1

/* $Id$ */

     2

     3

/** @file pathfind.cpp */

     4

     5

#include "stdafx.h"

     6

#include "openttd.h"

     7

#include "bridge_map.h"

     8

#include "station_map.h"

     9

#include "depot.h"

    10

#include "functions.h"

    11

#include "landscape.h"

    12

#include "map.h"

    13

#include "tile.h"

    14

#include "pathfind.h"

    16

#include "debug.h"

    17

#include "tunnel_map.h"

    18

#include "variables.h"

    19

#include "depot.h"

    20

#include "tunnelbridge_map.h"

    21

    22

/* remember which tiles we have already visited so we don't visit them again. */

    23

static bool TPFSetTileBit(TrackPathFinder *tpf, TileIndex tile, int dir)

    24

{

    25

	uint hash, val, offs;

    26

	TrackPathFinderLink *link, *new_link;

    27

	uint bits = 1 << dir;

    28

    29

	if (tpf->disable_tile_hash)

    30

		return true;

    31

    32

	hash = PATHFIND_HASH_TILE(tile);

    33

    34

	val = tpf->hash_head[hash];

    35

    36

	if (val == 0) {

    37

		/* unused hash entry, set the appropriate bit in it and return true

    38

		 * to indicate that a bit was set. */

    39

		tpf->hash_head[hash] = bits;

    40

		tpf->hash_tile[hash] = tile;

    41

		return true;

    42

	} else if (!(val & 0x8000)) {

    43

		/* single tile */

    44

    45

		if (tile == tpf->hash_tile[hash]) {

    46

			/* found another bit for the same tile,

    47

			 * check if this bit is already set, if so, return false */

    48

			if (val & bits)

    49

				return false;

    50

    51

			/* otherwise set the bit and return true to indicate that the bit

    52

			 * was set */

    53

			tpf->hash_head[hash] = val | bits;

    54

			return true;

    55

		} else {

    56

			/* two tiles with the same hash, need to make a link */

    57

    58

			/* allocate a link. if out of links, handle this by returning

    59

			 * that a tile was already visisted. */

    60

			if (tpf->num_links_left == 0) {

    61

				return false;

    62

			}

    63

			tpf->num_links_left--;

    64

			link = tpf->new_link++;

    65

    66

			/* move the data that was previously in the hash_??? variables

    67

			 * to the link struct, and let the hash variables point to the link */

    68

			link->tile = tpf->hash_tile[hash];

    69

			tpf->hash_tile[hash] = PATHFIND_GET_LINK_OFFS(tpf, link);

    70

    71

			link->flags = tpf->hash_head[hash];

    72

			tpf->hash_head[hash] = 0xFFFF; // multi link

    73

    74

			link->next = 0xFFFF;

    75

		}

    76

	} else {

    77

		/* a linked list of many tiles,

    78

		 * find the one corresponding to the tile, if it exists.

    79

		 * otherwise make a new link */

    80

    81

		offs = tpf->hash_tile[hash];

    82

		do {

    83

			link = PATHFIND_GET_LINK_PTR(tpf, offs);

    84

			if (tile == link->tile) {

    85

				/* found the tile in the link list,

    86

				 * check if the bit was alrady set, if so return false to indicate that the

    87

				 * bit was already set */

    88

				if (link->flags & bits)

    89

					return false;

    90

				link->flags |= bits;

    91

				return true;

    92

			}

    93

		} while ((offs=link->next) != 0xFFFF);

    94

	}

    95

    96

	/* get here if we need to add a new link to link,

    97

	 * first, allocate a new link, in the same way as before */

    98

	if (tpf->num_links_left == 0) {

    99

			return false;

   100

	}

   101

	tpf->num_links_left--;

   102

	new_link = tpf->new_link++;

   103

   104

	/* then fill the link with the new info, and establish a ptr from the old

   105

	 * link to the new one */

   106

	new_link->tile = tile;

   107

	new_link->flags = bits;

   108

	new_link->next = 0xFFFF;

   109

   110

	link->next = PATHFIND_GET_LINK_OFFS(tpf, new_link);

   111

	return true;

   112

}

   113

   114

static const byte _bits_mask[4] = {

   115

	0x19,

   116

	0x16,

   117

	0x25,

   118

	0x2A,

   119

};

   120

   121

static const DiagDirection _tpf_new_direction[14] = {

   122

	DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW, DIAGDIR_SE,

   123

	INVALID_DIAGDIR, INVALID_DIAGDIR,

   124

	DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE,

   125

};

   126

   127

static const DiagDirection _tpf_prev_direction[14] = {

   128

	DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW,

   129

	INVALID_DIAGDIR, INVALID_DIAGDIR,

   130

	DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE, DIAGDIR_NW,

   131

};

   132

   133

   134

static const byte _otherdir_mask[4] = {

   135

	0x10,

   136

	0,

   137

	0x5,

   138

	0x2A,

   139

};

   140

   141

static void TPFMode2(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)

   142

{

   143

	uint bits;

   144

	RememberData rd;

   145

   146

	assert(tpf->tracktype == TRANSPORT_WATER);

   147

   148

	/* This addition will sometimes overflow by a single tile.

   149

	 * The use of TILE_MASK here makes sure that we still point at a valid

   150

	 * tile, and then this tile will be in the sentinel row/col, so GetTileTrackStatus will fail. */

   151

	tile = TILE_MASK(tile + TileOffsByDiagDir(direction));

   152

   153

	if (++tpf->rd.cur_length > 50)

   154

		return;

   155

   156

	bits = GetTileTrackStatus(tile, tpf->tracktype, tpf->sub_type);

   157

	bits = (byte)((bits | (bits >> 8)) & _bits_mask[direction]);

   158

	if (bits == 0)

   159

		return;

   160

   161

	assert(TileX(tile) != MapMaxX() && TileY(tile) != MapMaxY());

   162

   163

	uint i = 0;

   164

	/* only one direction */

   165

	if (KillFirstBit(bits) == 0) {

   166

		i = FindFirstBit(bits);

   167

		rd = tpf->rd;

   168

		goto continue_here;

   169

	}

   170

	/* several directions */

   171

	do {

   172

		i = FindFirstBit(bits);

   173

		rd = tpf->rd;

   174

   175

		/* Change direction 4 times only */

   176

		if ((byte)i != tpf->rd.pft_var6) {

   177

			if (++tpf->rd.depth > 4) {

   178

				tpf->rd = rd;

   179

				return;

   180

			}

   181

			tpf->rd.pft_var6 = (byte)i;

   182

		}

   183

   184

continue_here:

   185

		tpf->the_dir = (Trackdir)(i + (HasBit(_otherdir_mask[direction], i) ? 8 : 0));

   186

   187

		if (!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, NULL)) {

   188

			TPFMode2(tpf, tile, _tpf_new_direction[tpf->the_dir]);

   189

		}

   190

   191

		tpf->rd = rd;

   192

	} while (ClrBit(bits, i) != 0);

   193

   194

}

   195

   196

   197

/* Returns the end tile and the length of a tunnel. The length does not

   198

 * include the starting tile (entry), it does include the end tile (exit).

   199

 */

   200

FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, DiagDirection dir)

   201

{

   202

	TileIndexDiff delta = TileOffsByDiagDir(dir);

   203

	uint z = GetTileZ(tile);

   204

	FindLengthOfTunnelResult flotr;

   205

   206

	flotr.length = 0;

   207

   208

	dir = ReverseDiagDir(dir);

   209

	do {

   210

		flotr.length++;

   211

		tile += delta;

   212

	} while(

   213

		!IsTunnelTile(tile) ||

   214

		GetTunnelBridgeDirection(tile) != dir ||

   215

		GetTileZ(tile) != z

   216

	);

   217

   218

	flotr.tile = tile;

   219

	return flotr;

   220

}

   221

   222

static const uint16 _tpfmode1_and[4] = { 0x1009, 0x16, 0x520, 0x2A00 };

   223

   224

static uint SkipToEndOfTunnel(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)

   225

{

   226

	FindLengthOfTunnelResult flotr;

   227

	TPFSetTileBit(tpf, tile, 14);

   228

	flotr = FindLengthOfTunnel(tile, direction);

   229

	tpf->rd.cur_length += flotr.length;

   230

	TPFSetTileBit(tpf, flotr.tile, 14);

   231

	return flotr.tile;

   232

}

   233

   234

static void TPFMode1(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction);

   235

   236

/** Most code of the "Normal" case of TPF Mode 1; for signals special tricks

   237

 * have to be done, but those happen in TPFMode1; this is just to prevent

   238

 * gotos ;). */

   239

static inline void TPFMode1_NormalCase(TrackPathFinder* tpf, TileIndex tile, TileIndex tile_org, DiagDirection direction)

   240

{

   241

	/* Check in case of rail if the owner is the same */

   242

	if (tpf->tracktype == TRANSPORT_RAIL) {

   243

		/* don't enter train depot from the back */

   244

		if (IsTileDepotType(tile, TRANSPORT_RAIL) && GetRailDepotDirection(tile) == direction) return;

   245

   246

		if (IsTileType(tile_org, MP_RAILWAY) || IsTileType(tile_org, MP_STATION) || IsTileType(tile_org, MP_TUNNELBRIDGE))

   247

			if (IsTileType(tile, MP_RAILWAY) || IsTileType(tile, MP_STATION) || IsTileType(tile, MP_TUNNELBRIDGE))

   248

				if (GetTileOwner(tile_org) != GetTileOwner(tile)) return;

   249

	}

   250

   251

	/* check if the new tile can be entered from that direction */

   252

	if (tpf->tracktype == TRANSPORT_ROAD) {

   253

		/* road stops and depots now have a track (r4419)

   254

		 * don't enter road stop from the back */

   255

		if (IsStandardRoadStopTile(tile) && ReverseDiagDir(GetRoadStopDir(tile)) != direction) return;

   256

		/* don't enter road depot from the back */

   257

		if (IsTileDepotType(tile, TRANSPORT_ROAD) && ReverseDiagDir(GetRoadDepotDirection(tile)) != direction) return;

   258

	}

   259

   260

	/* Check if the new tile is a tunnel or bridge head and that the direction

   261

	 * and transport type match */

   262

	if (IsTileType(tile, MP_TUNNELBRIDGE)) {

   263

		if (GetTunnelBridgeDirection(tile) != direction ||

   264

				GetTunnelBridgeTransportType(tile) != tpf->tracktype) {

   265

			return;

   266

		}

   267

	}

   268

   269

	tpf->rd.cur_length++;

   270

   271

	uint bits = GetTileTrackStatus(tile, tpf->tracktype, tpf->sub_type);

   272

   273

	if ((byte)bits != tpf->var2) {

   274

		bits &= _tpfmode1_and[direction];

   275

		bits |= bits >> 8;

   276

	}

   277

	bits &= 0xBF;

   278

   279

	if (bits != 0) {

   280

		if (!tpf->disable_tile_hash || (tpf->rd.cur_length <= 64 && (KillFirstBit(bits) == 0 || ++tpf->rd.depth <= 7))) {

   281

			do {

   282

				int i = FIND_FIRST_BIT(bits);

   283

				bits = KillFirstBit(bits);

   284

   285

				tpf->the_dir = (Trackdir)((_otherdir_mask[direction] & (byte)(1 << i)) ? (i + 8) : i);

   286

				RememberData rd = tpf->rd;

   287

   288

				if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&

   289

						!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {

   290

					TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);

   291

				}

   292

				tpf->rd = rd;

   293

			} while (bits != 0);

   294

		}

   295

	}

   296

}

   297

   298

static void TPFMode1(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)

   299

{

   300

	TileIndex tile_org = tile;

   301

   302

	if (IsTileType(tile, MP_TUNNELBRIDGE)) {

   303

		if (IsTunnel(tile)) {

   304

			if (GetTunnelBridgeTransportType(tile) != tpf->tracktype) {

   305

				return;

   306

			}

   307

			/* Only skip through the tunnel if heading inwards. We can

   308

			 * be headed outwards if our starting position was in a

   309

			 * tunnel and we're pathfinding backwards */

   310

			if (GetTunnelBridgeDirection(tile) == direction) {

   311

				tile = SkipToEndOfTunnel(tpf, tile, direction);

   312

			} else if (GetTunnelBridgeDirection(tile) != ReverseDiagDir(direction)) {

   313

				/* We don't support moving through the sides of a tunnel

   314

				 * entrance :-) */

   315

				return;

   316

			}

   317

		} else {

   318

			TileIndex tile_end;

   319

			if (GetTunnelBridgeDirection(tile) != direction ||

   320

					GetTunnelBridgeTransportType(tile) != tpf->tracktype) {

   321

				return;

   322

			}

   323

			//fprintf(stderr, "%s: Planning over bridge\n", __func__);

   324

			// TODO doesn't work - WHAT doesn't work?

   325

			TPFSetTileBit(tpf, tile, 14);

   326

			tile_end = GetOtherBridgeEnd(tile);

   327

			tpf->rd.cur_length += DistanceManhattan(tile, tile_end);

   328

			tile = tile_end;

   329

			TPFSetTileBit(tpf, tile, 14);

   330

		}

   331

	}

   332

	tile += TileOffsByDiagDir(direction);

   333

   334

	TPFMode1_NormalCase(tpf, tile, tile_org, direction);

   335

   336

	/* the next is only used when signals are checked.

   337

	 * seems to go in 2 directions simultaneously */

   338

   339

	/* if i can get rid of this, tail end recursion can be used to minimize

   340

	 * stack space dramatically. */

   341

   342

	/* If we are doing signal setting, we must reverse at evere tile, so we

   343

	 * iterate all the tracks in a signal block, even when a normal train would

   344

	 * not reach it (for example, when two lines merge */

   345

	if (tpf->hasbit_13)

   346

		return;

   347

   348

	direction = ReverseDiagDir(direction);

   349

	tile += TileOffsByDiagDir(direction);

   350

   351

	uint bits = GetTileTrackStatus(tile, tpf->tracktype, tpf->sub_type);

   352

	bits |= (bits >> 8);

   353

   354

	if ( (byte)bits != tpf->var2) {

   355

		bits &= _bits_mask[direction];

   356

	}

   357

   358

	bits &= 0xBF;

   359

	if (bits == 0)

   360

		return;

   361

   362

	do {

   363

		uint i = FIND_FIRST_BIT(bits);

   364

		bits = KillFirstBit(bits);

   365

   366

		tpf->the_dir = (Trackdir)((_otherdir_mask[direction] & (byte)(1 << i)) ? (i + 8) : i);

   367

		RememberData rd = tpf->rd;

   368

		if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&

   369

				!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {

   370

			TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);

   371

		}

   372

		tpf->rd = rd;

   373

	} while (bits != 0);

   374

}

   375

   376

void FollowTrack(TileIndex tile, uint16 flags, uint sub_type, DiagDirection direction, TPFEnumProc *enum_proc, TPFAfterProc *after_proc, void *data)

   377

{

   378

	TrackPathFinder tpf;

   379

   380

	assert(direction < 4);

   381

   382

	/* initialize path finder variables */

   383

	tpf.userdata = data;

   384

	tpf.enum_proc = enum_proc;

   385

	tpf.new_link = tpf.links;

   386

	tpf.num_links_left = lengthof(tpf.links);

   387

   388

	tpf.rd.cur_length = 0;

   389

	tpf.rd.depth = 0;

   390

	tpf.rd.pft_var6 = 0;

   391

   392

	tpf.var2 = HasBit(flags, 15) ? 0x43 : 0xFF; // 0x8000

   393

   394

	tpf.disable_tile_hash = HasBit(flags, 12);  // 0x1000

   395

	tpf.hasbit_13         = HasBit(flags, 13);  // 0x2000

   396

   397

   398

	tpf.tracktype = (TransportType)(flags & 0xFF);

   399

	tpf.sub_type = sub_type;

   400

   401

	if (HasBit(flags, 11)) {

   402

		tpf.rd.pft_var6 = 0xFF;

   403

		tpf.enum_proc(tile, data, INVALID_TRACKDIR, 0, 0);

   404

		TPFMode2(&tpf, tile, direction);

   405

	} else {

   406

		/* clear the hash_heads */

   407

		memset(tpf.hash_head, 0, sizeof(tpf.hash_head));

   408

		TPFMode1(&tpf, tile, direction);

   409

	}

   410

   411

	if (after_proc != NULL)

   412

		after_proc(&tpf);

   413

}

   414

   415

struct StackedItem {

   416

	TileIndex tile;

   417

	uint16 cur_length; ///< This is the current length to this tile.

   418

	uint16 priority;   ///< This is the current length + estimated length to the goal.

   419

	TrackdirByte track;

   420

	byte depth;

   421

	byte state;

   422

	byte first_track;

   423

};

   424

   425

static const Trackdir _new_trackdir[6][4] = {

   426

{TRACKDIR_X_NE,    INVALID_TRACKDIR, TRACKDIR_X_SW,    INVALID_TRACKDIR,},

   427

{INVALID_TRACKDIR, TRACKDIR_Y_SE,    INVALID_TRACKDIR, TRACKDIR_Y_NW,},

   428

{INVALID_TRACKDIR, TRACKDIR_UPPER_E, TRACKDIR_UPPER_W, INVALID_TRACKDIR,},

   429

{TRACKDIR_LOWER_E, INVALID_TRACKDIR, INVALID_TRACKDIR, TRACKDIR_LOWER_W,},

   430

{TRACKDIR_LEFT_N,  TRACKDIR_LEFT_S,  INVALID_TRACKDIR, INVALID_TRACKDIR,},

   431

{INVALID_TRACKDIR, INVALID_TRACKDIR, TRACKDIR_RIGHT_S, TRACKDIR_RIGHT_N,},

   432

};

   433

   434

struct HashLink {

   435

	TileIndex tile;

   436

	uint16 typelength;

   437

	uint16 next;

   438

};

   439

   440

struct NewTrackPathFinder {

   441

	NTPEnumProc *enum_proc;

   442

	void *userdata;

   443

	TileIndex dest;

   444

   445

	TransportType tracktype;

   446

	RailTypeMask railtypes;

   447

	uint maxlength;

   448

   449

	HashLink *new_link;

   450

	uint num_links_left;

   451

   452

	uint nstack;

   453

	StackedItem stack[256];     ///< priority queue of stacked items

   454

   455

	uint16 hash_head[0x400];    ///< hash heads. 0 means unused. 0xFFFC = length, 0x3 = dir

   456

	TileIndex hash_tile[0x400]; ///< tiles. or links.

   457

   458

	HashLink links[0x400];      ///< hash links

   459

   460

};

   461

#define NTP_GET_LINK_OFFS(tpf, link) ((byte*)(link) - (byte*)tpf->links)

   462

#define NTP_GET_LINK_PTR(tpf, link_offs) (HashLink*)((byte*)tpf->links + (link_offs))

   463

   464

#define ARR(i) tpf->stack[(i)-1]

   465

   466

/** called after a new element was added in the queue at the last index.

   467

 * move it down to the proper position */

   468

static inline void HeapifyUp(NewTrackPathFinder *tpf)

   469

{

   470

	StackedItem si;

   471

	int i = ++tpf->nstack;

   472

   473

	while (i != 1 && ARR(i).priority < ARR(i>>1).priority) {

   474

		/* the child element is larger than the parent item.

   475

		 * swap the child item and the parent item. */

   476

		si = ARR(i); ARR(i) = ARR(i >> 1); ARR(i >> 1) = si;

   477

		i >>= 1;

   478

	}

   479

}

   480

   481

/** called after the element 0 was eaten. fill it with a new element */

   482

static inline void HeapifyDown(NewTrackPathFinder *tpf)

   483

{

   484

	StackedItem si;

   485

	int i = 1, j;

   486

	int n;

   487

   488

	assert(tpf->nstack > 0);

   489

	n = --tpf->nstack;

   490

   491

	if (n == 0) return; // heap is empty so nothing to do?

   492

   493

	/* copy the last item to index 0. we use it as base for heapify. */

   494

	ARR(1) = ARR(n + 1);

   495

   496

	while ((j = i * 2) <= n) {

   497

		/* figure out which is smaller of the children. */

   498

		if (j != n && ARR(j).priority > ARR(j + 1).priority)