1 // FGGround - a class to provide ground control at larger airports.
3 // Written by David Luff, started March 2002.
5 // Copyright (C) 2002 David C. Luff - david.luff@nottingham.ac.uk
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.
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.
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.
21 #include <simgear/misc/sg_path.hxx>
22 #include <simgear/math/sg_random.h>
23 #include <simgear/debug/logstream.hxx>
24 #include <simgear/misc/sgstream.hxx>
25 #include <simgear/constants.h>
26 #include <Main/globals.hxx>
32 #include "ATCutils.hxx"
34 SG_USING_STD(ifstream);
41 for(unsigned int i=0; i < arcs.size(); ++i) {
46 // Make sure that a_path.cost += distance is safe from the moment it's created.
51 FGGround::FGGround() {
53 networkLoadOK = false;
56 FGGround::~FGGround() {
59 void FGGround::ParseRwyExits(node* np, char* es) {
63 const char delimiters[] = "-";
64 token = strtok(estr, delimiters);
65 while(token != NULL) {
67 //cout << "token = " << token << endl;
68 //cout << "rwy number = " << i << endl;
69 //runways[(atoi(token))].exits.push_back(np);
70 runways[i].exits.push_back(np);
71 //cout << "token = " << token << '\n';
72 token = strtok(NULL, delimiters);
77 // Load the ground logical network of the current instances airport
78 // Return true if successfull.
79 // TODO - currently the file is assumed to reside in the base/ATC directory.
80 // This might change to something more thought out in the future.
81 // NOTE - currently it is assumed that all nodes are loaded before any arcs.
82 // It won't work ATM if this doesn't hold true.
83 bool FGGround::LoadNetwork() {
88 int gateCount = 0; // This is used to allocate gateID's from zero upwards
89 // This may well change in the future - probably to reading in the real-world
90 // gate numbers from file.
93 SGPath path = globals->get_fg_root();
94 //string taxiPath = "ATC/" + ident + ".taxi";
95 string taxiPath = "ATC/KEMT.taxi"; // FIXME - HARDWIRED FOR TESTING
96 path.append(taxiPath);
98 SG_LOG(SG_GENERAL, SG_INFO, "Trying to read taxiway data for " << ident << "...");
99 //cout << "Trying to read taxiway data for " << ident << "..." << endl;
100 fin.open(path.c_str(), ios::in);
102 SG_LOG(SG_GENERAL, SG_ALERT, "Unable to open taxiway data input file " << path.c_str());
103 //cout << "Unable to open taxiway data input file " << path.c_str() << endl;
111 // Node, arc, or [End]?
112 //cout << "Read in ground network element type = " << buf << endl;
113 if(!strcmp(buf, "[End]")) { // TODO - maybe make this more robust to spelling errors by just looking for '['
114 SG_LOG(SG_GENERAL, SG_INFO, "Done reading " << path.c_str() << endl);
116 } else if(!strcmp(buf, "N")) {
119 np->struct_type = NODE;
121 np->nodeID = atoi(buf);
123 np->pos.setlon(atof(buf));
125 np->pos.setlat(atof(buf));
127 np->pos.setelev(atof(buf));
128 fin >> buf; // node type
129 if(!strcmp(buf, "J")) {
131 } else if(!strcmp(buf, "T")) {
132 np->type = TJUNCTION;
133 } else if(!strcmp(buf, "H")) {
136 SG_LOG(SG_GENERAL, SG_ALERT, "**** ERROR ***** Unknown node type in taxi network...\n");
140 fin >> buf; // rwy exit information - gets parsed later - FRAGILE - will break if buf is reused.
142 fin >> ch; // strip the leading " off
145 fin.unsetf(ios::skipws);
147 if((ch == '"') || (ch == 0x0A)) {
149 } // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
152 fin.setf(ios::skipws);
153 network.push_back(np);
154 // FIXME - fragile - replies on buf not getting modified from exits read to here
155 // see if we also need to push it onto the runway exit list
156 //cout << "strlen(buf) = " << strlen(buf) << endl;
157 if(strlen(buf) > 2) {
158 //cout << "Calling ParseRwyExits for " << buf << endl;
159 ParseRwyExits(np, buf);
161 } else if(!strcmp(buf, "A")) {
163 ap->struct_type = ARC;
169 if(!strcmp(buf, "R")) {
171 } else if(!strcmp(buf, "T")) {
174 SG_LOG(SG_GENERAL, SG_ALERT, "**** ERROR ***** Unknown arc type in taxi network...\n");
180 if(!strcmp(buf, "Y")) {
182 } else if(!strcmp(buf, "N")) {
183 ap->directed = false;
185 SG_LOG(SG_GENERAL, SG_ALERT, "**** ERROR ***** Unknown arc directed value in taxi network - should be Y/N !!!\n");
192 fin.unsetf(ios::skipws);
195 if((ch == '"') || (ch == 0x0A)) {
197 } // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
199 fin.setf(ios::skipws);
200 ap->distance = (int)dclGetHorizontalSeparation(network[ap->n1]->pos, network[ap->n2]->pos);
201 //cout << "Distance = " << ap->distance << '\n';
202 network[ap->n1]->arcs.push_back(ap);
203 network[ap->n2]->arcs.push_back(ap);
204 } else if(!strcmp(buf, "G")) {
206 gp->struct_type = NODE;
209 gp->nodeID = atoi(buf);
211 gp->pos.setlon(atof(buf));
213 gp->pos.setlat(atof(buf));
215 gp->pos.setelev(atof(buf));
216 fin >> buf; // gate type - ignore this for now
217 fin >> buf; // gate heading
218 gp->heading = atoi(buf);
222 fin.unsetf(ios::skipws);
225 if((ch == '"') || (ch == 0x0A)) {
227 } // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
229 fin.setf(ios::skipws);
230 gp->id = gateCount; // Warning - this will likely change in the future.
232 network.push_back(gp);
233 gates[gateCount] = gp;
236 // Something has gone seriously pear-shaped
237 SG_LOG(SG_GENERAL, SG_ALERT, "********* ERROR - unknown ground network element type... aborting read of " << path.c_str() << '\n');
246 void FGGround::Init() {
249 // For now we'll hardwire the threshold end
250 Point3D P010(-118.037483, 34.081358, 296 * SG_FEET_TO_METER);
252 ortho.Init(P010, hdg);
254 networkLoadOK = LoadNetwork();
257 void FGGround::Update() {
258 // Each time step, what do we need to do?
259 // We need to go through the list of outstanding requests and acknowedgements
260 // and process at least one of them.
261 // We need to go through the list of planes under our control and check if
262 // any need to be addressed.
263 // We need to check for planes not under our control coming within our
264 // control area and address if necessary.
266 // Lets take the example of a plane which has just contacted ground
267 // following landing - presumably requesting where to go?
268 // First we need to establish the position of the plane within the logical network.
269 // Next we need to decide where its going.
272 // Return a random gate ID of an unused gate.
273 // Two error values may be returned and must be checked for by the calling function:
274 // -2 signifies that no gates exist at this airport.
275 // -1 signifies that all gates are currently full.
276 int FGGround::GetRandomGateID() {
277 // Check that this airport actually has some gates!!
282 gate_vec_type gateVec;
287 gatesItr = gates.begin();
288 while(gatesItr != gates.end()) {
289 if((gatesItr->second)->used == false) {
290 gateVec.push_back(gatesItr->second);
296 // Check that there are some unused gates!
297 if(!gateVec.size()) {
301 // Randomly select one from the list
303 thenum = (int)(sg_random() * gateVec.size());
304 ID = gateVec[thenum]->id;
309 // Return a pointer to an unused gate node
310 Gate* FGGround::GetGateNode() {
311 int id = GetRandomGateID();
320 // WARNING - This is hardwired to my prototype logical network format
321 // and will almost certainly change when Bernie's stuff comes on-line.
322 node* FGGround::GetThresholdNode(string rwyID) {
323 // For now go through all the nodes and parse their names
324 // Maybe in the future we'll map threshold nodes by ID
325 //cout << "Size of network is " << network.size() << '\n';
326 for(unsigned int i=0; i<network.size(); ++i) {
327 //cout << "Name = " << network[i]->name << '\n';
328 if(network[i]->name.size()) {
329 string s = network[i]->name;
330 // Warning - the next bit is fragile and dependent on my current naming scheme
331 //cout << "substr = " << s.substr(0,3) << '\n';
332 //cout << "size of s = " << s.size() << '\n';
333 if(s.substr(0,3) == "rwy") {
334 //cout << "subsubstr = " << s.substr(4, s.size() - 4) << '\n';
335 if(s.substr(4, s.size() - 4) == rwyID) {
344 // Get a path from a point on a runway to a gate
347 // Get a path from a node to another node
348 // Eventually we will need complex algorithms for this taking other traffic,
349 // shortest path and suitable paths into accout.
350 // For now we'll just call the shortest path algorithm.
351 ground_network_path_type FGGround::GetPath(node* A, node* B) {
352 return(GetShortestPath(A, B));
355 // Get a path from a node to a runway threshold
356 ground_network_path_type FGGround::GetPath(node* A, string rwyID) {
357 node* b = GetThresholdNode(rwyID);
359 SG_LOG(SG_GENERAL, SG_ALERT, "ERROR - unable to find path to runway theshold in ground.cxx\n");
360 ground_network_path_type emptyPath;
361 emptyPath.erase(emptyPath.begin(), emptyPath.end());
364 return GetShortestPath(A, b);
367 // A shortest path algorithm from memory (ie. I can't find the bl&*dy book again!)
368 // I'm sure there must be enchancements that we can make to this, such as biasing the
369 // order in which the nodes are searched out from in favour of those geographically
370 // closer to the destination.
371 // Note that we are working with the master set of nodes and arcs so we mustn't change
372 // or delete them - we only delete the paths that we create during the algorithm.
373 ground_network_path_type FGGround::GetShortestPath(node* A, node* B) {
375 shortest_path_map_type pathMap;
376 node_array_type nodesLeft;
379 int pathsCreated = 0;
381 // Initialise the algorithm
382 nodesLeft.push_back(A);
383 pathPtr = new a_path;
385 pathPtr->path.push_back(A);
387 pathMap[A->nodeID] = pathPtr;
388 bool solution_found = false; // Flag to indicate that at least one candidate path has been found
389 int solution_cost = -1; // Cost of current best cost solution. -1 indicates no solution found yet.
390 a_path solution_path;
392 node* nPtr; // nPtr is used to point to the node we are currently working with
394 while(nodesLeft.size()) {
395 //cout << "\n*****nodesLeft*****\n";
396 //for(unsigned int i=0; i<nodesLeft.size(); ++i) {
397 //cout << nodesLeft[i]->nodeID << '\n';
399 //cout << "*******************\n\n";
400 nPtr = *nodesLeft.begin(); // Thought - definate optimization possibilities here in the choice of which nodes we process first.
401 nodesLeft.erase(nodesLeft.begin());
402 //cout << "Walking out from node " << nPtr->nodeID << '\n';
403 for(unsigned int i=0; i<nPtr->arcs.size(); ++i) {
404 //cout << "ARC TO " << ((nPtr->arcs[i]->n1 == nPtr->nodeID) ? nPtr->arcs[i]->n2 : nPtr->arcs[i]->n1) << '\n';
406 if((solution_found) && (solution_cost <= pathMap[nPtr->nodeID]->cost)) {
407 // Do nothing - we've already found a solution and this partial path is already more expensive
409 // This path could still be better than the current solution - check it out
410 for(unsigned int i=0; i<(nPtr->arcs.size()); i++) {
411 // Map the new path against the end node, ie. *not* the one we just started with.
412 unsigned int end_nodeID = ((nPtr->arcs[i]->n1 == nPtr->nodeID) ? nPtr->arcs[i]->n2 : nPtr->arcs[i]->n1);
413 //cout << "end_nodeID = " << end_nodeID << '\n';
414 //cout << "pathMap size is " << pathMap.size() << '\n';
415 if(end_nodeID == nPtr->nodeID) {
416 //cout << "Circular arc!\n";
417 // Then its a circular arc - don't bother!!
418 //nPtr->arcs.erase(nPtr->arcs.begin() + i);
420 // see if the end node is already in the map or not
421 if(pathMap.find(end_nodeID) == pathMap.end()) {
422 //cout << "Not in the map" << endl;;
423 // Not in the map - easy!
424 pathPtr = new a_path;
426 *pathPtr = *pathMap[nPtr->nodeID]; // *copy* the path
427 pathPtr->path.push_back(nPtr->arcs[i]);
428 pathPtr->path.push_back(network[end_nodeID]);
429 pathPtr->cost += nPtr->arcs[i]->distance;
430 pathMap[end_nodeID] = pathPtr;
431 nodesLeft.push_back(network[end_nodeID]); // By definition this can't be in the list already, or
432 // it would also have been in the map and hence OR'd with this one.
433 if(end_nodeID == B->nodeID) {
434 //cout << "Solution found!!!" << endl;
435 // Since this node wasn't in the map this is by definition the first solution
436 solution_cost = pathPtr->cost;
437 solution_path = *pathPtr;
438 solution_found = true;
441 //cout << "Already in the map" << endl;
442 // In the map - not so easy - need to get rid of an arc from the higher cost one.
443 //cout << "Current cost of node " << end_nodeID << " is " << pathMap[end_nodeID]->cost << endl;
444 int newCost = pathMap[nPtr->nodeID]->cost + nPtr->arcs[i]->distance;
445 //cout << "New cost is of node " << nPtr->nodeID << " is " << newCost << endl;
446 if(newCost >= pathMap[end_nodeID]->cost) {
447 // No need to do anything.
448 //cout << "Not doing anything!" << endl;
450 delete pathMap[end_nodeID];
453 pathPtr = new a_path;
455 *pathPtr = *pathMap[nPtr->nodeID]; // *copy* the path
456 pathPtr->path.push_back(nPtr->arcs[i]);
457 pathPtr->path.push_back(network[end_nodeID]);
458 pathPtr->cost += nPtr->arcs[i]->distance;
459 pathMap[end_nodeID] = pathPtr;
461 // We need to add this node to the list-to-do again to force a recalculation
462 // onwards from this node with the new lower cost to node cost.
463 nodesLeft.push_back(network[end_nodeID]);
465 if(end_nodeID == B->nodeID) {
466 //cout << "Solution found!!!" << endl;
467 // Need to check if there is a previous better solution
468 if((solution_cost < 0) || (pathPtr->cost < solution_cost)) {
469 solution_cost = pathPtr->cost;
470 solution_path = *pathPtr;
471 solution_found = true;
481 // delete all the paths before returning
482 shortest_path_map_iterator spItr = pathMap.begin();
483 while(spItr != pathMap.end()) {
484 if(spItr->second != NULL) {
485 delete spItr->second;
491 //cout << "pathsCreated = " << pathsCreated << '\n';
492 if(pathsCreated > 0) {
493 SG_LOG(SG_GENERAL, SG_ALERT, "WARNING - Possible memory leak in FGGround::GetShortestPath\n\
494 Please report to flightgear-devel@flightgear.org\n");
497 //cout << (solution_found ? "Result: solution found\n" : "Result: no solution found\n");
498 return(solution_path.path); // TODO - we really ought to have a fallback position incase a solution isn't found.
503 // Randomly or otherwise populate some of the gates with parked planes
504 // (might eventually be done by the AIMgr if and when lots of AI traffic is generated)
506 // Return a list of exits from a given runway
507 // It is up to the calling function to check for non-zero size of returned array before use
508 node_array_type FGGround::GetExits(int rwyID) {
509 return(runways[rwyID].exits);
513 void FGGround::NewArrival(plane_rec plane) {
514 // What are we going to do here?
515 // We need to start a new ground_rec and add the plane_rec to it
516 // We need to decide what gate we are going to clear it to.
517 // Then we need to add clearing it to that gate to the pending transmissions queue? - or simply transmit?
518 // Probably simply transmit for now and think about a transmission queue later if we need one.
519 // We might need one though in order to add a little delay for response time.
520 ground_rec* g = new ground_rec;
521 g->plane_rec = plane;
522 g->current_pos = ConvertWGS84ToXY(plane.pos);
523 g->node = GetNode(g->current_pos); // TODO - might need to sort out node/arc here
526 ground_traffic.push_back(g);
530 void FGGround::NewContact(plane_rec plane) {
531 // This is a bit of a convienience function at the moment and is likely to change.
532 if(at a gate or apron)
538 void FGGround::NextClearance(ground_rec &g) {
539 // Need to work out where we can clear g to.
540 // Assume the pilot doesn't need progressive instructions
541 // We *should* already have a gate or holding point assigned by the time we get here
542 // but it wouldn't do any harm to check.
544 // For now though we will hardwire it to clear to the final destination.
547 void FGGround::AssignGate(ground_rec &g) {
548 // We'll cheat for now - since we only have the user's aircraft and a couple of airports implemented
549 // we'll hardwire the gate!
550 // In the long run the logic of which gate or area to send the plane to could be somewhat non-trivial.