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 cout << "**** ERROR ***** Unknown node type in taxi network...\n";
140 fin >> buf; // rwy exit information - gets parsed later - FRAGILE - will break if buf is reused.
144 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 "
151 fin.setf(ios::skipws);
152 network.push_back(np);
153 // FIXME - fragile - replies on buf not getting modified from exits read to here
154 // see if we also need to push it onto the runway exit list
155 cout << "strlen(buf) = " << strlen(buf) << endl;
156 if(strlen(buf) > 2) {
157 cout << "Calling ParseRwyExits for " << buf << endl;
158 ParseRwyExits(np, buf);
160 } else if(!strcmp(buf, "A")) {
162 ap->struct_type = ARC;
168 if(!strcmp(buf, "R")) {
170 } else if(!strcmp(buf, "T")) {
173 cout << "**** ERROR ***** Unknown arc type in taxi network...\n";
179 if(!strcmp(buf, "Y")) {
181 } else if(!strcmp(buf, "N")) {
182 ap->directed = false;
184 cout << "**** ERROR ***** Unknown arc directed value in taxi network - should be Y/N !!!\n";
191 fin.unsetf(ios::skipws);
194 if((ch == '"') || (ch == 0x0A)) {
196 } // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
198 fin.setf(ios::skipws);
199 ap->distance = (int)dclGetHorizontalSeparation(network[ap->n1]->pos, network[ap->n2]->pos);
200 //cout << "Distance = " << ap->distance << '\n';
201 network[ap->n1]->arcs.push_back(ap);
202 network[ap->n2]->arcs.push_back(ap);
203 } else if(!strcmp(buf, "G")) {
205 gp->struct_type = NODE;
208 gp->nodeID = atoi(buf);
210 gp->pos.setlon(atof(buf));
212 gp->pos.setlat(atof(buf));
214 gp->pos.setelev(atof(buf));
215 fin >> buf; // gate type - ignore this for now
216 fin >> buf; // gate heading
217 gp->heading = atoi(buf);
221 fin.unsetf(ios::skipws);
224 if((ch == '"') || (ch == 0x0A)) {
226 } // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
228 fin.setf(ios::skipws);
229 gp->id = gateCount; // Warning - this will likely change in the future.
231 network.push_back(gp);
232 gates[gateCount] = gp;
235 // Something has gone seriously pear-shaped
236 cout << "********* ERROR - unknown ground network element type... aborting read of " << path.c_str() << '\n';
245 void FGGround::Init() {
248 // For now we'll hardwire the threshold end
249 Point3D P010(-118.037483, 34.081358, 296 * SG_FEET_TO_METER);
251 ortho.Init(P010, hdg);
253 networkLoadOK = LoadNetwork();
256 void FGGround::Update() {
257 // Each time step, what do we need to do?
258 // We need to go through the list of outstanding requests and acknowedgements
259 // and process at least one of them.
260 // We need to go through the list of planes under our control and check if
261 // any need to be addressed.
262 // We need to check for planes not under our control coming within our
263 // control area and address if necessary.
265 // Lets take the example of a plane which has just contacted ground
266 // following landing - presumably requesting where to go?
267 // First we need to establish the position of the plane within the logical network.
268 // Next we need to decide where its going.
271 // Return a random gate ID of an unused gate.
272 // Two error values may be returned and must be checked for by the calling function:
273 // -2 signifies that no gates exist at this airport.
274 // -1 signifies that all gates are currently full.
275 int FGGround::GetRandomGateID() {
276 // Check that this airport actually has some gates!!
281 gate_vec_type gateVec;
286 gatesItr = gates.begin();
287 while(gatesItr != gates.end()) {
288 if((gatesItr->second)->used == false) {
289 gateVec.push_back(gatesItr->second);
295 // Check that there are some unused gates!
296 if(!gateVec.size()) {
300 // Randomly select one from the list
302 thenum = (int)(sg_random() * gateVec.size());
303 ID = gateVec[thenum]->id;
308 // Return a pointer to an unused gate node
309 Gate* FGGround::GetGateNode() {
310 int id = GetRandomGateID();
318 // Get a path from a point on a runway to a gate
321 // Get a path from a node to another node
322 // Eventually we will need complex algorithms for this taking other traffic,
323 // shortest path and suitable paths into accout.
324 // For now we'll just call the shortest path algorithm.
325 ground_network_path_type FGGround::GetPath(node* A, node* B) {
326 return(GetShortestPath(A, B));
330 // A shortest path algorithm from memory (ie. I can't find the bl&*dy book again!)
331 // I'm sure there must be enchancements that we can make to this, such as biasing the
332 // order in which the nodes are searched out from in favour of those geographically
333 // closer to the destination.
334 // Note that we are working with the master set of nodes and arcs so we mustn't change
335 // or delete them - we only delete the paths that we create during the algorithm.
336 ground_network_path_type FGGround::GetShortestPath(node* A, node* B) {
338 shortest_path_map_type pathMap;
339 node_array_type nodesLeft;
342 int pathsCreated = 0;
344 // Initialise the algorithm
345 nodesLeft.push_back(A);
346 pathPtr = new a_path;
348 pathPtr->path.push_back(A);
350 pathMap[A->nodeID] = pathPtr;
351 bool solution_found = false; // Flag to indicate that at least one candidate path has been found
352 int solution_cost = -1; // Cost of current best cost solution. -1 indicates no solution found yet.
353 a_path solution_path;
355 node* nPtr; // nPtr is used to point to the node we are currently working with
357 while(nodesLeft.size()) {
358 //cout << "\n*****nodesLeft*****\n";
359 //for(unsigned int i=0; i<nodesLeft.size(); ++i) {
360 //cout << nodesLeft[i]->nodeID << '\n';
362 //cout << "*******************\n\n";
363 nPtr = *nodesLeft.begin(); // Thought - definate optimization possibilities here in the choice of which nodes we process first.
364 nodesLeft.erase(nodesLeft.begin());
365 //cout << "Walking out from node " << nPtr->nodeID << '\n';
366 for(unsigned int i=0; i<nPtr->arcs.size(); ++i) {
367 //cout << "ARC TO " << ((nPtr->arcs[i]->n1 == nPtr->nodeID) ? nPtr->arcs[i]->n2 : nPtr->arcs[i]->n1) << '\n';
369 if((solution_found) && (solution_cost <= pathMap[nPtr->nodeID]->cost)) {
370 // Do nothing - we've already found a solution and this partial path is already more expensive
372 // This path could still be better than the current solution - check it out
373 for(unsigned int i=0; i<(nPtr->arcs.size()); i++) {
374 // Map the new path against the end node, ie. *not* the one we just started with.
375 unsigned int end_nodeID = ((nPtr->arcs[i]->n1 == nPtr->nodeID) ? nPtr->arcs[i]->n2 : nPtr->arcs[i]->n1);
376 //cout << "end_nodeID = " << end_nodeID << '\n';
377 //cout << "pathMap size is " << pathMap.size() << '\n';
378 if(end_nodeID == nPtr->nodeID) {
379 //cout << "Circular arc!\n";
380 // Then its a circular arc - don't bother!!
381 //nPtr->arcs.erase(nPtr->arcs.begin() + i);
383 // see if the end node is already in the map or not
384 if(pathMap.find(end_nodeID) == pathMap.end()) {
385 //cout << "Not in the map" << endl;;
386 // Not in the map - easy!
387 pathPtr = new a_path;
389 *pathPtr = *pathMap[nPtr->nodeID]; // *copy* the path
390 pathPtr->path.push_back(nPtr->arcs[i]);
391 pathPtr->path.push_back(network[end_nodeID]);
392 pathPtr->cost += nPtr->arcs[i]->distance;
393 pathMap[end_nodeID] = pathPtr;
394 nodesLeft.push_back(network[end_nodeID]); // By definition this can't be in the list already, or
395 // it would also have been in the map and hence OR'd with this one.
396 if(end_nodeID == B->nodeID) {
397 //cout << "Solution found!!!" << endl;
398 // Since this node wasn't in the map this is by definition the first solution
399 solution_cost = pathPtr->cost;
400 solution_path = *pathPtr;
401 solution_found = true;
404 //cout << "Already in the map" << endl;
405 // In the map - not so easy - need to get rid of an arc from the higher cost one.
406 //cout << "Current cost of node " << end_nodeID << " is " << pathMap[end_nodeID]->cost << endl;
407 int newCost = pathMap[nPtr->nodeID]->cost + nPtr->arcs[i]->distance;
408 //cout << "New cost is of node " << nPtr->nodeID << " is " << newCost << endl;
409 if(newCost >= pathMap[end_nodeID]->cost) {
410 // No need to do anything.
411 //cout << "Not doing anything!" << endl;
413 delete pathMap[end_nodeID];
416 pathPtr = new a_path;
418 *pathPtr = *pathMap[nPtr->nodeID]; // *copy* the path
419 pathPtr->path.push_back(nPtr->arcs[i]);
420 pathPtr->path.push_back(network[end_nodeID]);
421 pathPtr->cost += nPtr->arcs[i]->distance;
422 pathMap[end_nodeID] = pathPtr;
424 // We need to add this node to the list-to-do again to force a recalculation
425 // onwards from this node with the new lower cost to node cost.
426 nodesLeft.push_back(network[end_nodeID]);
428 if(end_nodeID == B->nodeID) {
429 //cout << "Solution found!!!" << endl;
430 // Need to check if there is a previous better solution
431 if((solution_cost < 0) || (pathPtr->cost < solution_cost)) {
432 solution_cost = pathPtr->cost;
433 solution_path = *pathPtr;
434 solution_found = true;
444 // delete all the paths before returning
445 shortest_path_map_iterator spItr = pathMap.begin();
446 while(spItr != pathMap.end()) {
447 if(spItr->second != NULL) {
448 delete spItr->second;
454 //cout << "pathsCreated = " << pathsCreated << '\n';
455 if(pathsCreated > 0) {
456 SG_LOG(SG_GENERAL, SG_ALERT, "WARNING - Possible memory leak in FGGround::GetShortestPath\n\
457 Please report to flightgear-devel@flightgear.org\n");
460 //cout << (solution_found ? "Result: solution found\n" : "Result: no solution found\n");
461 return(solution_path.path); // TODO - we really ought to have a fallback position incase a solution isn't found.
466 // Randomly or otherwise populate some of the gates with parked planes
467 // (might eventually be done by the AIMgr if and when lots of AI traffic is generated)
469 // Return a list of exits from a given runway
470 // It is up to the calling function to check for non-zero size of returned array before use
471 node_array_type FGGround::GetExits(int rwyID) {
472 return(runways[rwyID].exits);
476 void FGGround::NewArrival(plane_rec plane) {
477 // What are we going to do here?
478 // We need to start a new ground_rec and add the plane_rec to it
479 // We need to decide what gate we are going to clear it to.
480 // Then we need to add clearing it to that gate to the pending transmissions queue? - or simply transmit?
481 // Probably simply transmit for now and think about a transmission queue later if we need one.
482 // We might need one though in order to add a little delay for response time.
483 ground_rec* g = new ground_rec;
484 g->plane_rec = plane;
485 g->current_pos = ConvertWGS84ToXY(plane.pos);
486 g->node = GetNode(g->current_pos); // TODO - might need to sort out node/arc here
489 ground_traffic.push_back(g);
493 void FGGround::NewContact(plane_rec plane) {
494 // This is a bit of a convienience function at the moment and is likely to change.
495 if(at a gate or apron)
501 void FGGround::NextClearance(ground_rec &g) {
502 // Need to work out where we can clear g to.
503 // Assume the pilot doesn't need progressive instructions
504 // We *should* already have a gate or holding point assigned by the time we get here
505 // but it wouldn't do any harm to check.
507 // For now though we will hardwire it to clear to the final destination.
510 void FGGround::AssignGate(ground_rec &g) {
511 // We'll cheat for now - since we only have the user's aircraft and a couple of airports implemented
512 // we'll hardwire the gate!
513 // In the long run the logic of which gate or area to send the plane to could be somewhat non-trivial.