src/AIModel/AIShip.cxx

   1 // FGAIShip - FGAIBase-derived class creates an AI ship
   2 //
   3 // Written by David Culp, started October 2003.
   4 // with major amendments and additions by Vivian Meazza, 2004 - 2007
   5 //
   6 // This program is free software; you can redistribute it and/or
   7 // modify it under the terms of the GNU General Public License as
   8 // published by the Free Software Foundation; either version 2 of the
   9 // License, or (at your option) any later version.
  10 //
  11 // This program is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with this program; if not, write to the Free Software
  18 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include <config.h>
  22 #endif
  23
  24 #ifdef _MSC_VER
  25 #  include <float.h>
  26 #  define finite _finite
  27 #elif defined(__sun) || defined(sgi)
  28 #  include <ieeefp.h>
  29 #endif
  30
  31 #include <math.h>
  32
  33 #include <simgear/sg_inlines.h>
  34 #include <simgear/math/sg_geodesy.hxx>
  35 #include <simgear/timing/sg_time.hxx>
  36 #include <simgear/math/sg_random.h>
  37
  38 #include <simgear/scene/util/SGNodeMasks.hxx>
  39 #include <Scenery/scenery.hxx>
  40
  41 #include "AIShip.hxx"
  42
  43
  44 FGAIShip::FGAIShip(object_type ot) :
  45 // allow HOT to be enabled
  46 FGAIBase(ot, true),
  47
  48
  49 _waiting(false),
  50 _new_waypoint(true),
  51 _tunnel(false),
  52 _initial_tunnel(false),
  53 _restart(false),
  54 _hdg_constant(0.01),
  55 _limit(100),
  56 _elevation_m(0),
  57 _elevation_ft(0),
  58 _tow_angle(0),
  59 _missed_count(0),
  60 _wp_range(0),
  61 _dt_count(0),
  62 _next_run(0),
  63 _roll_constant(0.001),
  64 _roll_factor(-0.0083335),
  65 _old_range(0),
  66 _range_rate(0),
  67 _missed_time_sec(30),
  68 _day(86400),
  69 _lead_angle(0),
  70 _xtrack_error(0),
  71 _curr_alt(0),
  72 _prev_alt(0),
  73 _until_time(""),
  74 _fp_init(false),
  75 _missed(false)
  76 {
  77         invisible = false;
  78 }
  79
  80 FGAIShip::~FGAIShip() {
  81 }
  82
  83 void FGAIShip::readFromScenario(SGPropertyNode* scFileNode) {
  84
  85     if (!scFileNode)
  86         return;
  87
  88     FGAIBase::readFromScenario(scFileNode);
  89
  90     setRudder(scFileNode->getFloatValue("rudder", 0.0));
  91     setName(scFileNode->getStringValue("name", "Titanic"));
  92     setRadius(scFileNode->getDoubleValue("turn-radius-ft", 2000));
  93     std::string flightplan = scFileNode->getStringValue("flightplan");
  94     setRepeat(scFileNode->getBoolValue("repeat", false));
  95     setRestart(scFileNode->getBoolValue("restart", false));
  96     setStartTime(scFileNode->getStringValue("time", ""));
  97     setLeadAngleGain(scFileNode->getDoubleValue("lead-angle-gain", 1.5));
  98     setLeadAngleLimit(scFileNode->getDoubleValue("lead-angle-limit-deg", 15));
  99     setLeadAngleProp(scFileNode->getDoubleValue("lead-angle-proportion", 0.75));
 100     setRudderConstant(scFileNode->getDoubleValue("rudder-constant", 0.5));
 101     setFixedTurnRadius(scFileNode->getDoubleValue("fixed-turn-radius-ft", 500));
 102     setSpeedConstant(scFileNode->getDoubleValue("speed-constant", 0.5));
 103     setSMPath(scFileNode->getStringValue("submodel-path", ""));
 104     setRollFactor(scFileNode->getDoubleValue("roll-factor", 1));
 105
 106     if (!flightplan.empty()) {
 107         SG_LOG(SG_AI, SG_ALERT, "getting flightplan: " << _name );
 108
 109         FGAIFlightPlan* fp = new FGAIFlightPlan(flightplan);
 110         setFlightPlan(fp);
 111     }
 112
 113 }
 114
 115 bool FGAIShip::init(bool search_in_AI_path) {
 116     prev = 0; // the one behind you
 117     curr = 0; // the one ahead
 118     next = 0; // the next plus 1
 119
 120     props->setStringValue("name", _name.c_str());
 121     props->setStringValue("waypoint/name-prev", _prev_name.c_str());
 122     props->setStringValue("waypoint/name-curr", _curr_name.c_str());
 123     props->setStringValue("waypoint/name-next", _next_name.c_str());
 124     props->setStringValue("submodels/path", _path.c_str());
 125     props->setStringValue("waypoint/start-time", _start_time.c_str());
 126     props->setStringValue("waypoint/wait-until-time", _until_time.c_str());
 127
 128     _hdg_lock = false;
 129     _rudder = 0.0;
 130     no_roll = false;
 131
 132     _rd_turn_radius_ft = _sp_turn_radius_ft = turn_radius_ft;
 133
 134     if (fp)
 135         _fp_init = initFlightPlan();
 136
 137     return FGAIBase::init(search_in_AI_path);
 138 }
 139
 140 void FGAIShip::bind() {
 141     FGAIBase::bind();
 142
 143     props->tie("surface-positions/rudder-pos-deg",
 144         SGRawValuePointer<float>(&_rudder));
 145     props->tie("controls/heading-lock",
 146         SGRawValuePointer<bool>(&_hdg_lock));
 147     props->tie("controls/tgt-speed-kts",
 148         SGRawValuePointer<double>(&tgt_speed));
 149     props->tie("controls/tgt-heading-degs",
 150         SGRawValuePointer<double>(&tgt_heading));
 151     props->tie("controls/constants/rudder",
 152         SGRawValuePointer<double>(&_rudder_constant));
 153     props->tie("controls/constants/roll-factor",
 154         SGRawValuePointer<double>(&_roll_factor));
 155     props->tie("controls/constants/roll",
 156         SGRawValuePointer<double>(&_roll_constant));
 157     props->tie("controls/constants/rudder",
 158         SGRawValuePointer<double>(&_rudder_constant));
 159     props->tie("controls/constants/speed",
 160         SGRawValuePointer<double>(&_speed_constant));
 161     props->tie("waypoint/range-nm",
 162         SGRawValuePointer<double>(&_wp_range));
 163     props->tie("waypoint/brg-deg",
 164         SGRawValuePointer<double>(&_course));
 165     props->tie("waypoint/rangerate-nm-sec",
 166         SGRawValuePointer<double>(&_range_rate));
 167     props->tie("waypoint/new",
 168         SGRawValuePointer<bool>(&_new_waypoint));
 169     props->tie("waypoint/missed",
 170         SGRawValuePointer<bool>(&_missed));
 171     props->tie("waypoint/missed-count-sec",
 172         SGRawValuePointer<double>(&_missed_count));
 173     props->tie("waypoint/missed-range-nm",
 174         SGRawValuePointer<double>(&_missed_range));
 175     props->tie("waypoint/missed-time-sec",
 176         SGRawValuePointer<double>(&_missed_time_sec));
 177     props->tie("waypoint/wait-count-sec",
 178         SGRawValuePointer<double>(&_wait_count));
 179     props->tie("waypoint/xtrack-error-ft",
 180         SGRawValuePointer<double>(&_xtrack_error));
 181     props->tie("waypoint/waiting",
 182         SGRawValuePointer<bool>(&_waiting));
 183     props->tie("waypoint/lead-angle-deg",
 184         SGRawValuePointer<double>(&_lead_angle));
 185     props->tie("waypoint/tunnel",
 186         SGRawValuePointer<bool>(&_tunnel));
 187     props->tie("waypoint/alt-curr-m",
 188         SGRawValuePointer<double>(&_curr_alt));
 189     props->tie("waypoint/alt-prev-m",
 190         SGRawValuePointer<double>(&_prev_alt));
 191     props->tie("submodels/serviceable",
 192         SGRawValuePointer<bool>(&_serviceable));
 193     props->tie("controls/turn-radius-ft",
 194         SGRawValuePointer<double>(&turn_radius_ft));
 195     props->tie("controls/turn-radius-corrected-ft",
 196         SGRawValuePointer<double>(&_rd_turn_radius_ft));
 197     props->tie("controls/constants/lead-angle/gain",
 198         SGRawValuePointer<double>(&_lead_angle_gain));
 199     props->tie("controls/constants/lead-angle/limit-deg",
 200         SGRawValuePointer<double>(&_lead_angle_limit));
 201     props->tie("controls/constants/lead-angle/proportion",
 202         SGRawValuePointer<double>(&_proportion));
 203     props->tie("controls/fixed-turn-radius-ft",
 204         SGRawValuePointer<double>(&_fixed_turn_radius));
 205     props->tie("controls/restart",
 206         SGRawValuePointer<bool>(&_restart));
 207     props->tie("velocities/speed-kts",
 208                 SGRawValuePointer<double>(&speed));
 209 }
 210
 211 void FGAIShip::unbind() {
 212     FGAIBase::unbind();
 213     props->untie("surface-positions/rudder-pos-deg");
 214     props->untie("controls/heading-lock");
 215     props->untie("controls/tgt-speed-kts");
 216     props->untie("controls/tgt-heading-degs");
 217     props->untie("controls/constants/roll");
 218     props->untie("controls/constants/rudder");
 219     props->untie("controls/constants/roll-factor");
 220     props->untie("controls/constants/speed");
 221     props->untie("waypoint/range-nm");
 222     props->untie("waypoint/range-brg-deg");
 223     props->untie("waypoint/rangerate-nm-sec");
 224     props->untie("waypoint/new");
 225     props->untie("waypoint/missed");
 226     props->untie("waypoint/missed-count-sec");
 227     props->untie("waypoint/missed-time-sec");
 228     props->untie("waypoint/missed-range");
 229     props->untie("waypoint/wait-count-sec");
 230     props->untie("waypoint/lead-angle-deg");
 231     props->untie("waypoint/xtrack-error-ft");
 232     props->untie("waypoint/waiting");
 233     props->untie("waypoint/tunnel");
 234     props->untie("waypoint/alt-curr-m");
 235     props->untie("waypoint/alt-prev-m");
 236     props->untie("submodels/serviceable");
 237     props->untie("controls/turn-radius-ft");
 238     props->untie("controls/turn-radius-corrected-ft");
 239     props->untie("controls/constants/lead-angle/gain");
 240     props->untie("controls/constants/lead-angle/limit-deg");
 241     props->untie("controls/constants/lead-angle/proportion");
 242     props->untie("controls/fixed-turn-radius-ft");
 243     props->untie("controls/constants/speed");
 244     props->untie("controls/restart");
 245     props->untie("velocities/speed-kts");
 246
 247 }
 248 void FGAIShip::update(double dt) {
 249     //SG_LOG(SG_AI, SG_ALERT, "updating Ship: " << _name <<hdg<<pitch<<roll);
 250     // For computation of rotation speeds we just use finite differences here.
 251     // That is perfectly valid since this thing is not driven by accelerations
 252     // but by just apply discrete changes at its velocity variables.
 253     // Update the velocity information stored in those nodes.
 254     // Transform that one to the horizontal local coordinate system.
 255     SGQuatd ec2hl = SGQuatd::fromLonLat(pos);
 256     // The orientation of the ship wrt the horizontal local frame
 257     SGQuatd hl2body = SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
 258     // and postrotate the orientation of the AIModel wrt the horizontal
 259     // local frame
 260     SGQuatd ec2body = ec2hl*hl2body;
 261     // The cartesian position of the ship in the wgs84 world
 262     SGVec3d cartPos = SGVec3d::fromGeod(pos);
 263
 264     // The simulation time this transform is meant for
 265     aip.setReferenceTime(globals->get_sim_time_sec());
 266
 267     // Compute the velocity in m/s in the body frame
 268     aip.setBodyLinearVelocity(SGVec3d(0.51444444*speed, 0, 0));
 269
 270     FGAIBase::update(dt);
 271     Run(dt);
 272     Transform();
 273     if (fp)
 274         setXTrackError();
 275
 276     // Only change these values if we are able to compute them safely
 277     if (SGLimits<double>::min() < dt) {
 278         // Now here is the finite difference ...
 279
 280         // Transform that one to the horizontal local coordinate system.
 281         SGQuatd ec2hlNew = SGQuatd::fromLonLat(pos);
 282         // compute the new orientation
 283         SGQuatd hl2bodyNew = SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
 284         // The rotation difference
 285         SGQuatd dOr = inverse(ec2body)*ec2hlNew*hl2bodyNew;
 286         SGVec3d dOrAngleAxis;
 287         dOr.getAngleAxis(dOrAngleAxis);
 288         // divided by the time difference provides a rotation speed vector
 289         dOrAngleAxis /= dt;
 290
 291         aip.setBodyAngularVelocity(dOrAngleAxis);
 292     }
 293 }
 294
 295 void FGAIShip::Run(double dt) {
 296     if (_fp_init)
 297         ProcessFlightPlan(dt);
 298
 299     string type = getTypeString();
 300
 301     double alpha;
 302     double rudder_limit;
 303     double raw_roll;
 304
 305     // adjust speed
 306     double speed_diff = tgt_speed - speed;
 307
 308     if (fabs(speed_diff) > 0.1) {
 309
 310         if (speed_diff > 0.0)
 311             speed += _speed_constant * dt;
 312
 313         if (speed_diff < 0.0)
 314             speed -= _speed_constant * dt;
 315
 316     }
 317
 318     // do not allow unreasonable speeds
 319     SG_CLAMP_RANGE(speed, -_limit * 0.75, _limit);
 320
 321     // convert speed to degrees per second
 322     speed_north_deg_sec = cos(hdg / SGD_RADIANS_TO_DEGREES)
 323         * speed * 1.686 / ft_per_deg_lat;
 324     speed_east_deg_sec = sin(hdg / SGD_RADIANS_TO_DEGREES)
 325         * speed * 1.686 / ft_per_deg_lon;
 326
 327     // set new position
 328     //cout << _name << " " << type << " run: " << _elevation_m << " " <<_elevation_ft << endl;
 329     pos.setLatitudeDeg(pos.getLatitudeDeg() + speed_north_deg_sec * dt);
 330     pos.setLongitudeDeg(pos.getLongitudeDeg() + speed_east_deg_sec * dt);
 331     pos.setElevationFt(tgt_altitude_ft);
 332     pitch = tgt_pitch;
 333
 334     // adjust heading based on current _rudder angle
 335     if (turn_radius_ft <= 0)
 336         turn_radius_ft = 0; // don't allow nonsense values
 337
 338     if (_rudder > 45)
 339         _rudder = 45;
 340
 341     if (_rudder < -45)
 342         _rudder = -45;
 343
 344
 345     //we assume that at slow speed ships will manoeuvre using engines/bow thruster
 346         if(type == "ship" || type == "carrier" || type == "escort"){
 347
 348                 if (fabs(speed)<=5)
 349                         _sp_turn_radius_ft = _fixed_turn_radius;
 350                 else {
 351                         // adjust turn radius for speed. The equation is very approximate.
 352                         // we need to allow for negative speeds
 353                         _sp_turn_radius_ft = 10 * pow ((fabs(speed) - 15), 2) + turn_radius_ft;
 354                 }
 355
 356         } else {
 357
 358                 if (fabs(speed) <= 40)
 359            _sp_turn_radius_ft = _fixed_turn_radius;
 360                 else {
 361                         // adjust turn radius for speed.
 362                         _sp_turn_radius_ft = turn_radius_ft;
 363                 }
 364         }
 365
 366
 367     if (_rudder <= -0.25 || _rudder >= 0.25) {
 368         // adjust turn radius for _rudder angle. The equation is even more approximate.
 369         float a = 19;
 370         float b = -0.2485;
 371         float c = 0.543;
 372
 373         _rd_turn_radius_ft = (a * exp(b * fabs(_rudder)) + c) * _sp_turn_radius_ft;
 374
 375         // calculate the angle, alpha, subtended by the arc traversed in time dt
 376         alpha = ((speed * 1.686 * dt) / _rd_turn_radius_ft) * SG_RADIANS_TO_DEGREES;
 377         //cout << _name << " alpha " << alpha << endl;
 378         // make sure that alpha is applied in the right direction
 379         hdg += alpha * sign(_rudder);
 380
 381         SG_NORMALIZE_RANGE(hdg, 0.0, 360.0);
 382
 383         //adjust roll for rudder angle and speed. Another bit of voodoo
 384         raw_roll = _roll_factor * speed * _rudder;
 385     } else {
 386         // _rudder angle is 0
 387         raw_roll = 0;
 388     }
 389
 390     //low pass filter
 391     if (speed < 0)
 392         roll = -roll;
 393
 394     roll = (raw_roll * _roll_constant) + (roll * (1 - _roll_constant));
 395
 396     // adjust target _rudder angle if heading lock engaged
 397     double rudder_diff = 0.0;
 398     if (_hdg_lock) {
 399         double rudder_sense = 0.0;
 400         double diff = fabs(hdg - tgt_heading);
 401         //cout << "_rudder diff" << diff << endl;
 402         if (diff > 180)
 403             diff = fabs(diff - 360);
 404
 405         double sum = hdg + diff;
 406
 407         if (sum > 360.0)
 408             sum -= 360.0;
 409
 410         if (fabs(sum - tgt_heading)< 1.0)
 411             rudder_sense = 1.0;
 412         else
 413             rudder_sense = -1.0;
 414
 415         if (speed < 0)
 416             rudder_sense = -rudder_sense;
 417
 418         if (diff < 15)
 419             _tgt_rudder = diff * rudder_sense;
 420         else
 421             _tgt_rudder = 45 * rudder_sense;
 422
 423         rudder_diff = _tgt_rudder - _rudder;
 424     }
 425
 426     // set the _rudder limit by speed
 427     if (type == "ship" || type == "carrier" || type == "escort"){
 428
 429         if (speed <= 40)
 430             rudder_limit = (-0.825 * speed) + 35;
 431         else
 432             rudder_limit = 2;
 433
 434     } else
 435         rudder_limit = 20;
 436
 437     if (fabs(rudder_diff)> 0.1) { // apply dead zone
 438
 439         if (rudder_diff > 0.0) {
 440             _rudder += _rudder_constant * dt;
 441
 442             if (_rudder > rudder_limit) // apply the _rudder limit
 443                 _rudder = rudder_limit;
 444
 445         } else if (rudder_diff < 0.0) {
 446             _rudder -= _rudder_constant * dt;
 447
 448             if (_rudder < -rudder_limit)
 449                 _rudder = -rudder_limit;
 450
 451         }
 452
 453         // do calculations for radar
 454         UpdateRadar(manager);
 455     }
 456 }//end function
 457
 458 void FGAIShip::AccelTo(double speed) {
 459     tgt_speed = speed;
 460 }
 461
 462 void FGAIShip::PitchTo(double angle) {
 463     tgt_pitch = angle;
 464 }
 465
 466 void FGAIShip::RollTo(double angle) {
 467     tgt_roll = angle;
 468 }
 469
 470 void FGAIShip::YawTo(double angle) {
 471 }
 472
 473 void FGAIShip::ClimbTo(double altitude) {
 474     tgt_altitude_ft = altitude;
 475     _setAltitude(altitude);
 476 }
 477
 478 void FGAIShip::TurnTo(double heading) {
 479     tgt_heading = heading - _lead_angle + _tow_angle;
 480     SG_NORMALIZE_RANGE(tgt_heading, 0.0, 360.0);
 481     _hdg_lock = true;
 482 }
 483
 484 double FGAIShip::sign(double x) {
 485     if (x < 0.0)
 486         return -1.0;
 487     else
 488         return 1.0;
 489 }
 490
 491 void FGAIShip::setFlightPlan(FGAIFlightPlan* f) {
 492     fp = f;
 493 }
 494
 495 void FGAIShip::setStartTime(const string& st) {
 496     _start_time = st;
 497 }
 498
 499 void FGAIShip::setUntilTime(const string& ut) {
 500     _until_time = ut;
 501     props->setStringValue("waypoint/wait-until-time", _until_time.c_str());
 502 }
 503
 504 void FGAIShip::setCurrName(const string& c) {
 505     _curr_name = c;
 506     props->setStringValue("waypoint/name-curr", _curr_name.c_str());
 507 }
 508
 509 void FGAIShip::setNextName(const string& n) {
 510     _next_name = n;
 511     props->setStringValue("waypoint/name-next", _next_name.c_str());
 512 }
 513
 514 void FGAIShip::setPrevName(const string& p) {
 515     _prev_name = p;
 516     props->setStringValue("waypoint/name-prev", _prev_name.c_str());
 517 }
 518
 519 void FGAIShip::setRepeat(bool r) {
 520     _repeat = r;
 521 }
 522
 523 void FGAIShip::setRestart(bool r) {
 524     _restart = r;
 525 }
 526
 527 void FGAIShip::setMissed(bool m) {
 528     _missed = m;
 529     props->setBoolValue("waypoint/missed", _missed);
 530 }
 531
 532 void FGAIShip::setRudder(float r) {
 533     _rudder = r;
 534 }
 535
 536 void FGAIShip::setRoll(double rl) {
 537     roll = rl;
 538 }
 539
 540 void FGAIShip::setLeadAngleGain(double g) {
 541     _lead_angle_gain = g;
 542 }
 543
 544 void FGAIShip::setLeadAngleLimit(double l) {
 545     _lead_angle_limit = l;
 546 }
 547
 548 void FGAIShip::setLeadAngleProp(double p) {
 549     _proportion = p;
 550 }
 551
 552 void FGAIShip::setRudderConstant(double rc) {
 553     _rudder_constant = rc;
 554 }
 555
 556 void FGAIShip::setSpeedConstant(double sc) {
 557     _speed_constant = sc;
 558 }
 559
 560 void FGAIShip::setFixedTurnRadius(double ftr) {
 561     _fixed_turn_radius = ftr;
 562 }
 563
 564 void FGAIShip::setRollFactor(double rf) {
 565     _roll_factor = rf * -0.0083335;
 566 }
 567
 568 void FGAIShip::setInitialTunnel(bool t) {
 569     _initial_tunnel = t;
 570     setTunnel(_initial_tunnel);
 571 }
 572
 573 void FGAIShip::setTunnel(bool t) {
 574     _tunnel = t;
 575 }
 576
 577 void FGAIShip::setWPNames() {
 578
 579     if (prev != 0)
 580         setPrevName(prev->getName());
 581     else
 582         setPrevName("");
 583
 584     if (curr != 0)
 585         setCurrName(curr->getName());
 586     else{
 587         setCurrName("");
 588         SG_LOG(SG_AI, SG_ALERT, "AIShip: current wp name error" );
 589     }
 590
 591     if (next != 0)
 592         setNextName(next->getName());
 593     else
 594         setNextName("");
 595
 596     SG_LOG(SG_AI, SG_DEBUG, "AIShip: prev wp name " << prev->getName());
 597     SG_LOG(SG_AI, SG_DEBUG, "AIShip: current wp name " << curr->getName());
 598     SG_LOG(SG_AI, SG_DEBUG, "AIShip: next wp name " << next->getName());
 599
 600 }
 601
 602 double FGAIShip::getRange(double lat, double lon, double lat2, double lon2) const {
 603
 604     double course, distance, az2;
 605
 606     //calculate the bearing and range of the second pos from the first
 607     geo_inverse_wgs_84(lat, lon, lat2, lon2, &course, &az2, &distance);
 608     distance *= SG_METER_TO_NM;
 609     return distance;
 610 }
 611
 612 double FGAIShip::getCourse(double lat, double lon, double lat2, double lon2) const {
 613
 614     double course, distance, recip;
 615
 616     //calculate the bearing and range of the second pos from the first
 617     geo_inverse_wgs_84(lat, lon, lat2, lon2, &course, &recip, &distance);
 618     if (tgt_speed >= 0) {
 619         return course;
 620         SG_LOG(SG_AI, SG_DEBUG, "AIShip: course " << course);
 621     } else {
 622         return recip;
 623         SG_LOG(SG_AI, SG_DEBUG, "AIShip: recip " << recip);
 624     }
 625 }
 626
 627 void FGAIShip::ProcessFlightPlan(double dt) {
 628
 629     if ( dt < 0.00001 ) {
 630         return;
 631     }
 632
 633     double time_sec = getDaySeconds();
 634
 635     _dt_count += dt;
 636
 637     ///////////////////////////////////////////////////////////////////////////
 638     // Check Execution time (currently once every 1 sec)
 639     // Add a bit of randomization to prevent the execution of all flight plans
 640     // in synchrony, which can add significant periodic framerate flutter.
 641     ///////////////////////////////////////////////////////////////////////////
 642
 643     //cout << "_start_sec " << _start_sec << " time_sec " << time_sec << endl;
 644     if (_dt_count < _next_run && _start_sec < time_sec)
 645         return;
 646
 647     _next_run = 0.05 + (0.025 * sg_random());
 648
 649     double until_time_sec = 0;
 650     _missed = false;
 651
 652     // check to see if we've reached the point for our next turn
 653     // if the range to the waypoint is less than the calculated turn
 654     // radius we can start the turn to the next leg
 655     _wp_range = getRange(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->getLatitude(), curr->getLongitude());
 656     _range_rate = (_wp_range - _old_range) / _dt_count;
 657     double sp_turn_radius_nm = _sp_turn_radius_ft / 6076.1155;
 658     // we need to try to identify a _missed waypoint
 659
 660     // calculate the time needed to turn through an arc of 90 degrees,
 661     // and allow a time error
 662     if (speed != 0)
 663         _missed_time_sec = 10 + ((SGD_PI * sp_turn_radius_nm * 60 * 60) / (2 * fabs(speed)));
 664     else
 665         _missed_time_sec = 10;
 666
 667     _missed_range = 4 * sp_turn_radius_nm;
 668
 669     //cout << _name << " range_rate " << _range_rate << " " << _new_waypoint<< endl ;
 670     //if ((_range_rate > 0) && !_new_waypoint){
 671     if (_range_rate > 0 && _wp_range < _missed_range && !_new_waypoint){
 672         _missed_count += _dt_count;
 673     }
 674
 675     if (_missed_count >= 120)
 676         setMissed(true);
 677     else if (_missed_count >= _missed_time_sec)
 678         setMissed(true);
 679     else
 680         setMissed(false);
 681
 682     _old_range = _wp_range;
 683     setWPNames();
 684
 685     if ((_wp_range < (sp_turn_radius_nm * 1.25)) || _missed || (_waiting && !_new_waypoint)) {
 686
 687         if (_next_name == "TUNNEL"){
 688             _tunnel = !_tunnel;
 689
 690             SG_LOG(SG_AI, SG_DEBUG, "AIShip: " << _name << " " << sp_turn_radius_nm );
 691
 692             fp->IncrementWaypoint(false);
 693             next = fp->getNextWaypoint();
 694
 695             if (next->getName() == "WAITUNTIL" || next->getName() == "WAIT"
 696                 || next->getName() == "END" || next->getName() == "TUNNEL")
 697                 return;
 698
 699             prev = curr;
 700             fp->IncrementWaypoint(false);
 701             curr = fp->getCurrentWaypoint();
 702             next = fp->getNextWaypoint();
 703
 704         }else if(_next_name == "END" || fp->getNextWaypoint() == 0) {
 705
 706             if (_repeat) {
 707                 SG_LOG(SG_AI, SG_INFO, "AIShip: "<< _name << " Flightplan repeating ");
 708                 fp->restart();
 709                 prev = curr;
 710                 curr = fp->getCurrentWaypoint();
 711                 next = fp->getNextWaypoint();
 712                 setWPNames();
 713                 _wp_range = getRange(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->getLatitude(), curr->getLongitude());
 714                 _old_range = _wp_range;
 715                 _range_rate = 0;
 716                 _new_waypoint = true;
 717                 _missed_count = 0;
 718                 _lead_angle = 0;
 719                 AccelTo(prev->getSpeed());
 720             } else if (_restart){
 721                 SG_LOG(SG_AI, SG_INFO, "AIShip: " << _name << " Flightplan restarting ");
 722                 _missed_count = 0;
 723                 initFlightPlan();
 724             } else {
 725                 SG_LOG(SG_AI, SG_ALERT, "AIShip: " << _name << " Flightplan dying ");
 726                 setDie(true);
 727                 _dt_count = 0;
 728                 return;
 729             }
 730
 731         } else if (_next_name == "WAIT") {
 732
 733             if (_wait_count < next->getTime_sec()) {
 734                 SG_LOG(SG_AI, SG_DEBUG, "AIShip: " << _name << " waiting ");
 735                 setSpeed(0);
 736                 _waiting = true;
 737                 _wait_count += _dt_count;
 738                 _dt_count = 0;
 739                 _lead_angle = 0;
 740                 return;
 741             } else {
 742                 SG_LOG(SG_AI, SG_DEBUG, "AIShip: " << _name
 743                     << " wait done: getting new waypoints ");
 744                 _waiting = false;
 745                 _wait_count = 0;
 746                 fp->IncrementWaypoint(false);
 747                 next = fp->getNextWaypoint();
 748
 749                 if (next->getName() == "WAITUNTIL" || next->getName() == "WAIT"
 750                     || next->getName() == "END" || next->getName() == "TUNNEL")
 751                     return;
 752
 753                 prev = curr;
 754                 fp->IncrementWaypoint(false);
 755                 curr = fp->getCurrentWaypoint();
 756                 next = fp->getNextWaypoint();
 757             }
 758
 759         } else if (_next_name == "WAITUNTIL") {
 760             time_sec = getDaySeconds();
 761             until_time_sec = processTimeString(next->getTime());
 762             _until_time = next->getTime();
 763             setUntilTime(next->getTime());
 764             if (until_time_sec > time_sec) {
 765                 SG_LOG(SG_AI, SG_INFO, "AIShip: " << _name << " "
 766                     << curr->getName() << " waiting until: "
 767                     << _until_time << " " << until_time_sec << " now " << time_sec );
 768                 setSpeed(0);
 769                 _lead_angle = 0;
 770                 _waiting = true;
 771                 return;
 772             } else {
 773                 SG_LOG(SG_AI, SG_INFO, "AIShip: "
 774                     << _name << " wait until done: getting new waypoints ");
 775                 setUntilTime("");
 776                 fp->IncrementWaypoint(false);
 777
 778                 while (next->getName() == "WAITUNTIL") {
 779                     fp->IncrementWaypoint(false);
 780                     next = fp->getNextWaypoint();
 781                 }
 782
 783                 if (next->getName() == "WAIT")
 784                     return;
 785
 786                 prev = curr;
 787                 fp->IncrementWaypoint(false);
 788                 curr = fp->getCurrentWaypoint();
 789                 next = fp->getNextWaypoint();
 790                 _waiting = false;
 791             }
 792
 793         } else {
 794             //now reorganise the waypoints, so that next becomes current and so on
 795             SG_LOG(SG_AI, SG_DEBUG, "AIShip: " << _name << " getting new waypoints ");
 796             fp->IncrementWaypoint(false);
 797             prev = fp->getPreviousWaypoint(); //first waypoint
 798             curr = fp->getCurrentWaypoint();  //second waypoint
 799             next = fp->getNextWaypoint();     //third waypoint (might not exist!)
 800         }
 801
 802         setWPNames();
 803         _new_waypoint = true;
 804         _missed_count = 0;
 805         _range_rate = 0;
 806         _lead_angle = 0;
 807         _wp_range = getRange(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->getLatitude(), curr->getLongitude());
 808         _old_range = _wp_range;
 809         setWPPos();
 810         object_type type = getType();
 811
 812         if (type != 10)
 813             AccelTo(prev->getSpeed());
 814
 815         _curr_alt = curr->getAltitude();
 816         _prev_alt = prev->getAltitude();
 817
 818     } else {
 819         _new_waypoint = false;
 820     }
 821
 822     //   now revise the required course for the next way point
 823     _course = getCourse(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->getLatitude(), curr->getLongitude());
 824
 825     if (finite(_course))
 826         TurnTo(_course);
 827     else
 828         SG_LOG(SG_AI, SG_ALERT, "AIShip: Bearing or Range is not a finite number");
 829
 830     _dt_count = 0;
 831 } // end Processing FlightPlan
 832
 833 bool FGAIShip::initFlightPlan() {
 834
 835     SG_LOG(SG_AI, SG_ALERT, "AIShip: " << _name << " initializing waypoints ");
 836
 837     bool init = false;
 838     _start_sec = 0;
 839     _tunnel = _initial_tunnel;
 840
 841     fp->restart();
 842     fp->IncrementWaypoint(false);
 843
 844     prev = fp->getPreviousWaypoint(); //first waypoint
 845     curr = fp->getCurrentWaypoint();  //second waypoint
 846     next = fp->getNextWaypoint();     //third waypoint (might not exist!)
 847
 848     while (curr->getName() == "WAIT" || curr->getName() == "WAITUNTIL") {  // don't wait when initialising
 849         SG_LOG(SG_AI, SG_DEBUG, "AIShip: " << _name << " re-initializing waypoints ");
 850         fp->IncrementWaypoint(false);
 851         curr = fp->getCurrentWaypoint();
 852         next = fp->getNextWaypoint();
 853     } // end while loop
 854
 855     if (!_start_time.empty()){
 856         _start_sec = processTimeString(_start_time);
 857         double day_sec = getDaySeconds();
 858
 859         if (_start_sec < day_sec){
 860             //cout << "flight plan has already started " << _start_time << endl;
 861             init = advanceFlightPlan(_start_sec, day_sec);
 862
 863         } else if (_start_sec > day_sec && _repeat) {
 864             //cout << "flight plan has not started, " << _start_time;
 865             //cout << "offsetting start time by -24 hrs" << endl;
 866             _start_sec -= _day;
 867             init = advanceFlightPlan(_start_sec, day_sec);
 868         }
 869
 870         if (init)
 871             _start_sec = 0; // set to zero for an immediate start of the Flight Plan
 872         else {
 873             fp->restart();
 874             fp->IncrementWaypoint(false);
 875             prev = fp->getPreviousWaypoint();
 876             curr = fp->getCurrentWaypoint();
 877             next = fp->getNextWaypoint();
 878             return false;
 879         }
 880
 881     } else {
 882         setLatitude(prev->getLatitude());
 883         setLongitude(prev->getLongitude());
 884         setSpeed(prev->getSpeed());
 885     }
 886
 887     setWPNames();
 888     setHeading(getCourse(prev->getLatitude(), prev->getLongitude(), curr->getLatitude(), curr->getLongitude()));
 889     _wp_range = getRange(prev->getLatitude(), prev->getLongitude(), curr->getLatitude(), curr->getLongitude());
 890     _old_range = _wp_range;
 891     _range_rate = 0;
 892     _hdg_lock = true;
 893     _missed = false;
 894     _missed_count = 0;
 895     _new_waypoint = true;
 896
 897     SG_LOG(SG_AI, SG_ALERT, "AIShip: " << _name << " done initialising waypoints " << _tunnel);
 898     if (prev)
 899         init = true;
 900
 901     if (init)
 902         return true;
 903     else
 904         return false;
 905
 906 } // end of initialization
 907
 908
 909 double FGAIShip::processTimeString(const string& theTime) {
 910
 911     int Hour;
 912     int Minute;
 913     int Second;
 914
 915     // first split theTime string into
 916     //  hour, minute, second and convert to int;
 917     Hour   = atoi(theTime.substr(0,2).c_str());
 918     Minute = atoi(theTime.substr(3,5).c_str());
 919     Second = atoi(theTime.substr(6,8).c_str());
 920
 921     // offset by a day-sec to allow for starting a day earlier
 922     double time_seconds = Hour * 3600
 923         + Minute * 60
 924         + Second;
 925
 926     return time_seconds;
 927 }
 928
 929 double FGAIShip::getDaySeconds () {
 930     // Date and time
 931     struct tm *t = globals->get_time_params()->getGmt();
 932
 933     double day_seconds = t->tm_hour * 3600
 934         + t->tm_min * 60
 935         + t->tm_sec;
 936
 937     return day_seconds;
 938 }
 939
 940 bool FGAIShip::advanceFlightPlan (double start_sec, double day_sec) {
 941
 942     double elapsed_sec = start_sec;
 943     double distance_nm = 0;
 944
 945     //cout << "advancing flight plan start_sec: " << start_sec << " " << day_sec << endl;
 946
 947     while ( elapsed_sec < day_sec ) {
 948
 949         if (next->getName() == "END" || fp->getNextWaypoint() == 0) {
 950
 951             if (_repeat ) {
 952                 //cout << _name << ": " << "restarting flightplan" << endl;
 953                 fp->restart();
 954                 curr = fp->getCurrentWaypoint();
 955                 next = fp->getNextWaypoint();
 956             } else {
 957                 //cout << _name << ": " << "ending flightplan" << endl;
 958                 setDie(true);
 959                 return false;
 960             }
 961
 962         } else if (next->getName() == "WAIT") {
 963             //cout << _name << ": begin WAIT: " << prev->name << " ";
 964             //cout << curr->name << " " << next->name << endl;
 965
 966             elapsed_sec += next->getTime_sec();
 967
 968             if ( elapsed_sec >= day_sec)
 969                 continue;
 970
 971             fp->IncrementWaypoint(false);
 972             next = fp->getNextWaypoint();
 973
 974             if (next->getName() != "WAITUNTIL" && next->getName() != "WAIT"
 975                 && next->getName() != "END") {
 976                     prev = curr;
 977                     fp->IncrementWaypoint(false);
 978                     curr = fp->getCurrentWaypoint();
 979                     next = fp->getNextWaypoint();
 980             }
 981
 982         } else if (next->getName() == "WAITUNTIL") {
 983             double until_sec = processTimeString(next->getTime());
 984
 985             if (until_sec > _start_sec && start_sec < 0)
 986                 until_sec -= _day;
 987
 988             if (elapsed_sec < until_sec)
 989                 elapsed_sec = until_sec;
 990
 991             if (elapsed_sec >= day_sec )
 992                 break;
 993
 994             fp->IncrementWaypoint(false);
 995             next = fp->getNextWaypoint();
 996
 997             if (next->getName() != "WAITUNTIL" && next->getName() != "WAIT") {
 998                 prev = curr;
 999                 fp->IncrementWaypoint(false);
1000                 curr = fp->getCurrentWaypoint();
1001                 next = fp->getNextWaypoint();
1002             }
1003
1004             //cout << _name << ": end WAITUNTIL: ";
1005             //cout << prev->name << " " << curr->name << " " << next->name <<  endl;
1006
1007         } else {
1008             distance_nm = getRange(prev->getLatitude(), prev->getLongitude(), curr->getLatitude(), curr->getLongitude());
1009             elapsed_sec += distance_nm * 60 * 60 / prev->getSpeed();
1010
1011             if (elapsed_sec >= day_sec)
1012                 continue;
1013
1014             fp->IncrementWaypoint(false);
1015             prev = fp->getPreviousWaypoint();
1016             curr = fp->getCurrentWaypoint();
1017             next = fp->getNextWaypoint();
1018         }
1019
1020     }   // end while
1021
1022     // the required position lies between the previous and current waypoints
1023     // so we will calculate the distance back up the track from the current waypoint
1024     // then calculate the lat and lon.
1025
1026     //cout << "advancing flight plan done elapsed_sec: " << elapsed_sec
1027     //    << " " << day_sec << endl;
1028
1029     double time_diff = elapsed_sec - day_sec;
1030     double lat, lon, recip;
1031
1032     //cout << " time diff " << time_diff << endl;
1033
1034     if (next->getName() == "WAIT" ){
1035         setSpeed(0);
1036         lat = curr->getLatitude();
1037         lon = curr->getLongitude();
1038         _wait_count= time_diff;
1039         _waiting = true;
1040     } else if (next->getName() == "WAITUNTIL") {
1041         setSpeed(0);
1042         lat = curr->getLatitude();
1043         lon = curr->getLongitude();
1044         _waiting = true;
1045     } else {
1046         setSpeed(prev->getSpeed());
1047         distance_nm = speed * time_diff / (60 * 60);
1048         double brg = getCourse(curr->getLatitude(), curr->getLongitude(), prev->getLatitude(), prev->getLongitude());
1049
1050         //cout << " brg " << brg << " from " << curr->name << " to " << prev->name << " "
1051         //    << " lat "  << curr->latitude << " lon " << curr->longitude
1052         //    << " distance m " << distance_nm * SG_NM_TO_METER << endl;
1053
1054         lat = geo_direct_wgs_84 (curr->getLatitude(), curr->getLongitude(), brg,
1055             distance_nm * SG_NM_TO_METER, &lat, &lon, &recip );
1056         lon = geo_direct_wgs_84 (curr->getLatitude(), curr->getLongitude(), brg,
1057             distance_nm * SG_NM_TO_METER, &lat, &lon, &recip );
1058         recip = geo_direct_wgs_84 (curr->getLatitude(), curr->getLongitude(), brg,
1059             distance_nm * SG_NM_TO_METER, &lat, &lon, &recip );
1060     }
1061
1062     setLatitude(lat);
1063     setLongitude(lon);
1064
1065     return true;
1066 }
1067
1068 void FGAIShip::setWPPos() {
1069
1070     if (curr->getName() == "END" || curr->getName() == "WAIT"
1071         || curr->getName() == "WAITUNTIL" || curr->getName() == "TUNNEL"){
1072             //cout << curr->name << " returning" << endl;
1073             return;
1074     }
1075
1076     double elevation_m = 0;
1077     wppos.setLatitudeDeg(curr->getLatitude());
1078     wppos.setLongitudeDeg(curr->getLongitude());
1079     wppos.setElevationM(0);
1080
1081     if (curr->getOn_ground()){
1082
1083         if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(wppos, 3000),
1084             elevation_m, &_material, 0)){
1085                 wppos.setElevationM(elevation_m);
1086         }
1087
1088         //cout << curr->name << " setting measured  elev " << elevation_m << endl;
1089
1090     } else {
1091         wppos.setElevationM(curr->getAltitude());
1092         //cout << curr->name << " setting FP elev " << elevation_m << endl;
1093     }
1094
1095     curr->setAltitude(wppos.getElevationM());
1096
1097 }
1098
1099 void FGAIShip::setXTrackError() {
1100
1101     double course = getCourse(prev->getLatitude(), prev->getLongitude(),
1102         curr->getLatitude(), curr->getLongitude());
1103     double brg = getCourse(pos.getLatitudeDeg(), pos.getLongitudeDeg(),
1104         curr->getLatitude(), curr->getLongitude());
1105     double xtrack_error_nm = sin((course - brg)* SG_DEGREES_TO_RADIANS) * _wp_range;
1106     double factor = -0.0045 * speed + 1;
1107     double limit = _lead_angle_limit * factor;
1108
1109     if (_wp_range > 0){
1110         _lead_angle = atan2(xtrack_error_nm,(_wp_range * _proportion)) * SG_RADIANS_TO_DEGREES;
1111     } else
1112         _lead_angle = 0;
1113
1114     _lead_angle *= _lead_angle_gain * factor;
1115     _xtrack_error = xtrack_error_nm * 6076.1155;
1116
1117     SG_CLAMP_RANGE(_lead_angle, -limit, limit);
1118
1119 }