OpenTTD
follow_track.hpp
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1 /* $Id: follow_track.hpp 27418 2015-10-30 16:18:03Z frosch $ */
2 
3 /*
4  * This file is part of OpenTTD.
5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
8  */
9 
12 #ifndef FOLLOW_TRACK_HPP
13 #define FOLLOW_TRACK_HPP
14 
15 #include "../pbs.h"
16 #include "../roadveh.h"
17 #include "../station_base.h"
18 #include "../train.h"
19 #include "../tunnelbridge.h"
20 #include "../tunnelbridge_map.h"
21 #include "../depot_map.h"
22 #include "pf_performance_timer.hpp"
23 
29 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
31 {
32  enum ErrorCode {
33  EC_NONE,
34  EC_OWNER,
35  EC_RAIL_TYPE,
36  EC_90DEG,
37  EC_NO_WAY,
38  EC_RESERVED,
39  };
40 
41  const VehicleType *m_veh;
48  bool m_is_tunnel;
49  bool m_is_bridge;
50  bool m_is_station;
52  ErrorCode m_err;
53  CPerformanceTimer *m_pPerf;
54  RailTypes m_railtypes;
55 
56  inline CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
57  {
58  Init(v, railtype_override, pPerf);
59  }
60 
61  inline CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
62  {
63  m_veh = NULL;
64  Init(o, railtype_override, pPerf);
65  }
66 
67  inline void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
68  {
69  assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
70  m_veh = v;
71  Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
72  }
73 
74  inline void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
75  {
76  assert((!IsRoadTT() || m_veh != NULL) && (!IsRailTT() || railtype_override != INVALID_RAILTYPES));
77  m_veh_owner = o;
78  m_pPerf = pPerf;
79  /* don't worry, all is inlined so compiler should remove unnecessary initializations */
86  m_tiles_skipped = 0;
87  m_err = EC_NONE;
88  m_railtypes = railtype_override;
89  }
90 
91  inline static TransportType TT() { return Ttr_type_; }
92  inline static bool IsWaterTT() { return TT() == TRANSPORT_WATER; }
93  inline static bool IsRailTT() { return TT() == TRANSPORT_RAIL; }
94  inline bool IsTram() { return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM); }
95  inline static bool IsRoadTT() { return TT() == TRANSPORT_ROAD; }
96  inline static bool Allow90degTurns() { return T90deg_turns_allowed_; }
97  inline static bool DoTrackMasking() { return Tmask_reserved_tracks; }
98 
101  {
102  assert(IsTram()); // this function shouldn't be called in other cases
103 
104  if (IsNormalRoadTile(tile)) {
105  RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
106  switch (rb) {
107  case ROAD_NW: return DIAGDIR_NW;
108  case ROAD_SW: return DIAGDIR_SW;
109  case ROAD_SE: return DIAGDIR_SE;
110  case ROAD_NE: return DIAGDIR_NE;
111  default: break;
112  }
113  }
114  return INVALID_DIAGDIR;
115  }
116 
121  inline bool Follow(TileIndex old_tile, Trackdir old_td)
122  {
123  m_old_tile = old_tile;
124  m_old_td = old_td;
125  m_err = EC_NONE;
126  assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
127  (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
129  if (ForcedReverse()) return true;
130  if (!CanExitOldTile()) return false;
131  FollowTileExit();
132  if (!QueryNewTileTrackStatus()) return TryReverse();
135  /* In case we can't enter the next tile, but are
136  * a normal road vehicle, then we can actually
137  * try to reverse as this is the end of the road.
138  * Trams can only turn on the appropriate bits in
139  * which case reaching this would mean a dead end
140  * near a building and in that case there would
141  * a "false" QueryNewTileTrackStatus result and
142  * as such reversing is already tried. The fact
143  * that function failed can have to do with a
144  * missing road bit, or inability to connect the
145  * different bits due to slopes. */
146  if (IsRoadTT() && !IsTram() && TryReverse()) return true;
147 
148  /* CanEnterNewTile already set a reason.
149  * Do NOT overwrite it (important for example for EC_RAIL_TYPE).
150  * Only set a reason if CanEnterNewTile was not called */
151  if (m_new_td_bits == TRACKDIR_BIT_NONE) m_err = EC_NO_WAY;
152 
153  return false;
154  }
155  if (!Allow90degTurns()) {
158  m_err = EC_90DEG;
159  return false;
160  }
161  }
162  return true;
163  }
164 
165  inline bool MaskReservedTracks()
166  {
167  if (!DoTrackMasking()) return true;
168 
169  if (m_is_station) {
170  /* Check skipped station tiles as well. */
172  for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
173  if (HasStationReservation(tile)) {
175  m_err = EC_RESERVED;
176  return false;
177  }
178  }
179  }
180 
182  /* Mask already reserved trackdirs. */
184  /* Mask out all trackdirs that conflict with the reservation. */
185  Track t;
188  }
190  m_err = EC_RESERVED;
191  return false;
192  }
193  return true;
194  }
195 
196 protected:
198  inline void FollowTileExit()
199  {
201  m_tiles_skipped = 0;
202 
203  /* extra handling for tunnels and bridges in our direction */
206  if (enterdir == m_exitdir) {
207  /* we are entering the tunnel / bridge */
208  if (IsTunnel(m_old_tile)) {
209  m_is_tunnel = true;
211  } else { // IsBridge(m_old_tile)
212  m_is_bridge = true;
214  }
216  return;
217  }
218  assert(ReverseDiagDir(enterdir) == m_exitdir);
219  }
220 
221  /* normal or station tile, do one step */
223  m_new_tile = TILE_ADD(m_old_tile, diff);
224 
225  /* special handling for stations */
226  if (IsRailTT() && HasStationTileRail(m_new_tile)) {
227  m_is_station = true;
228  } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
229  m_is_station = true;
230  } else {
231  m_is_station = false;
232  }
233  }
234 
237  {
238  CPerfStart perf(*m_pPerf);
239  if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
241  } else {
242  m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
243 
244  if (IsTram() && m_new_td_bits == 0) {
245  /* GetTileTrackStatus() returns 0 for single tram bits.
246  * As we cannot change it there (easily) without breaking something, change it here */
247  switch (GetSingleTramBit(m_new_tile)) {
248  case DIAGDIR_NE:
249  case DIAGDIR_SW:
251  break;
252 
253  case DIAGDIR_NW:
254  case DIAGDIR_SE:
256  break;
257 
258  default: break;
259  }
260  }
261  }
262  return (m_new_td_bits != TRACKDIR_BIT_NONE);
263  }
264 
266  inline bool CanExitOldTile()
267  {
268  /* road stop can be left at one direction only unless it's a drive-through stop */
269  if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
271  if (exitdir != m_exitdir) {
272  m_err = EC_NO_WAY;
273  return false;
274  }
275  }
276 
277  /* single tram bits can only be left in one direction */
278  if (IsTram()) {
280  if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
281  m_err = EC_NO_WAY;
282  return false;
283  }
284  }
285 
286  /* road depots can be also left in one direction only */
287  if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
289  if (exitdir != m_exitdir) {
290  m_err = EC_NO_WAY;
291  return false;
292  }
293  }
294  return true;
295  }
296 
298  inline bool CanEnterNewTile()
299  {
300  if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
301  /* road stop can be entered from one direction only unless it's a drive-through stop */
303  if (ReverseDiagDir(exitdir) != m_exitdir) {
304  m_err = EC_NO_WAY;
305  return false;
306  }
307  }
308 
309  /* single tram bits can only be entered from one direction */
310  if (IsTram()) {
312  if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
313  m_err = EC_NO_WAY;
314  return false;
315  }
316  }
317 
318  /* road and rail depots can also be entered from one direction only */
319  if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
321  if (ReverseDiagDir(exitdir) != m_exitdir) {
322  m_err = EC_NO_WAY;
323  return false;
324  }
325  /* don't try to enter other company's depots */
327  m_err = EC_OWNER;
328  return false;
329  }
330  }
331  if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
333  if (ReverseDiagDir(exitdir) != m_exitdir) {
334  m_err = EC_NO_WAY;
335  return false;
336  }
337  }
338 
339  /* rail transport is possible only on tiles with the same owner as vehicle */
340  if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
341  /* different owner */
342  m_err = EC_NO_WAY;
343  return false;
344  }
345 
346  /* rail transport is possible only on compatible rail types */
347  if (IsRailTT()) {
348  RailType rail_type = GetTileRailType(m_new_tile);
349  if (!HasBit(m_railtypes, rail_type)) {
350  /* incompatible rail type */
351  m_err = EC_RAIL_TYPE;
352  return false;
353  }
354  }
355 
356  /* tunnel holes and bridge ramps can be entered only from proper direction */
358  if (IsTunnel(m_new_tile)) {
359  if (!m_is_tunnel) {
361  if (tunnel_enterdir != m_exitdir) {
362  m_err = EC_NO_WAY;
363  return false;
364  }
365  }
366  } else { // IsBridge(m_new_tile)
367  if (!m_is_bridge) {
369  if (ramp_enderdir != m_exitdir) {
370  m_err = EC_NO_WAY;
371  return false;
372  }
373  }
374  }
375  }
376 
377  /* special handling for rail stations - get to the end of platform */
378  if (IsRailTT() && m_is_station) {
379  /* entered railway station
380  * get platform length */
382  /* how big step we must do to get to the last platform tile; */
383  m_tiles_skipped = length - 1;
384  /* move to the platform end */
386  diff *= m_tiles_skipped;
387  m_new_tile = TILE_ADD(m_new_tile, diff);
388  return true;
389  }
390 
391  return true;
392  }
393 
395  inline bool ForcedReverse()
396  {
397  /* rail and road depots cause reversing */
398  if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
400  if (exitdir != m_exitdir) {
401  /* reverse */
404  m_exitdir = exitdir;
405  m_tiles_skipped = 0;
407  return true;
408  }
409  }
410 
411  /* single tram bits cause reversing */
412  if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
413  /* reverse */
417  m_tiles_skipped = 0;
419  return true;
420  }
421 
422  return false;
423  }
424 
426  inline bool TryReverse()
427  {
428  if (IsRoadTT() && !IsTram()) {
429  /* if we reached the end of road, we can reverse the RV and continue moving */
431  /* new tile will be the same as old one */
433  /* set new trackdir bits to all reachable trackdirs */
437  /* we have some trackdirs reachable after reversal */
438  return true;
439  }
440  }
441  m_err = EC_NO_WAY;
442  return false;
443  }
444 
445 public:
447  int GetSpeedLimit(int *pmin_speed = NULL) const
448  {
449  int min_speed = 0;
450  int max_speed = INT_MAX; // no limit
451 
452  /* Check for on-bridge speed limit */
453  if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
455  if (IsRoadTT()) spd *= 2;
456  if (max_speed > spd) max_speed = spd;
457  }
458  /* Check for speed limit imposed by railtype */
459  if (IsRailTT()) {
460  uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
461  if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
462  }
463 
464  /* if min speed was requested, return it */
465  if (pmin_speed != NULL) *pmin_speed = min_speed;
466  return max_speed;
467  }
468 };
469 
473 
477 
480 
481 #endif /* FOLLOW_TRACK_HPP */