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 downwindReported(false),
  43 longFinalReported(false),
  44 longFinalAcknowledged(false),
  45 finalReported(false),
  46 finalAcknowledged(false),
  47 onRwy(false),
  48 nextOnRwy(false),
  49 opType(TTT_UNKNOWN),
  50 leg(LEG_UNKNOWN),
  51 landingType(AIP_LT_UNKNOWN),
  52 isUser(false)
  53 {
  54         plane.callsign = "UNKNOWN";
  55 }
  56
  57 TowerPlaneRec::TowerPlaneRec(PlaneRec p) :
  58 clearedToLand(false),
  59 clearedToLineUp(false),
  60 clearedToTakeOff(false),
  61 holdShortReported(false),
  62 downwindReported(false),
  63 longFinalReported(false),
  64 longFinalAcknowledged(false),
  65 finalReported(false),
  66 finalAcknowledged(false),
  67 onRwy(false),
  68 nextOnRwy(false),
  69 opType(TTT_UNKNOWN),
  70 leg(LEG_UNKNOWN),
  71 landingType(AIP_LT_UNKNOWN),
  72 isUser(false)
  73 {
  74         plane = p;
  75 }
  76
  77 TowerPlaneRec::TowerPlaneRec(Point3D pt) :
  78 clearedToLand(false),
  79 clearedToLineUp(false),
  80 clearedToTakeOff(false),
  81 holdShortReported(false),
  82 downwindReported(false),
  83 longFinalReported(false),
  84 longFinalAcknowledged(false),
  85 finalReported(false),
  86 finalAcknowledged(false),
  87 onRwy(false),
  88 nextOnRwy(false),
  89 opType(TTT_UNKNOWN),
  90 leg(LEG_UNKNOWN),
  91 landingType(AIP_LT_UNKNOWN),
  92 isUser(false)
  93 {
  94         plane.callsign = "UNKNOWN";
  95         pos = pt;
  96 }
  97
  98 TowerPlaneRec::TowerPlaneRec(PlaneRec p, Point3D pt) :
  99 clearedToLand(false),
 100 clearedToLineUp(false),
 101 clearedToTakeOff(false),
 102 holdShortReported(false),
 103 downwindReported(false),
 104 longFinalReported(false),
 105 longFinalAcknowledged(false),
 106 finalReported(false),
 107 finalAcknowledged(false),
 108 onRwy(false),
 109 nextOnRwy(false),
 110 opType(TTT_UNKNOWN),
 111 leg(LEG_UNKNOWN),
 112 landingType(AIP_LT_UNKNOWN),
 113 isUser(false)
 114 {
 115         plane = p;
 116         pos = pt;
 117 }
 118
 119
 120 // FGTower
 121
 122 FGTower::FGTower() {
 123         ATCmgr = globals->get_ATC_mgr();
 124
 125         // Init the property nodes - TODO - need to make sure we're getting surface winds.
 126         wind_from_hdg = fgGetNode("/environment/wind-from-heading-deg", true);
 127         wind_speed_knots = fgGetNode("/environment/wind-speed-kt", true);
 128
 129         update_count = 0;
 130         update_count_max = 15;
 131
 132         holdListItr = holdList.begin();
 133         appListItr = appList.begin();
 134         depListItr = depList.begin();
 135         rwyListItr = rwyList.begin();
 136         circuitListItr = circuitList.begin();
 137         trafficListItr = trafficList.begin();
 138
 139         freqClear = true;
 140
 141         timeSinceLastDeparture = 9999;
 142         departed = false;
 143 }
 144
 145 FGTower::~FGTower() {
 146         if(!separateGround) {
 147                 delete ground;
 148         }
 149 }
 150
 151 void FGTower::Init() {
 152     display = false;
 153
 154         // Pointers to user's position
 155         user_lon_node = fgGetNode("/position/longitude-deg", true);
 156         user_lat_node = fgGetNode("/position/latitude-deg", true);
 157         user_elev_node = fgGetNode("/position/altitude-ft", true);
 158         user_hdg_node = fgGetNode("/orientation/heading-deg", true);
 159
 160         // Need some way to initialise rwyOccupied flag correctly if the user is on the runway and to know its the user.
 161         // I'll punt the startup issue for now though!!!
 162         rwyOccupied = false;
 163
 164         // Setup the ground control at this airport
 165         AirportATC a;
 166         //cout << "Tower ident = " << ident << '\n';
 167         if(ATCmgr->GetAirportATCDetails(ident, &a)) {
 168                 if(a.ground_freq) {             // Ground control
 169                         ground = (FGGround*)ATCmgr->GetATCPointer(ident, GROUND);
 170                         separateGround = true;
 171                         if(ground == NULL) {
 172                                 // Something has gone wrong :-(
 173                                 SG_LOG(SG_ATC, SG_WARN, "ERROR - ground has frequency but can't get ground pointer :-(");
 174                                 ground = new FGGround(ident);
 175                                 separateGround = false;
 176                                 ground->Init();
 177                                 if(display) {
 178                                         ground->SetDisplay();
 179                                 } else {
 180                                         ground->SetNoDisplay();
 181                                 }
 182                         }
 183                 } else {
 184                         // Initialise ground anyway to do the shortest path stuff!
 185                         // Note that we're now responsible for updating and deleting this - NOT the ATCMgr.
 186                         ground = new FGGround(ident);
 187                         separateGround = false;
 188                         ground->Init();
 189                         if(display) {
 190                                 ground->SetDisplay();
 191                         } else {
 192                                 ground->SetNoDisplay();
 193                         }
 194                 }
 195         } else {
 196                 SG_LOG(SG_ATC, SG_ALERT, "Unable to find airport details for " << ident << " in FGTower::Init()");
 197                 // Initialise ground anyway to avoid segfault later
 198                 ground = new FGGround(ident);
 199                 separateGround = false;
 200                 ground->Init();
 201                 if(display) {
 202                         ground->SetDisplay();
 203                 } else {
 204                         ground->SetNoDisplay();
 205                 }
 206         }
 207
 208         // Get the airport elevation
 209         aptElev = dclGetAirportElev(ident.c_str()) * SG_FEET_TO_METER;
 210
 211         DoRwyDetails();
 212
 213         // FIXME - this currently assumes use of the active rwy by the user.
 214         rwyOccupied = OnAnyRunway(Point3D(user_lon_node->getDoubleValue(), user_lat_node->getDoubleValue(), 0.0));
 215         if(rwyOccupied) {
 216                 // Assume the user is started at the threshold ready to take-off
 217                 TowerPlaneRec* t = new TowerPlaneRec;
 218                 t->plane.callsign = "Charlie Foxtrot Sierra";   // C-FGFS !!! - fixme - this is a bit hardwired
 219                 t->plane.type = GA_SINGLE;
 220                 t->opType = TTT_UNKNOWN;        // We don't know if the user wants to do circuits or a departure...
 221                 t->landingType = AIP_LT_UNKNOWN;
 222                 t->leg = TAKEOFF_ROLL;
 223                 t->isUser = true;
 224                 t->planePtr = NULL;
 225                 t->clearedToTakeOff = true;
 226                 rwyList.push_back(t);
 227                 departed = false;
 228         }
 229 }
 230
 231 void FGTower::Update(double dt) {
 232         //cout << "T" << flush;
 233         // Each time step, what do we need to do?
 234         // We need to go through the list of outstanding requests and acknowedgements
 235         // and process at least one of them.
 236         // We need to go through the list of planes under our control and check if
 237         // any need to be addressed.
 238         // We need to check for planes not under our control coming within our
 239         // control area and address if necessary.
 240
 241         // TODO - a lot of the below probably doesn't need to be called every frame and should be staggered.
 242
 243         // Sort the arriving planes
 244
 245         /*
 246         if(ident == "KEMT") {
 247                 cout << update_count << "\ttL: " << trafficList.size() << "  cL: " << circuitList.size() << "  hL: " << holdList.size() << "  aL: " << appList.size() << '\n';
 248         }
 249         */
 250
 251         if(departed != false) {
 252                 timeSinceLastDeparture += dt;
 253                 //if(ident == "KEMT")
 254                 //      cout << "  dt = " << dt << "  timeSinceLastDeparture = " << timeSinceLastDeparture << '\n';
 255         }
 256
 257         if(respond) {
 258                 if(!responseReqd) SG_LOG(SG_ATC, SG_ALERT, "ERROR - respond is true and responseReqd is false in FGTower::Update(...)");
 259                 Respond();
 260                 respond = false;
 261                 responseReqd = false;
 262         }
 263
 264         // Calculate the eta of each plane to the threshold.
 265         // For ground traffic this is the fastest they can get there.
 266         // For air traffic this is the middle approximation.
 267         if(update_count == 1) {
 268                 doThresholdETACalc();
 269         }
 270
 271         // Order the list of traffic as per expected threshold use and flag any conflicts
 272         if(update_count == 2) {
 273                 //bool conflicts = doThresholdUseOrder();
 274                 doThresholdUseOrder();
 275         }
 276
 277         // sortConficts() !!!
 278
 279         if(update_count == 4) {
 280                 CheckHoldList(dt);
 281         }
 282
 283         // Uggh - HACK - why have we got rwyOccupied - wouldn't simply testing rwyList.size() do?
 284         if(rwyList.size()) {
 285                 rwyOccupied = true;
 286         } else {
 287                 rwyOccupied = false;
 288         }
 289
 290         if(update_count == 5 && rwyOccupied) {
 291                 CheckRunwayList(dt);
 292         }
 293
 294         if(update_count == 6) {
 295                 CheckCircuitList(dt);
 296         }
 297
 298         if(update_count == 7) {
 299                 CheckApproachList(dt);
 300         }
 301
 302         // TODO - do one plane from the departure list and set departed = false when out of consideration
 303
 304         //doCommunication();
 305
 306         if(!separateGround) {
 307                 // The display stuff might have to get more clever than this when not separate
 308                 // since the tower and ground might try communicating simultaneously even though
 309                 // they're mean't to be the same contoller/frequency!!
 310                 if(display) {
 311                         ground->SetDisplay();
 312                 } else {
 313                         ground->SetNoDisplay();
 314                 }
 315                 ground->Update(dt);
 316         }
 317
 318         ++update_count;
 319         // How big should ii get - ie how long should the update cycle interval stretch?
 320         if(update_count >= update_count_max) {
 321                 update_count = 0;
 322         }
 323
 324         // Call the base class update for the response time handling.
 325         FGATC::Update(dt);
 326
 327         if(ident == "KEMT") {
 328                 // For AI debugging convienience - may be removed
 329                 Point3D user_pos;
 330                 user_pos.setlon(user_lon_node->getDoubleValue());
 331                 user_pos.setlat(user_lat_node->getDoubleValue());
 332                 user_pos.setelev(user_elev_node->getDoubleValue());
 333                 Point3D user_ortho_pos = ortho.ConvertToLocal(user_pos);
 334                 fgSetDouble("/AI/user/ortho-x", user_ortho_pos.x());
 335                 fgSetDouble("/AI/user/ortho-y", user_ortho_pos.y());
 336                 fgSetDouble("/AI/user/elev", user_elev_node->getDoubleValue());
 337         }
 338 }
 339
 340 void FGTower::Respond() {
 341         //cout << "Respond() called\n";
 342         TowerPlaneRec* t = FindPlane(responseID);
 343         if(t) {
 344                 // This will grow!!!
 345                 if(t->downwindReported) {
 346                         t->downwindReported = false;
 347                         int i = 1;
 348                         for(tower_plane_rec_list_iterator twrItr = circuitList.begin(); twrItr != circuitList.end(); twrItr++) {
 349                                 if((*twrItr)->plane.callsign == responseID) break;
 350                                 ++i;
 351                         }
 352                         string trns = "Number ";
 353                         trns += ConvertNumToSpokenDigits(i);
 354                         trns += " ";
 355                         trns += t->plane.callsign;
 356                         if(display) {
 357                                 globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 358                         }
 359                         freqClear = true;       // FIXME - set this to come true after enough time to render the message
 360                         if(t->isUser && t->opType == TTT_UNKNOWN) {
 361                                 t->opType = CIRCUIT;
 362                         }
 363                 }
 364         }
 365 }
 366
 367 // Do one plane from the hold list
 368 void FGTower::CheckHoldList(double dt) {
 369         //cout << "ug\n";
 370         if(holdList.size()) {
 371                 //cout << "*holdListItr = " << *holdListItr << endl;
 372                 if(holdListItr == holdList.end()) {
 373                         holdListItr = holdList.begin();
 374                 }
 375                 //cout << "*holdListItr = " << *holdListItr << endl;
 376                 //Process(*holdListItr);
 377                 TowerPlaneRec* t = *holdListItr;
 378                 //cout << "t = " << t << endl;
 379                 if(t->holdShortReported) {
 380                         //cout << "ding\n";
 381                         double responseTime = 10.0;             // seconds - this should get more sophisticated at some point
 382                         if(t->clearanceCounter > responseTime) {
 383                                 if(t->nextOnRwy) {
 384                                         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!!)
 385                                                 // Do nothing for now - consider acknowloging hold short eventually
 386                                         } else {
 387                                                 // Lets Roll !!!!
 388                                                 string trns = t->plane.callsign;
 389                                                 //if(departed plane < some threshold in time away) {
 390                                                 if(0) {         // FIXME
 391                                                         trns += " line up";
 392                                                         t->clearedToLineUp = true;
 393                                                         t->planePtr->RegisterTransmission(3);   // cleared to line-up
 394                                                         t->leg = TAKEOFF_ROLL;
 395                                                 //} else if(arriving plane < some threshold away) {
 396                                                 } else if(GetTrafficETA(2) < 150.0) {
 397                                                         trns += " cleared immediate take-off";
 398                                                         if(trafficList.size()) {
 399                                                                 tower_plane_rec_list_iterator trfcItr = trafficList.begin();
 400                                                                 trfcItr++;      // At the moment the holding plane should be first in trafficList.
 401                                                                 // Note though that this will break if holding planes aren't put in trafficList in the future.
 402                                                                 TowerPlaneRec* trfc = *trfcItr;
 403                                                                 trns += "... traffic is";
 404                                                                 switch(trfc->plane.type) {
 405                                                                 case UNKNOWN:
 406                                                                         break;
 407                                                                 case GA_SINGLE:
 408                                                                         trns += " a Cessna";    // TODO - add ability to specify actual plane type somewhere
 409                                                                         break;
 410                                                                 case GA_HP_SINGLE:
 411                                                                         trns += " a Piper";
 412                                                                         break;
 413                                                                 case GA_TWIN:
 414                                                                         trns += " a King-air";
 415                                                                         break;
 416                                                                 case GA_JET:
 417                                                                         trns += " a Learjet";
 418                                                                         break;
 419                                                                 case MEDIUM:
 420                                                                         trns += " a Regional";
 421                                                                         break;
 422                                                                 case HEAVY:
 423                                                                         trns += " a Heavy";
 424                                                                         break;
 425                                                                 case MIL_JET:
 426                                                                         trns += " Military";
 427                                                                         break;
 428                                                                 }
 429                                                                 //if(trfc->opType == STRAIGHT_IN || trfc->opType == TTT_UNKNOWN) {
 430                                                                 if(trfc->opType == STRAIGHT_IN) {
 431                                                                         double miles_out = CalcDistOutMiles(trfc);
 432                                                                         if(miles_out < 2) {
 433                                                                                 trns += " on final";
 434                                                                         } else {
 435                                                                                 trns += " on ";
 436                                                                                 trns += ConvertNumToSpokenDigits((int)miles_out);
 437                                                                                 trns += " mile final";
 438                                                                         }
 439                                                                 } else if(trfc->opType == CIRCUIT) {
 440                                                                         cout << "Getting leg of " << trfc->plane.callsign << '\n';
 441                                                                         switch(trfc->leg) {
 442                                                                         case FINAL:
 443                                                                                 trns += " on final";
 444                                                                                 break;
 445                                                                         case TURN4:
 446                                                                                 trns += " turning final";
 447                                                                                 break;
 448                                                                         case BASE:
 449                                                                                 trns += " on base";
 450                                                                                 break;
 451                                                                         case TURN3:
 452                                                                                 trns += " turning base";
 453                                                                                 break;
 454                                                                         case DOWNWIND:
 455                                                                                 trns += " in circuit";  // At the moment the user plane is generally flagged as unknown opType when downwind incase its a downwind departure which means we won't get here.
 456                                                                                 break;
 457                                                                         // And to eliminate compiler warnings...
 458                                                                         case TAKEOFF_ROLL: break;
 459                                                                         case CLIMBOUT:     break;
 460                                                                         case TURN1:        break;
 461                                                                         case CROSSWIND:    break;
 462                                                                         case TURN2:        break;
 463                                                                         case LANDING_ROLL: break;
 464                                                                         case LEG_UNKNOWN:  break;
 465                                                                         }
 466                                                                 }
 467                                                         } else {
 468                                                                 // By definition there should be some arriving traffic if we're cleared for immediate takeoff
 469                                                                 SG_LOG(SG_ATC, SG_WARN, "Warning: Departing traffic cleared for *immediate* take-off despite no arriving traffic in FGTower");
 470                                                         }
 471                                                         t->clearedToTakeOff = true;
 472                                                         t->planePtr->RegisterTransmission(4);   // cleared to take-off - TODO differentiate between immediate and normal take-off
 473                                                         t->leg = TAKEOFF_ROLL;
 474                                                         departed = false;
 475                                                         timeSinceLastDeparture = 0.0;
 476                                                 } else {
 477                                                         trns += " cleared for take-off";
 478                                                         // TODO - add traffic is... ?
 479                                                         t->clearedToTakeOff = true;
 480                                                         t->planePtr->RegisterTransmission(4);   // cleared to take-off
 481                                                         t->leg = TAKEOFF_ROLL;
 482                                                         departed = false;
 483                                                         timeSinceLastDeparture = 0.0;
 484                                                 }
 485                                                 if(display) {
 486                                                         globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 487                                                 }
 488                                                 t->holdShortReported = false;
 489                                                 t->clearanceCounter = 0;
 490                                                 rwyList.push_back(t);
 491                                                 rwyOccupied = true;
 492                                                 holdList.erase(holdListItr);
 493                                                 holdListItr = holdList.begin();
 494                                         }
 495                                 } else {
 496                                         // Tell him to hold and what position he is.
 497                                         // Not currently sure under which circumstances we do or don't bother transmitting this.
 498                                         string trns = t->plane.callsign;
 499                                         trns += " hold position";
 500                                         if(display) {
 501                                                 globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 502                                         }
 503                                         t->holdShortReported = false;
 504                                         t->clearanceCounter = 0;
 505                                         // TODO - add some idea of what traffic is blocking him.
 506                                 }
 507                         } else {
 508                                 t->clearanceCounter += (dt * holdList.size() * update_count_max);
 509                         }
 510                 } else {        // not responding to report, but still need to clear if clear
 511                         //cout << "dong\n";
 512                         if(t->nextOnRwy) {
 513                                 //cout << "departed = " << departed << '\n';
 514                                 //cout << "timeSinceLastDeparture = " << timeSinceLastDeparture << '\n';
 515                                 if(rwyOccupied) {
 516                                         // Do nothing for now - consider acknowloging hold short eventually
 517                                 } else if(timeSinceLastDeparture <= 60.0 && departed == true) {
 518                                         // Do nothing - this is a bit of a hack - should maybe do line up be ready here
 519                                 } else {
 520                                         // Lets Roll !!!!
 521                                         string trns = t->plane.callsign;
 522                                         //cout << "******************* squaggle\n";
 523                                         //cout << "departed = " << departed << '\n';
 524                                         //cout << "timeSinceLastDeparture = " << timeSinceLastDeparture << '\n';
 525                                         //if(departed plane < some threshold in time away) {
 526                                                 if(0) {         // FIXME
 527                                                         //cout << "A\n";
 528                                                         trns += " line up";
 529                                                         t->clearedToLineUp = true;
 530                                                         t->planePtr->RegisterTransmission(3);   // cleared to line-up
 531                                                         t->leg = TAKEOFF_ROLL;
 532                                         //} else if(arriving plane < some threshold away) {
 533                                                 } else if(GetTrafficETA(2) < 150.0 && (timeSinceLastDeparture > 60.0 || departed == false)) {   // Hack - hardwired time
 534                                                         //cout << "B\n";
 535                                                         trns += " cleared immediate take-off";
 536                                                         // TODO - add traffic is... ?
 537                                                         t->clearedToTakeOff = true;
 538                                                         t->planePtr->RegisterTransmission(4);   // cleared to take-off - TODO differentiate between immediate and normal take-off
 539                                                         t->leg = TAKEOFF_ROLL;
 540                                                         departed = false;
 541                                                         timeSinceLastDeparture = 0.0;
 542                                                 } else if(timeSinceLastDeparture > 60.0 || departed == false) { // Hack - test for timeSinceLastDeparture should be in lineup block eventually
 543                                                         //cout << "C\n";
 544                                                         trns += " cleared for take-off";
 545                                                         // TODO - add traffic is... ?
 546                                                         t->clearedToTakeOff = true;
 547                                                         t->planePtr->RegisterTransmission(4);   // cleared to take-off
 548                                                         t->leg = TAKEOFF_ROLL;
 549                                                         departed = false;
 550                                                         timeSinceLastDeparture = 0.0;
 551                                                 } else {
 552                                                         //cout << "D\n";
 553                                                 }
 554                                                 if(display) {
 555                                                         globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 556                                                 }
 557                                                 rwyList.push_back(t);
 558                                                 rwyOccupied = true;
 559                                                 holdList.erase(holdListItr);
 560                                                 holdListItr = holdList.begin();
 561                                 }
 562                         }
 563                         // TODO - rationalise the considerable code duplication above!
 564                 }
 565                 ++holdListItr;
 566         }
 567 }
 568
 569 // do the ciruit list
 570 void FGTower::CheckCircuitList(double dt) {
 571         // Clear the constraints - we recalculate here.
 572         base_leg_pos = 0.0;
 573         downwind_leg_pos = 0.0;
 574         crosswind_leg_pos = 0.0;
 575
 576         if(circuitList.size()) {        // Do one plane from the circuit
 577                 if(circuitListItr == circuitList.end()) {
 578                         circuitListItr = circuitList.begin();
 579                 }
 580                 TowerPlaneRec* t = *circuitListItr;
 581                 if(t->isUser) {
 582                         t->pos.setlon(user_lon_node->getDoubleValue());
 583                         t->pos.setlat(user_lat_node->getDoubleValue());
 584                         t->pos.setelev(user_elev_node->getDoubleValue());
 585                 } else {
 586                         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.
 587                         t->landingType = t->planePtr->GetLandingOption();
 588                         //cout << "AI plane landing option is " << t->landingType << '\n';
 589                 }
 590                 Point3D tortho = ortho.ConvertToLocal(t->pos);
 591                 if(t->isUser) {
 592                         // Need to figure out which leg he's on
 593                         //cout << "rwy.hdg = " << rwy.hdg << " user hdg = " << user_hdg_node->getDoubleValue();
 594                         double ho = GetAngleDiff_deg(user_hdg_node->getDoubleValue(), rwy.hdg);
 595                         //cout << " ho = " << ho << " abs(ho = " << abs(ho) << '\n';
 596                         // TODO FIXME - get the wind and convert this to track, or otherwise use track somehow!!!
 597                         // If it's gusty might need to filter the value, although we are leaving 30 degrees each way leeway!
 598                         if(abs(ho) < 30) {
 599                                 // could be either takeoff, climbout or landing - check orthopos.y
 600                                 //cout << "tortho.y = " << tortho.y() << '\n';
 601                                 if((tortho.y() < 0) || (t->leg == TURN4) || (t->leg == FINAL)) {
 602                                         t->leg = FINAL;
 603                                         //cout << "Final\n";
 604                                 } else {
 605                                         t->leg = CLIMBOUT;      // TODO - check elev wrt. apt elev to differentiate takeoff roll and climbout
 606                                         //cout << "Climbout\n";
 607                                         // If it's the user we may be unsure of his/her intentions.
 608                                         // (Hopefully the AI planes won't try confusing the sim!!!)
 609                                         if(t->opType == TTT_UNKNOWN) {
 610                                                 if(tortho.y() > 5000) {
 611                                                         // 5 km out from threshold - assume it's a departure
 612                                                         t->opType = OUTBOUND;   // TODO - could check if the user has climbed significantly above circuit altitude as well.
 613                                                         // Since we are unknown operation we should be in depList already.
 614                                                         circuitList.erase(circuitListItr);
 615                                                         RemoveFromTrafficList(t->plane.callsign);
 616                                                         circuitListItr = circuitList.begin();
 617                                                 }
 618                                         } else if(t->opType == CIRCUIT) {
 619                                                 if(tortho.y() > 10000) {
 620                                                         // 10 km out - assume the user has abandoned the circuit!!
 621                                                         t->opType = OUTBOUND;
 622                                                         depList.push_back(t);
 623                                                         circuitList.erase(circuitListItr);
 624                                                         circuitListItr = circuitList.begin();
 625                                                 }
 626                                         }
 627                                 }
 628                         } else if(abs(ho) < 60) {
 629                                 // turn1 or turn 4
 630                                 // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 631                                 if((t->leg == CLIMBOUT) || (t->leg == TURN1)) {
 632                                         t->leg = TURN1;
 633                                         //cout << "Turn1\n";
 634                                 } else {
 635                                         t->leg = TURN4;
 636                                         //cout << "Turn4\n";
 637                                 }
 638                         } else if(abs(ho) < 120) {
 639                                 // crosswind or base
 640                                 // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 641                                 if((t->leg == TURN1) || (t->leg == CROSSWIND)) {
 642                                         t->leg = CROSSWIND;
 643                                         //cout << "Crosswind\n";
 644                                 } else {
 645                                         t->leg = BASE;
 646                                         //cout << "Base\n";
 647                                 }
 648                         } else if(abs(ho) < 150) {
 649                                 // turn2 or turn 3
 650                                 // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 651                                 if((t->leg == CROSSWIND) || (t->leg == TURN2)) {
 652                                         t->leg = TURN2;
 653                                         //cout << "Turn2\n";
 654                                 } else {
 655                                         t->leg = TURN3;
 656                                         // Probably safe now to assume the user is flying a circuit
 657                                         t->opType = CIRCUIT;
 658                                         //cout << "Turn3\n";
 659                                 }
 660                         } else {
 661                                 // downwind
 662                                 t->leg = DOWNWIND;
 663                                 //cout << "Downwind\n";
 664                         }
 665                         if(t->leg == FINAL) {
 666                                 if(OnActiveRunway(t->pos)) {
 667                                         t->leg = LANDING_ROLL;
 668                                 }
 669                         }
 670                 } else {
 671                         t->leg = t->planePtr->GetLeg();
 672                 }
 673
 674                 // Set the constraints IF this is the first plane in the circuit
 675                 // 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!!
 676                 if(circuitListItr == circuitList.begin()) {
 677                         switch(t->leg) {
 678                         case FINAL:
 679                                 // 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.
 680                                 base_leg_pos = tortho.y();
 681                                 //cout << "base_leg_pos = " << base_leg_pos << '\n';
 682                                 break;
 683                         case TURN4:
 684                                 // Fall through to base
 685                         case BASE:
 686                                 base_leg_pos = tortho.y();
 687                                 //cout << "base_leg_pos = " << base_leg_pos << '\n';
 688                                 break;
 689                         case TURN3:
 690                                 // Fall through to downwind
 691                         case DOWNWIND:
 692                                 // Only have the downwind leg pos as turn-to-base constraint if more negative than we already have.
 693                                 base_leg_pos = (tortho.y() < base_leg_pos ? tortho.y() : base_leg_pos);
 694                                 //cout << "base_leg_pos = " << base_leg_pos;
 695                                 downwind_leg_pos = tortho.x();          // Assume that a following plane can simply be constrained by the immediately in front downwind plane
 696                                 //cout << " downwind_leg_pos = " << downwind_leg_pos << '\n';
 697                                 break;
 698                         case TURN2:
 699                                 // Fall through to crosswind
 700                         case CROSSWIND:
 701                                 crosswind_leg_pos = tortho.y();
 702                                 //cout << "crosswind_leg_pos = " << crosswind_leg_pos << '\n';
 703                                 break;
 704                         case TURN1:
 705                                 // Fall through to climbout
 706                         case CLIMBOUT:
 707                                 // Only use current by constraint as largest
 708                                 crosswind_leg_pos = (tortho.y() > crosswind_leg_pos ? tortho.y() : crosswind_leg_pos);
 709                                 //cout << "crosswind_leg_pos = " << crosswind_leg_pos << '\n';
 710                                 break;
 711                         case TAKEOFF_ROLL:
 712                                 break;
 713                         case LEG_UNKNOWN:
 714                                 break;
 715                         case LANDING_ROLL:
 716                                 break;
 717                         default:
 718                                 break;
 719                         }
 720                 }
 721
 722                 if(t->leg == FINAL) {
 723                         if(t->landingType == FULL_STOP) t->opType = INBOUND;
 724                 } else if(t->leg == LANDING_ROLL) {
 725                         rwyList.push_front(t);
 726                         RemoveFromTrafficList(t->plane.callsign);
 727                         if(t->isUser) {
 728                                 t->opType = TTT_UNKNOWN;
 729                         }       // TODO - allow the user to specify opType via ATC menu
 730                         circuitListItr = circuitList.erase(circuitListItr);
 731                         if(circuitListItr == circuitList.end() ) {
 732                                 circuitListItr = circuitList.begin();
 733                         }
 734                 }
 735                 ++circuitListItr;
 736         }
 737 }
 738
 739 // 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!!
 740 // FIXME - at the moment it looks like we're only doing the first plane from the rwy list.
 741 // (However, at the moment there should only be one airplane on the rwy at once, until we
 742 // start allowing planes to line up whilst previous arrival clears the rwy.)
 743 void FGTower::CheckRunwayList(double dt) {
 744         if(rwyOccupied) {
 745                 if(!rwyList.size()) {
 746                         rwyOccupied = false;
 747                 } else {
 748                         rwyListItr = rwyList.begin();
 749                         TowerPlaneRec* t = *rwyListItr;
 750                         if(t->isUser) {
 751                                 t->pos.setlon(user_lon_node->getDoubleValue());
 752                                 t->pos.setlat(user_lat_node->getDoubleValue());
 753                                 t->pos.setelev(user_elev_node->getDoubleValue());
 754                         } else {
 755                                 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.
 756                         }
 757                         bool on_rwy = OnActiveRunway(t->pos);
 758                         if(!on_rwy) {
 759                                 if((t->opType == INBOUND) || (t->opType == STRAIGHT_IN)) {
 760                                         rwyList.pop_front();
 761                                         delete t;
 762                                         // TODO - tell it to taxi / contact ground / don't delete it etc!
 763                                 } else if(t->opType == OUTBOUND) {
 764                                         depList.push_back(t);
 765                                         rwyList.pop_front();
 766                                         departed = true;
 767                                         timeSinceLastDeparture = 0.0;
 768                                 } else if(t->opType == CIRCUIT) {
 769                                         circuitList.push_back(t);
 770                                         AddToTrafficList(t);
 771                                         rwyList.pop_front();
 772                                         departed = true;
 773                                         timeSinceLastDeparture = 0.0;
 774                                 } else if(t->opType == TTT_UNKNOWN) {
 775                                         depList.push_back(t);
 776                                         circuitList.push_back(t);
 777                                         AddToTrafficList(t);
 778                                         rwyList.pop_front();
 779                                         departed = true;
 780                                         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.
 781                                 } else {
 782                                         // HELP - we shouldn't ever get here!!!
 783                                 }
 784                         }
 785                 }
 786         }
 787 }
 788
 789 // Do one plane from the approach list
 790 void FGTower::CheckApproachList(double dt) {
 791         if(appList.size()) {
 792                 if(appListItr == appList.end()) {
 793                         appListItr = appList.begin();
 794                 }
 795                 TowerPlaneRec* t = *appListItr;
 796                 //cout << "t = " << t << endl;
 797                 if(t->isUser) {
 798                         t->pos.setlon(user_lon_node->getDoubleValue());
 799                         t->pos.setlat(user_lat_node->getDoubleValue());
 800                         t->pos.setelev(user_elev_node->getDoubleValue());
 801                 } else {
 802                         // TODO - set/update the position if it's an AI plane
 803                 }
 804                 if(t->nextOnRwy && !(t->clearedToLand)) {
 805                         // check distance away and whether runway occupied
 806                         // and schedule transmission if necessary
 807                 }
 808                 ++appListItr;
 809         }
 810 }
 811
 812 // Returns true if positions of crosswind/downwind/base leg turns should be constrained by previous traffic
 813 // plus the constraint position as a rwy orientated orthopos (meters)
 814 bool FGTower::GetCrosswindConstraint(double& cpos) {
 815         if(crosswind_leg_pos != 0.0) {
 816                 cpos = crosswind_leg_pos;
 817                 return(true);
 818         } else {
 819                 cpos = 0.0;
 820                 return(false);
 821         }
 822 }
 823 bool FGTower::GetDownwindConstraint(double& dpos) {
 824         if(downwind_leg_pos != 0.0) {
 825                 dpos = downwind_leg_pos;
 826                 return(true);
 827         } else {
 828                 dpos = 0.0;
 829                 return(false);
 830         }
 831 }
 832 bool FGTower::GetBaseConstraint(double& bpos) {
 833         if(base_leg_pos != 0.0) {
 834                 bpos = base_leg_pos;
 835                 return(true);
 836         } else {
 837                 bpos = 0.0;
 838                 return(false);
 839         }
 840 }
 841
 842
 843 // Figure out which runways are active.
 844 // For now we'll just be simple and do one active runway - eventually this will get much more complex
 845 // This is a private function - public interface to the results of this is through GetActiveRunway
 846 void FGTower::DoRwyDetails() {
 847         //cout << "GetRwyDetails called" << endl;
 848
 849         // Based on the airport-id and wind get the active runway
 850
 851         //wind
 852         double hdg = wind_from_hdg->getDoubleValue();
 853         double speed = wind_speed_knots->getDoubleValue();
 854         hdg = (speed == 0.0 ? 270.0 : hdg);
 855         //cout << "Heading = " << hdg << '\n';
 856
 857         FGRunway runway;
 858         bool rwyGood = globals->get_runways()->search(ident, int(hdg), &runway);
 859         if(rwyGood) {
 860                 activeRwy = runway.rwy_no;
 861                 rwy.rwyID = runway.rwy_no;
 862                 SG_LOG(SG_ATC, SG_INFO, "Active runway for airport " << ident << " is " << activeRwy);
 863
 864                 // Get the threshold position
 865                 double other_way = runway.heading - 180.0;
 866                 while(other_way <= 0.0) {
 867                         other_way += 360.0;
 868                 }
 869         // move to the +l end/center of the runway
 870                 //cout << "Runway center is at " << runway.lon << ", " << runway.lat << '\n';
 871         Point3D origin = Point3D(runway.lon, runway.lat, aptElev);
 872                 Point3D ref = origin;
 873         double tshlon, tshlat, tshr;
 874                 double tolon, tolat, tor;
 875                 rwy.length = runway.length * SG_FEET_TO_METER;
 876                 rwy.width = runway.width * SG_FEET_TO_METER;
 877         geo_direct_wgs_84 ( aptElev, ref.lat(), ref.lon(), other_way,
 878                                 rwy.length / 2.0 - 25.0, &tshlat, &tshlon, &tshr );
 879         geo_direct_wgs_84 ( aptElev, ref.lat(), ref.lon(), runway.heading,
 880                                 rwy.length / 2.0 - 25.0, &tolat, &tolon, &tor );
 881                 // Note - 25 meters in from the runway end is a bit of a hack to put the plane ahead of the user.
 882                 // now copy what we need out of runway into rwy
 883         rwy.threshold_pos = Point3D(tshlon, tshlat, aptElev);
 884                 Point3D takeoff_end = Point3D(tolon, tolat, aptElev);
 885                 //cout << "Threshold position = " << tshlon << ", " << tshlat << ", " << aptElev << '\n';
 886                 //cout << "Takeoff position = " << tolon << ", " << tolat << ", " << aptElev << '\n';
 887                 rwy.hdg = runway.heading;
 888                 // Set the projection for the local area based on this active runway
 889                 ortho.Init(rwy.threshold_pos, rwy.hdg);
 890                 rwy.end1ortho = ortho.ConvertToLocal(rwy.threshold_pos);        // should come out as zero
 891                 rwy.end2ortho = ortho.ConvertToLocal(takeoff_end);
 892         } else {
 893                 SG_LOG(SG_ATC, SG_ALERT, "Help  - can't get good runway in FGTower!!");
 894                 activeRwy = "NN";
 895         }
 896 }
 897
 898
 899 // Figure out if a given position lies on the active runway
 900 // Might have to change when we consider more than one active rwy.
 901 bool FGTower::OnActiveRunway(Point3D pt) {
 902         // TODO - check that the centre calculation below isn't confused by displaced thesholds etc.
 903         Point3D xyc((rwy.end1ortho.x() + rwy.end2ortho.x())/2.0, (rwy.end1ortho.y() + rwy.end2ortho.y())/2.0, 0.0);
 904         Point3D xyp = ortho.ConvertToLocal(pt);
 905
 906         //cout << "Length offset = " << fabs(xyp.y() - xyc.y()) << '\n';
 907         //cout << "Width offset = " << fabs(xyp.x() - xyc.x()) << '\n';
 908
 909         double rlen = rwy.length/2.0 + 5.0;
 910         double rwidth = rwy.width/2.0;
 911         double ldiff = fabs(xyp.y() - xyc.y());
 912         double wdiff = fabs(xyp.x() - xyc.x());
 913
 914         return((ldiff < rlen) && (wdiff < rwidth));
 915 }
 916
 917
 918 // Figure out if a given position lies on any runway or not
 919 // Only call this at startup - reading the runways database is expensive and needs to be fixed!
 920 bool FGTower::OnAnyRunway(Point3D pt) {
 921         ATCData ad;
 922         double dist = current_commlist->FindClosest(lon, lat, elev, ad, TOWER, 10.0);
 923         if(dist < 0.0) {
 924                 return(false);
 925         }
 926         // Based on the airport-id, go through all the runways and check for a point in them
 927
 928         // TODO - do we actually need to search for the airport - surely we already know our ident and
 929         // can just search runways of our airport???
 930         //cout << "Airport ident is " << ad.ident << '\n';
 931         FGRunway runway;
 932         bool rwyGood = globals->get_runways()->search(ad.ident, &runway);
 933         if(!rwyGood) {
 934                 SG_LOG(SG_ATC, SG_WARN, "Unable to find any runways for airport ID " << ad.ident << " in FGTower");
 935         }
 936         bool on = false;
 937         while(runway.id == ad.ident) {
 938                 on = OnRunway(pt, runway);
 939                 //cout << "Runway " << runway.rwy_no << ": On = " << (on ? "true\n" : "false\n");
 940                 if(on) return(true);
 941                 globals->get_runways()->next(&runway);
 942         }
 943         return(on);
 944 }
 945
 946
 947 // Returns true if successful
 948 bool FGTower::RemoveFromTrafficList(string id) {
 949         tower_plane_rec_list_iterator twrItr;
 950         for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
 951                 TowerPlaneRec* tpr = *twrItr;
 952                 if(tpr->plane.callsign == id) {
 953                         trafficList.erase(twrItr);
 954                         return(true);
 955                 }
 956         }
 957         SG_LOG(SG_ATC, SG_WARN, "Warning - unable to remove aircraft " << id << " from trafficList in FGTower");
 958         return(false);
 959 }
 960
 961
 962 // Add a tower plane rec with ETA to the traffic list in the correct position ETA-wise
 963 // and set nextOnRwy if so.
 964 // Returns true if this could cause a threshold ETA conflict with other traffic, false otherwise.
 965 // For planes holding they are put in the first position with time to go, and the return value is
 966 // true if in the first position (nextOnRwy) and false otherwise.
 967 // See the comments in FGTower::doThresholdUseOrder for notes on the ordering
 968 bool FGTower::AddToTrafficList(TowerPlaneRec* t, bool holding) {
 969         //cout << "ADD: " << trafficList.size();
 970         //cout << "AddToTrafficList called, currently size = " << trafficList.size() << ", holding = " << holding << '\n';
 971         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.
 972         double departure_sep_time = 60.0;       // Separation time behind departing airplanes.  Comments above also apply.
 973         bool conflict = false;
 974         double lastETA = 0.0;
 975         bool firstTime = true;
 976         // FIXME - make this more robust for different plane types eg. light following heavy.
 977         tower_plane_rec_list_iterator twrItr;
 978         //twrItr = trafficList.begin();
 979         //while(1) {
 980         for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
 981                 //if(twrItr == trafficList.end()) {
 982                 //      cout << "  END  ";
 983                 //      trafficList.push_back(t);
 984                 //      return(holding ? firstTime : conflict);
 985                 //} else {
 986                         TowerPlaneRec* tpr = *twrItr;
 987                         if(holding) {
 988                                 //cout << (tpr->isUser ? "USER!\n" : "NOT user\n");
 989                                 //cout << "tpr->eta - lastETA = " << tpr->eta - lastETA << '\n';
 990                                 double dep_allowance = (timeSinceLastDeparture < departure_sep_time ? departure_sep_time - timeSinceLastDeparture : 0.0);
 991                                 double slot_time = (firstTime ? separation_time + dep_allowance : separation_time + departure_sep_time);
 992                                 // separation_time + departure_sep_time in the above accounts for the fact that the arrival could be touch and go,
 993                                 // and if not needs time to clear the rwy anyway.
 994                                 if(tpr->eta  - lastETA > slot_time) {
 995                                         t->nextOnRwy = firstTime;
 996                                         trafficList.insert(twrItr, t);
 997                                         //cout << "\tH\t" << trafficList.size() << '\n';
 998                                         return(firstTime);
 999                                 }
1000                                 firstTime = false;
1001                         } else {
1002                                 if(t->eta < tpr->eta) {
1003                                         // Ugg - this one's tricky.
1004                                         // It depends on what the two planes are doing and whether there's a conflict what we do.
1005                                         if(tpr->eta - t->eta > separation_time) {       // No probs, plane 2 can squeeze in before plane 1 with no apparent conflict
1006                                                 if(tpr->nextOnRwy) {
1007                                                         tpr->nextOnRwy = false;
1008                                                         t->nextOnRwy = true;
1009                                                 }
1010                                                 trafficList.insert(twrItr, t);
1011                                         } else {        // Ooops - this ones tricky - we have a potential conflict!
1012                                                 conflict = true;
1013                                                 // HACK - just add anyway for now and flag conflict - TODO - FIX THIS using CIRCUIT/STRAIGHT_IN and VFR/IFR precedence rules.
1014                                                 if(tpr->nextOnRwy) {
1015                                                         tpr->nextOnRwy = false;
1016                                                         t->nextOnRwy = true;
1017                                                 }
1018                                                 trafficList.insert(twrItr, t);
1019                                         }
1020                                         //cout << "\tC\t" << trafficList.size() << '\n';
1021                                         return(conflict);
1022                                 }
1023                         }
1024                 //}
1025                 //++twrItr;
1026         }
1027         // If we get here we must be at the end of the list, or maybe the list is empty.
1028         if(!trafficList.size()) {
1029                 t->nextOnRwy = true;
1030                 // conflict and firstTime should be false and true respectively in this case anyway.
1031         }
1032         trafficList.push_back(t);
1033         //cout << "\tE\t" << trafficList.size() << '\n';
1034         return(holding ? firstTime : conflict);
1035 }
1036
1037
1038 // Calculate the eta of a plane to the threshold.
1039 // For ground traffic this is the fastest they can get there.
1040 // For air traffic this is the middle approximation.
1041 void FGTower::CalcETA(TowerPlaneRec* tpr, bool printout) {
1042         // For now we'll be very crude and hardwire expected speeds to C172-like values
1043         // The speeds below are specified in knots IAS and then converted to m/s
1044         double app_ias = 100.0 * 0.514444;                      // Speed during straight-in approach
1045         double circuit_ias = 80.0 * 0.514444;           // Speed around circuit
1046         double final_ias = 70.0 * 0.514444;             // Speed during final approach
1047
1048         //if(printout) {
1049         //      cout << "In CalcETA, airplane ident = " << tpr->plane.callsign << '\n';
1050         //      cout << (tpr->isUser ? "USER\n" : "AI\n");
1051         //}
1052
1053         // Sign convention - dist_out is -ve for approaching planes and +ve for departing planes
1054         // dist_across is +ve in the pattern direction - ie a plane correctly on downwind will have a +ve dist_across
1055
1056         Point3D op = ortho.ConvertToLocal(tpr->pos);
1057         //if(printout) {
1058         //      cout << "Orthopos is " << op.x() << ", " << op.y() << '\n';
1059         //      cout << "opType is " << tpr->opType << '\n';
1060         //}
1061         double dist_out_m = op.y();
1062         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
1063         //cout << "Doing ETA calc for " << tpr->plane.callsign << '\n';
1064
1065         if(tpr->opType == STRAIGHT_IN) {
1066                 double dist_to_go_m = sqrt((dist_out_m * dist_out_m) + (dist_across_m * dist_across_m));
1067                 if(dist_to_go_m < 1000) {
1068                         tpr->eta = dist_to_go_m / final_ias;
1069                 } else {
1070                         tpr->eta = (1000.0 / final_ias) + ((dist_to_go_m - 1000.0) / app_ias);
1071                 }
1072         } else if(tpr->opType == CIRCUIT || tpr->opType == TTT_UNKNOWN) {       // Hack alert - UNKNOWN has sort of been added here as a temporary hack.
1073                 // It's complicated - depends on if base leg is delayed or not
1074                 //if(printout) {
1075                 //      cout << "Leg = " << tpr->leg << '\n';
1076                 //}
1077                 if(tpr->leg == LANDING_ROLL) {
1078                         tpr->eta = 0;
1079                 } else if((tpr->leg == FINAL) || (tpr->leg == TURN4)) {
1080                         tpr->eta = fabs(dist_out_m) / final_ias;
1081                 } else if((tpr->leg == BASE) || (tpr->leg == TURN3)) {
1082                         tpr->eta = (fabs(dist_out_m) / final_ias) + (dist_across_m / circuit_ias);
1083                 } else {
1084                         // Need to calculate where base leg is likely to be
1085                         // FIXME - for now I'll hardwire it to 1000m which is what AILocalTraffic uses!!!
1086                         // 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
1087                         double nominal_base_dist_out_m = -1000;
1088                         double current_base_dist_out_m;
1089                         if(!GetBaseConstraint(current_base_dist_out_m)) {
1090                                 current_base_dist_out_m = nominal_base_dist_out_m;
1091                         }
1092                         double nominal_dist_across_m = 1000;    // Hardwired value from AILocalTraffic
1093                         double current_dist_across_m;
1094                         if(!GetDownwindConstraint(current_dist_across_m)) {
1095                                 current_dist_across_m = nominal_dist_across_m;
1096                         }
1097                         double nominal_cross_dist_out_m = 2000; // Bit of a guess - AI plane turns to crosswind at 600ft agl.
1098                         tpr->eta = fabs(current_base_dist_out_m) / final_ias;   // final
1099                         //if(printout) cout << "a = " << tpr->eta << '\n';
1100                         if((tpr->leg == DOWNWIND) || (tpr->leg == TURN2)) {
1101                                 tpr->eta += dist_across_m / circuit_ias;
1102                                 //if(printout) cout << "b = " << tpr->eta << '\n';
1103                                 tpr->eta += fabs(current_base_dist_out_m - dist_out_m) / circuit_ias;
1104                                 //if(printout) cout << "c = " << tpr->eta << '\n';
1105                         } else if((tpr->leg == CROSSWIND) || (tpr->leg == TURN1)) {
1106                                 if(dist_across_m > nominal_dist_across_m) {
1107                                         tpr->eta += dist_across_m / circuit_ias;
1108                                 } else {
1109                                         tpr->eta += nominal_dist_across_m / circuit_ias;
1110                                 }
1111                                 // should we use the dist across of the previous plane if there is previous still on downwind?
1112                                 //if(printout) cout << "bb = " << tpr->eta << '\n';
1113                                 if(dist_out_m > nominal_cross_dist_out_m) {
1114                                         tpr->eta += fabs(current_base_dist_out_m - dist_out_m) / circuit_ias;
1115                                 } else {
1116                                         tpr->eta += fabs(current_base_dist_out_m - nominal_cross_dist_out_m) / circuit_ias;
1117                                 }
1118                                 //if(printout) cout << "cc = " << tpr->eta << '\n';
1119                                 if(nominal_dist_across_m > dist_across_m) {
1120                                         tpr->eta += (nominal_dist_across_m - dist_across_m) / circuit_ias;
1121                                 } else {
1122                                         // Nothing to add
1123                                 }
1124                                 //if(printout) cout << "dd = " << tpr->eta << '\n';
1125                         } else {
1126                                 // We've only just started - why not use a generic estimate?
1127                                 tpr->eta = 240.0;
1128                         }
1129                 }
1130                 //if(printout) {
1131                 //      cout << "ETA = " << tpr->eta << '\n';
1132                 //}
1133         } else {
1134                 tpr->eta = 99999;
1135         }
1136 }
1137
1138
1139 // Calculate the distance of a plane to the threshold in meters
1140 // TODO - Modify to calculate flying distance of a plane in the circuit
1141 double FGTower::CalcDistOutM(TowerPlaneRec* tpr) {
1142         return(dclGetHorizontalSeparation(rwy.threshold_pos, tpr->pos));
1143 }
1144
1145
1146 // Calculate the distance of a plane to the threshold in miles
1147 // TODO - Modify to calculate flying distance of a plane in the circuit
1148 double FGTower::CalcDistOutMiles(TowerPlaneRec* tpr) {
1149         return(CalcDistOutM(tpr) / 1600.0);             // FIXME - use a proper constant if possible.
1150 }
1151
1152
1153 // Iterate through all the lists and call CalcETA for all the planes.
1154 void FGTower::doThresholdETACalc() {
1155         tower_plane_rec_list_iterator twrItr;
1156         // Do the approach list first
1157         for(twrItr = appList.begin(); twrItr != appList.end(); twrItr++) {
1158                 TowerPlaneRec* tpr = *twrItr;
1159                 CalcETA(tpr);
1160         }
1161         // Then the circuit list
1162         for(twrItr = circuitList.begin(); twrItr != circuitList.end(); twrItr++) {
1163                 TowerPlaneRec* tpr = *twrItr;
1164                 CalcETA(tpr);
1165         }
1166 }
1167
1168
1169 // Check that the planes in traffic list are correctly ordered,
1170 // that the nearest (timewise) is flagged next on rwy, and return
1171 // true if any threshold use conflicts are detected, false otherwise.
1172 bool FGTower::doThresholdUseOrder() {
1173         bool conflict = false;
1174
1175         // Wipe out traffic list, go through circuit, app and hold list, and reorder them in traffic list.
1176         // Here's the rather simplistic assumptions we're using:
1177         // Currently all planes are assumed to be GA light singles with corresponding speeds and separation times.
1178         // In order of priority for runway use:
1179         // STRAIGHT_IN > CIRCUIT > HOLDING_FOR_DEPARTURE
1180         // No modification of planes speeds occurs - conflicts are resolved by delaying turn for base,
1181         // and holding planes until a space.
1182         // When calculating if a holding plane can use the runway, time clearance from last departure
1183         // as well as time clearance to next arrival must be considered.
1184
1185         trafficList.clear();
1186
1187         tower_plane_rec_list_iterator twrItr;
1188         // Do the approach list first
1189         for(twrItr = appList.begin(); twrItr != appList.end(); twrItr++) {
1190                 TowerPlaneRec* tpr = *twrItr;
1191                 conflict = AddToTrafficList(tpr);
1192         }
1193         // Then the circuit list
1194         for(twrItr = circuitList.begin(); twrItr != circuitList.end(); twrItr++) {
1195                 TowerPlaneRec* tpr = *twrItr;
1196                 conflict = AddToTrafficList(tpr);
1197         }
1198         // And finally the hold list
1199         for(twrItr = holdList.begin(); twrItr != holdList.end(); twrItr++) {
1200                 TowerPlaneRec* tpr = *twrItr;
1201                 AddToTrafficList(tpr, true);
1202         }
1203
1204         if(0) {
1205         //if(ident == "KEMT") {
1206                 for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
1207                         TowerPlaneRec* tpr = *twrItr;
1208                         cout << tpr->plane.callsign << '\t' << tpr->eta << '\t';
1209                 }
1210                 cout << '\n';
1211         }
1212
1213         return(conflict);
1214 }
1215
1216 /*
1217 void FGTower::doCommunication() {
1218 }
1219 */
1220
1221 // Return the ETA of plane no. list_pos (1-based) in the traffic list.
1222 // i.e. list_pos = 1 implies next to use runway.
1223 double FGTower::GetTrafficETA(unsigned int list_pos, bool printout) {
1224         if(trafficList.size() < list_pos) {
1225                 return(99999);
1226         }
1227
1228         tower_plane_rec_list_iterator twrItr;
1229         twrItr = trafficList.begin();
1230         for(unsigned int i = 1; i < list_pos; i++, twrItr++);
1231         TowerPlaneRec* tpr = *twrItr;
1232         CalcETA(tpr, printout);
1233         //cout << "ETA returned = " << tpr->eta << '\n';
1234         return(tpr->eta);
1235 }
1236
1237
1238 void FGTower::ContactAtHoldShort(PlaneRec plane, FGAIPlane* requestee, tower_traffic_type operation) {
1239         // HACK - assume that anything contacting at hold short is new for now - FIXME LATER
1240         TowerPlaneRec* t = new TowerPlaneRec;
1241         t->plane = plane;
1242         t->planePtr = requestee;
1243         t->holdShortReported = true;
1244         t->clearanceCounter = 0;
1245         t->clearedToLineUp = false;
1246         t->clearedToTakeOff = false;
1247         t->opType = operation;
1248
1249         //cout << "Hold Short reported by " << plane.callsign << '\n';
1250
1251         bool next = AddToTrafficList(t, true);
1252
1253         if(next) {
1254                 //cout << "Next to take off - respond with clearance\n";
1255                 double teta = GetTrafficETA(2);
1256                 if(teta < 150.0) {
1257                         t->clearanceCounter = 7.0;      // This reduces the delay before response to 3 secs if an immediate takeoff is reqd
1258                         //cout << "Reducing response time to request due imminent traffic\n";
1259                 }
1260         } else {
1261                 //cout << "Not next to take off - respond with hold\n";
1262         }
1263
1264         //cout << "t = " << t << '\n';
1265
1266         holdList.push_back(t);
1267 }
1268
1269 void FGTower::RequestLandingClearance(string ID) {
1270         //cout << "Request Landing Clearance called...\n";
1271
1272         // Assume this comes from the user - have another function taking a pointer to the AIplane for the AI traffic.
1273         // For now we'll also assume that the user is a light plane and can get him/her to join the circuit if necessary.
1274
1275         TowerPlaneRec* t = new TowerPlaneRec;
1276         t->isUser = true;
1277         t->clearedToLand = false;
1278         t->pos.setlon(user_lon_node->getDoubleValue());
1279         t->pos.setlat(user_lat_node->getDoubleValue());
1280         t->pos.setelev(user_elev_node->getDoubleValue());
1281
1282         // TODO
1283         // Calculate where the user is in relation to the active runway and it's circuit
1284         // and set the op-type as appropriate.
1285
1286         // HACK - to get up and running I'm going to assume that the user contacts tower on a staight-in final for now.
1287         t->opType = STRAIGHT_IN;
1288
1289         t->plane.type = GA_SINGLE;      // FIXME - Another assumption!
1290         t->plane.callsign = ID;
1291
1292         appList.push_back(t);   // Not necessarily permanent
1293         AddToTrafficList(t);
1294 }
1295
1296 void FGTower::RequestDepartureClearance(string ID) {
1297         //cout << "Request Departure Clearance called...\n";
1298 }
1299 //void FGTower::ReportFinal(string ID);
1300 //void FGTower::ReportLongFinal(string ID);
1301 //void FGTower::ReportOuterMarker(string ID);
1302 //void FGTower::ReportMiddleMarker(string ID);
1303 //void FGTower::ReportInnerMarker(string ID);
1304 //void FGTower::ReportGoingAround(string ID);
1305 void FGTower::ReportRunwayVacated(string ID) {
1306         //cout << "Report Runway Vacated Called...\n";
1307 }
1308
1309 TowerPlaneRec* FGTower::FindPlane(string ID) {
1310         tower_plane_rec_list_iterator twrItr;
1311         // Do the approach list first
1312         for(twrItr = appList.begin(); twrItr != appList.end(); twrItr++) {
1313                 if((*twrItr)->plane.callsign == ID) return(*twrItr);
1314         }
1315         // Then the circuit list
1316         for(twrItr = circuitList.begin(); twrItr != circuitList.end(); twrItr++) {
1317                 if((*twrItr)->plane.callsign == ID) return(*twrItr);
1318         }
1319         // And finally the hold list
1320         for(twrItr = holdList.begin(); twrItr != holdList.end(); twrItr++) {
1321                 if((*twrItr)->plane.callsign == ID) return(*twrItr);
1322         }
1323         SG_LOG(SG_ATC, SG_WARN, "Unable to find " << ID << " in FGTower::FindPlane(...)");
1324         return(NULL);
1325 }
1326
1327 void FGTower::ReportDownwind(string ID) {
1328         //cout << "ReportDownwind(...) called\n";
1329         // Tell the plane reporting what number she is in the circuit
1330         TowerPlaneRec* t = FindPlane(ID);
1331         if(t) {
1332                 t->downwindReported = true;
1333                 responseReqd = true;
1334         } else {
1335                 SG_LOG(SG_ATC, SG_WARN, "WARNING: Unable to find plane " << ID << " in FGTower::ReportDownwind(...)");
1336         }
1337 }
1338
1339 ostream& operator << (ostream& os, tower_traffic_type ttt) {
1340         switch(ttt) {
1341         case(CIRCUIT):      return(os << "CIRCUIT");
1342         case(INBOUND):      return(os << "INBOUND");
1343         case(OUTBOUND):     return(os << "OUTBOUND");
1344         case(TTT_UNKNOWN):  return(os << "UNKNOWN");
1345         case(STRAIGHT_IN):  return(os << "STRAIGHT_IN");
1346         }
1347         return(os << "ERROR - Unknown switch in tower_traffic_type operator << ");
1348 }
1349