summaryrefslogtreecommitdiff
path: root/pbs.c
blob: 2fac8f9e8e9e10501fd50da7885235d76fb21bff (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
/* $Id$ */

#include "stdafx.h"
#include "openttd.h"
#include "functions.h"
#include "pbs.h"
#include "debug.h"
#include "map.h"
#include "tile.h"
#include "npf.h"
#include "pathfind.h"
#include "depot.h"

/** @file pbs.c Path-Based-Signalling implementation file
 *  @see pbs.h */

/* reserved track encoding:
 normal railway tracks:
   map3hi bits 4..6 = 'Track'number of reserved track + 1, if this is zero it means nothing is reserved on this tile
   map3hi bit  7    = if this is set, then the opposite track ('Track'number^1) is also reserved
 waypoints/stations:
   map3lo bit 6 set = track is reserved
 tunnels/bridges:
   map3hi bit 0 set = track with 'Track'number 0 is reserved
   map3hi bit 1 set = track with 'Track'number 1 is reserved
 level crossings:
   map5 bit 0 set = the rail track is reserved
*/

/**
 * maps an encoded reserved track (from map3lo bits 4..7)
 * to the tracks that are reserved.
 * 0xFF are invalid entries and should never be accessed.
 */
static const byte encrt_to_reserved[16] = {
	0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0xFF,
	0xFF, 0xFF, 0xFF, 0x0C, 0x0C, 0x30, 0x30, 0xFF
};

/**
 * maps an encoded reserved track (from map3lo bits 4..7)
 * to the track(dir)s that are unavailable due to reservations.
 * 0xFFFF are invalid entries and should never be accessed.
 */
static const uint16 encrt_to_unavail[16] = {
	0x0000, 0x3F3F, 0x3F3F, 0x3737, 0x3B3B, 0x1F1F, 0x2F2F, 0xFFFF,
	0xFFFF, 0xFFFF, 0xFFFF, 0x3F3F, 0x3F3F, 0x3F3F, 0x3F3F, 0xFFFF
};

void PBSReserveTrack(TileIndex tile, Track track) {
	assert(IsValidTile(tile));
	assert(track <= 5);
	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if ((_m[tile].m5 & ~1) == 0xC4) {
				// waypoint
				SETBIT(_m[tile].m3, 6);
			} else {
				// normal rail track
				byte encrt = (_m[tile].m4 & 0xF0) >> 4; // get current encoded info (see comments at top of file)

				if (encrt == 0) // nothing reserved before
					encrt = track + 1;
				else if (encrt == (track^1) + 1) // opposite track reserved before
					encrt |= 8;

				_m[tile].m4 &= ~0xF0;
				_m[tile].m4 |= encrt << 4;
			}
			break;
		case MP_TUNNELBRIDGE:
			_m[tile].m4 |= (1 << track) & 3;
			break;
		case MP_STATION:
			SETBIT(_m[tile].m3, 6);
			break;
		case MP_STREET:
			// make sure it is a railroad crossing
			if (!IsLevelCrossing(tile)) return;
			SETBIT(_m[tile].m5, 0);
			break;
		default:
			return;
	}
	// if debugging, mark tile dirty to show reserved status
	if (_debug_pbs_level >= 1)
		MarkTileDirtyByTile(tile);
}

byte PBSTileReserved(TileIndex tile) {
	assert(IsValidTile(tile));
	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if ((_m[tile].m5 & ~1) == 0xC4) {
				// waypoint
				// check if its reserved
				if (!HASBIT(_m[tile].m3, 6)) return 0;
				// return the track for the correct direction
				return HASBIT(_m[tile].m5, 0) ? 2 : 1;
			} else {
				// normal track
				byte res = encrt_to_reserved[(_m[tile].m4 & 0xF0) >> 4];
				assert(res != 0xFF);
				return res;
			}
		case MP_TUNNELBRIDGE:
			return (_m[tile].m4 & 3);
		case MP_STATION:
			// check if its reserved
			if (!HASBIT(_m[tile].m3, 6)) return 0;
			// return the track for the correct direction
			return HASBIT(_m[tile].m5, 0) ? 2 : 1;
		case MP_STREET:
			// make sure its a railroad crossing
			if (!IsLevelCrossing(tile)) return 0;
			// check if its reserved
			if (!HASBIT(_m[tile].m5, 0)) return 0;
			// return the track for the correct direction
			return HASBIT(_m[tile].m5, 3) ? 1 : 2;
		default:
			return 0;
	}
}

uint16 PBSTileUnavail(TileIndex tile) {
	assert(IsValidTile(tile));
	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if ((_m[tile].m5 & ~1) == 0xC4) {
				// waypoint
				return HASBIT(_m[tile].m3, 6) ? TRACKDIR_BIT_MASK : 0;
			} else {
				// normal track
				uint16 res = encrt_to_unavail[(_m[tile].m4 & 0xF0) >> 4];
				assert(res != 0xFFFF);
				return res;
			}
		case MP_TUNNELBRIDGE:
			return (_m[tile].m4 & 3) | ((_m[tile].m4 & 3) << 8);
		case MP_STATION:
			return HASBIT(_m[tile].m3, 6) ? TRACKDIR_BIT_MASK : 0;
		case MP_STREET:
			// make sure its a railroad crossing
			if (!IsLevelCrossing(tile)) return 0;
			// check if its reserved
			return (HASBIT(_m[tile].m5, 0)) ? TRACKDIR_BIT_MASK : 0;
		default:
			return 0;
	}
}

void PBSClearTrack(TileIndex tile, Track track) {
	assert(IsValidTile(tile));
	assert(track <= 5);
	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if ((_m[tile].m5 & ~1) == 0xC4) {
				// waypoint
				CLRBIT(_m[tile].m3, 6);
			} else {
				// normal rail track
				byte encrt = (_m[tile].m4 & 0xF0) >> 4;

				if (encrt == track + 1)
					encrt = 0;
				else if (encrt == track + 1 + 8)
					encrt = (track^1) + 1;
				else if (encrt == (track^1) + 1 + 8)
					encrt &= 7;

				_m[tile].m4 &= ~0xF0;
				_m[tile].m4 |= encrt << 4;
			}
			break;
		case MP_TUNNELBRIDGE:
			_m[tile].m4 &= ~((1 << track) & 3);
			break;
		case MP_STATION:
			CLRBIT(_m[tile].m3, 6);
			break;
		case MP_STREET:
			// make sure it is a railroad crossing
			if (!IsLevelCrossing(tile)) return;
			CLRBIT(_m[tile].m5, 0);
			break;
		default:
			return;
	}
	// if debugging, mark tile dirty to show reserved status
	if (_debug_pbs_level >= 1)
		MarkTileDirtyByTile(tile);
}

void PBSClearPath(TileIndex tile, Trackdir trackdir, TileIndex end_tile, Trackdir end_trackdir) {
	uint16 res;
	FindLengthOfTunnelResult flotr;
	assert(IsValidTile(tile));
	assert(IsValidTrackdir(trackdir));

	do {
		PBSClearTrack(tile, TrackdirToTrack(trackdir));

		if (tile == end_tile && TrackdirToTrack(trackdir) == TrackdirToTrack(end_trackdir))
			return;

		if (IsTileType(tile, MP_TUNNELBRIDGE) && (_m[tile].m5 & 0xF0)==0 && (unsigned)(_m[tile].m5 & 3) == TrackdirToExitdir(trackdir)) {
			// this is a tunnel
			flotr = FindLengthOfTunnel(tile, TrackdirToExitdir(trackdir));

			tile = flotr.tile;
		} else {
			byte exitdir = TrackdirToExitdir(trackdir);
			tile = AddTileIndexDiffCWrap(tile, TileIndexDiffCByDir(exitdir));
		}

		res = PBSTileReserved(tile);
		res |= res << 8;
		res &= TrackdirReachesTrackdirs(trackdir);
		trackdir = FindFirstBit2x64(res);

	} while (res != 0);
}

bool PBSIsPbsSignal(TileIndex tile, Trackdir trackdir)
{
	assert(IsValidTile(tile));
	assert(IsValidTrackdir(trackdir));

	if (!_patches.new_pathfinding_all)
		return false;

	if (!IsTileType(tile, MP_RAILWAY))
		return false;

	if (GetRailTileType(tile) != RAIL_TYPE_SIGNALS)
		return false;

	if (!HasSignalOnTrackdir(tile, trackdir))
		return false;

	if (GetSignalType(tile, TrackdirToTrack(trackdir)) == 4)
		return true;
	else
		return false;
}

typedef struct SetSignalsDataPbs {
	int cur;

	// these are used to keep track of the signals.
	byte bit[NUM_SSD_ENTRY];
	TileIndex tile[NUM_SSD_ENTRY];
} SetSignalsDataPbs;

// This function stores the signals inside the SetSignalsDataPbs struct, passed as callback to FollowTrack() in the PBSIsPbsSegment() function below
static bool SetSignalsEnumProcPBS(uint tile, SetSignalsDataPbs *ssd, int trackdir, uint length, byte *state)
{
	// the tile has signals?
	if (IsTileType(tile, MP_RAILWAY)) {
		if (HasSignalOnTrack(tile, TrackdirToTrack(trackdir))) {

				if (ssd->cur != NUM_SSD_ENTRY) {
					ssd->tile[ssd->cur] = tile; // remember the tile index
					ssd->bit[ssd->cur] = TrackdirToTrack(trackdir); // and the controlling bit number
					ssd->cur++;
				}
				return true;
		} else if (IsTileDepotType(tile, TRANSPORT_RAIL))
			return true; // don't look further if the tile is a depot
	}
	return false;
}

bool PBSIsPbsSegment(uint tile, Trackdir trackdir)
{
	SetSignalsDataPbs ssd;
	bool result = PBSIsPbsSignal(tile, trackdir);
	DiagDirection direction = TrackdirToExitdir(trackdir);//GetDepotDirection(tile,TRANSPORT_RAIL);
	int i;

	ssd.cur = 0;

	FollowTrack(tile, 0xC000 | TRANSPORT_RAIL, direction, (TPFEnumProc*)SetSignalsEnumProcPBS, NULL, &ssd);
	for(i=0; i!=ssd.cur; i++) {
		uint tile = ssd.tile[i];
		byte bit = ssd.bit[i];
		if (!PBSIsPbsSignal(tile, bit) && !PBSIsPbsSignal(tile, bit | 8))
			return false;
		result = true;
	}

	return result;
}