src/ATC/tower.cxx

   1 // FGTower - a class to provide tower control at towered airports.
   2 //
   3 // Written by David Luff, started March 2002.
   4 //
   5 // Copyright (C) 2002  David C. Luff - david.luff@nottingham.ac.uk
   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., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21 #include <Main/globals.hxx>
  22 #include <Airports/runways.hxx>
  23 #include <simgear/math/sg_geodesy.hxx>
  24 #include <simgear/debug/logstream.hxx>
  25
  26 #include "tower.hxx"
  27 #include "ATCdisplay.hxx"
  28 #include "ATCmgr.hxx"
  29 #include "ATCutils.hxx"
  30 #include "commlist.hxx"
  31 #include "AILocalTraffic.hxx"
  32
  33 SG_USING_STD(cout);
  34
  35 // TowerPlaneRec
  36
  37 TowerPlaneRec::TowerPlaneRec() :
  38 clearedToLand(false),
  39 clearedToLineUp(false),
  40 clearedToTakeOff(false),
  41 holdShortReported(false),
  42 longFinalReported(false),
  43 longFinalAcknowledged(false),
  44 finalReported(false),
  45 finalAcknowledged(false),
  46 onRwy(false),
  47 nextOnRwy(false),
  48 opType(TTT_UNKNOWN),
  49 leg(LEG_UNKNOWN),
  50 landingType(AIP_LT_UNKNOWN),
  51 isUser(false)
  52 {
  53         plane.callsign = "UNKNOWN";
  54 }
  55
  56 TowerPlaneRec::TowerPlaneRec(PlaneRec p) :
  57 clearedToLand(false),
  58 clearedToLineUp(false),
  59 clearedToTakeOff(false),
  60 holdShortReported(false),
  61 longFinalReported(false),
  62 longFinalAcknowledged(false),
  63 finalReported(false),
  64 finalAcknowledged(false),
  65 onRwy(false),
  66 nextOnRwy(false),
  67 opType(TTT_UNKNOWN),
  68 leg(LEG_UNKNOWN),
  69 landingType(AIP_LT_UNKNOWN),
  70 isUser(false)
  71 {
  72         plane = p;
  73 }
  74
  75 TowerPlaneRec::TowerPlaneRec(Point3D pt) :
  76 clearedToLand(false),
  77 clearedToLineUp(false),
  78 clearedToTakeOff(false),
  79 holdShortReported(false),
  80 longFinalReported(false),
  81 longFinalAcknowledged(false),
  82 finalReported(false),
  83 finalAcknowledged(false),
  84 onRwy(false),
  85 nextOnRwy(false),
  86 opType(TTT_UNKNOWN),
  87 leg(LEG_UNKNOWN),
  88 landingType(AIP_LT_UNKNOWN),
  89 isUser(false)
  90 {
  91         plane.callsign = "UNKNOWN";
  92         pos = pt;
  93 }
  94
  95 TowerPlaneRec::TowerPlaneRec(PlaneRec p, Point3D pt) :
  96 clearedToLand(false),
  97 clearedToLineUp(false),
  98 clearedToTakeOff(false),
  99 holdShortReported(false),
 100 longFinalReported(false),
 101 longFinalAcknowledged(false),
 102 finalReported(false),
 103 finalAcknowledged(false),
 104 onRwy(false),
 105 nextOnRwy(false),
 106 opType(TTT_UNKNOWN),
 107 leg(LEG_UNKNOWN),
 108 landingType(AIP_LT_UNKNOWN),
 109 isUser(false)
 110 {
 111         plane = p;
 112         pos = pt;
 113 }
 114
 115
 116 // FGTower
 117
 118 FGTower::FGTower() {
 119         ATCmgr = globals->get_ATC_mgr();
 120
 121         // Init the property nodes - TODO - need to make sure we're getting surface winds.
 122         wind_from_hdg = fgGetNode("/environment/wind-from-heading-deg", true);
 123         wind_speed_knots = fgGetNode("/environment/wind-speed-kt", true);
 124
 125         update_count = 0;
 126         update_count_max = 15;
 127
 128         holdListItr = holdList.begin();
 129         appListItr = appList.begin();
 130         depListItr = depList.begin();
 131         rwyListItr = rwyList.begin();
 132         circuitListItr = circuitList.begin();
 133         trafficListItr = trafficList.begin();
 134
 135         freqClear = true;
 136
 137         timeSinceLastDeparture = 9999;
 138         departed = false;
 139 }
 140
 141 FGTower::~FGTower() {
 142         if(!separateGround) {
 143                 delete ground;
 144         }
 145 }
 146
 147 void FGTower::Init() {
 148     display = false;
 149
 150         // Pointers to user's position
 151         user_lon_node = fgGetNode("/position/longitude-deg", true);
 152         user_lat_node = fgGetNode("/position/latitude-deg", true);
 153         user_elev_node = fgGetNode("/position/altitude-ft", true);
 154         user_hdg_node = fgGetNode("/orientation/heading-deg", true);
 155
 156         // Need some way to initialise rwyOccupied flag correctly if the user is on the runway and to know its the user.
 157         // I'll punt the startup issue for now though!!!
 158         rwyOccupied = false;
 159
 160         // Setup the ground control at this airport
 161         AirportATC a;
 162         //cout << "Tower ident = " << ident << '\n';
 163         if(ATCmgr->GetAirportATCDetails(ident, &a)) {
 164                 if(a.ground_freq) {             // Ground control
 165                         ground = (FGGround*)ATCmgr->GetATCPointer(ident, GROUND);
 166                         separateGround = true;
 167                         if(ground == NULL) {
 168                                 // Something has gone wrong :-(
 169                                 SG_LOG(SG_ATC, SG_WARN, "ERROR - ground has frequency but can't get ground pointer :-(");
 170                                 ground = new FGGround(ident);
 171                                 separateGround = false;
 172                                 ground->Init();
 173                                 if(display) {
 174                                         ground->SetDisplay();
 175                                 } else {
 176                                         ground->SetNoDisplay();
 177                                 }
 178                         }
 179                 } else {
 180                         // Initialise ground anyway to do the shortest path stuff!
 181                         // Note that we're now responsible for updating and deleting this - NOT the ATCMgr.
 182                         ground = new FGGround(ident);
 183                         separateGround = false;
 184                         ground->Init();
 185                         if(display) {
 186                                 ground->SetDisplay();
 187                         } else {
 188                                 ground->SetNoDisplay();
 189                         }
 190                 }
 191         } else {
 192                 SG_LOG(SG_ATC, SG_ALERT, "Unable to find airport details for " << ident << " in FGTower::Init()");
 193                 // Initialise ground anyway to avoid segfault later
 194                 ground = new FGGround(ident);
 195                 separateGround = false;
 196                 ground->Init();
 197                 if(display) {
 198                         ground->SetDisplay();
 199                 } else {
 200                         ground->SetNoDisplay();
 201                 }
 202         }
 203
 204         // Get the airport elevation
 205         aptElev = dclGetAirportElev(ident.c_str()) * SG_FEET_TO_METER;
 206
 207         DoRwyDetails();
 208
 209         // FIXME - this currently assumes use of the active rwy by the user.
 210         rwyOccupied = OnAnyRunway(Point3D(user_lon_node->getDoubleValue(), user_lat_node->getDoubleValue(), 0.0));
 211         if(rwyOccupied) {
 212                 // Assume the user is started at the threshold ready to take-off
 213                 TowerPlaneRec* t = new TowerPlaneRec;
 214                 t->plane.callsign = "Charlie Foxtrot Sierra";   // C-FGFS !!! - fixme - this is a bit hardwired
 215                 t->plane.type = GA_SINGLE;
 216                 t->opType = TTT_UNKNOWN;        // We don't know if the user wants to do circuits or a departure...
 217                 t->landingType = AIP_LT_UNKNOWN;
 218                 t->leg = TAKEOFF_ROLL;
 219                 t->isUser = true;
 220                 t->planePtr = NULL;
 221                 t->clearedToTakeOff = true;
 222                 rwyList.push_back(t);
 223                 departed = false;
 224         }
 225 }
 226
 227 void FGTower::Update(double dt) {
 228         //cout << "T" << flush;
 229         // Each time step, what do we need to do?
 230         // We need to go through the list of outstanding requests and acknowedgements
 231         // and process at least one of them.
 232         // We need to go through the list of planes under our control and check if
 233         // any need to be addressed.
 234         // We need to check for planes not under our control coming within our
 235         // control area and address if necessary.
 236
 237         // TODO - a lot of the below probably doesn't need to be called every frame and should be staggered.
 238
 239         // Sort the arriving planes
 240
 241         /*
 242         if(ident == "KEMT") {
 243                 cout << update_count << "\ttL: " << trafficList.size() << "  cL: " << circuitList.size() << "  hL: " << holdList.size() << "  aL: " << appList.size() << '\n';
 244         }
 245         */
 246
 247         if(departed != false) {
 248                 timeSinceLastDeparture += dt;
 249                 //if(ident == "KEMT")
 250                 //      cout << "  dt = " << dt << "  timeSinceLastDeparture = " << timeSinceLastDeparture << '\n';
 251         }
 252
 253         // Calculate the eta of each plane to the threshold.
 254         // For ground traffic this is the fastest they can get there.
 255         // For air traffic this is the middle approximation.
 256         if(update_count == 1) {
 257                 doThresholdETACalc();
 258         }
 259
 260         // Order the list of traffic as per expected threshold use and flag any conflicts
 261         if(update_count == 2) {
 262                 //bool conflicts = doThresholdUseOrder();
 263                 doThresholdUseOrder();
 264         }
 265
 266         // sortConficts() !!!
 267
 268         // Do one plane from the hold list
 269         if(update_count == 4) {
 270                 //cout << "ug\n";
 271                 if(holdList.size()) {
 272                         //cout << "*holdListItr = " << *holdListItr << endl;
 273                         if(holdListItr == holdList.end()) {
 274                                 holdListItr = holdList.begin();
 275                         }
 276                         //cout << "*holdListItr = " << *holdListItr << endl;
 277                         //Process(*holdListItr);
 278                         TowerPlaneRec* t = *holdListItr;
 279                         //cout << "t = " << t << endl;
 280                         if(t->holdShortReported) {
 281                                 //cout << "ding\n";
 282                                 double responseTime = 10.0;             // seconds - this should get more sophisticated at some point
 283                                 if(t->clearanceCounter > responseTime) {
 284                                         if(t->nextOnRwy) {
 285                                                 if(rwyOccupied) {       // TODO - ought to add a sanity check that it isn't this plane only on the runway (even though it shouldn't be!!)
 286                                                         // Do nothing for now - consider acknowloging hold short eventually
 287                                                 } else {
 288                                                         // Lets Roll !!!!
 289                                                         string trns = t->plane.callsign;
 290                                                         //if(departed plane < some threshold in time away) {
 291                                                         if(0) {         // FIXME
 292                                                                 trns += " line up";
 293                                                                 t->clearedToLineUp = true;
 294                                                                 t->planePtr->RegisterTransmission(3);   // cleared to line-up
 295                                                                 t->leg = TAKEOFF_ROLL;
 296                                                         //} else if(arriving plane < some threshold away) {
 297                                                         } else if(GetTrafficETA(2) < 150.0) {
 298                                                                 trns += " cleared immediate take-off";
 299                                                                 if(trafficList.size()) {
 300                                                                         tower_plane_rec_list_iterator trfcItr = trafficList.begin();
 301                                                                         trfcItr++;      // At the moment the holding plane should be first in trafficList.
 302                                                                         // Note though that this will break if holding planes aren't put in trafficList in the future.
 303                                                                         TowerPlaneRec* trfc = *trfcItr;
 304                                                                         trns += "... traffic is";
 305                                                                         switch(trfc->plane.type) {
 306                                                                         case UNKNOWN:
 307                                                                                 break;
 308                                                                         case GA_SINGLE:
 309                                                                                 trns += " a Cessna";    // TODO - add ability to specify actual plane type somewhere
 310                                                                                 break;
 311                                                                         case GA_HP_SINGLE:
 312                                                                                 trns += " a Piper";
 313                                                                                 break;
 314                                                                         case GA_TWIN:
 315                                                                                 trns += " a King-air";
 316                                                                                 break;
 317                                                                         case GA_JET:
 318                                                                                 trns += " a Learjet";
 319                                                                                 break;
 320                                                                         case MEDIUM:
 321                                                                                 trns += " a Regional";
 322                                                                                 break;
 323                                                                         case HEAVY:
 324                                                                                 trns += " a Heavy";
 325                                                                                 break;
 326                                                                         case MIL_JET:
 327                                                                                 trns += " Military";
 328                                                                                 break;
 329                                                                         }
 330                                                                         if(trfc->opType == STRAIGHT_IN || trfc->opType == TTT_UNKNOWN) {
 331                                                                                 double miles_out = CalcDistOutMiles(trfc);
 332                                                                                 if(miles_out < 2) {
 333                                                                                         trns += " on final";
 334                                                                                 } else {
 335                                                                                         trns += " on ";
 336                                                                                         trns += ConvertNumToSpokenDigits((int)miles_out);
 337                                                                                         trns += " mile final";
 338                                                                                 }
 339                                                                         } else if(trfc->opType == CIRCUIT) {
 340                                                                                 switch(trfc->leg) {
 341                                                                                 case FINAL:
 342                                                                                         trns += " on final";
 343                                                                                         break;
 344                                                                                 case TURN4:
 345                                                                                         trns += " turning final";
 346                                                                                         break;
 347                                                                                 case BASE:
 348                                                                                         trns += " on base";
 349                                                                                         break;
 350                                                                                 case TURN3:
 351                                                                                         trns += " turning base";
 352                                                                                         break;
 353                                                                                 case DOWNWIND:
 354                                                                                         trns += " in circuit";
 355                                                                                         break;
 356                                                                                 // And to eliminate compiler warnings...
 357                                                                                 case TAKEOFF_ROLL: break;
 358                                                                                 case CLIMBOUT:     break;
 359                                                                                 case TURN1:        break;
 360                                                                                 case CROSSWIND:    break;
 361                                                                                 case TURN2:        break;
 362                                                                                 case LANDING_ROLL: break;
 363                                                                                 case LEG_UNKNOWN:  break;
 364                                                                                 }
 365                                                                         }
 366                                                                 } else {
 367                                                                         // By definition there should be some arriving traffic if we're cleared for immediate takeoff
 368                                                                         SG_LOG(SG_ATC, SG_WARN, "Warning: Departing traffic cleared for *immediate* take-off despite no arriving traffic in FGTower");
 369                                                                 }
 370                                                                 t->clearedToTakeOff = true;
 371                                                                 t->planePtr->RegisterTransmission(4);   // cleared to take-off - TODO differentiate between immediate and normal take-off
 372                                                                 t->leg = TAKEOFF_ROLL;
 373                                                                 departed = false;
 374                                                                 timeSinceLastDeparture = 0.0;
 375                                                         } else {
 376                                                                 trns += " cleared for take-off";
 377                                                                 // TODO - add traffic is... ?
 378                                                                 t->clearedToTakeOff = true;
 379                                                                 t->planePtr->RegisterTransmission(4);   // cleared to take-off
 380                                                                 t->leg = TAKEOFF_ROLL;
 381                                                                 departed = false;
 382                                                                 timeSinceLastDeparture = 0.0;
 383                                                         }
 384                                                         if(display) {
 385                                                                 globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 386                                                         }
 387                                                         t->holdShortReported = false;
 388                                                         t->clearanceCounter = 0;
 389                                                         rwyList.push_back(t);
 390                                                         rwyOccupied = true;
 391                                                         holdList.erase(holdListItr);
 392                                                         holdListItr = holdList.begin();
 393                                                 }
 394                                         } else {
 395                                                 // Tell him to hold and what position he is.
 396                                                 // Not currently sure under which circumstances we do or don't bother transmitting this.
 397                                                 string trns = t->plane.callsign;
 398                                                 trns += " hold position";
 399                                                 if(display) {
 400                                                         globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 401                                                 }
 402                                                 t->holdShortReported = false;
 403                                                 t->clearanceCounter = 0;
 404                                                 // TODO - add some idea of what traffic is blocking him.
 405                                         }
 406                                 } else {
 407                                         t->clearanceCounter += (dt * holdList.size() * update_count_max);
 408                                 }
 409                         } else {        // not responding to report, but still need to clear if clear
 410                                 //cout << "dong\n";
 411                                 if(t->nextOnRwy) {
 412                                         //cout << "departed = " << departed << '\n';
 413                                         //cout << "timeSinceLastDeparture = " << timeSinceLastDeparture << '\n';
 414                                         if(rwyOccupied) {
 415                                                 // Do nothing for now - consider acknowloging hold short eventually
 416                                         } else if(timeSinceLastDeparture <= 60.0 && departed == true) {
 417                                                 // Do nothing - this is a bit of a hack - should maybe do line up be ready here
 418                                         } else {
 419                                                 // Lets Roll !!!!
 420                                                 string trns = t->plane.callsign;
 421                                                 //cout << "******************* squaggle\n";
 422                                                 //cout << "departed = " << departed << '\n';
 423                                                 //cout << "timeSinceLastDeparture = " << timeSinceLastDeparture << '\n';
 424                                                 //if(departed plane < some threshold in time away) {
 425                                                         if(0) {         // FIXME
 426                                                                 //cout << "A\n";
 427                                                                 trns += " line up";
 428                                                                 t->clearedToLineUp = true;
 429                                                                 t->planePtr->RegisterTransmission(3);   // cleared to line-up
 430                                                                 t->leg = TAKEOFF_ROLL;
 431                                                 //} else if(arriving plane < some threshold away) {
 432                                                         } else if(GetTrafficETA(2) < 150.0 && (timeSinceLastDeparture > 60.0 || departed == false)) {   // Hack - hardwired time
 433                                                                 //cout << "B\n";
 434                                                                 trns += " cleared immediate take-off";
 435                                                                 // TODO - add traffic is... ?
 436                                                                 t->clearedToTakeOff = true;
 437                                                                 t->planePtr->RegisterTransmission(4);   // cleared to take-off - TODO differentiate between immediate and normal take-off
 438                                                                 t->leg = TAKEOFF_ROLL;
 439                                                                 departed = false;
 440                                                                 timeSinceLastDeparture = 0.0;
 441                                                         } else if(timeSinceLastDeparture > 60.0 || departed == false) { // Hack - test for timeSinceLastDeparture should be in lineup block eventually
 442                                                                 //cout << "C\n";
 443                                                                 trns += " cleared for take-off";
 444                                                                 // TODO - add traffic is... ?
 445                                                                 t->clearedToTakeOff = true;
 446                                                                 t->planePtr->RegisterTransmission(4);   // cleared to take-off
 447                                                                 t->leg = TAKEOFF_ROLL;
 448                                                                 departed = false;
 449                                                                 timeSinceLastDeparture = 0.0;
 450                                                         } else {
 451                                                                 //cout << "D\n";
 452                                                         }
 453                                                         if(display) {
 454                                                                 globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 455                                                         }
 456                                                         rwyList.push_back(t);
 457                                                         rwyOccupied = true;
 458                                                         holdList.erase(holdListItr);
 459                                                         holdListItr = holdList.begin();
 460                                         }
 461                                 }
 462                                 // TODO - rationalise the considerable code duplication above!
 463                         }
 464                         ++holdListItr;
 465                 }
 466         }
 467
 468         // Uggh - HACK - why have we got rwyOccupied - wouldn't simply testing rwyList.size() do?
 469         if(rwyList.size()) {
 470                 rwyOccupied = true;
 471         } else {
 472                 rwyOccupied = false;
 473         }
 474
 475         // Do the runway list - we'll do the whole runway list since it's important and there'll never be many planes on the rwy at once!!
 476         // FIXME - at the moment it looks like we're only doing the first plane from the rwy list.
 477         // (However, at the moment there should only be one airplane on the rwy at once, until we
 478         // start allowing planes to line up whilst previous arrival clears the rwy.)
 479         if(update_count == 5) {
 480                 if(rwyOccupied) {
 481                         if(!rwyList.size()) {
 482                                 rwyOccupied = false;
 483                         } else {
 484                                 rwyListItr = rwyList.begin();
 485                                 TowerPlaneRec* t = *rwyListItr;
 486                                 if(t->isUser) {
 487                                         t->pos.setlon(user_lon_node->getDoubleValue());
 488                                         t->pos.setlat(user_lat_node->getDoubleValue());
 489                                         t->pos.setelev(user_elev_node->getDoubleValue());
 490                                 } else {
 491                                         t->pos = t->planePtr->GetPos();         // We should probably only set the pos's on one walk through the traffic list in the update function, to save a few CPU should we end up duplicating this.
 492                                 }
 493                                 bool on_rwy = OnActiveRunway(t->pos);
 494                                 if(!on_rwy) {
 495                                         if((t->opType == INBOUND) || (t->opType == STRAIGHT_IN)) {
 496                                                 rwyList.pop_front();
 497                                                 delete t;
 498                                                 // TODO - tell it to taxi / contact ground / don't delete it etc!
 499                                         } else if(t->opType == OUTBOUND) {
 500                                                 depList.push_back(t);
 501                                                 rwyList.pop_front();
 502                                                 departed = true;
 503                                                 timeSinceLastDeparture = 0.0;
 504                                         } else if(t->opType == CIRCUIT) {
 505                                                 circuitList.push_back(t);
 506                                                 AddToTrafficList(t);
 507                                                 rwyList.pop_front();
 508                                                 departed = true;
 509                                                 timeSinceLastDeparture = 0.0;
 510                                         } else if(t->opType == TTT_UNKNOWN) {
 511                                                 depList.push_back(t);
 512                                                 circuitList.push_back(t);
 513                                                 AddToTrafficList(t);
 514                                                 rwyList.pop_front();
 515                                                 departed = true;
 516                                                 timeSinceLastDeparture = 0.0;   // TODO - we need to take into account that the user might taxi-in when flagged opType UNKNOWN - check speed/altitude etc to make decision as to what user is up to.
 517                                         } else {
 518                                                 // HELP - we shouldn't ever get here!!!
 519                                         }
 520                                 }
 521                         }
 522                 }
 523         }
 524
 525         // do the ciruit list
 526         if(update_count == 6) {
 527                 // Clear the constraints - we recalculate here.
 528                 base_leg_pos = 0.0;
 529                 downwind_leg_pos = 0.0;
 530                 crosswind_leg_pos = 0.0;
 531
 532                 if(circuitList.size()) {        // Do one plane from the circuit
 533                         if(circuitListItr == circuitList.end()) {
 534                                 circuitListItr = circuitList.begin();
 535                         }
 536                         TowerPlaneRec* t = *circuitListItr;
 537                         if(t->isUser) {
 538                                 t->pos.setlon(user_lon_node->getDoubleValue());
 539                                 t->pos.setlat(user_lat_node->getDoubleValue());
 540                                 t->pos.setelev(user_elev_node->getDoubleValue());
 541                         } else {
 542                                 t->pos = t->planePtr->GetPos();         // We should probably only set the pos's on one walk through the traffic list in the update function, to save a few CPU should we end up duplicating this.
 543                                 t->landingType = t->planePtr->GetLandingOption();
 544                                 //cout << "AI plane landing option is " << t->landingType << '\n';
 545                         }
 546                         Point3D tortho = ortho.ConvertToLocal(t->pos);
 547                         if(t->isUser) {
 548                                 // Need to figure out which leg he's on
 549                                 //cout << "rwy.hdg = " << rwy.hdg << " user hdg = " << user_hdg_node->getDoubleValue();
 550                                 double ho = GetAngleDiff_deg(user_hdg_node->getDoubleValue(), rwy.hdg);
 551                                 //cout << " ho = " << ho << '\n';
 552                                 // TODO FIXME - get the wind and convert this to track, or otherwise use track somehow!!!
 553                                 // If it's gusty might need to filter the value, although we are leaving 30 degrees each way leeway!
 554                                 if(abs(ho) < 30) {
 555                                         // could be either takeoff, climbout or landing - check orthopos.y
 556                                         //cout << "tortho.y = " << tortho.y() << '\n';
 557                                         if((tortho.y() < 0) || (t->leg == TURN4) || (t->leg == FINAL)) {
 558                                                 t->leg = FINAL;
 559                                                 //cout << "Final\n";
 560                                         } else {
 561                                                 t->leg = CLIMBOUT;      // TODO - check elev wrt. apt elev to differentiate takeoff roll and climbout
 562                                                 //cout << "Climbout\n";
 563                                                 // If it's the user we may be unsure of his/her intentions.
 564                                                 // (Hopefully the AI planes won't try confusing the sim!!!)
 565                                                 if(t->opType == TTT_UNKNOWN) {
 566                                                         if(tortho.y() > 5000) {
 567                                                                 // 5 km out from threshold - assume it's a departure
 568                                                                 t->opType = OUTBOUND;   // TODO - could check if the user has climbed significantly above circuit altitude as well.
 569                                                                 // Since we are unknown operation we should be in depList already.
 570                                                                 circuitList.erase(circuitListItr);
 571                                                                 RemoveFromTrafficList(t->plane.callsign);
 572                                                                 circuitListItr = circuitList.begin();
 573                                                         }
 574                                                 } else if(t->opType == CIRCUIT) {
 575                                                         if(tortho.y() > 10000) {
 576                                                                 // 10 km out - assume the user has abandoned the circuit!!
 577                                                                 t->opType = OUTBOUND;
 578                                                                 depList.push_back(t);
 579                                                                 circuitList.erase(circuitListItr);
 580                                                                 circuitListItr = circuitList.begin();
 581                                                         }
 582                                                 }
 583                                         }
 584                                 } else if(abs(ho) < 60) {
 585                                         // turn1 or turn 4
 586                                         // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 587                                         if((t->leg == CLIMBOUT) || (t->leg == TURN1)) {
 588                                                 t->leg = TURN1;
 589                                                 //cout << "Turn1\n";
 590                                         } else {
 591                                                 t->leg = TURN4;
 592                                                 //cout << "Turn4\n";
 593                                         }
 594                                 } else if(abs(ho) < 120) {
 595                                         // crosswind or base
 596                                         // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 597                                         if((t->leg == TURN1) || (t->leg == CROSSWIND)) {
 598                                                 t->leg = CROSSWIND;
 599                                                 //cout << "Crosswind\n";
 600                                         } else {
 601                                                 t->leg = BASE;
 602                                                 //cout << "Base\n";
 603                                         }
 604                                 } else if(abs(ho) < 150) {
 605                                         // turn2 or turn 3
 606                                         // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 607                                         if((t->leg == CROSSWIND) || (t->leg == TURN2)) {
 608                                                 t->leg = TURN2;
 609                                                 //cout << "Turn2\n";
 610                                         } else {
 611                                                 t->leg = TURN3;
 612                                                 // Probably safe now to assume the user is flying a circuit
 613                                                 t->opType = CIRCUIT;
 614                                                 //cout << "Turn3\n";
 615                                         }
 616                                 } else {
 617                                         // downwind
 618                                         t->leg = DOWNWIND;
 619                                         //cout << "Downwind\n";
 620                                 }
 621                                 if(t->leg == FINAL) {
 622                                         if(OnActiveRunway(t->pos)) {
 623                                                 t->leg = LANDING_ROLL;
 624                                         }
 625                                 }
 626                         } else {
 627                                 t->leg = t->planePtr->GetLeg();
 628                         }
 629
 630                         // Set the constraints IF this is the first plane in the circuit
 631                         // TODO - at the moment we're constraining plane 2 based on plane 1 - this won't (or might not) work for 3 planes in the circuit!!
 632                         if(circuitListItr == circuitList.begin()) {
 633                                 switch(t->leg) {
 634                                 case FINAL:
 635                                         // Base leg must be at least as far out as the plane is - actually possibly not necessary for separation, but we'll use that for now.
 636                                         base_leg_pos = tortho.y();
 637                                         //cout << "base_leg_pos = " << base_leg_pos << '\n';
 638                                         break;
 639                                 case TURN4:
 640                                         // Fall through to base
 641                                 case BASE:
 642                                         base_leg_pos = tortho.y();
 643                                         //cout << "base_leg_pos = " << base_leg_pos << '\n';
 644                                         break;
 645                                 case TURN3:
 646                                         // Fall through to downwind
 647                                 case DOWNWIND:
 648                                         // Only have the downwind leg pos as turn-to-base constraint if more negative than we already have.
 649                                         base_leg_pos = (tortho.y() < base_leg_pos ? tortho.y() : base_leg_pos);
 650                                         //cout << "base_leg_pos = " << base_leg_pos;
 651                                         downwind_leg_pos = tortho.x();          // Assume that a following plane can simply be constrained by the immediately in front downwind plane
 652                                         //cout << " downwind_leg_pos = " << downwind_leg_pos << '\n';
 653                                         break;
 654                                 case TURN2:
 655                                         // Fall through to crosswind
 656                                 case CROSSWIND:
 657                                         crosswind_leg_pos = tortho.y();
 658                                         //cout << "crosswind_leg_pos = " << crosswind_leg_pos << '\n';
 659                                         break;
 660                                 case TURN1:
 661                                         // Fall through to climbout
 662                                 case CLIMBOUT:
 663                                         // Only use current by constraint as largest
 664                                         crosswind_leg_pos = (tortho.y() > crosswind_leg_pos ? tortho.y() : crosswind_leg_pos);
 665                                         //cout << "crosswind_leg_pos = " << crosswind_leg_pos << '\n';
 666                                         break;
 667                                 case TAKEOFF_ROLL:
 668                                         break;
 669                                 case LEG_UNKNOWN:
 670                                         break;
 671                                 case LANDING_ROLL:
 672                                         break;
 673                                 default:
 674                                         break;
 675                                 }
 676                         }
 677
 678                         if(t->leg == FINAL) {
 679                                 if(t->landingType == FULL_STOP) t->opType = INBOUND;
 680                         } else if(t->leg == LANDING_ROLL) {
 681                                 rwyList.push_front(t);
 682                                 RemoveFromTrafficList(t->plane.callsign);
 683                                 if(t->isUser) {
 684                                         t->opType = TTT_UNKNOWN;
 685                                 }       // TODO - allow the user to specify opType via ATC menu
 686                                 circuitListItr = circuitList.erase(circuitListItr);
 687                                 if(circuitListItr == circuitList.end() ) {
 688                                         circuitListItr = circuitList.begin();
 689                                 }
 690                         }
 691                         ++circuitListItr;
 692                 }
 693         }
 694
 695         // Do one plane from the approach list
 696         if(update_count == 7) {
 697                 if(appList.size()) {
 698                         if(appListItr == appList.end()) {
 699                                 appListItr = appList.begin();
 700                         }
 701                         TowerPlaneRec* t = *appListItr;
 702                         //cout << "t = " << t << endl;
 703                         if(t->isUser) {
 704                                 t->pos.setlon(user_lon_node->getDoubleValue());
 705                                 t->pos.setlat(user_lat_node->getDoubleValue());
 706                                 t->pos.setelev(user_elev_node->getDoubleValue());
 707                         } else {
 708                                 // TODO - set/update the position if it's an AI plane
 709                         }
 710                         if(t->nextOnRwy && !(t->clearedToLand)) {
 711                                 // check distance away and whether runway occupied
 712                                 // and schedule transmission if necessary
 713                         }
 714                         ++appListItr;
 715                 }
 716         }
 717
 718         // TODO - do one plane from the departure list and set departed = false when out of consideration
 719
 720         //doCommunication();
 721
 722         if(!separateGround) {
 723                 // The display stuff might have to get more clever than this when not separate
 724                 // since the tower and ground might try communicating simultaneously even though
 725                 // they're mean't to be the same contoller/frequency!!
 726                 if(display) {
 727                         ground->SetDisplay();
 728                 } else {
 729                         ground->SetNoDisplay();
 730                 }
 731                 ground->Update(dt);
 732         }
 733
 734         ++update_count;
 735         // How big should ii get - ie how long should the update cycle interval stretch?
 736         if(update_count >= update_count_max) {
 737                 update_count = 0;
 738         }
 739
 740         // Call the base class update for the response time handling.
 741         FGATC::Update(dt);
 742
 743         if(ident == "KEMT") {
 744                 // For AI debugging convienience - may be removed
 745                 Point3D user_pos;
 746                 user_pos.setlon(user_lon_node->getDoubleValue());
 747                 user_pos.setlat(user_lat_node->getDoubleValue());
 748                 user_pos.setelev(user_elev_node->getDoubleValue());
 749                 Point3D user_ortho_pos = ortho.ConvertToLocal(user_pos);
 750                 fgSetDouble("/AI/user/ortho-x", user_ortho_pos.x());
 751                 fgSetDouble("/AI/user/ortho-y", user_ortho_pos.y());
 752                 fgSetDouble("/AI/user/elev", user_elev_node->getDoubleValue());
 753         }
 754 }
 755
 756
 757 // Returns true if positions of crosswind/downwind/base leg turns should be constrained by previous traffic
 758 // plus the constraint position as a rwy orientated orthopos (meters)
 759 bool FGTower::GetCrosswindConstraint(double& cpos) {
 760         if(crosswind_leg_pos != 0.0) {
 761                 cpos = crosswind_leg_pos;
 762                 return(true);
 763         } else {
 764                 cpos = 0.0;
 765                 return(false);
 766         }
 767 }
 768 bool FGTower::GetDownwindConstraint(double& dpos) {
 769         if(downwind_leg_pos != 0.0) {
 770                 dpos = downwind_leg_pos;
 771                 return(true);
 772         } else {
 773                 dpos = 0.0;
 774                 return(false);
 775         }
 776 }
 777 bool FGTower::GetBaseConstraint(double& bpos) {
 778         if(base_leg_pos != 0.0) {
 779                 bpos = base_leg_pos;
 780                 return(true);
 781         } else {
 782                 bpos = 0.0;
 783                 return(false);
 784         }
 785 }
 786
 787
 788 // Figure out which runways are active.
 789 // For now we'll just be simple and do one active runway - eventually this will get much more complex
 790 // This is a private function - public interface to the results of this is through GetActiveRunway
 791 void FGTower::DoRwyDetails() {
 792         //cout << "GetRwyDetails called" << endl;
 793
 794         // Based on the airport-id and wind get the active runway
 795
 796         //wind
 797         double hdg = wind_from_hdg->getDoubleValue();
 798         double speed = wind_speed_knots->getDoubleValue();
 799         hdg = (speed == 0.0 ? 270.0 : hdg);
 800         //cout << "Heading = " << hdg << '\n';
 801
 802         FGRunway runway;
 803         bool rwyGood = globals->get_runways()->search(ident, int(hdg), &runway);
 804         if(rwyGood) {
 805                 activeRwy = runway.rwy_no;
 806                 rwy.rwyID = runway.rwy_no;
 807                 SG_LOG(SG_ATC, SG_INFO, "Active runway for airport " << ident << " is " << activeRwy);
 808
 809                 // Get the threshold position
 810                 double other_way = runway.heading - 180.0;
 811                 while(other_way <= 0.0) {
 812                         other_way += 360.0;
 813                 }
 814         // move to the +l end/center of the runway
 815                 //cout << "Runway center is at " << runway.lon << ", " << runway.lat << '\n';
 816         Point3D origin = Point3D(runway.lon, runway.lat, aptElev);
 817                 Point3D ref = origin;
 818         double tshlon, tshlat, tshr;
 819                 double tolon, tolat, tor;
 820                 rwy.length = runway.length * SG_FEET_TO_METER;
 821                 rwy.width = runway.width * SG_FEET_TO_METER;
 822         geo_direct_wgs_84 ( aptElev, ref.lat(), ref.lon(), other_way,
 823                                 rwy.length / 2.0 - 25.0, &tshlat, &tshlon, &tshr );
 824         geo_direct_wgs_84 ( aptElev, ref.lat(), ref.lon(), runway.heading,
 825                                 rwy.length / 2.0 - 25.0, &tolat, &tolon, &tor );
 826                 // Note - 25 meters in from the runway end is a bit of a hack to put the plane ahead of the user.
 827                 // now copy what we need out of runway into rwy
 828         rwy.threshold_pos = Point3D(tshlon, tshlat, aptElev);
 829                 Point3D takeoff_end = Point3D(tolon, tolat, aptElev);
 830                 //cout << "Threshold position = " << tshlon << ", " << tshlat << ", " << aptElev << '\n';
 831                 //cout << "Takeoff position = " << tolon << ", " << tolat << ", " << aptElev << '\n';
 832                 rwy.hdg = runway.heading;
 833                 // Set the projection for the local area based on this active runway
 834                 ortho.Init(rwy.threshold_pos, rwy.hdg);
 835                 rwy.end1ortho = ortho.ConvertToLocal(rwy.threshold_pos);        // should come out as zero
 836                 rwy.end2ortho = ortho.ConvertToLocal(takeoff_end);
 837         } else {
 838                 SG_LOG(SG_ATC, SG_ALERT, "Help  - can't get good runway in FGTower!!");
 839                 activeRwy = "NN";
 840         }
 841 }
 842
 843
 844 // Figure out if a given position lies on the active runway
 845 // Might have to change when we consider more than one active rwy.
 846 bool FGTower::OnActiveRunway(Point3D pt) {
 847         // TODO - check that the centre calculation below isn't confused by displaced thesholds etc.
 848         Point3D xyc((rwy.end1ortho.x() + rwy.end2ortho.x())/2.0, (rwy.end1ortho.y() + rwy.end2ortho.y())/2.0, 0.0);
 849         Point3D xyp = ortho.ConvertToLocal(pt);
 850
 851         //cout << "Length offset = " << fabs(xyp.y() - xyc.y()) << '\n';
 852         //cout << "Width offset = " << fabs(xyp.x() - xyc.x()) << '\n';
 853
 854         double rlen = rwy.length/2.0 + 5.0;
 855         double rwidth = rwy.width/2.0;
 856         double ldiff = fabs(xyp.y() - xyc.y());
 857         double wdiff = fabs(xyp.x() - xyc.x());
 858
 859         return((ldiff < rlen) && (wdiff < rwidth));
 860 }
 861
 862
 863 // Figure out if a given position lies on any runway or not
 864 // Only call this at startup - reading the runways database is expensive and needs to be fixed!
 865 bool FGTower::OnAnyRunway(Point3D pt) {
 866         ATCData ad;
 867         double dist = current_commlist->FindClosest(lon, lat, elev, ad, TOWER, 10.0);
 868         if(dist < 0.0) {
 869                 return(false);
 870         }
 871         // Based on the airport-id, go through all the runways and check for a point in them
 872
 873         // TODO - do we actually need to search for the airport - surely we already know our ident and
 874         // can just search runways of our airport???
 875         //cout << "Airport ident is " << ad.ident << '\n';
 876         FGRunway runway;
 877         bool rwyGood = globals->get_runways()->search(ad.ident, &runway);
 878         if(!rwyGood) {
 879                 SG_LOG(SG_ATC, SG_WARN, "Unable to find any runways for airport ID " << ad.ident << " in FGTower");
 880         }
 881         bool on = false;
 882         while(runway.id == ad.ident) {
 883                 on = OnRunway(pt, runway);
 884                 //cout << "Runway " << runway.rwy_no << ": On = " << (on ? "true\n" : "false\n");
 885                 if(on) return(true);
 886                 globals->get_runways()->next(&runway);
 887         }
 888         return(on);
 889 }
 890
 891
 892 // Returns true if successful
 893 bool FGTower::RemoveFromTrafficList(string id) {
 894         tower_plane_rec_list_iterator twrItr;
 895         for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
 896                 TowerPlaneRec* tpr = *twrItr;
 897                 if(tpr->plane.callsign == id) {
 898                         trafficList.erase(twrItr);
 899                         return(true);
 900                 }
 901         }
 902         SG_LOG(SG_ATC, SG_WARN, "Warning - unable to remove aircraft " << id << " from trafficList in FGTower");
 903         return(false);
 904 }
 905
 906
 907 // Add a tower plane rec with ETA to the traffic list in the correct position ETA-wise
 908 // and set nextOnRwy if so.
 909 // Returns true if this could cause a threshold ETA conflict with other traffic, false otherwise.
 910 // For planes holding they are put in the first position with time to go, and the return value is
 911 // true if in the first position (nextOnRwy) and false otherwise.
 912 // See the comments in FGTower::doThresholdUseOrder for notes on the ordering
 913 bool FGTower::AddToTrafficList(TowerPlaneRec* t, bool holding) {
 914         //cout << "ADD: " << trafficList.size();
 915         //cout << "AddToTrafficList called, currently size = " << trafficList.size() << ", holding = " << holding << '\n';
 916         double separation_time = 90.0;  // seconds - this is currently a guess for light plane separation, and includes a few seconds for a holding plane to taxi onto the rwy.
 917         double departure_sep_time = 60.0;       // Separation time behind departing airplanes.  Comments above also apply.
 918         bool conflict = false;
 919         double lastETA = 0.0;
 920         bool firstTime = true;
 921         // FIXME - make this more robust for different plane types eg. light following heavy.
 922         tower_plane_rec_list_iterator twrItr;
 923         //twrItr = trafficList.begin();
 924         //while(1) {
 925         for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
 926                 //if(twrItr == trafficList.end()) {
 927                 //      cout << "  END  ";
 928                 //      trafficList.push_back(t);
 929                 //      return(holding ? firstTime : conflict);
 930                 //} else {
 931                         TowerPlaneRec* tpr = *twrItr;
 932                         if(holding) {
 933                                 //cout << (tpr->isUser ? "USER!\n" : "NOT user\n");
 934                                 //cout << "tpr->eta - lastETA = " << tpr->eta - lastETA << '\n';
 935                                 double dep_allowance = (timeSinceLastDeparture < departure_sep_time ? departure_sep_time - timeSinceLastDeparture : 0.0);
 936                                 double slot_time = (firstTime ? separation_time + dep_allowance : separation_time + departure_sep_time);
 937                                 // separation_time + departure_sep_time in the above accounts for the fact that the arrival could be touch and go,
 938                                 // and if not needs time to clear the rwy anyway.
 939                                 if(tpr->eta  - lastETA > slot_time) {
 940                                         t->nextOnRwy = firstTime;
 941                                         trafficList.insert(twrItr, t);
 942                                         //cout << "\tH\t" << trafficList.size() << '\n';
 943                                         return(firstTime);
 944                                 }
 945                                 firstTime = false;
 946                         } else {
 947                                 if(t->eta < tpr->eta) {
 948                                         // Ugg - this one's tricky.
 949                                         // It depends on what the two planes are doing and whether there's a conflict what we do.
 950                                         if(tpr->eta - t->eta > separation_time) {       // No probs, plane 2 can squeeze in before plane 1 with no apparent conflict
 951                                                 if(tpr->nextOnRwy) {
 952                                                         tpr->nextOnRwy = false;
 953                                                         t->nextOnRwy = true;
 954                                                 }
 955                                                 trafficList.insert(twrItr, t);
 956                                         } else {        // Ooops - this ones tricky - we have a potential conflict!
 957                                                 conflict = true;
 958                                                 // HACK - just add anyway for now and flag conflict - TODO - FIX THIS using CIRCUIT/STRAIGHT_IN and VFR/IFR precedence rules.
 959                                                 if(tpr->nextOnRwy) {
 960                                                         tpr->nextOnRwy = false;
 961                                                         t->nextOnRwy = true;
 962                                                 }
 963                                                 trafficList.insert(twrItr, t);
 964                                         }
 965                                         //cout << "\tC\t" << trafficList.size() << '\n';
 966                                         return(conflict);
 967                                 }
 968                         }
 969                 //}
 970                 //++twrItr;
 971         }
 972         // If we get here we must be at the end of the list, or maybe the list is empty.
 973         if(!trafficList.size()) {
 974                 t->nextOnRwy = true;
 975                 // conflict and firstTime should be false and true respectively in this case anyway.
 976         }
 977         trafficList.push_back(t);
 978         //cout << "\tE\t" << trafficList.size() << '\n';
 979         return(holding ? firstTime : conflict);
 980 }
 981
 982
 983 // Calculate the eta of a plane to the threshold.
 984 // For ground traffic this is the fastest they can get there.
 985 // For air traffic this is the middle approximation.
 986 void FGTower::CalcETA(TowerPlaneRec* tpr, bool printout) {
 987         // For now we'll be very crude and hardwire expected speeds to C172-like values
 988         // The speeds below are specified in knots IAS and then converted to m/s
 989         double app_ias = 100.0 * 0.514444;                      // Speed during straight-in approach
 990         double circuit_ias = 80.0 * 0.514444;           // Speed around circuit
 991         double final_ias = 70.0 * 0.514444;             // Speed during final approach
 992
 993         //if(printout) {
 994         //      cout << "In CalcETA, airplane ident = " << tpr->plane.callsign << '\n';
 995         //      cout << (tpr->isUser ? "USER\n" : "AI\n");
 996         //}
 997
 998         // Sign convention - dist_out is -ve for approaching planes and +ve for departing planes
 999         // dist_across is +ve in the pattern direction - ie a plane correctly on downwind will have a +ve dist_across
1000
1001         Point3D op = ortho.ConvertToLocal(tpr->pos);
1002         //if(printout) {
1003         //      cout << "Orthopos is " << op.x() << ", " << op.y() << '\n';
1004         //      cout << "opType is " << tpr->opType << '\n';
1005         //}
1006         double dist_out_m = op.y();
1007         double dist_across_m = fabs(op.x());    // FIXME = the fabs is a hack to cope with the fact that we don't know the circuit direction yet
1008         //cout << "Doing ETA calc for " << tpr->plane.callsign << '\n';
1009
1010         if(tpr->opType == STRAIGHT_IN) {
1011                 double dist_to_go_m = sqrt((dist_out_m * dist_out_m) + (dist_across_m * dist_across_m));
1012                 if(dist_to_go_m < 1000) {
1013                         tpr->eta = dist_to_go_m / final_ias;
1014                 } else {
1015                         tpr->eta = (1000.0 / final_ias) + ((dist_to_go_m - 1000.0) / app_ias);
1016                 }
1017         } else if(tpr->opType == CIRCUIT || tpr->opType == TTT_UNKNOWN) {       // Hack alert - UNKNOWN has sort of been added here as a temporary hack.
1018                 // It's complicated - depends on if base leg is delayed or not
1019                 //if(printout) {
1020                 //      cout << "Leg = " << tpr->leg << '\n';
1021                 //}
1022                 if(tpr->leg == LANDING_ROLL) {
1023                         tpr->eta = 0;
1024                 } else if((tpr->leg == FINAL) || (tpr->leg == TURN4)) {
1025                         tpr->eta = fabs(dist_out_m) / final_ias;
1026                 } else if((tpr->leg == BASE) || (tpr->leg == TURN3)) {
1027                         tpr->eta = (fabs(dist_out_m) / final_ias) + (dist_across_m / circuit_ias);
1028                 } else {
1029                         // Need to calculate where base leg is likely to be
1030                         // FIXME - for now I'll hardwire it to 1000m which is what AILocalTraffic uses!!!
1031                         // TODO - as a matter of design - AILocalTraffic should get the nominal no-traffic base turn distance from Tower, since in real life the published pattern might differ from airport to airport
1032                         double nominal_base_dist_out_m = -1000;
1033                         double current_base_dist_out_m;
1034                         if(!GetBaseConstraint(current_base_dist_out_m)) {
1035                                 current_base_dist_out_m = nominal_base_dist_out_m;
1036                         }
1037                         double nominal_dist_across_m = 1000;    // Hardwired value from AILocalTraffic
1038                         double current_dist_across_m;
1039                         if(!GetDownwindConstraint(current_dist_across_m)) {
1040                                 current_dist_across_m = nominal_dist_across_m;
1041                         }
1042                         double nominal_cross_dist_out_m = 2000; // Bit of a guess - AI plane turns to crosswind at 600ft agl.
1043                         tpr->eta = fabs(current_base_dist_out_m) / final_ias;   // final
1044                         //if(printout) cout << "a = " << tpr->eta << '\n';
1045                         if((tpr->leg == DOWNWIND) || (tpr->leg == TURN2)) {
1046                                 tpr->eta += dist_across_m / circuit_ias;
1047                                 //if(printout) cout << "b = " << tpr->eta << '\n';
1048                                 tpr->eta += fabs(current_base_dist_out_m - dist_out_m) / circuit_ias;
1049                                 //if(printout) cout << "c = " << tpr->eta << '\n';
1050                         } else if((tpr->leg == CROSSWIND) || (tpr->leg == TURN1)) {
1051                                 if(dist_across_m > nominal_dist_across_m) {
1052                                         tpr->eta += dist_across_m / circuit_ias;
1053                                 } else {
1054                                         tpr->eta += nominal_dist_across_m / circuit_ias;
1055                                 }
1056                                 // should we use the dist across of the previous plane if there is previous still on downwind?
1057                                 //if(printout) cout << "bb = " << tpr->eta << '\n';
1058                                 if(dist_out_m > nominal_cross_dist_out_m) {
1059                                         tpr->eta += fabs(current_base_dist_out_m - dist_out_m) / circuit_ias;
1060                                 } else {
1061                                         tpr->eta += fabs(current_base_dist_out_m - nominal_cross_dist_out_m) / circuit_ias;
1062                                 }
1063                                 //if(printout) cout << "cc = " << tpr->eta << '\n';
1064                                 if(nominal_dist_across_m > dist_across_m) {
1065                                         tpr->eta += (nominal_dist_across_m - dist_across_m) / circuit_ias;
1066                                 } else {
1067                                         // Nothing to add
1068                                 }
1069                                 //if(printout) cout << "dd = " << tpr->eta << '\n';
1070                         } else {
1071                                 // We've only just started - why not use a generic estimate?
1072                                 tpr->eta = 240.0;
1073                         }
1074                 }
1075                 //if(printout) {
1076                 //      cout << "ETA = " << tpr->eta << '\n';
1077                 //}
1078         } else {
1079                 tpr->eta = 99999;
1080         }
1081 }
1082
1083
1084 // Calculate the distance of a plane to the threshold in meters
1085 // TODO - Modify to calculate flying distance of a plane in the circuit
1086 double FGTower::CalcDistOutM(TowerPlaneRec* tpr) {
1087         return(dclGetHorizontalSeparation(rwy.threshold_pos, tpr->pos));
1088 }
1089
1090
1091 // Calculate the distance of a plane to the threshold in miles
1092 // TODO - Modify to calculate flying distance of a plane in the circuit
1093 double FGTower::CalcDistOutMiles(TowerPlaneRec* tpr) {
1094         return(CalcDistOutM(tpr) / 1600.0);             // FIXME - use a proper constant if possible.
1095 }
1096
1097
1098 // Iterate through all the lists and call CalcETA for all the planes.
1099 void FGTower::doThresholdETACalc() {
1100         tower_plane_rec_list_iterator twrItr;
1101         // Do the approach list first
1102         for(twrItr = appList.begin(); twrItr != appList.end(); twrItr++) {
1103                 TowerPlaneRec* tpr = *twrItr;
1104                 CalcETA(tpr);
1105         }
1106         // Then the circuit list
1107         for(twrItr = circuitList.begin(); twrItr != circuitList.end(); twrItr++) {
1108                 TowerPlaneRec* tpr = *twrItr;
1109                 CalcETA(tpr);
1110         }
1111 }
1112
1113
1114 // Check that the planes in traffic list are correctly ordered,
1115 // that the nearest (timewise) is flagged next on rwy, and return
1116 // true if any threshold use conflicts are detected, false otherwise.
1117 bool FGTower::doThresholdUseOrder() {
1118         bool conflict = false;
1119
1120         // Wipe out traffic list, go through circuit, app and hold list, and reorder them in traffic list.
1121         // Here's the rather simplistic assumptions we're using:
1122         // Currently all planes are assumed to be GA light singles with corresponding speeds and separation times.
1123         // In order of priority for runway use:
1124         // STRAIGHT_IN > CIRCUIT > HOLDING_FOR_DEPARTURE
1125         // No modification of planes speeds occurs - conflicts are resolved by delaying turn for base,
1126         // and holding planes until a space.
1127         // When calculating if a holding plane can use the runway, time clearance from last departure
1128         // as well as time clearance to next arrival must be considered.
1129
1130         trafficList.clear();
1131
1132         tower_plane_rec_list_iterator twrItr;
1133         // Do the approach list first
1134         for(twrItr = appList.begin(); twrItr != appList.end(); twrItr++) {
1135                 TowerPlaneRec* tpr = *twrItr;
1136                 conflict = AddToTrafficList(tpr);
1137         }
1138         // Then the circuit list
1139         for(twrItr = circuitList.begin(); twrItr != circuitList.end(); twrItr++) {
1140                 TowerPlaneRec* tpr = *twrItr;
1141                 conflict = AddToTrafficList(tpr);
1142         }
1143         // And finally the hold list
1144         for(twrItr = holdList.begin(); twrItr != holdList.end(); twrItr++) {
1145                 TowerPlaneRec* tpr = *twrItr;
1146                 AddToTrafficList(tpr, true);
1147         }
1148
1149         if(0) {
1150         //if(ident == "KEMT") {
1151                 for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
1152                         TowerPlaneRec* tpr = *twrItr;
1153                         cout << tpr->plane.callsign << '\t' << tpr->eta << '\t';
1154                 }
1155                 cout << '\n';
1156         }
1157
1158         return(conflict);
1159 }
1160
1161 /*
1162 void FGTower::doCommunication() {
1163 }
1164 */
1165
1166 // Return the ETA of plane no. list_pos (1-based) in the traffic list.
1167 // i.e. list_pos = 1 implies next to use runway.
1168 double FGTower::GetTrafficETA(unsigned int list_pos, bool printout) {
1169         if(trafficList.size() < list_pos) {
1170                 return(99999);
1171         }
1172
1173         tower_plane_rec_list_iterator twrItr;
1174         twrItr = trafficList.begin();
1175         for(unsigned int i = 1; i < list_pos; i++, twrItr++);
1176         TowerPlaneRec* tpr = *twrItr;
1177         CalcETA(tpr, printout);
1178         //cout << "ETA returned = " << tpr->eta << '\n';
1179         return(tpr->eta);
1180 }
1181
1182
1183 void FGTower::ContactAtHoldShort(PlaneRec plane, FGAIPlane* requestee, tower_traffic_type operation) {
1184         // HACK - assume that anything contacting at hold short is new for now - FIXME LATER
1185         TowerPlaneRec* t = new TowerPlaneRec;
1186         t->plane = plane;
1187         t->planePtr = requestee;
1188         t->holdShortReported = true;
1189         t->clearanceCounter = 0;
1190         t->clearedToLineUp = false;
1191         t->clearedToTakeOff = false;
1192         t->opType = operation;
1193
1194         //cout << "Hold Short reported by " << plane.callsign << '\n';
1195
1196         bool next = AddToTrafficList(t, true);
1197
1198         if(next) {
1199                 //cout << "Next to take off - respond with clearance\n";
1200                 double teta = GetTrafficETA(2);
1201                 if(teta < 150.0) {
1202                         t->clearanceCounter = 7.0;      // This reduces the delay before response to 3 secs if an immediate takeoff is reqd
1203                         //cout << "Reducing response time to request due imminent traffic\n";
1204                 }
1205         } else {
1206                 //cout << "Not next to take off - respond with hold\n";
1207         }
1208
1209         //cout << "t = " << t << '\n';
1210
1211         holdList.push_back(t);
1212 }
1213
1214 void FGTower::RequestLandingClearance(string ID) {
1215         //cout << "Request Landing Clearance called...\n";
1216
1217         // Assume this comes from the user - have another function taking a pointer to the AIplane for the AI traffic.
1218         // For now we'll also assume that the user is a light plane and can get him/her to join the circuit if necessary.
1219
1220         TowerPlaneRec* t = new TowerPlaneRec;
1221         t->isUser = true;
1222         t->clearedToLand = false;
1223         t->pos.setlon(user_lon_node->getDoubleValue());
1224         t->pos.setlat(user_lat_node->getDoubleValue());
1225         t->pos.setelev(user_elev_node->getDoubleValue());
1226
1227         // TODO
1228         // Calculate where the user is in relation to the active runway and it's circuit
1229         // and set the op-type as appropriate.
1230
1231         // HACK - to get up and running I'm going to assume that the user contacts tower on a staight-in final for now.
1232         t->opType = STRAIGHT_IN;
1233
1234         t->plane.type = GA_SINGLE;      // FIXME - Another assumption!
1235         t->plane.callsign = ID;
1236
1237         appList.push_back(t);   // Not necessarily permanent
1238         AddToTrafficList(t);
1239 }
1240
1241 void FGTower::RequestDepartureClearance(string ID) {
1242         //cout << "Request Departure Clearance called...\n";
1243 }
1244 //void FGTower::ReportFinal(string ID);
1245 //void FGTower::ReportLongFinal(string ID);
1246 //void FGTower::ReportOuterMarker(string ID);
1247 //void FGTower::ReportMiddleMarker(string ID);
1248 //void FGTower::ReportInnerMarker(string ID);
1249 //void FGTower::ReportGoingAround(string ID);
1250 void FGTower::ReportRunwayVacated(string ID) {
1251         //cout << "Report Runway Vacated Called...\n";
1252 }
1253
1254 void FGTower::ReportDownwind(string ID) {
1255         // Tell the plane reporting what number she is in the circuit
1256 }
1257
1258 ostream& operator << (ostream& os, tower_traffic_type ttt) {
1259         switch(ttt) {
1260         case(CIRCUIT):      return(os << "CIRCUIT");
1261         case(INBOUND):      return(os << "INBOUND");
1262         case(OUTBOUND):     return(os << "OUTBOUND");
1263         case(TTT_UNKNOWN):  return(os << "UNKNOWN");
1264         case(STRAIGHT_IN):  return(os << "STRAIGHT_IN");
1265         }
1266         return(os << "ERROR - Unknown switch in tower_traffic_type operator << ");
1267 }
1268