src/AIModel/AIGroundVehicle.cxx

   1 // FGAIGroundVehicle - FGAIShip-derived class creates an AI Ground Vehicle
   2 // by adding a ground following utility
   3 //
   4 // Written by Vivian Meazza, started August 2009.
   5 // - vivian.meazza at lineone.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/sg_inlines.h>
  26
  27 #include <Main/viewer.hxx>
  28 #include <Scenery/scenery.hxx>
  29 #include <Scenery/tilemgr.hxx>
  30 #include <Airports/dynamics.hxx>
  31
  32 #include "AIGroundVehicle.hxx"
  33
  34 FGAIGroundVehicle::FGAIGroundVehicle() :
  35 FGAIShip(otGroundVehicle),
  36
  37 _pitch(0),
  38 _pitch_deg(0),
  39 _speed_kt(0),
  40 _selected_ac(0),
  41 _range_ft(0),
  42 _relbrg (0),
  43 _parent_speed(0),
  44 _dt_count(0),
  45 _next_run(0),
  46 _parent_x_offset(0),
  47 _parent_y_offset(0),
  48 _parent("")
  49
  50 {
  51     invisible = false;
  52 }
  53
  54 FGAIGroundVehicle::~FGAIGroundVehicle() {}
  55
  56 void FGAIGroundVehicle::readFromScenario(SGPropertyNode* scFileNode) {
  57     if (!scFileNode)
  58         return;
  59
  60     FGAIShip::readFromScenario(scFileNode);
  61
  62     setNoRoll(scFileNode->getBoolValue("no-roll", true));
  63     setName(scFileNode->getStringValue("name", "groundvehicle"));
  64     setSMPath(scFileNode->getStringValue("submodel-path", ""));
  65     setContactX1offset(scFileNode->getDoubleValue("contact-x1-offset", 0.0));
  66     setContactX2offset(scFileNode->getDoubleValue("contact-x2-offset", 0.0));
  67     setXOffset(scFileNode->getDoubleValue("hitch-x-offset", 38.55));
  68     setYOffset(scFileNode->getDoubleValue("hitch-y-offset", 0.0));
  69     setPitchoffset(scFileNode->getDoubleValue("pitch-offset", 0.0));
  70     setRolloffset(scFileNode->getDoubleValue("roll-offset", 0.0));
  71     setYawoffset(scFileNode->getDoubleValue("yaw-offset", 0.0));
  72     setPitchCoeff(scFileNode->getDoubleValue("pitch-coefficient", 0.1));
  73     setElevCoeff(scFileNode->getDoubleValue("elevation-coefficient", 0.25));
  74     setParentName(scFileNode->getStringValue("parent", ""));
  75     setTowAngleGain(scFileNode->getDoubleValue("tow-angle-gain", 2.0));
  76     setTowAngleLimit(scFileNode->getDoubleValue("tow-angle-limit-deg", 2.0));
  77     //we may need these later for towed vehicles
  78     //    setSubID(scFileNode->getIntValue("SubID", 0));
  79     //    setGroundOffset(scFileNode->getDoubleValue("ground-offset", 0.0));
  80     //    setFormate(scFileNode->getBoolValue("formate", true));
  81 }
  82
  83 void FGAIGroundVehicle::bind() {
  84     FGAIShip::bind();
  85
  86     props->tie("controls/constants/elevation-coeff",
  87         SGRawValuePointer<double>(&_elevation_coeff));
  88     props->tie("controls/constants/pitch-coeff",
  89         SGRawValuePointer<double>(&_pitch_coeff));
  90     props->tie("position/ht-AGL-ft",
  91         SGRawValuePointer<double>(&_ht_agl_ft));
  92     props->tie("hitch/rel-bearing-deg",
  93          SGRawValuePointer<double>(&_relbrg));
  94     props->tie("hitch/tow-angle-deg",
  95          SGRawValuePointer<double>(&_tow_angle));
  96     props->tie("hitch/range-ft",
  97         SGRawValuePointer<double>(&_range_ft));
  98     props->tie("hitch/x-offset-ft",
  99         SGRawValuePointer<double>(&_x_offset));
 100     props->tie("hitch/y-offset-ft",
 101         SGRawValuePointer<double>(&_y_offset));
 102     props->tie("hitch/parent-x-offset-ft",
 103         SGRawValuePointer<double>(&_parent_x_offset));
 104     props->tie("hitch/parent-y-offset-ft",
 105         SGRawValuePointer<double>(&_parent_y_offset));
 106     props->tie("controls/constants/tow-angle/gain",
 107         SGRawValuePointer<double>(&_tow_angle_gain));
 108     props->tie("controls/constants/tow-angle/limit-deg",
 109         SGRawValuePointer<double>(&_tow_angle_limit));
 110     props->tie("controls/contact-x1-offset-ft",
 111         SGRawValuePointer<double>(&_contact_x1_offset));
 112     props->tie("controls/contact-x2-offset-ft",
 113         SGRawValuePointer<double>(&_contact_x2_offset));
 114 }
 115
 116 void FGAIGroundVehicle::unbind() {
 117     FGAIShip::unbind();
 118
 119     props->untie("controls/constants/elevation-coeff");
 120     props->untie("position/ht-AGL-ft");
 121     props->untie("controls/constants/pitch-coeff");
 122     props->untie("hitch/rel-bearing-deg");
 123     props->untie("hitch/tow-angle-deg");
 124     props->untie("hitch/range-ft");
 125     props->untie("hitch/x-offset-ft");
 126     props->untie("hitch/y-offset-ft");
 127     props->untie("hitch/parent-x-offset-ft");
 128     props->untie("hitch/parent-y-offset-ft");
 129     props->untie("controls/constants/tow-angle/gain");
 130     props->untie("controls/constants/tow-angle/limit-deg");
 131     props->untie("controls/contact-x1-offset-ft");
 132     props->untie("controls/contact-x2-offset-ft");
 133 }
 134
 135 bool FGAIGroundVehicle::init(bool search_in_AI_path) {
 136     if (!FGAIShip::init(search_in_AI_path))
 137         return false;
 138
 139     invisible = false;
 140     _limit = 200;
 141     no_roll = true;
 142
 143     return true;
 144 }
 145
 146 void FGAIGroundVehicle::update(double dt) {
 147     //    SG_LOG(SG_GENERAL, SG_ALERT, "updating GroundVehicle: " << _name );
 148
 149     RunGroundVehicle(dt);
 150 //    FGAIShip::update(dt);
 151 }
 152
 153 void FGAIGroundVehicle::setNoRoll(bool nr) {
 154     no_roll = nr;
 155 }
 156
 157 void FGAIGroundVehicle::setContactX1offset(double x1) {
 158     _contact_x1_offset = x1;
 159 }
 160
 161 void FGAIGroundVehicle::setContactX2offset(double x2) {
 162     _contact_x2_offset = x2;
 163 }
 164
 165 void FGAIGroundVehicle::setXOffset(double x) {
 166     _x_offset = x;
 167 }
 168
 169 void FGAIGroundVehicle::setYOffset(double y) {
 170     _y_offset = y;
 171 }
 172
 173 void FGAIGroundVehicle::setPitchCoeff(double pc) {
 174     _pitch_coeff = pc;
 175 }
 176
 177 void FGAIGroundVehicle::setElevCoeff(double ec) {
 178     _elevation_coeff = ec;
 179 }
 180
 181 void FGAIGroundVehicle::setTowAngleGain(double g) {
 182     _tow_angle_gain = g;
 183 }
 184
 185 void FGAIGroundVehicle::setTowAngleLimit(double l) {
 186     _tow_angle_limit = l;
 187 }
 188
 189 void FGAIGroundVehicle::setElevation(double h, double dt, double coeff){
 190     double c = dt / (coeff + dt);
 191     _elevation_ft = (h * c) + (_elevation_ft * (1 - c));
 192 }
 193
 194 void FGAIGroundVehicle::setPitch(double p, double dt, double coeff){
 195     double c = dt / (coeff + dt);
 196     _pitch_deg = (p * c) + (_pitch_deg * (1 - c));
 197 }
 198
 199 void FGAIGroundVehicle::setParentName(const string& p) {
 200     _parent = p;
 201 }
 202
 203 void FGAIGroundVehicle::setTowAngle(double ta, double dt, double coeff){
 204     //_tow_angle = ta * _tow_angle_gain;
 205     _tow_angle = pow(ta,2) * sign(ta);
 206     SG_CLAMP_RANGE(_tow_angle, -_tow_angle_limit, _tow_angle_limit);
 207 }
 208
 209 bool FGAIGroundVehicle::getGroundElev(SGGeod inpos) {
 210
 211     double height_m ;
 212
 213     if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(inpos, 10000), height_m, &_material,0)){
 214             _ht_agl_ft = inpos.getElevationFt() - height_m * SG_METER_TO_FEET;
 215
 216             if (_material) {
 217                 const vector<string>& names = _material->get_names();
 218
 219                 _solid = _material->get_solid();
 220
 221                 if (!names.empty())
 222                     props->setStringValue("material/name", names[0].c_str());
 223                 else
 224                     props->setStringValue("material/name", "");
 225
 226                 //cout << "material " << names[0].c_str()
 227                 //    << " _elevation_m " << _elevation_m
 228                 //    << " solid " << _solid
 229                 //    << " load " << _load_resistance
 230                 //    << " frictionFactor " << _frictionFactor
 231                 //    << endl;
 232
 233             }
 234
 235             return true;
 236     } else {
 237         return false;
 238     }
 239
 240 }
 241
 242 bool FGAIGroundVehicle::getPitch() {
 243
 244     if (!_tunnel){
 245
 246         double vel = props->getDoubleValue("velocities/true-airspeed-kt", 0);
 247         double contact_offset_x1_m = _contact_x1_offset * SG_FEET_TO_METER;
 248         double contact_offset_x2_m = _contact_x2_offset * SG_FEET_TO_METER;
 249
 250         SGVec3d front(-contact_offset_x1_m, 0, 0);
 251         SGVec3d rear(-contact_offset_x2_m, 0, 0);
 252         SGVec3d Front = getCartPosAt(front);
 253         SGVec3d Rear = getCartPosAt(rear);
 254
 255         SGGeod geodFront = SGGeod::fromCart(Front);
 256         SGGeod geodRear = SGGeod::fromCart(Rear);
 257
 258         double front_elev_m = 0;
 259         double rear_elev_m = 0;
 260         double elev_front = 0;
 261         double elev_rear = 0;
 262         double max_alt = 10000;
 263
 264         if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(geodFront, 10000), elev_front,
 265              &_material, 0)){
 266                 front_elev_m = elev_front;
 267         } else
 268             return false;
 269
 270         if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(geodRear, 10000),
 271             elev_rear, &_material,0)){
 272                 rear_elev_m = elev_rear;
 273         } else
 274             return false;
 275
 276         if (vel >= 0){
 277             double diff = front_elev_m - rear_elev_m;
 278             _pitch = atan2 (diff,
 279                 fabs(contact_offset_x1_m) + fabs(contact_offset_x2_m)) * SG_RADIANS_TO_DEGREES;
 280             _elevation = (rear_elev_m + diff/2) * SG_METER_TO_FEET;
 281         } else {
 282             double diff = rear_elev_m - front_elev_m;
 283             _pitch = atan2 (diff,
 284                 fabs(contact_offset_x1_m) + fabs(contact_offset_x2_m)) * SG_RADIANS_TO_DEGREES;
 285             _elevation = (front_elev_m + diff/2) * SG_METER_TO_FEET;
 286             _pitch = -_pitch;
 287         }
 288
 289     } else {
 290
 291         if (prev->altitude == 0 || curr->altitude == 0) return false;
 292
 293         static double distance;
 294         static double d_alt;
 295         static double curr_alt;
 296         static double prev_alt;
 297
 298         if (_new_waypoint){
 299             curr_alt = curr->altitude * SG_METER_TO_FEET;
 300             prev_alt = prev->altitude * SG_METER_TO_FEET;
 301             d_alt = curr_alt - prev_alt;
 302
 303             distance = SGGeodesy::distanceM(SGGeod::fromDeg(prev->longitude, prev->latitude),
 304             SGGeod::fromDeg(curr->longitude, curr->latitude));
 305
 306             _pitch = atan2(d_alt, distance * SG_METER_TO_FEET) * SG_RADIANS_TO_DEGREES;
 307         }
 308
 309
 310         double distance_to_go = SGGeodesy::distanceM(SGGeod::fromDeg(pos.getLongitudeDeg(), pos.getLatitudeDeg()),
 311             SGGeod::fromDeg(curr->longitude, curr->latitude));
 312
 313         //cout << "distance curr & prev " << prev->name << " " << curr->name << " " << distance * SG_METER_TO_FEET
 314         //     << " distance to go " << distance_to_go * SG_METER_TO_FEET
 315         //     << " d_alt ft " << d_alt
 316         //     << endl;
 317
 318         if (distance_to_go > distance)
 319             _elevation = prev_alt;
 320         else
 321             _elevation = curr_alt - (tan(_pitch * SG_DEGREES_TO_RADIANS) * distance_to_go * SG_METER_TO_FEET);
 322
 323     }
 324
 325     getGroundElev(pos);
 326
 327     return true;
 328 }
 329
 330 void FGAIGroundVehicle::setParent() {
 331
 332     const SGPropertyNode *ai = fgGetNode("/ai/models", true);
 333
 334     for (int i = ai->nChildren() - 1; i >= -1; i--) {
 335         const SGPropertyNode *model;
 336
 337         if (i < 0) { // last iteration: selected model
 338             model = _selected_ac;
 339         } else {
 340             model = ai->getChild(i);
 341             string path = ai->getPath();
 342             const string name = model->getStringValue("name");
 343
 344             if (!model->nChildren()){
 345                 continue;
 346             }
 347             if (name == _parent) {
 348                 _selected_ac = model;  // save selected model for last iteration
 349                 break;
 350             }
 351
 352         }
 353         if (!model)
 354             continue;
 355
 356     }// end for loop
 357
 358     if (_selected_ac != 0){
 359         const string name = _selected_ac->getStringValue("name");
 360         double lat = _selected_ac->getDoubleValue("position/latitude-deg");
 361         double lon = _selected_ac->getDoubleValue("position/longitude-deg");
 362         double elevation = _selected_ac->getDoubleValue("position/altitude-ft");
 363         double hitch_x_offset_m = _selected_ac->getDoubleValue("hitch/x-offset-ft")
 364             * SG_FEET_TO_METER;
 365         double hitch_y_offset_m = _selected_ac->getDoubleValue("hitch/y-offset-ft")
 366             * SG_FEET_TO_METER;
 367
 368         _selectedpos.setLatitudeDeg(lat);
 369         _selectedpos.setLongitudeDeg(lon);
 370         _selectedpos.setElevationFt(elevation);
 371
 372         _parent_x_offset = _selected_ac->getDoubleValue("hitch/x-offset-ft");
 373         _parent_y_offset = _selected_ac->getDoubleValue("hitch/y-offset-ft");
 374         _parent_speed    = _selected_ac->getDoubleValue("velocities/true-airspeed-kt");
 375
 376         SGVec3d rear_hitch(-hitch_x_offset_m, hitch_y_offset_m, 0);
 377         SGVec3d RearHitch = getCartHitchPosAt(rear_hitch);
 378
 379         SGGeod rearpos = SGGeod::fromCart(RearHitch);
 380
 381         double user_lat = rearpos.getLatitudeDeg();
 382         double user_lon = rearpos.getLongitudeDeg();
 383
 384         double range, bearing;
 385
 386         calcRangeBearing(pos.getLatitudeDeg(), pos.getLongitudeDeg(),
 387             user_lat, user_lon, range, bearing);
 388         _range_ft = range * 6076.11549;
 389         _relbrg = calcRelBearingDeg(bearing, hdg);
 390     } else {
 391         SG_LOG(SG_GENERAL, SG_ALERT, "AIGroundVeh1cle: " << _name
 392                 << " parent not found: dying ");
 393         setDie(true);
 394     }
 395
 396 }
 397
 398 void FGAIGroundVehicle::calcRangeBearing(double lat, double lon, double lat2, double lon2,
 399                             double &range, double &bearing) const
 400 {
 401     // calculate the bearing and range of the second pos from the first
 402     double az2, distance;
 403     geo_inverse_wgs_84(lat, lon, lat2, lon2, &bearing, &az2, &distance);
 404     range = distance * SG_METER_TO_NM;
 405 }
 406
 407 double FGAIGroundVehicle::calcRelBearingDeg(double bearing, double heading)
 408 {
 409     double angle = bearing - heading;
 410     SG_NORMALIZE_RANGE(angle, -180.0, 180.0);
 411     return angle;
 412 }
 413
 414 SGVec3d FGAIGroundVehicle::getCartHitchPosAt(const SGVec3d& _off) const {
 415     double hdg = _selected_ac->getDoubleValue("orientation/true-heading-deg");
 416     double pitch = _selected_ac->getDoubleValue("orientation/pitch-deg");
 417     double roll = _selected_ac->getDoubleValue("orientation/roll-deg");
 418
 419     // Transform that one to the horizontal local coordinate system.
 420     SGQuatd hlTrans = SGQuatd::fromLonLat(_selectedpos);
 421
 422     // and postrotate the orientation of the AIModel wrt the horizontal
 423     // local frame
 424     hlTrans *= SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
 425
 426     // The offset converted to the usual body fixed coordinate system
 427     // rotated to the earth fiexed coordinates axis
 428     SGVec3d off = hlTrans.backTransform(_off);
 429
 430     // Add the position offset of the AIModel to gain the earth centered position
 431     SGVec3d cartPos = SGVec3d::fromGeod(_selectedpos);
 432
 433     return cartPos + off;
 434 }
 435
 436 void FGAIGroundVehicle::AdvanceFP(){
 437
 438     double count = 0;
 439     string parent_next_name =_selected_ac->getStringValue("waypoint/name-next");
 440
 441     while(fp->getNextWaypoint() != 0 && fp->getNextWaypoint()->name != "END" && count < 5){
 442         SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 443             <<" advancing waypoint to: " << parent_next_name);
 444
 445         if (fp->getNextWaypoint()->name == parent_next_name){
 446             SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 447                 << " not setting waypoint already at: " << fp->getNextWaypoint()->name);
 448             return;
 449         }
 450
 451         prev = curr;
 452         fp->IncrementWaypoint(false);
 453         curr = fp->getCurrentWaypoint();
 454         next = fp->getNextWaypoint();
 455
 456         if (fp->getNextWaypoint()->name == parent_next_name){
 457             SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 458             << " waypoint set to: " << fp->getNextWaypoint()->name);
 459             return;
 460         }
 461
 462         count++;
 463
 464     }// end while loop
 465
 466     while(fp->getPreviousWaypoint() != 0 && fp->getPreviousWaypoint()->name != "END"
 467         && count > -10){
 468             SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 469             << " retreating waypoint to: " << parent_next_name
 470             << " at: " << fp->getNextWaypoint()->name);
 471
 472         if (fp->getNextWaypoint()->name == parent_next_name){
 473             SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 474                 << " not setting waypoint already at:" << fp->getNextWaypoint()->name );
 475             return;
 476         }
 477
 478         prev = curr;
 479         fp->DecrementWaypoint(false);
 480         curr = fp->getCurrentWaypoint();
 481         next = fp->getNextWaypoint();
 482
 483         if (fp->getNextWaypoint()->name == parent_next_name){
 484             SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 485             << " waypoint set to: " << fp->getNextWaypoint()->name);
 486             return;
 487         }
 488
 489         count--;
 490
 491     }// end while loop
 492 }
 493
 494 void FGAIGroundVehicle::setTowSpeed(){
 495
 496     double diff = _range_ft - _x_offset;
 497     double  x = 0;
 498
 499     if (_range_ft > _x_offset * 3) x = 50;
 500
 501     if (_relbrg < -90 || _relbrg > 90){
 502         setSpeed(_parent_speed - 5 - x);
 503         //cout << _name << " case 1r _relbrg spd - 5 " << _relbrg << " " << diff << endl;
 504     }else if (_range_ft > _x_offset + 0.25 && _relbrg >= -90 && _relbrg <= 90){
 505         setSpeed(_parent_speed + 1 + x);
 506         //cout << _name << " case 2r _relbrg spd + 1 " << _relbrg << " "
 507         //    << diff << " range " << _range_ft << endl;
 508     } else if (_range_ft < _x_offset - 0.25 && _relbrg >= -90 && _relbrg <= 90){
 509         setSpeed(_parent_speed - 1 - x);
 510         //cout << _name << " case 3r _relbrg spd - 2 " << _relbrg << " "
 511         //    << diff << " " << _range_ft << endl;
 512     } else {
 513         setSpeed(_parent_speed);
 514         //cout << _name << " else r _relbrg " << _relbrg << " " << diff << endl;
 515     }
 516
 517 }
 518
 519 void FGAIGroundVehicle::RunGroundVehicle(double dt){
 520
 521     _dt_count += dt;
 522
 523     ///////////////////////////////////////////////////////////////////////////
 524     // Check execution time (currently once every 0.05 sec or 20 fps)
 525     // Add a bit of randomization to prevent the execution of all flight plans
 526     // in synchrony, which can add significant periodic framerate flutter.
 527     ///////////////////////////////////////////////////////////////////////////
 528
 529     //cout << "_start_sec " << _start_sec << " time_sec " << time_sec << endl;
 530     if (_dt_count < _next_run)
 531         return;
 532
 533     _next_run = 0.055 + (0.015 * sg_random());
 534
 535     if (getPitch()){
 536         setElevation(_elevation, _dt_count, _elevation_coeff);
 537         ClimbTo(_elevation_ft);
 538         setPitch(_pitch, _dt_count, _pitch_coeff);
 539         PitchTo(_pitch_deg);
 540     }
 541
 542     if(_parent == ""){
 543         AccelTo(prev->speed);
 544         FGAIShip::update(_dt_count);
 545         _dt_count = 0;
 546         return;
 547     }
 548
 549     setParent();
 550
 551     string parent_next_name = _selected_ac->getStringValue("waypoint/name-next");
 552     bool parent_waiting = _selected_ac->getBoolValue("waypoint/waiting");
 553
 554     if (parent_next_name == "END" && fp->getNextWaypoint()->name != "END" ){
 555         SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 556             << " setting END: getting new waypoints ");
 557         AdvanceFP();
 558         setWPNames();
 559         /*} else if (parent_next_name == "WAIT" && fp->getNextWaypoint()->name != "WAIT" ){*/
 560     } else if (parent_waiting && !_waiting){
 561         SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 562             << " setting WAIT/WAITUNTIL: getting new waypoints ");
 563         AdvanceFP();
 564         setWPNames();
 565         _waiting = true;
 566     } else if (parent_next_name != "WAIT" && fp->getNextWaypoint()->name == "WAIT"){
 567         SG_LOG(SG_GENERAL, SG_DEBUG, "AIGroundVeh1cle: " << _name
 568             << " wait done: getting new waypoints ");
 569         _waiting = false;
 570         _wait_count = 0;
 571         fp->IncrementWaypoint(false);
 572         next = fp->getNextWaypoint();
 573
 574         if (next->name == "WAITUNTIL" || next->name == "WAIT"
 575             || next->name == "END"){
 576         } else {
 577             prev = curr;
 578             fp->IncrementWaypoint(false);
 579             curr = fp->getCurrentWaypoint();
 580             next = fp->getNextWaypoint();
 581         }
 582
 583         setWPNames();
 584     } else if (_range_ft > _parent_x_offset * 4){
 585         SG_LOG(SG_GENERAL, SG_INFO, "AIGroundVeh1cle: " << _name
 586             << " rescue: reforming train " << _range_ft << " " << _x_offset * 15);
 587
 588         setTowAngle(0, dt, 1);
 589         setSpeed(_parent_speed * 2);
 590
 591     } else if (_parent_speed > 1){
 592
 593         setTowSpeed();
 594         setTowAngle(_relbrg, dt, 1);
 595
 596     } else if (_parent_speed < -1){
 597
 598         setTowSpeed();
 599
 600         if (_relbrg < 0)
 601             setTowAngle(-(180 - (360 + _relbrg)), dt, 1);
 602         else
 603             setTowAngle(-(180 - _relbrg), dt, 1);
 604
 605     } else
 606         setSpeed(_parent_speed);
 607
 608     FGAIShip::update(_dt_count);
 609     _dt_count = 0;
 610
 611 }
 612
 613 // end AIGroundvehicle