1

/* $Id$ */

     2

     3

#include "stdafx.h"

     4

#include "openttd.h"

     5

#include "bridge_map.h"

     6

#include "station_map.h"

     7

#include "depot.h"

     8

#include "functions.h"

     9

#include "map.h"

    10

#include "tile.h"

    11

#include "pathfind.h"

    12

#include "rail.h"

    13

#include "debug.h"

    14

#include "tunnel_map.h"

    15

#include "variables.h"

    16

#include "depot.h"

    17

    18

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

    19

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

    20

{

    21

	uint hash, val, offs;

    22

	TrackPathFinderLink *link, *new_link;

    23

	uint bits = 1 << dir;

    24

    25

	if (tpf->disable_tile_hash)

    26

		return true;

    27

    28

	hash = PATHFIND_HASH_TILE(tile);

    29

    30

	val = tpf->hash_head[hash];

    31

    32

	if (val == 0) {

    33

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

    34

		 * to indicate that a bit was set. */

    35

		tpf->hash_head[hash] = bits;

    36

		tpf->hash_tile[hash] = tile;

    37

		return true;

    38

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

    39

		/* single tile */

    40

    41

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

    42

			/* found another bit for the same tile,

    43

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

    44

			if (val & bits)

    45

				return false;

    46

    47

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

    48

			 * was set */

    49

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

    50

			return true;

    51

		} else {

    52

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

    53

    54

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

    55

			 * that a tile was already visisted. */

    56

			if (tpf->num_links_left == 0) {

    57

				return false;

    58

			}

    59

			tpf->num_links_left--;

    60

			link = tpf->new_link++;

    61

    62

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

    63

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

    64

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

    65

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

    66

    67

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

    68

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

    69

    70

			link->next = 0xFFFF;

    71

		}

    72

	} else {

    73

		/* a linked list of many tiles,

    74

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

    75

		 * otherwise make a new link */

    76

    77

		offs = tpf->hash_tile[hash];

    78

		do {

    79

			link = PATHFIND_GET_LINK_PTR(tpf, offs);

    80

			if (tile == link->tile) {

    81

				/* found the tile in the link list,

    82

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

    83

				 * bit was already set */

    84

				if (link->flags & bits)

    85

					return false;

    86

				link->flags |= bits;

    87

				return true;

    88

			}

    89

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

    90

	}

    91

    92

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

    93

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

    94

	if (tpf->num_links_left == 0) {

    95

			return false;

    96

	}

    97

	tpf->num_links_left--;

    98

	new_link = tpf->new_link++;

    99

   100

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

   101

	 * link to the new one */

   102

	new_link->tile = tile;

   103

	new_link->flags = bits;

   104

	new_link->next = 0xFFFF;

   105

   106

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

   107

	return true;

   108

}

   109

   110

static const byte _bits_mask[4] = {

   111

	0x19,

   112

	0x16,

   113

	0x25,

   114

	0x2A,

   115

};

   116

   117

static const byte _tpf_new_direction[14] = {

   118

	0, 1, 0, 1, 2, 1,

   119

	0, 0,

   120

	2, 3, 3, 2, 3, 0,

   121

};

   122

   123

static const byte _tpf_prev_direction[14] = {

   124

	0, 1, 1, 0, 1, 2,

   125

	0, 0,

   126

	2, 3, 2, 3, 0, 3,

   127

};

   128

   129

   130

static const byte _otherdir_mask[4] = {

   131

	0x10,

   132

	0,

   133

	0x5,

   134

	0x2A,

   135

};

   136

   137

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

   138

{

   139

	uint bits;

   140

	int i;

   141

	RememberData rd;

   142

   143

	assert(tpf->tracktype == TRANSPORT_WATER);

   144

   145

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

   146

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

   147

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

   148

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

   149

   150

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

   151

		return;

   152

   153

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

   154

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

   155

	if (bits == 0)

   156

		return;

   157

   158

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

   159

   160

	if ( (bits & (bits - 1)) == 0 ) {

   161

		/* only one direction */

   162

		i = 0;

   163

		while (!(bits&1))

   164

			i++, bits>>=1;

   165

   166

		rd = tpf->rd;

   167

		goto continue_here;

   168

	}

   169

	/* several directions */

   170

	i=0;

   171

	do {

   172

		if (!(bits & 1)) continue;

   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 = 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 (++i, bits>>=1);

   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

		GetTunnelDirection(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

const byte _ffb_64[128] = {

   235

 0,  0,  1,  0,  2,  0,  1,  0,

   236

 3,  0,  1,  0,  2,  0,  1,  0,

   237

 4,  0,  1,  0,  2,  0,  1,  0,

   238

 3,  0,  1,  0,  2,  0,  1,  0,

   239

 5,  0,  1,  0,  2,  0,  1,  0,

   240

 3,  0,  1,  0,  2,  0,  1,  0,

   241

 4,  0,  1,  0,  2,  0,  1,  0,

   242

 3,  0,  1,  0,  2,  0,  1,  0,

   243

   244

 0,  0,  0,  2,  0,  4,  4,  6,

   245

 0,  8,  8, 10,  8, 12, 12, 14,

   246

 0, 16, 16, 18, 16, 20, 20, 22,

   247

16, 24, 24, 26, 24, 28, 28, 30,

   248

 0, 32, 32, 34, 32, 36, 36, 38,

   249

32, 40, 40, 42, 40, 44, 44, 46,

   250

32, 48, 48, 50, 48, 52, 52, 54,

   251

48, 56, 56, 58, 56, 60, 60, 62,

   252

};

   253

   254

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

   255

{

   256

	uint bits;

   257

	int i;

   258

	RememberData rd;

   259

	TileIndex tile_org = tile;

   260

	bool is_bridge = false;

   261

	bool is_tunnel = false;

   262

   263

	if (IsTileType(tile, MP_TUNNEL) && GetTunnelDirection(tile) == direction) {

   264

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

   265

			return;

   266

		}

   267

		tile = SkipToEndOfTunnel(tpf, tile, direction);

   268

		is_tunnel = true;

   269

	} else if ((IsTileType(tile, MP_STREET_BRIDGE) || IsTileType(tile, MP_RAILWAY_BRIDGE)) && GetBridgeRampDirection(tile) == direction) {

   270

		TileIndex tile_end;

   271

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

   272

			return;

   273

		}

   274

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

   275

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

   276

		TPFSetTileBit(tpf, tile, 14);

   277

		tile_end = GetOtherBridgeEnd(tile);

   278

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

   279

		tile = tile_end;

   280

		TPFSetTileBit(tpf, tile, 14);

   281

		is_bridge = true;

   282

	} else {

   283

		tile += TileOffsByDiagDir(direction);

   284

	}

   285

   286

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

   287

	if (tpf->tracktype == TRANSPORT_RAIL) {

   288

		// don't enter train depot from the back

   289

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

   290

   291

		if (IsTileType(tile_org, MP_RAILWAY) || IsTileType(tile_org, MP_STATION) || IsTileType(tile_org, MP_TUNNEL) || IsTileType(tile_org, MP_RAILWAY_BRIDGE))

   292

			if (IsTileType(tile, MP_RAILWAY) || IsTileType(tile, MP_STATION) || IsTileType(tile, MP_TUNNEL) || IsTileType(tile, MP_RAILWAY_BRIDGE))

   293

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

   294

	}

   295

   296

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

   297

	if (tpf->tracktype == TRANSPORT_ROAD) {

   298

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

   299

		// don't enter road stop from the back

   300

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

   301

		// don't enter road depot from the back

   302

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

   303

	}

   304

   305

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

   306

	 * and transport type match */

   307

	if (IsTunnelTile(tile)) {

   308

		if ((!is_tunnel && GetTunnelDirection(tile) != direction) ||

   309

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

   310

			return;

   311

		}

   312

	}

   313

   314

	if (IsBridgeTile(tile)) {

   315

		if ((!is_bridge && GetBridgeRampDirection(tile) == ReverseDiagDir(direction)) ||

   316

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

   317

			return;

   318

		}

   319

	}

   320

   321

	tpf->rd.cur_length++;

   322

   323

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

   324

   325

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

   326

		bits &= _tpfmode1_and[direction];

   327

		bits = bits | (bits>>8);

   328

	}

   329

	bits &= 0xBF;

   330

   331

	if (bits != 0) {

   332

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

   333

			do {

   334

				i = FIND_FIRST_BIT(bits);

   335

				bits = KILL_FIRST_BIT(bits);

   336

   337

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

   338

				rd = tpf->rd;

   339

   340

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

   341

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

   342

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

   343

				}

   344

				tpf->rd = rd;

   345

			} while (bits != 0);

   346

		}

   347

	}

   348

   349

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

   350

	 * seems to go in 2 directions simultaneously */

   351

   352

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

   353

	 * stack space dramatically. */

   354

   355

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

   356

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

   357

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

   358

	if (tpf->hasbit_13)

   359

		return;

   360

   361

	direction = ReverseDiagDir(direction);

   362

	//tile += TileOffsByDiagDir(direction);

   363

	tile = tile_org;

   364

   365

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

   366

	bits |= (bits >> 8);

   367

   368

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

   369

		bits &= _bits_mask[direction];

   370

	}

   371

   372

	bits &= 0xBF;

   373

	if (bits == 0)

   374

		return;

   375

   376

	do {

   377

		i = FIND_FIRST_BIT(bits);

   378

		bits = KILL_FIRST_BIT(bits);

   379

   380

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

   381

		rd = tpf->rd;

   382

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

   383

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

   384

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

   385

		}

   386

		tpf->rd = rd;

   387

	} while (bits != 0);

   388

}

   389

   390

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

   391

{

   392

	TrackPathFinder tpf;

   393

   394

	assert(direction < 4);

   395

   396

	/* initialize path finder variables */

   397

	tpf.userdata = data;

   398

	tpf.enum_proc = enum_proc;

   399

	tpf.new_link = tpf.links;

   400

	tpf.num_links_left = lengthof(tpf.links);

   401

   402

	tpf.rd.cur_length = 0;

   403

	tpf.rd.depth = 0;

   404

	tpf.rd.pft_var6 = 0;

   405

   406

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

   407

   408

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

   409

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

   410

   411

   412

	tpf.tracktype = (byte)flags;

   413

   414

	if (HASBIT(flags, 11)) {

   415

		tpf.rd.pft_var6 = 0xFF;

   416

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

   417

		TPFMode2(&tpf, tile, direction);

   418

	} else {

   419

		/* clear the hash_heads */

   420

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

   421

		TPFMode1(&tpf, tile, direction);

   422

	}

   423

   424

	if (after_proc != NULL)

   425

		after_proc(&tpf);

   426

}

   427

   428

typedef struct {

   429

	TileIndex tile;

   430

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

   431

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

   432

	byte track;

   433

	byte depth;

   434

	byte state;

   435

	byte first_track;

   436

} StackedItem;

   437

   438

static const byte _new_track[6][4] = {

   439

{0,    0xff, 8,    0xff,},

   440

{0xff, 1,    0xff, 9,},

   441

{0xff, 2,    10,   0xff,},

   442

{3,    0xff, 0xff, 11,},

   443

{12,   4,    0xff, 0xff,},

   444

{0xff, 0xff, 5,    13,},

   445

};

   446

   447

typedef struct HashLink {

   448

	TileIndex tile;

   449

	uint16 typelength;

   450

	uint16 next;

   451

} HashLink;

   452

   453

typedef struct {

   454

	NTPEnumProc *enum_proc;

   455

	void *userdata;

   456

	TileIndex dest;

   457

   458

	TransportType tracktype;

   459

	RailTypeMask railtypes;

   460

	uint maxlength;

   461

   462

	HashLink *new_link;

   463

	uint num_links_left;

   464

   465

	uint nstack;

   466

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

   467

   468

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

   469

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

   470

   471

	HashLink links[0x400]; // hash links

   472

   473

} NewTrackPathFinder;

   474

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

   475

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

   476

   477

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

   478

   479

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

   480

// move it down to the proper position

   481

static inline void HeapifyUp(NewTrackPathFinder *tpf)

   482

{

   483

	StackedItem si;

   484

	int i = ++tpf->nstack;

   485

   486

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

   487

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

   488

		// swap the child item and the parent item.

   489

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

   490

		i>>=1;

   491

	}

   492

}

   493

   494

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

   495

static inline void HeapifyDown(NewTrackPathFinder *tpf)

   496

{

   497

	StackedItem si;

   498

	int i = 1, j;

   499

	int n;

   500

   501

	assert(tpf->nstack > 0);

   502

	n = --tpf->nstack;

   503

   504

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

   505