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 #include <simgear/scene/util/SGNodeMasks.hxx>
  38
  39 #include "AIShip.hxx"
  40
  41
  42 FGAIShip::FGAIShip(object_type ot) :
  43     FGAIBase(ot),
  44     _dt_count(0),
  45     _next_run(0)
  46 {
  47 }
  48
  49 FGAIShip::~FGAIShip() {
  50 }
  51
  52 void FGAIShip::readFromScenario(SGPropertyNode* scFileNode) {
  53
  54     if (!scFileNode)
  55         return;
  56
  57     FGAIBase::readFromScenario(scFileNode);
  58
  59     setRudder(scFileNode->getFloatValue("rudder", 0.0));
  60     setName(scFileNode->getStringValue("name", "Titanic"));
  61     setRadius(scFileNode->getDoubleValue("turn-radius-ft", 2000));
  62     std::string flightplan = scFileNode->getStringValue("flightplan");
  63     setRepeat(scFileNode->getBoolValue("repeat", false));
  64     setStartTime(scFileNode->getStringValue("time", ""));
  65
  66     if (!flightplan.empty()) {
  67         FGAIFlightPlan* fp = new FGAIFlightPlan(flightplan);
  68         setFlightPlan(fp);
  69     }
  70
  71 }
  72
  73 bool FGAIShip::init(bool search_in_AI_path) {
  74     prev = 0; // the one behind you
  75     curr = 0; // the one ahead
  76     next = 0; // the next plus 1
  77
  78     _until_time = "";
  79
  80     props->setStringValue("name", _name.c_str());
  81     props->setStringValue("position/waypoint-name-prev", _prev_name.c_str());
  82     props->setStringValue("position/waypoint-name-curr", _curr_name.c_str());
  83     props->setStringValue("position/waypoint-name-next", _next_name.c_str());
  84     props->setStringValue("submodels/path", _path.c_str());
  85     props->setStringValue("position/waypoint-start-time", _start_time.c_str());
  86     props->setStringValue("position/waypoint-wait-until-time", _until_time.c_str());
  87
  88     _hdg_lock = false;
  89     _rudder = 0.0;
  90     no_roll = false;
  91
  92     _rudder_constant = 0.5;
  93     _roll_constant = 0.001;
  94     _speed_constant = 0.05;
  95     _hdg_constant = 0.01;
  96     _roll_factor = -0.0083335;
  97
  98     _rd_turn_radius_ft = _sp_turn_radius_ft = turn_radius_ft;
  99
 100     _fp_init = false;
 101     _missed = false;
 102     _waiting = false;
 103     _new_waypoint = true;
 104
 105     _missed_count = 0;
 106     _wait_count = 0;
 107     _missed_time_sec = 30;
 108
 109     _day = 86400;
 110
 111
 112     _wp_range = _old_range = 0;
 113     _range_rate = 0;
 114
 115     if (fp)
 116         _fp_init = initFlightPlan();
 117
 118     return FGAIBase::init(search_in_AI_path);
 119 }
 120
 121 void FGAIShip::initModel(osg::Node *node) {
 122     FGAIBase::initModel(node);
 123     model->setNodeMask(model->getNodeMask() | SG_NODEMASK_TERRAIN_BIT);
 124 }
 125
 126 void FGAIShip::bind() {
 127     FGAIBase::bind();
 128
 129     props->tie("surface-positions/rudder-pos-deg",
 130         SGRawValuePointer<float>(&_rudder));
 131     props->tie("controls/heading-lock",
 132         SGRawValuePointer<bool>(&_hdg_lock));
 133     props->tie("controls/tgt-speed-kts",
 134         SGRawValuePointer<double>(&tgt_speed));
 135     props->tie("controls/tgt-heading-degs",
 136         SGRawValuePointer<double>(&tgt_heading));
 137     props->tie("controls/constants/rudder",
 138         SGRawValuePointer<double>(&_rudder_constant));
 139     props->tie("controls/constants/roll-factor",
 140         SGRawValuePointer<double>(&_roll_factor));
 141     props->tie("controls/constants/roll",
 142         SGRawValuePointer<double>(&_roll_constant));
 143     props->tie("controls/constants/rudder",
 144         SGRawValuePointer<double>(&_rudder_constant));
 145     props->tie("controls/constants/speed",
 146         SGRawValuePointer<double>(&_speed_constant));
 147     props->tie("position/waypoint-range-nm",
 148         SGRawValuePointer<double>(&_wp_range));
 149     props->tie("position/waypoint-range-old-nm",
 150         SGRawValuePointer<double>(&_old_range));
 151     props->tie("position/waypoint-range-rate-nm-sec",
 152         SGRawValuePointer<double>(&_range_rate));
 153     props->tie("position/waypoint-new",
 154         SGRawValuePointer<bool>(&_new_waypoint));
 155     props->tie("position/waypoint-missed",
 156         SGRawValuePointer<bool>(&_missed));
 157     props->tie("position/waypoint-missed-count",
 158         SGRawValuePointer<double>(&_missed_count));
 159     props->tie("position/waypoint-missed-time-sec",
 160         SGRawValuePointer<double>(&_missed_time_sec));
 161     props->tie("position/waypoint-wait-count",
 162         SGRawValuePointer<double>(&_wait_count));
 163     props->tie("position/waypoint-waiting",
 164         SGRawValuePointer<bool>(&_waiting));
 165     props->tie("submodels/serviceable",
 166         SGRawValuePointer<bool>(&_serviceable));
 167     props->tie("controls/turn-radius-ft",
 168         SGRawValuePointer<double>(&turn_radius_ft));
 169 }
 170
 171 void FGAIShip::unbind() {
 172     FGAIBase::unbind();
 173     props->untie("surface-positions/rudder-pos-deg");
 174     props->untie("controls/heading-lock");
 175     props->untie("controls/tgt-speed-kts");
 176     props->untie("controls/tgt-heading-degs");
 177     props->untie("controls/constants/roll");
 178     props->untie("controls/constants/rudder");
 179     props->untie("controls/constants/roll-factor");
 180     props->untie("controls/constants/speed");
 181     props->untie("position/waypoint-range-nm");
 182     props->untie("position/waypoint-range-old-nm");
 183     props->untie("position/waypoint-range-rate-nm-sec");
 184     props->untie("position/waypoint-new");
 185     props->untie("position/waypoint-missed");
 186     props->untie("position/waypoint-missed-count");
 187     props->untie("position/waypoint-missed-time-sec");
 188     props->untie("position/waypoint-wait-count");
 189     props->untie("position/waypoint-waiting");
 190     props->untie("submodels/serviceable");
 191     props->untie("controls/turn-radius-ft");
 192 }
 193
 194 void FGAIShip::update(double dt) {
 195     // For computation of rotation speeds we just use finite differences here.
 196     // That is perfectly valid since this thing is not driven by accelerations
 197     // but by just apply discrete changes at its velocity variables.
 198     // Update the velocity information stored in those nodes.
 199     // Transform that one to the horizontal local coordinate system.
 200     SGQuatd ec2hl = SGQuatd::fromLonLat(pos);
 201     // The orientation of the carrier wrt the horizontal local frame
 202     SGQuatd hl2body = SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
 203     // and postrotate the orientation of the AIModel wrt the horizontal
 204     // local frame
 205     SGQuatd ec2body = ec2hl*hl2body;
 206     // The cartesian position of the carrier in the wgs84 world
 207     SGVec3d cartPos = SGVec3d::fromGeod(pos);
 208
 209     // The simulation time this transform is meant for
 210     aip.setReferenceTime(globals->get_sim_time_sec());
 211
 212     // Compute the velocity in m/s in the body frame
 213     aip.setBodyLinearVelocity(SGVec3d(0.51444444*speed, 0, 0));
 214
 215     FGAIBase::update(dt);
 216     Run(dt);
 217     Transform();
 218
 219     // Only change these values if we are able to compute them safely
 220     if (SGLimits<double>::min() < dt) {
 221         // Now here is the finite difference ...
 222
 223         // Transform that one to the horizontal local coordinate system.
 224         SGQuatd ec2hlNew = SGQuatd::fromLonLat(pos);
 225         // compute the new orientation
 226         SGQuatd hl2bodyNew = SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
 227         // The rotation difference
 228         SGQuatd dOr = inverse(ec2body)*ec2hlNew*hl2bodyNew;
 229         SGVec3d dOrAngleAxis;
 230         dOr.getAngleAxis(dOrAngleAxis);
 231         // divided by the time difference provides a rotation speed vector
 232         dOrAngleAxis /= dt;
 233
 234         aip.setBodyAngularVelocity(dOrAngleAxis);
 235     }
 236 }
 237
 238 void FGAIShip::Run(double dt) {
 239     //cout << _name << " init: " << _fp_init << endl;
 240     if (_fp_init)
 241         ProcessFlightPlan(dt);
 242
 243     //    double speed_north_deg_sec;
 244     //    double speed_east_deg_sec;
 245     double alpha;
 246     double rudder_limit;
 247     double raw_roll;
 248
 249     // adjust speed
 250     double speed_diff = tgt_speed - speed;
 251
 252     if (fabs(speed_diff) > 0.1) {
 253
 254         if (speed_diff > 0.0)
 255             speed += _speed_constant * dt;
 256
 257         if (speed_diff < 0.0)
 258             speed -= _speed_constant * dt;
 259
 260     }
 261
 262     // do not allow unreasonable ship speeds
 263     if (speed > 40)
 264         speed = 40;
 265
 266     // convert speed to degrees per second
 267     speed_north_deg_sec = cos(hdg / SGD_RADIANS_TO_DEGREES)
 268         * speed * 1.686 / ft_per_deg_lat;
 269     speed_east_deg_sec = sin(hdg / SGD_RADIANS_TO_DEGREES)
 270         * speed * 1.686 / ft_per_deg_lon;
 271
 272     // set new position
 273     pos.setLatitudeDeg(pos.getLatitudeDeg() + speed_north_deg_sec * dt);
 274     pos.setLongitudeDeg(pos.getLongitudeDeg() + speed_east_deg_sec * dt);
 275
 276     // adjust heading based on current _rudder angle
 277     if (turn_radius_ft <= 0)
 278         turn_radius_ft = 0; // don't allow nonsense values
 279
 280     if (_rudder > 45)
 281         _rudder = 45;
 282
 283     if (_rudder < -45)
 284         _rudder = -45;
 285
 286     //we assume that at slow speed ships will manoeuvre using engines/bow thruster
 287     if (fabs(speed)<=5)
 288         _sp_turn_radius_ft = 500;
 289     else
 290         // adjust turn radius for speed. The equation is very approximate.
 291         // we need to allow for negative speeds
 292         _sp_turn_radius_ft = 10 * pow ((fabs(speed) - 15), 2) + turn_radius_ft;
 293
 294     if (_rudder <= -0.25 || _rudder >= 0.25) {
 295         // adjust turn radius for _rudder angle. The equation is even more approximate.
 296         float a = 19;
 297         float b = -0.2485;
 298         float c = 0.543;
 299
 300         _rd_turn_radius_ft = (a * exp(b * fabs(_rudder)) + c) * _sp_turn_radius_ft;
 301
 302         // calculate the angle, alpha, subtended by the arc traversed in time dt
 303         alpha = ((speed * 1.686 * dt) / _rd_turn_radius_ft) * SG_RADIANS_TO_DEGREES;
 304
 305         // make sure that alpha is applied in the right direction
 306         hdg += alpha * sign(_rudder);
 307
 308         SG_NORMALIZE_RANGE(hdg, 0.0, 360.0);
 309
 310         //adjust roll for rudder angle and speed. Another bit of voodoo
 311         raw_roll = _roll_factor * speed * _rudder;
 312     } else {
 313         // _rudder angle is 0
 314         raw_roll = 0;
 315     }
 316
 317     //low pass filter
 318     if (speed < 0)
 319         roll = -roll;
 320
 321     roll = (raw_roll * _roll_constant) + (roll * (1 - _roll_constant));
 322
 323     // adjust target _rudder angle if heading lock engaged
 324     double rudder_diff = 0.0;
 325     if (_hdg_lock) {
 326         double rudder_sense = 0.0;
 327         double diff = fabs(hdg - tgt_heading);
 328         //cout << "_rudder diff" << diff << endl;
 329         if (diff > 180)
 330             diff = fabs(diff - 360);
 331
 332         double sum = hdg + diff;
 333
 334         if (sum > 360.0)
 335             sum -= 360.0;
 336
 337         if (fabs(sum - tgt_heading)< 1.0)
 338             rudder_sense = 1.0;
 339         else
 340             rudder_sense = -1.0;
 341
 342         if (speed < 0)
 343             rudder_sense = -rudder_sense;
 344
 345         if (diff < 15)
 346             _tgt_rudder = diff * rudder_sense;
 347         else
 348             _tgt_rudder = 45 * rudder_sense;
 349
 350         rudder_diff = _tgt_rudder - _rudder;
 351     }
 352
 353     // set the _rudder limit by speed
 354     if (speed <= 40)
 355         rudder_limit = (-0.825 * speed) + 35;
 356     else
 357         rudder_limit = 2;
 358
 359     if (fabs(rudder_diff)> 0.1) { // apply dead zone
 360
 361         if (rudder_diff > 0.0) {
 362             _rudder += _rudder_constant * dt;
 363
 364             if (_rudder > rudder_limit) // apply the _rudder limit
 365                 _rudder = rudder_limit;
 366
 367         } else if (rudder_diff < 0.0) {
 368             _rudder -= _rudder_constant * dt;
 369
 370             if (_rudder < -rudder_limit)
 371                 _rudder = -rudder_limit;
 372
 373         }
 374
 375         // do calculations for radar
 376         UpdateRadar(manager);
 377     }
 378 }//end function
 379
 380 void FGAIShip::AccelTo(double speed) {
 381     tgt_speed = speed;
 382 }
 383
 384 void FGAIShip::PitchTo(double angle) {
 385     tgt_pitch = angle;
 386 }
 387
 388 void FGAIShip::RollTo(double angle) {
 389     tgt_roll = angle;
 390 }
 391
 392 void FGAIShip::YawTo(double angle) {
 393 }
 394
 395 void FGAIShip::ClimbTo(double altitude) {
 396 }
 397
 398
 399 void FGAIShip::TurnTo(double heading) {
 400     tgt_heading = heading;
 401     _hdg_lock = true;
 402 }
 403
 404 double FGAIShip::sign(double x) {
 405     if (x < 0.0)
 406         return -1.0;
 407     else
 408         return 1.0;
 409 }
 410
 411 void FGAIShip::setFlightPlan(FGAIFlightPlan* f) {
 412     fp = f;
 413 }
 414
 415 void FGAIShip::setName(const string& n) {
 416     _name = n;
 417 }
 418
 419 void FGAIShip::setStartTime(const string& st) {
 420     _start_time = st;
 421 }
 422
 423 void FGAIShip::setUntilTime(const string& ut) {
 424     _until_time = ut;
 425     props->setStringValue("position/waypoint-wait-until-time", _until_time.c_str());
 426 }
 427
 428 void FGAIShip::setCurrName(const string& c) {
 429     _curr_name = c;
 430     props->setStringValue("position/waypoint-name-curr", _curr_name.c_str());
 431 }
 432
 433 void FGAIShip::setNextName(const string& n) {
 434     _next_name = n;
 435     props->setStringValue("position/waypoint-name-next", _next_name.c_str());
 436 }
 437
 438 void FGAIShip::setPrevName(const string& p) {
 439     _prev_name = p;
 440     props->setStringValue("position/waypoint-name-prev", _prev_name.c_str());
 441 }
 442
 443 void FGAIShip::setRepeat(bool r) {
 444     _repeat = r;
 445 }
 446
 447 void FGAIShip::setMissed(bool m) {
 448     _missed = m;
 449     props->setBoolValue("position/waypoint-missed", _missed);
 450 }
 451
 452 void FGAIShip::setRudder(float r) {
 453     _rudder = r;
 454 }
 455
 456 void FGAIShip::setRoll(double rl) {
 457     roll = rl;
 458 }
 459
 460 void FGAIShip::setWPNames() {
 461
 462     if (prev != 0)
 463         setPrevName(prev->name);
 464     else
 465         setPrevName("");
 466
 467     setCurrName(curr->name);
 468
 469     if (next != 0)
 470         setNextName(next->name);
 471     else
 472         setNextName("");
 473
 474     SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: prev wp name " << prev->name);
 475     SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: current wp name " << curr->name);
 476     SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: next wp name " << next->name);
 477
 478 }
 479
 480 double FGAIShip::getRange(double lat, double lon, double lat2, double lon2) const {
 481
 482     double course, distance, az2;
 483
 484     //calculate the bearing and range of the second pos from the first
 485     geo_inverse_wgs_84(lat, lon, lat2, lon2, &course, &az2, &distance);
 486     distance *= SG_METER_TO_NM;
 487     return distance;
 488 }
 489
 490 double FGAIShip::getCourse(double lat, double lon, double lat2, double lon2) const {
 491
 492     double course, distance, recip;
 493
 494     //calculate the bearing and range of the second pos from the first
 495     geo_inverse_wgs_84(lat, lon, lat2, lon2, &course, &recip, &distance);
 496     if (tgt_speed >= 0) {
 497         return course;
 498     } else {
 499         return recip;
 500     }
 501 }
 502
 503 void FGAIShip::ProcessFlightPlan(double dt) {
 504
 505     double time_sec = getDaySeconds();
 506     double until_time_sec = 0;
 507
 508     _missed = false;
 509     _dt_count += dt;
 510
 511     ///////////////////////////////////////////////////////////////////////////
 512     // Check Execution time (currently once every 1 sec)
 513     // Add a bit of randomization to prevent the execution of all flight plans
 514     // in synchrony, which can add significant periodic framerate flutter.
 515     ///////////////////////////////////////////////////////////////////////////
 516
 517     //cout << "_start_sec " << _start_sec << " time_sec " << time_sec << endl;
 518     if (_dt_count < _next_run && _start_sec < time_sec)
 519         return;
 520
 521     _next_run = 1.0 + (0.5 * sg_random());
 522
 523     // check to see if we've reached the point for our next turn
 524     // if the range to the waypoint is less than the calculated turn
 525     // radius we can start the turn to the next leg
 526     _wp_range = getRange(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->latitude, curr->longitude);
 527     _range_rate = (_wp_range - _old_range) / _dt_count;
 528     double sp_turn_radius_nm = _sp_turn_radius_ft / 6076.1155;
 529
 530     // we need to try to identify a _missed waypoint
 531
 532     // calculate the time needed to turn through an arc of 90 degrees, and allow an error of 30 secs
 533     if (speed != 0)
 534         _missed_time_sec = 30 + ((SGD_PI * sp_turn_radius_nm * 60 * 60) / (2 * fabs(speed)));
 535     else
 536         _missed_time_sec = 30;
 537
 538     if ((_range_rate > 0) && (_wp_range < 3 * sp_turn_radius_nm) && !_new_waypoint)
 539         _missed_count += _dt_count;
 540
 541     if (_missed_count >= _missed_time_sec) {
 542         setMissed(true);
 543     } else {
 544         setMissed(false);
 545     }
 546
 547     _old_range = _wp_range;
 548     setWPNames();
 549
 550     if ((_wp_range < sp_turn_radius_nm) || _missed || _waiting && !_new_waypoint) {
 551
 552         if (_next_name == "END") {
 553
 554             if (_repeat) {
 555                 SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: Flightplan restarting ");
 556                 fp->restart();
 557                 prev = curr;
 558                 curr = fp->getCurrentWaypoint();
 559                 next = fp->getNextWaypoint();
 560                 setWPNames();
 561                 _wp_range = getRange(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->latitude, curr->longitude);
 562                 _old_range = _wp_range;
 563                 _range_rate = 0;
 564                 _new_waypoint = true;
 565                 _missed_count = 0;
 566                 AccelTo(prev->speed);
 567             } else {
 568                 SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: Flightplan dieing ");
 569                 setDie(true);
 570                 _dt_count = 0;
 571                 return;
 572             }
 573
 574         } else if (_next_name == "WAIT") {
 575
 576             if (_wait_count < next->time_sec) {
 577                 SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name << " waiting ");
 578                 setSpeed(0);
 579                 _waiting = true;
 580                 _wait_count += _dt_count;
 581                 _dt_count = 0;
 582                 return;
 583             } else {
 584                 SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name
 585                     << " wait done: getting new waypoints ");
 586                 _waiting = false;
 587                 _wait_count = 0;
 588                 fp->IncrementWaypoint(false);
 589                 next = fp->getNextWaypoint();
 590
 591                 if (next->name == "WAITUNTIL" || next->name == "WAIT"
 592                         || next->name == "END")
 593                     return;
 594
 595                 prev = curr;
 596                 fp->IncrementWaypoint(false);
 597                 curr = fp->getCurrentWaypoint();
 598                 next = fp->getNextWaypoint();
 599             }
 600
 601         } else if (_next_name == "WAITUNTIL") {
 602             time_sec = getDaySeconds();
 603             until_time_sec = processTimeString(next->time);
 604             _until_time = next->time;
 605             setUntilTime(next->time);
 606             if (until_time_sec > time_sec) {
 607                 SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name << " waiting until: "
 608                     << _until_time << " " << until_time_sec << " now " << time_sec );
 609                 setSpeed(0);
 610                 _waiting = true;
 611                 return;
 612             } else {
 613                 SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: "
 614                     << _name << " wait until done: getting new waypoints ");
 615                 setUntilTime("");
 616                 fp->IncrementWaypoint(false);
 617
 618                 while (next->name == "WAITUNTIL") {
 619                     fp->IncrementWaypoint(false);
 620                     next = fp->getNextWaypoint();
 621                 }
 622
 623                 if (next->name == "WAIT")
 624                     return;
 625
 626                 prev = curr;
 627                 fp->IncrementWaypoint(false);
 628                 curr = fp->getCurrentWaypoint();
 629                 next = fp->getNextWaypoint();
 630                 _waiting = false;
 631             }
 632
 633         } else {
 634             //now reorganise the waypoints, so that next becomes current and so on
 635             SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name << " getting new waypoints ");
 636             fp->IncrementWaypoint(false);
 637             prev = fp->getPreviousWaypoint(); //first waypoint
 638             curr = fp->getCurrentWaypoint();  //second waypoint
 639             next = fp->getNextWaypoint();     //third waypoint (might not exist!)
 640         }
 641
 642         setWPNames();
 643         _new_waypoint = true;
 644         _missed_count = 0;
 645         _range_rate = 0;
 646         _wp_range = getRange(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->latitude, curr->longitude);
 647         _old_range = _wp_range;
 648         AccelTo(prev->speed);
 649     } else {
 650         _new_waypoint = false;
 651     }
 652
 653     //   now revise the required course for the next way point
 654     double course = getCourse(pos.getLatitudeDeg(), pos.getLongitudeDeg(), curr->latitude, curr->longitude);
 655
 656     if (finite(course))
 657         TurnTo(course);
 658     else
 659         SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: Bearing or Range is not a finite number");
 660
 661      _dt_count = 0;
 662 } // end Processing FlightPlan
 663
 664 bool FGAIShip::initFlightPlan() {
 665
 666     SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name << " initializing waypoints ");
 667
 668     bool init = false;
 669
 670     _start_sec = 0;
 671
 672     fp->restart();
 673     fp->IncrementWaypoint(false);
 674
 675     prev = fp->getPreviousWaypoint(); //first waypoint
 676     curr = fp->getCurrentWaypoint();  //second waypoint
 677     next = fp->getNextWaypoint();     //third waypoint (might not exist!)
 678
 679     while (curr->name == "WAIT" || curr->name == "WAITUNTIL") {  // don't wait when initialising
 680         SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name << " re-initializing waypoints ");
 681         fp->IncrementWaypoint(false);
 682         curr = fp->getCurrentWaypoint();
 683         next = fp->getNextWaypoint();
 684     }
 685
 686     if (!_start_time.empty()){
 687         _start_sec = processTimeString(_start_time);
 688         double day_sec = getDaySeconds();
 689
 690         if (_start_sec < day_sec){
 691             //cout << "flight plan has already started " << _start_time << endl;
 692             init = advanceFlightPlan(_start_sec, day_sec);
 693
 694         } else if (_start_sec > day_sec && _repeat) {
 695             //cout << "flight plan has not started, " << _start_time;
 696             //cout << "offsetting start time by -24 hrs" << endl;
 697             _start_sec -= _day;
 698             init = advanceFlightPlan(_start_sec, day_sec);
 699         }
 700
 701         if (init)
 702             _start_sec = 0; // set to zero for an immediate start of the Flight Plan
 703         else {
 704             fp->restart();
 705             fp->IncrementWaypoint(false);
 706             prev = fp->getPreviousWaypoint();
 707             curr = fp->getCurrentWaypoint();
 708             next = fp->getNextWaypoint();
 709             return false;
 710         }
 711
 712     } else {
 713     setLatitude(prev->latitude);
 714     setLongitude(prev->longitude);
 715     setSpeed(prev->speed);
 716     }
 717
 718     setWPNames();
 719     setHeading(getCourse(prev->latitude, prev->longitude, curr->latitude, curr->longitude));
 720     _wp_range = getRange(prev->latitude, prev->longitude, curr->latitude, curr->longitude);
 721     _old_range = _wp_range;
 722     _range_rate = 0;
 723     _hdg_lock = true;
 724     _missed = false;
 725     _missed_count = 0;
 726     _new_waypoint = true;
 727
 728     SG_LOG(SG_GENERAL, SG_DEBUG, "AIShip: " << _name << " done initialising waypoints ");
 729     if (prev)
 730         init = true;
 731
 732     if (init)
 733         return true;
 734     else
 735         return false;
 736
 737 } // end of initialization
 738
 739
 740 double FGAIShip::processTimeString(const string& theTime) {
 741
 742     int Hour;
 743     int Minute;
 744     int Second;
 745
 746     // first split theTime string into
 747     //  hour, minute, second and convert to int;
 748     Hour   = atoi(theTime.substr(0,2).c_str());
 749     Minute = atoi(theTime.substr(3,5).c_str());
 750     Second = atoi(theTime.substr(6,8).c_str());
 751
 752     // offset by a day-sec to allow for starting a day earlier
 753     double time_seconds = Hour * 3600
 754         + Minute * 60
 755         + Second;
 756
 757     return time_seconds;
 758 }
 759
 760 double FGAIShip::getDaySeconds () {
 761     // Date and time
 762     struct tm *t = globals->get_time_params()->getGmt();
 763
 764     double day_seconds = t->tm_hour * 3600
 765         + t->tm_min * 60
 766         + t->tm_sec;
 767
 768     return day_seconds;
 769 }
 770
 771 bool FGAIShip::advanceFlightPlan (double start_sec, double day_sec) {
 772
 773     double elapsed_sec = start_sec;
 774     double distance_nm = 0;
 775
 776     //cout << "advancing flight plan start_sec: " << start_sec << " " << day_sec << endl;
 777
 778     while ( elapsed_sec < day_sec ) {
 779
 780         if (next->name == "END") {
 781
 782             if (_repeat ) {
 783                 //cout << _name << ": " << "restarting flightplan" << endl;
 784                 fp->restart();
 785                 curr = fp->getCurrentWaypoint();
 786                 next = fp->getNextWaypoint();
 787             } else {
 788                 //cout << _name << ": " << "ending flightplan" << endl;
 789                 setDie(true);
 790                 return false;
 791             }
 792
 793         } else if (next->name == "WAIT") {
 794             //cout << _name << ": begin WAIT: " << prev->name << " ";
 795             //cout << curr->name << " " << next->name << endl;
 796
 797             elapsed_sec += next->time_sec;
 798
 799             if ( elapsed_sec >= day_sec)
 800                 continue;
 801
 802             fp->IncrementWaypoint(false);
 803             next = fp->getNextWaypoint();
 804
 805             if (next->name != "WAITUNTIL" && next->name != "WAIT"
 806                     && next->name != "END") {
 807                 prev = curr;
 808                 fp->IncrementWaypoint(false);
 809                 curr = fp->getCurrentWaypoint();
 810                 next = fp->getNextWaypoint();
 811             }
 812
 813         } else if (next->name == "WAITUNTIL") {
 814             double until_sec = processTimeString(next->time);
 815
 816             if (until_sec > _start_sec && start_sec < 0)
 817                 until_sec -= _day;
 818
 819             if (elapsed_sec < until_sec)
 820                 elapsed_sec = until_sec;
 821
 822             if (elapsed_sec >= day_sec )
 823                 break;
 824
 825             fp->IncrementWaypoint(false);
 826             next = fp->getNextWaypoint();
 827
 828             if (next->name != "WAITUNTIL" && next->name != "WAIT") {
 829                 prev = curr;
 830                 fp->IncrementWaypoint(false);
 831                 curr = fp->getCurrentWaypoint();
 832                 next = fp->getNextWaypoint();
 833             }
 834
 835             //cout << _name << ": end WAITUNTIL: ";
 836             //cout << prev->name << " " << curr->name << " " << next->name <<  endl;
 837
 838         } else {
 839             distance_nm = getRange(prev->latitude, prev->longitude, curr->latitude, curr->longitude);
 840             elapsed_sec += distance_nm * 60 * 60 / prev->speed;
 841
 842             if (elapsed_sec >= day_sec)
 843                 continue;
 844
 845             fp->IncrementWaypoint(false);
 846             prev = fp->getPreviousWaypoint();
 847             curr = fp->getCurrentWaypoint();
 848             next = fp->getNextWaypoint();
 849         }
 850
 851     }   // end while
 852
 853     // the required position lies between the previous and current waypoints
 854     // so we will calculate the distance back up the track from the current waypoint
 855     // then calculate the lat and lon.
 856     /*cout << "advancing flight plan done elapsed_sec: " << elapsed_sec
 857         << " " << day_sec << endl;*/
 858
 859     double time_diff = elapsed_sec - day_sec;
 860     double lat, lon, recip;
 861
 862     //cout << " time diff " << time_diff << endl;
 863
 864     if (next->name == "WAIT" ){
 865         setSpeed(0);
 866         lat = curr->latitude;
 867         lon = curr->longitude;
 868         _wait_count= time_diff;
 869         _waiting = true;
 870     } else if (next->name == "WAITUNTIL") {
 871         setSpeed(0);
 872         lat = curr->latitude;
 873         lon = curr->longitude;
 874         _waiting = true;
 875     } else {
 876         setSpeed(prev->speed);
 877         distance_nm = speed * time_diff / (60 * 60);
 878         double brg = getCourse(curr->latitude, curr->longitude, prev->latitude, prev->longitude);
 879
 880         //cout << " brg " << brg << " from " << curr->name << " to " << prev->name << " "
 881         //    << " lat "  << curr->latitude << " lon " << curr->longitude
 882         //    << " distance m " << distance_nm * SG_NM_TO_METER << endl;
 883
 884         lat = geo_direct_wgs_84 (curr->latitude, curr->longitude, brg,
 885             distance_nm * SG_NM_TO_METER, &lat, &lon, &recip );
 886         lon = geo_direct_wgs_84 (curr->latitude, curr->longitude, brg,
 887             distance_nm * SG_NM_TO_METER, &lat, &lon, &recip );
 888         recip = geo_direct_wgs_84 (curr->latitude, curr->longitude, brg,
 889             distance_nm * SG_NM_TO_METER, &lat, &lon, &recip );
 890     }
 891
 892     //cout << "Pos " << lat << ", " << lon << " recip " << recip << endl;
 893
 894     setLatitude(lat);
 895     setLongitude(lon);
 896     return true;
 897 }