt_yaw)
1167 }
1168
1169
1170 bool FGAIAircraft::reachedEndOfCruise(double &distance) {
1171     FGAIFlightPlan::waypoint* curr = fp->getCurrentWaypoint();
1172     if (curr->name == "BOD") {
1173         double dist = fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr);
1174         double descentSpeed = (getPerformance()->vDescent() * SG_NM_TO_METER) / 3600.0;     // convert from kts to meter/s
1175         double descentRate  = (getPerformance()->descentRate() * SG_FEET_TO_METER) / 60.0;  // convert from feet/min to meter/s
1176
1177         double verticalDistance  = ((altitude_ft - 2000.0) - trafficRef->getArrivalAirport()->getElevation()) *SG_FEET_TO_METER;
1178         double descentTimeNeeded = verticalDistance / descentRate;
1179         double distanceCovered   = descentSpeed * descentTimeNeeded;
1180
1181         //cerr << "Tracking  : " << fgGetString("/ai/track-callsign");
1182         if (trafficRef->getCallSign() == fgGetString("/ai/track-callsign")) {
1183             cerr << "Checking for end of cruise stage for :" << trafficRef->getCallSign() << endl;
1184             cerr << "Descent rate      : " << descentRate << endl;
1185             cerr << "Descent speed     : " << descentSpeed << endl;
1186             cerr << "VerticalDistance  : " << verticalDistance << ". Altitude : " << altitude_ft << ". Elevation " << trafficRef->getArrivalAirport()->getElevation() << endl;
1187             cerr << "DecentTimeNeeded  : " << descentTimeNeeded << endl;
1188             cerr << "DistanceCovered   : " << distanceCovered   << endl;
1189         }
1190         //cerr << "Distance = " << distance << endl;
1191         distance = distanceCovered;
1192         if (dist < distanceCovered) {
1193               if (trafficRef->getCallSign() == fgGetString("/ai/track-callsign")) {
1194                    //exit(1);
1195               }
1196               return true;
1197         } else {
1198               return false;
1199         }
1200     } else {
1201          return false;
1202     }
1203 }
1204
1205 void FGAIAircraft::resetPositionFromFlightPlan()
1206 {
1207     // the one behind you
1208     FGAIFlightPlan::waypoint* prev = 0;
1209     // the one ahead
1210     FGAIFlightPlan::waypoint* curr = 0;
1211     // the next plus 1
1212     FGAIFlightPlan::waypoint* next = 0;
1213
1214     prev = fp->getPreviousWaypoint();
1215     curr = fp->getCurrentWaypoint();
1216     next = fp->getNextWaypoint();
1217
1218     setLatitude(prev->latitude);
1219     setLongitude(prev->longitude);
1220     double tgt_heading = fp->getBearing(curr, next);
1221     setHeading(tgt_heading);
1222     setAltitude(prev->altitude);
1223     setSpeed(prev->speed);
1224 }
1225
1226 double FGAIAircraft::getBearing(double crse)
1227 {
1228   double hdgDiff = fabs(hdg-crse);
1229   if (hdgDiff > 180)
1230       hdgDiff = fabs(hdgDiff - 360);
1231   return hdgDiff;
1232 }
1233
1234 time_t FGAIAircraft::checkForArrivalTime(string wptName) {
1235      FGAIFlightPlan::waypoint* curr = 0;
1236      curr = fp->getCurrentWaypoint();
1237
1238      double tracklength = fp->checkTrackLength(wptName);
1239      if (tracklength > 0.1) {
1240           tracklength += fp->getDistanceToGo(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr);
1241      } else {
1242          return 0;
1243      }
1244      time_t now = time(NULL) + fgGetLong("/sim/time/warp");
1245      time_t arrivalTime = fp->getArrivalTime();
1246
1247      time_t ete = tracklength / ((speed * SG_NM_TO_METER) / 3600.0);
1248      time_t secondsToGo = arrivalTime - now;
1249      if (trafficRef->getCallSign() == fgGetString("/ai/track-callsign")) {
1250           cerr << "Checking arrival time: ete " << ete << ". Time to go : " << secondsToGo << ". Track length = " << tracklength << endl;
1251      }
1252      return (ete - secondsToGo); // Positive when we're too slow...
1253 }