summaryrefslogtreecommitdiff
path: root/src/pathfinder/yapf/yapf_costrail.hpp
blob: 2f4834633a5aa29e86fe17ff8640671dd506b817 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
/*
 * This file is part of OpenTTD.
 * 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.
 * 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.
 * 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/>.
 */

/** @file yapf_costrail.hpp Cost determination for rails. */

#ifndef YAPF_COSTRAIL_HPP
#define YAPF_COSTRAIL_HPP

#include "../../pbs.h"

template <class Types>
class CYapfCostRailT : public CYapfCostBase {
public:
	typedef typename Types::Tpf Tpf;              ///< the pathfinder class (derived from THIS class)
	typedef typename Types::TrackFollower TrackFollower;
	typedef typename Types::NodeList::Titem Node; ///< this will be our node type
	typedef typename Node::Key Key;               ///< key to hash tables
	typedef typename Node::CachedData CachedData;

protected:

	/* Structure used inside PfCalcCost() to keep basic tile information. */
	struct TILE {
		TileIndex   tile;
		Trackdir    td;
		TileType    tile_type;
		RailType    rail_type;

		TILE()
		{
			tile = INVALID_TILE;
			td = INVALID_TRACKDIR;
			tile_type = MP_VOID;
			rail_type = INVALID_RAILTYPE;
		}

		TILE(TileIndex tile, Trackdir td)
		{
			this->tile = tile;
			this->td = td;
			this->tile_type = GetTileType(tile);
			this->rail_type = GetTileRailType(tile);
		}
	};

protected:
	/**
	 * @note maximum cost doesn't work with caching enabled
	 * @todo fix maximum cost failing with caching (e.g. FS#2900)
	 */
	int           m_max_cost;
	CBlobT<int>   m_sig_look_ahead_costs;
	bool          m_disable_cache;

public:
	bool          m_stopped_on_first_two_way_signal;
protected:

	static const int s_max_segment_cost = 10000;

	CYapfCostRailT() : m_max_cost(0), m_disable_cache(false), m_stopped_on_first_two_way_signal(false)
	{
		/* pre-compute look-ahead penalties into array */
		int p0 = Yapf().PfGetSettings().rail_look_ahead_signal_p0;
		int p1 = Yapf().PfGetSettings().rail_look_ahead_signal_p1;
		int p2 = Yapf().PfGetSettings().rail_look_ahead_signal_p2;
		int *pen = m_sig_look_ahead_costs.GrowSizeNC(Yapf().PfGetSettings().rail_look_ahead_max_signals);
		for (uint i = 0; i < Yapf().PfGetSettings().rail_look_ahead_max_signals; i++) {
			pen[i] = p0 + i * (p1 + i * p2);
		}
	}

	/** to access inherited path finder */
	Tpf& Yapf()
	{
		return *static_cast<Tpf *>(this);
	}

public:
	inline int SlopeCost(TileIndex tile, Trackdir td)
	{
		CPerfStart perf_cost(Yapf().m_perf_slope_cost);
		if (!stSlopeCost(tile, td)) return 0;
		return Yapf().PfGetSettings().rail_slope_penalty;
	}

	inline int CurveCost(Trackdir td1, Trackdir td2)
	{
		assert(IsValidTrackdir(td1));
		assert(IsValidTrackdir(td2));
		int cost = 0;
		if (TrackFollower::Allow90degTurns()
				&& HasTrackdir(TrackdirCrossesTrackdirs(td1), td2)) {
			/* 90-deg curve penalty */
			cost += Yapf().PfGetSettings().rail_curve90_penalty;
		} else if (td2 != NextTrackdir(td1)) {
			/* 45-deg curve penalty */
			cost += Yapf().PfGetSettings().rail_curve45_penalty;
		}
		return cost;
	}

	inline int SwitchCost(TileIndex tile1, TileIndex tile2, DiagDirection exitdir)
	{
		if (IsPlainRailTile(tile1) && IsPlainRailTile(tile2)) {
			bool t1 = KillFirstBit(GetTrackBits(tile1) & DiagdirReachesTracks(ReverseDiagDir(exitdir))) != TRACK_BIT_NONE;
			bool t2 = KillFirstBit(GetTrackBits(tile2) & DiagdirReachesTracks(exitdir)) != TRACK_BIT_NONE;
			if (t1 && t2) return Yapf().PfGetSettings().rail_doubleslip_penalty;
		}
		return 0;
	}

	/** Return one tile cost (base cost + level crossing penalty). */
	inline int OneTileCost(TileIndex &tile, Trackdir trackdir)
	{
		int cost = 0;
		/* set base cost */
		if (IsDiagonalTrackdir(trackdir)) {
			cost += YAPF_TILE_LENGTH;
			switch (GetTileType(tile)) {
				case MP_ROAD:
					/* Increase the cost for level crossings */
					if (IsLevelCrossing(tile)) {
						cost += Yapf().PfGetSettings().rail_crossing_penalty;
					}
					break;

				default:
					break;
			}
		} else {
			/* non-diagonal trackdir */
			cost = YAPF_TILE_CORNER_LENGTH;
		}
		return cost;
	}

	/** Check for a reserved station platform. */
	inline bool IsAnyStationTileReserved(TileIndex tile, Trackdir trackdir, int skipped)
	{
		TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(trackdir)));
		for (; skipped >= 0; skipped--, tile += diff) {
			if (HasStationReservation(tile)) return true;
		}
		return false;
	}

	/** The cost for reserved tiles, including skipped ones. */
	inline int ReservationCost(Node &n, TileIndex tile, Trackdir trackdir, int skipped)
	{
		if (n.m_num_signals_passed >= m_sig_look_ahead_costs.Size() / 2) return 0;
		if (!IsPbsSignal(n.m_last_signal_type)) return 0;

		if (IsRailStationTile(tile) && IsAnyStationTileReserved(tile, trackdir, skipped)) {
			return Yapf().PfGetSettings().rail_pbs_station_penalty * (skipped + 1);
		} else if (TrackOverlapsTracks(GetReservedTrackbits(tile), TrackdirToTrack(trackdir))) {
			int cost = Yapf().PfGetSettings().rail_pbs_cross_penalty;
			if (!IsDiagonalTrackdir(trackdir)) cost = (cost * YAPF_TILE_CORNER_LENGTH) / YAPF_TILE_LENGTH;
			return cost * (skipped + 1);
		}
		return 0;
	}

	int SignalCost(Node &n, TileIndex tile, Trackdir trackdir)
	{
		int cost = 0;
		/* if there is one-way signal in the opposite direction, then it is not our way */
		CPerfStart perf_cost(Yapf().m_perf_other_cost);
		if (IsTileType(tile, MP_RAILWAY)) {
			bool has_signal_against = HasSignalOnTrackdir(tile, ReverseTrackdir(trackdir));
			bool has_signal_along = HasSignalOnTrackdir(tile, trackdir);
			if (has_signal_against && !has_signal_along && IsOnewaySignal(tile, TrackdirToTrack(trackdir))) {
				/* one-way signal in opposite direction */
				n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
			} else {
				if (has_signal_along) {
					SignalState sig_state = GetSignalStateByTrackdir(tile, trackdir);
					SignalType sig_type = GetSignalType(tile, TrackdirToTrack(trackdir));

					n.m_last_signal_type = sig_type;

					/* cache the look-ahead polynomial constant only if we didn't pass more signals than the look-ahead limit is */
					int look_ahead_cost = (n.m_num_signals_passed < m_sig_look_ahead_costs.Size()) ? m_sig_look_ahead_costs.Data()[n.m_num_signals_passed] : 0;
					if (sig_state != SIGNAL_STATE_RED) {
						/* green signal */
						n.flags_u.flags_s.m_last_signal_was_red = false;
						/* negative look-ahead red-signal penalties would cause problems later, so use them as positive penalties for green signal */
						if (look_ahead_cost < 0) {
							/* add its negation to the cost */
							cost -= look_ahead_cost;
						}
					} else {
						/* we have a red signal in our direction
						 * was it first signal which is two-way? */
						if (!IsPbsSignal(sig_type) && Yapf().TreatFirstRedTwoWaySignalAsEOL() && n.flags_u.flags_s.m_choice_seen && has_signal_against && n.m_num_signals_passed == 0) {
							/* yes, the first signal is two-way red signal => DEAD END. Prune this branch... */
							Yapf().PruneIntermediateNodeBranch();
							n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
							Yapf().m_stopped_on_first_two_way_signal = true;
							return -1;
						}
						n.m_last_red_signal_type = sig_type;
						n.flags_u.flags_s.m_last_signal_was_red = true;

						/* look-ahead signal penalty */
						if (!IsPbsSignal(sig_type) && look_ahead_cost > 0) {
							/* add the look ahead penalty only if it is positive */
							cost += look_ahead_cost;
						}

						/* special signal penalties */
						if (n.m_num_signals_passed == 0) {
							switch (sig_type) {
								case SIGTYPE_COMBO:
								case SIGTYPE_EXIT:   cost += Yapf().PfGetSettings().rail_firstred_exit_penalty; break; // first signal is red pre-signal-exit
								case SIGTYPE_NORMAL:
								case SIGTYPE_ENTRY:  cost += Yapf().PfGetSettings().rail_firstred_penalty; break;
								default: break;
							}
						}
					}

					n.m_num_signals_passed++;
					n.m_segment->m_last_signal_tile = tile;
					n.m_segment->m_last_signal_td = trackdir;
				}

				if (has_signal_against && IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) {
					cost += n.m_num_signals_passed < Yapf().PfGetSettings().rail_look_ahead_max_signals ? Yapf().PfGetSettings().rail_pbs_signal_back_penalty : 0;
				}
			}
		}
		return cost;
	}

	inline int PlatformLengthPenalty(int platform_length)
	{
		int cost = 0;
		const Train *v = Yapf().GetVehicle();
		assert(v != nullptr);
		assert(v->type == VEH_TRAIN);
		assert(v->gcache.cached_total_length != 0);
		int missing_platform_length = CeilDiv(v->gcache.cached_total_length, TILE_SIZE) - platform_length;
		if (missing_platform_length < 0) {
			/* apply penalty for longer platform than needed */
			cost += Yapf().PfGetSettings().rail_longer_platform_penalty + Yapf().PfGetSettings().rail_longer_platform_per_tile_penalty * -missing_platform_length;
		} else if (missing_platform_length > 0) {
			/* apply penalty for shorter platform than needed */
			cost += Yapf().PfGetSettings().rail_shorter_platform_penalty + Yapf().PfGetSettings().rail_shorter_platform_per_tile_penalty * missing_platform_length;
		}
		return cost;
	}

public:
	inline void SetMaxCost(int max_cost)
	{
		m_max_cost = max_cost;
	}

	/**
	 * Called by YAPF to calculate the cost from the origin to the given node.
	 *  Calculates only the cost of given node, adds it to the parent node cost
	 *  and stores the result into Node::m_cost member
	 */
	inline bool PfCalcCost(Node &n, const TrackFollower *tf)
	{
		assert(!n.flags_u.flags_s.m_targed_seen);
		assert(tf->m_new_tile == n.m_key.m_tile);
		assert((HasTrackdir(tf->m_new_td_bits, n.m_key.m_td)));

		CPerfStart perf_cost(Yapf().m_perf_cost);

		/* Does the node have some parent node? */
		bool has_parent = (n.m_parent != nullptr);

		/* Do we already have a cached segment? */
		CachedData &segment = *n.m_segment;
		bool is_cached_segment = (segment.m_cost >= 0);

		int parent_cost = has_parent ? n.m_parent->m_cost : 0;

		/* Each node cost contains 2 or 3 main components:
		 *  1. Transition cost - cost of the move from previous node (tile):
		 *    - curve cost (or zero for straight move)
		 *  2. Tile cost:
		 *    - base tile cost
		 *      - YAPF_TILE_LENGTH for diagonal tiles
		 *      - YAPF_TILE_CORNER_LENGTH for non-diagonal tiles
		 *    - tile penalties
		 *      - tile slope penalty (upward slopes)
		 *      - red signal penalty
		 *      - level crossing penalty
		 *      - speed-limit penalty (bridges)
		 *      - station platform penalty
		 *      - penalty for reversing in the depot
		 *      - etc.
		 *  3. Extra cost (applies to the last node only)
		 *    - last red signal penalty
		 *    - penalty for too long or too short platform on the destination station
		 */
		int transition_cost = 0;
		int extra_cost = 0;

		/* Segment: one or more tiles connected by contiguous tracks of the same type.
		 * Each segment cost includes 'Tile cost' for all its tiles (including the first
		 * and last), and the 'Transition cost' between its tiles. The first transition
		 * cost of segment entry (move from the 'parent' node) is not included!
		 */
		int segment_entry_cost = 0;
		int segment_cost = 0;

		const Train *v = Yapf().GetVehicle();

		/* start at n.m_key.m_tile / n.m_key.m_td and walk to the end of segment */
		TILE cur(n.m_key.m_tile, n.m_key.m_td);

		/* the previous tile will be needed for transition cost calculations */
		TILE prev = !has_parent ? TILE() : TILE(n.m_parent->GetLastTile(), n.m_parent->GetLastTrackdir());

		EndSegmentReasonBits end_segment_reason = ESRB_NONE;

		TrackFollower tf_local(v, Yapf().GetCompatibleRailTypes(), &Yapf().m_perf_ts_cost);

		if (!has_parent) {
			/* We will jump to the middle of the cost calculator assuming that segment cache is not used. */
			assert(!is_cached_segment);
			/* Skip the first transition cost calculation. */
			goto no_entry_cost;
		}

		for (;;) {
			/* Transition cost (cost of the move from previous tile) */
			transition_cost = Yapf().CurveCost(prev.td, cur.td);
			transition_cost += Yapf().SwitchCost(prev.tile, cur.tile, TrackdirToExitdir(prev.td));

			/* First transition cost counts against segment entry cost, other transitions
			 * inside segment will come to segment cost (and will be cached) */
			if (segment_cost == 0) {
				/* We just entered the loop. First transition cost goes to segment entry cost)*/
				segment_entry_cost = transition_cost;
				transition_cost = 0;

				/* It is the right time now to look if we can reuse the cached segment cost. */
				if (is_cached_segment) {
					/* Yes, we already know the segment cost. */
					segment_cost = segment.m_cost;
					/* We know also the reason why the segment ends. */
					end_segment_reason = segment.m_end_segment_reason;
					/* We will need also some information about the last signal (if it was red). */
					if (segment.m_last_signal_tile != INVALID_TILE) {
						assert(HasSignalOnTrackdir(segment.m_last_signal_tile, segment.m_last_signal_td));
						SignalState sig_state = GetSignalStateByTrackdir(segment.m_last_signal_tile, segment.m_last_signal_td);
						bool is_red = (sig_state == SIGNAL_STATE_RED);
						n.flags_u.flags_s.m_last_signal_was_red = is_red;
						if (is_red) {
							n.m_last_red_signal_type = GetSignalType(segment.m_last_signal_tile, TrackdirToTrack(segment.m_last_signal_td));
						}
					}
					/* No further calculation needed. */
					cur = TILE(n.GetLastTile(), n.GetLastTrackdir());
					break;
				}
			} else {
				/* Other than first transition cost count as the regular segment cost. */
				segment_cost += transition_cost;
			}

no_entry_cost: // jump here at the beginning if the node has no parent (it is the first node)

			/* All other tile costs will be calculated here. */
			segment_cost += Yapf().OneTileCost(cur.tile, cur.td);

			/* If we skipped some tunnel/bridge/station tiles, add their base cost */
			segment_cost += YAPF_TILE_LENGTH * tf->m_tiles_skipped;

			/* Slope cost. */
			segment_cost += Yapf().SlopeCost(cur.tile, cur.td);

			/* Signal cost (routine can modify segment data). */
			segment_cost += Yapf().SignalCost(n, cur.tile, cur.td);

			/* Reserved tiles. */
			segment_cost += Yapf().ReservationCost(n, cur.tile, cur.td, tf->m_tiles_skipped);

			end_segment_reason = segment.m_end_segment_reason;

			/* Tests for 'potential target' reasons to close the segment. */
			if (cur.tile == prev.tile) {
				/* Penalty for reversing in a depot. */
				assert(IsRailDepot(cur.tile));
				segment_cost += Yapf().PfGetSettings().rail_depot_reverse_penalty;

			} else if (IsRailDepotTile(cur.tile)) {
				/* We will end in this pass (depot is possible target) */
				end_segment_reason |= ESRB_DEPOT;

			} else if (cur.tile_type == MP_STATION && IsRailWaypoint(cur.tile)) {
				if (v->current_order.IsType(OT_GOTO_WAYPOINT) &&
						GetStationIndex(cur.tile) == v->current_order.GetDestination() &&
						!Waypoint::Get(v->current_order.GetDestination())->IsSingleTile()) {
					/* This waypoint is our destination; maybe this isn't an unreserved
					 * one, so check that and if so see that as the last signal being
					 * red. This way waypoints near stations should work better. */
					CFollowTrackRail ft(v);
					TileIndex t = cur.tile;
					Trackdir td = cur.td;
					/* Arbitrary maximum tiles to follow to avoid infinite loops. */
					uint max_tiles = 20;
					while (ft.Follow(t, td)) {
						assert(t != ft.m_new_tile);
						t = ft.m_new_tile;
						if (t == cur.tile || --max_tiles == 0) {
							/* We looped back on ourself or found another loop, bail out. */
							td = INVALID_TRACKDIR;
							break;
						}
						if (KillFirstBit(ft.m_new_td_bits) != TRACKDIR_BIT_NONE) {
							/* We encountered a junction; it's going to be too complex to
							 * handle this perfectly, so just bail out. There is no simple
							 * free path, so try the other possibilities. */
							td = INVALID_TRACKDIR;
							break;
						}
						td = RemoveFirstTrackdir(&ft.m_new_td_bits);
						/* If this is a safe waiting position we're done searching for it */
						if (IsSafeWaitingPosition(v, t, td, true, _settings_game.pf.forbid_90_deg)) break;
					}

					/* In the case this platform is (possibly) occupied we add penalty so the
					 * other platforms of this waypoint are evaluated as well, i.e. we assume
					 * that there is a red signal in the waypoint when it's occupied. */
					if (td == INVALID_TRACKDIR ||
							!IsSafeWaitingPosition(v, t, td, true, _settings_game.pf.forbid_90_deg) ||
							!IsWaitingPositionFree(v, t, td, _settings_game.pf.forbid_90_deg)) {
						extra_cost += Yapf().PfGetSettings().rail_lastred_penalty;
					}
				}
				/* Waypoint is also a good reason to finish. */
				end_segment_reason |= ESRB_WAYPOINT;

			} else if (tf->m_is_station) {
				/* Station penalties. */
				uint platform_length = tf->m_tiles_skipped + 1;
				/* We don't know yet if the station is our target or not. Act like
				 * if it is pass-through station (not our destination). */
				segment_cost += Yapf().PfGetSettings().rail_station_penalty * platform_length;
				/* We will end in this pass (station is possible target) */
				end_segment_reason |= ESRB_STATION;

			} else if (TrackFollower::DoTrackMasking() && cur.tile_type == MP_RAILWAY) {
				/* Searching for a safe tile? */
				if (HasSignalOnTrackdir(cur.tile, cur.td) && !IsPbsSignal(GetSignalType(cur.tile, TrackdirToTrack(cur.td)))) {
					end_segment_reason |= ESRB_SAFE_TILE;
				}
			}

			/* Apply min/max speed penalties only when inside the look-ahead radius. Otherwise
			 * it would cause desync in MP. */
			if (n.m_num_signals_passed < m_sig_look_ahead_costs.Size())
			{
				int min_speed = 0;
				int max_speed = tf->GetSpeedLimit(&min_speed);
				int max_veh_speed = std::min<int>(v->GetDisplayMaxSpeed(), v->current_order.GetMaxSpeed());
				if (max_speed < max_veh_speed) {
					extra_cost += YAPF_TILE_LENGTH * (max_veh_speed - max_speed) * (4 + tf->m_tiles_skipped) / max_veh_speed;
				}
				if (min_speed > max_veh_speed) {
					extra_cost += YAPF_TILE_LENGTH * (min_speed - max_veh_speed);
				}
			}

			/* Finish if we already exceeded the maximum path cost (i.e. when
			 * searching for the nearest depot). */
			if (m_max_cost > 0 && (parent_cost + segment_entry_cost + segment_cost) > m_max_cost) {
				end_segment_reason |= ESRB_PATH_TOO_LONG;
			}

			/* Move to the next tile/trackdir. */
			tf = &tf_local;
			tf_local.Init(v, Yapf().GetCompatibleRailTypes(), &Yapf().m_perf_ts_cost);

			if (!tf_local.Follow(cur.tile, cur.td)) {
				assert(tf_local.m_err != TrackFollower::EC_NONE);
				/* Can't move to the next tile (EOL?). */
				if (tf_local.m_err == TrackFollower::EC_RAIL_ROAD_TYPE) {
					end_segment_reason |= ESRB_RAIL_TYPE;
				} else {
					end_segment_reason |= ESRB_DEAD_END;
				}

				if (TrackFollower::DoTrackMasking() && !HasOnewaySignalBlockingTrackdir(cur.tile, cur.td)) {
					end_segment_reason |= ESRB_SAFE_TILE;
				}
				break;
			}

			/* Check if the next tile is not a choice. */
			if (KillFirstBit(tf_local.m_new_td_bits) != TRACKDIR_BIT_NONE) {
				/* More than one segment will follow. Close this one. */
				end_segment_reason |= ESRB_CHOICE_FOLLOWS;
				break;
			}

			/* Gather the next tile/trackdir/tile_type/rail_type. */
			TILE next(tf_local.m_new_tile, (Trackdir)FindFirstBit2x64(tf_local.m_new_td_bits));

			if (TrackFollower::DoTrackMasking() && IsTileType(next.tile, MP_RAILWAY)) {
				if (HasSignalOnTrackdir(next.tile, next.td) && IsPbsSignal(GetSignalType(next.tile, TrackdirToTrack(next.td)))) {
					/* Possible safe tile. */
					end_segment_reason |= ESRB_SAFE_TILE;
				} else if (HasSignalOnTrackdir(next.tile, ReverseTrackdir(next.td)) && GetSignalType(next.tile, TrackdirToTrack(next.td)) == SIGTYPE_PBS_ONEWAY) {
					/* Possible safe tile, but not so good as it's the back of a signal... */
					end_segment_reason |= ESRB_SAFE_TILE | ESRB_DEAD_END;
					extra_cost += Yapf().PfGetSettings().rail_lastred_exit_penalty;
				}
			}

			/* Check the next tile for the rail type. */
			if (next.rail_type != cur.rail_type) {
				/* Segment must consist from the same rail_type tiles. */
				end_segment_reason |= ESRB_RAIL_TYPE;
				break;
			}

			/* Avoid infinite looping. */
			if (next.tile == n.m_key.m_tile && next.td == n.m_key.m_td) {
				end_segment_reason |= ESRB_INFINITE_LOOP;
				break;
			}

			if (segment_cost > s_max_segment_cost) {
				/* Potentially in the infinite loop (or only very long segment?). We should
				 * not force it to finish prematurely unless we are on a regular tile. */
				if (IsTileType(tf->m_new_tile, MP_RAILWAY)) {
					end_segment_reason |= ESRB_SEGMENT_TOO_LONG;
					break;
				}
			}

			/* Any other reason bit set? */
			if (end_segment_reason != ESRB_NONE) {
				break;
			}

			/* For the next loop set new prev and cur tile info. */
			prev = cur;
			cur = next;

		} // for (;;)

		/* Don't consider path any further it if exceeded max_cost. */
		if (end_segment_reason & ESRB_PATH_TOO_LONG) return false;

		bool target_seen = false;
		if ((end_segment_reason & ESRB_POSSIBLE_TARGET) != ESRB_NONE) {
			/* Depot, station or waypoint. */
			if (Yapf().PfDetectDestination(cur.tile, cur.td)) {
				/* Destination found. */
				target_seen = true;
			}
		}

		/* Update the segment if needed. */
		if (!is_cached_segment) {
			/* Write back the segment information so it can be reused the next time. */
			segment.m_cost = segment_cost;
			segment.m_end_segment_reason = end_segment_reason & ESRB_CACHED_MASK;
			/* Save end of segment back to the node. */
			n.SetLastTileTrackdir(cur.tile, cur.td);
		}

		/* Do we have an excuse why not to continue pathfinding in this direction? */
		if (!target_seen && (end_segment_reason & ESRB_ABORT_PF_MASK) != ESRB_NONE) {
			/* Reason to not continue. Stop this PF branch. */
			return false;
		}

		/* Special costs for the case we have reached our target. */
		if (target_seen) {
			n.flags_u.flags_s.m_targed_seen = true;
			/* Last-red and last-red-exit penalties. */
			if (n.flags_u.flags_s.m_last_signal_was_red) {
				if (n.m_last_red_signal_type == SIGTYPE_EXIT) {
					/* last signal was red pre-signal-exit */
					extra_cost += Yapf().PfGetSettings().rail_lastred_exit_penalty;
				} else if (!IsPbsSignal(n.m_last_red_signal_type)) {
					/* Last signal was red, but not exit or path signal. */
					extra_cost += Yapf().PfGetSettings().rail_lastred_penalty;
				}
			}

			/* Station platform-length penalty. */
			if ((end_segment_reason & ESRB_STATION) != ESRB_NONE) {
				const BaseStation *st = BaseStation::GetByTile(n.GetLastTile());
				assert(st != nullptr);
				uint platform_length = st->GetPlatformLength(n.GetLastTile(), ReverseDiagDir(TrackdirToExitdir(n.GetLastTrackdir())));
				/* Reduce the extra cost caused by passing-station penalty (each station receives it in the segment cost). */
				extra_cost -= Yapf().PfGetSettings().rail_station_penalty * platform_length;
				/* Add penalty for the inappropriate platform length. */
				extra_cost += PlatformLengthPenalty(platform_length);
			}
		}

		/* total node cost */
		n.m_cost = parent_cost + segment_entry_cost + segment_cost + extra_cost;

		return true;
	}

	inline bool CanUseGlobalCache(Node &n) const
	{
		return !m_disable_cache
			&& (n.m_parent != nullptr)
			&& (n.m_parent->m_num_signals_passed >= m_sig_look_ahead_costs.Size());
	}

	inline void ConnectNodeToCachedData(Node &n, CachedData &ci)
	{
		n.m_segment = &ci;
		if (n.m_segment->m_cost < 0) {
			n.m_segment->m_last_tile = n.m_key.m_tile;
			n.m_segment->m_last_td = n.m_key.m_td;
		}
	}

	void DisableCache(bool disable)
	{
		m_disable_cache = disable;
	}
};

#endif /* YAPF_COSTRAIL_HPP */