summaryrefslogtreecommitdiff
path: root/src/pathfinder/follow_track.hpp
blob: 70660d6537e4cbe05c984575b65051acdea89a13 (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
/* $Id$ */

/*
 * 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 follow_track.hpp Template function for track followers */

#ifndef  FOLLOW_TRACK_HPP
#define  FOLLOW_TRACK_HPP

#include "../pbs.h"
#include "../roadveh.h"
#include "../station_base.h"
#include "../train.h"
#include "../tunnelbridge.h"
#include "../tunnelbridge_map.h"
#include "../depot_map.h"
#include "pf_performance_timer.hpp"

/** Track follower helper template class (can serve pathfinders and vehicle
 *  controllers). See 6 different typedefs below for 3 different transport
 *  types w/ or w/o 90-deg turns allowed */
template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
struct CFollowTrackT
{
	enum ErrorCode {
		EC_NONE,
		EC_OWNER,
		EC_RAIL_TYPE,
		EC_90DEG,
		EC_NO_WAY,
		EC_RESERVED,
	};

	const VehicleType  *m_veh;           ///< moving vehicle
	Owner               m_veh_owner;     ///< owner of the vehicle
	TileIndex           m_old_tile;      ///< the origin (vehicle moved from) before move
	Trackdir            m_old_td;        ///< the trackdir (the vehicle was on) before move
	TileIndex           m_new_tile;      ///< the new tile (the vehicle has entered)
	TrackdirBits        m_new_td_bits;   ///< the new set of available trackdirs
	DiagDirection       m_exitdir;       ///< exit direction (leaving the old tile)
	bool                m_is_tunnel;     ///< last turn passed tunnel
	bool                m_is_bridge;     ///< last turn passed bridge ramp
	bool                m_is_station;    ///< last turn passed station
	int                 m_tiles_skipped; ///< number of skipped tunnel or station tiles
	ErrorCode           m_err;
	CPerformanceTimer  *m_pPerf;
	RailTypes           m_railtypes;

	FORCEINLINE CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
	{
		Init(v, railtype_override, pPerf);
	}

	FORCEINLINE CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
	{
		m_veh = NULL;
		Init(o, railtype_override, pPerf);
	}

	FORCEINLINE void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
	{
		assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
		m_veh = v;
		Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
	}

	FORCEINLINE void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
	{
		assert((!IsRoadTT() || m_veh != NULL) && (!IsRailTT() || railtype_override != INVALID_RAILTYPES));
		m_veh_owner = o;
		m_pPerf = pPerf;
		/* don't worry, all is inlined so compiler should remove unnecessary initializations */
		m_new_tile = INVALID_TILE;
		m_new_td_bits = TRACKDIR_BIT_NONE;
		m_exitdir = INVALID_DIAGDIR;
		m_is_station = m_is_bridge = m_is_tunnel = false;
		m_tiles_skipped = 0;
		m_err = EC_NONE;
		m_railtypes = railtype_override;
	}

	FORCEINLINE static TransportType TT() {return Ttr_type_;}
	FORCEINLINE static bool IsWaterTT() {return TT() == TRANSPORT_WATER;}
	FORCEINLINE static bool IsRailTT() {return TT() == TRANSPORT_RAIL;}
	FORCEINLINE bool IsTram() {return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM);}
	FORCEINLINE static bool IsRoadTT() {return TT() == TRANSPORT_ROAD;}
	FORCEINLINE static bool Allow90degTurns() {return T90deg_turns_allowed_;}
	FORCEINLINE static bool DoTrackMasking() {return IsRailTT() && Tmask_reserved_tracks;}

	/** Tests if a tile is a road tile with a single tramtrack (tram can reverse) */
	FORCEINLINE DiagDirection GetSingleTramBit(TileIndex tile)
	{
		assert(IsTram()); // this function shouldn't be called in other cases

		if (IsNormalRoadTile(tile)) {
			RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
			switch (rb) {
				case ROAD_NW: return DIAGDIR_NW;
				case ROAD_SW: return DIAGDIR_SW;
				case ROAD_SE: return DIAGDIR_SE;
				case ROAD_NE: return DIAGDIR_NE;
				default: break;
			}
		}
		return INVALID_DIAGDIR;
	}

	/** main follower routine. Fills all members and return true on success.
	 *  Otherwise returns false if track can't be followed. */
	inline bool Follow(TileIndex old_tile, Trackdir old_td)
	{
		m_old_tile = old_tile;
		m_old_td = old_td;
		m_err = EC_NONE;
		assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
		       (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
		m_exitdir = TrackdirToExitdir(m_old_td);
		if (ForcedReverse()) return true;
		if (!CanExitOldTile()) return false;
		FollowTileExit();
		if (!QueryNewTileTrackStatus()) return TryReverse();
		if (!CanEnterNewTile()) return false;
		m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
		if (m_new_td_bits == TRACKDIR_BIT_NONE) {
			m_err = EC_NO_WAY;
			return false;
		}
		if (!Allow90degTurns()) {
			m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
			if (m_new_td_bits == TRACKDIR_BIT_NONE) {
				m_err = EC_90DEG;
				return false;
			}
		}
		return true;
	}

	inline bool MaskReservedTracks()
	{
		if (!DoTrackMasking()) return true;

		if (m_is_station) {
			/* Check skipped station tiles as well. */
			TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
			for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
				if (HasStationReservation(tile)) {
					m_new_td_bits = TRACKDIR_BIT_NONE;
					m_err = EC_RESERVED;
					return false;
				}
			}
		}

		TrackBits reserved = GetReservedTrackbits(m_new_tile);
		/* Mask already reserved trackdirs. */
		m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
		/* Mask out all trackdirs that conflict with the reservation. */
		Track t;
		FOR_EACH_SET_TRACK(t, TrackdirBitsToTrackBits(m_new_td_bits)) {
			if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
		}
		if (m_new_td_bits == TRACKDIR_BIT_NONE) {
			m_err = EC_RESERVED;
			return false;
		}
		return true;
	}

protected:
	/** Follow the m_exitdir from m_old_tile and fill m_new_tile and m_tiles_skipped */
	FORCEINLINE void FollowTileExit()
	{
		m_is_station = m_is_bridge = m_is_tunnel = false;
		m_tiles_skipped = 0;

		/* extra handling for tunnels and bridges in our direction */
		if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
			DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
			if (enterdir == m_exitdir) {
				/* we are entering the tunnel / bridge */
				if (IsTunnel(m_old_tile)) {
					m_is_tunnel = true;
					m_new_tile = GetOtherTunnelEnd(m_old_tile);
				} else { // IsBridge(m_old_tile)
					m_is_bridge = true;
					m_new_tile = GetOtherBridgeEnd(m_old_tile);
				}
				m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
				return;
			}
			assert(ReverseDiagDir(enterdir) == m_exitdir);
		}

		/* normal or station tile, do one step */
		TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
		m_new_tile = TILE_ADD(m_old_tile, diff);

		/* special handling for stations */
		if (IsRailTT() && HasStationTileRail(m_new_tile)) {
			m_is_station = true;
		} else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
			m_is_station = true;
		} else {
			m_is_station = false;
		}
	}

	/** stores track status (available trackdirs) for the new tile into m_new_td_bits */
	FORCEINLINE bool QueryNewTileTrackStatus()
	{
		CPerfStart perf(*m_pPerf);
		if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
			m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
		} else {
			m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));

			if (IsTram() && m_new_td_bits == 0) {
				/* GetTileTrackStatus() returns 0 for single tram bits.
				 * As we cannot change it there (easily) without breaking something, change it here */
				switch (GetSingleTramBit(m_new_tile)) {
					case DIAGDIR_NE:
					case DIAGDIR_SW:
						m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
						break;

					case DIAGDIR_NW:
					case DIAGDIR_SE:
						m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
						break;

					default: break;
				}
			}
		}
		return (m_new_td_bits != TRACKDIR_BIT_NONE);
	}

	/** return true if we can leave m_old_tile in m_exitdir */
	FORCEINLINE bool CanExitOldTile()
	{
		/* road stop can be left at one direction only unless it's a drive-through stop */
		if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
			DiagDirection exitdir = GetRoadStopDir(m_old_tile);
			if (exitdir != m_exitdir) {
				m_err = EC_NO_WAY;
				return false;
			}
		}

		/* single tram bits can only be left in one direction */
		if (IsTram()) {
			DiagDirection single_tram = GetSingleTramBit(m_old_tile);
			if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
				m_err = EC_NO_WAY;
				return false;
			}
		}

		/* road depots can be also left in one direction only */
		if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
			DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
			if (exitdir != m_exitdir) {
				m_err = EC_NO_WAY;
				return false;
			}
		}
		return true;
	}

	/** return true if we can enter m_new_tile from m_exitdir */
	FORCEINLINE bool CanEnterNewTile()
	{
		if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
			/* road stop can be entered from one direction only unless it's a drive-through stop */
			DiagDirection exitdir = GetRoadStopDir(m_new_tile);
			if (ReverseDiagDir(exitdir) != m_exitdir) {
				m_err = EC_NO_WAY;
				return false;
			}
		}

		/* single tram bits can only be entered from one direction */
		if (IsTram()) {
			DiagDirection single_tram = GetSingleTramBit(m_new_tile);
			if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
				m_err = EC_NO_WAY;
				return false;
			}
		}

		/* road and rail depots can also be entered from one direction only */
		if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
			DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
			if (ReverseDiagDir(exitdir) != m_exitdir) {
				m_err = EC_NO_WAY;
				return false;
			}
			/* don't try to enter other company's depots */
			if (GetTileOwner(m_new_tile) != m_veh_owner) {
				m_err = EC_OWNER;
				return false;
			}
		}
		if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
			DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
			if (ReverseDiagDir(exitdir) != m_exitdir) {
				m_err = EC_NO_WAY;
				return false;
			}
		}

		/* rail transport is possible only on tiles with the same owner as vehicle */
		if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
			/* different owner */
			m_err = EC_NO_WAY;
			return false;
		}

		/* rail transport is possible only on compatible rail types */
		if (IsRailTT()) {
			RailType rail_type = GetTileRailType(m_new_tile);
			if (!HasBit(m_railtypes, rail_type)) {
				/* incompatible rail type */
				m_err = EC_RAIL_TYPE;
				return false;
			}
		}

		/* tunnel holes and bridge ramps can be entered only from proper direction */
		if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
			if (IsTunnel(m_new_tile)) {
				if (!m_is_tunnel) {
					DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
					if (tunnel_enterdir != m_exitdir) {
						m_err = EC_NO_WAY;
						return false;
					}
				}
			} else { // IsBridge(m_new_tile)
				if (!m_is_bridge) {
					DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
					if (ramp_enderdir != m_exitdir) {
						m_err = EC_NO_WAY;
						return false;
					}
				}
			}
		}

		/* special handling for rail stations - get to the end of platform */
		if (IsRailTT() && m_is_station) {
			/* entered railway station
			 * get platform length */
			uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
			/* how big step we must do to get to the last platform tile; */
			m_tiles_skipped = length - 1;
			/* move to the platform end */
			TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
			diff *= m_tiles_skipped;
			m_new_tile = TILE_ADD(m_new_tile, diff);
			return true;
		}

		return true;
	}

	/** return true if we must reverse (in depots and single tram bits) */
	FORCEINLINE bool ForcedReverse()
	{
		/* rail and road depots cause reversing */
		if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
			DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
			if (exitdir != m_exitdir) {
				/* reverse */
				m_new_tile = m_old_tile;
				m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
				m_exitdir = exitdir;
				m_tiles_skipped = 0;
				m_is_tunnel = m_is_bridge = m_is_station = false;
				return true;
			}
		}

		/* single tram bits cause reversing */
		if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
			/* reverse */
			m_new_tile = m_old_tile;
			m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
			m_exitdir = ReverseDiagDir(m_exitdir);
			m_tiles_skipped = 0;
			m_is_tunnel = m_is_bridge = m_is_station = false;
			return true;
		}

		return false;
	}

	/** return true if we successfully reversed at end of road/track */
	FORCEINLINE bool TryReverse()
	{
		if (IsRoadTT() && !IsTram()) {
			/* if we reached the end of road, we can reverse the RV and continue moving */
			m_exitdir = ReverseDiagDir(m_exitdir);
			/* new tile will be the same as old one */
			m_new_tile = m_old_tile;
			/* set new trackdir bits to all reachable trackdirs */
			QueryNewTileTrackStatus();
			m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
			if (m_new_td_bits != TRACKDIR_BIT_NONE) {
				/* we have some trackdirs reachable after reversal */
				return true;
			}
		}
		m_err = EC_NO_WAY;
		return false;
	}

public:
	/** Helper for pathfinders - get min/max speed on the m_old_tile/m_old_td */
	int GetSpeedLimit(int *pmin_speed = NULL) const
	{
		int min_speed = 0;
		int max_speed = INT_MAX; // no limit

		/* Check for on-bridge speed limit */
		if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
			int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
			if (IsRoadTT()) spd *= 2;
			if (max_speed > spd) max_speed = spd;
		}
		/* Check for speed limit imposed by railtype */
		if (IsRailTT()) {
			uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
			if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
		}

		/* if min speed was requested, return it */
		if (pmin_speed) *pmin_speed = min_speed;
		return max_speed;
	}
};

typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;

typedef CFollowTrackT<TRANSPORT_WATER, Ship,        false> CFollowTrackWaterNo90;
typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;

typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;

#endif /* FOLLOW_TRACK_HPP */