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, 0,0,

   119

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

   120

};

   121

   122

static const byte _tpf_prev_direction[14] = {

   123

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

   124

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

   125

};

   126

   127

   128

static const byte _otherdir_mask[4] = {

   129

	0x10,

   130

	0,

   131

	0x5,

   132

	0x2A,

   133

};

   134

   135

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

   136

{

   137

	uint bits;

   138

	int i;

   139

	RememberData rd;

   140

   141

	assert(tpf->tracktype == TRANSPORT_WATER);

   142

   143

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

   144

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

   145

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

   146

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

   147

   148

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

   149

		return;

   150

   151

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

   152

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

   153

	if (bits == 0)

   154

		return;

   155

   156

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

   157

   158

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

   159

		/* only one direction */

   160

		i = 0;

   161

		while (!(bits&1))

   162

			i++, bits>>=1;

   163

   164

		rd = tpf->rd;

   165

		goto continue_here;

   166

	}

   167

	/* several directions */

   168

	i=0;

   169

	do {

   170

		if (!(bits & 1)) continue;

   171

		rd = tpf->rd;

   172

   173

		// Change direction 4 times only

   174

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

   175

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

   176

				tpf->rd = rd;

   177

				return;

   178

			}

   179

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

   180

		}

   181

   182

continue_here:;

   183

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

   184

   185

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

   186

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

   187

		}

   188

   189

		tpf->rd = rd;

   190

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

   191

   192

}

   193

   194

   195

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

   196

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

   197

 */

   198

FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, DiagDirection dir)

   199

{

   200

	TileIndexDiff delta = TileOffsByDir(dir);

   201

	uint z = GetTileZ(tile);

   202

	FindLengthOfTunnelResult flotr;

   203

   204

	flotr.length = 0;

   205

   206

	dir = ReverseDiagDir(dir);

   207

	do {

   208

		flotr.length++;

   209

		tile += delta;

   210

	} while(

   211

		!IsTunnelTile(tile) ||

   212

		GetTunnelDirection(tile) != dir ||

   213

		GetTileZ(tile) != z

   214

	);

   215

   216

	flotr.tile = tile;

   217

	return flotr;

   218

}

   219

   220

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

   221

   222

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

   223

{

   224

	FindLengthOfTunnelResult flotr;

   225

	TPFSetTileBit(tpf, tile, 14);

   226

	flotr = FindLengthOfTunnel(tile, direction);

   227

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

   228

	TPFSetTileBit(tpf, flotr.tile, 14);

   229

	return flotr.tile;

   230

}

   231

   232

const byte _ffb_64[128] = {

   233

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

   234

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

   235

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

   236

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

   237

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

   238

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

   239

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

   240

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

   241

   242

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

   243

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

   244

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

   245

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

   246

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

   247

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

   248

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

   249

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

   250

};

   251

   252

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

   253

{

   254

	uint bits;

   255

	int i;

   256

	RememberData rd;

   257

	TileIndex tile_org = tile;

   258

   279

		}

   280

	}

   281

	tile += TileOffsByDir(direction);

   282

   283

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

   284

	if (tpf->tracktype == TRANSPORT_RAIL) {

   285

		// don't enter train depot from the back

   286

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

   287

   288

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

   289

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

   291

	}

   292

   293

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

   294

	if (tpf->tracktype == TRANSPORT_ROAD) {

   295

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

   296

		// don't enter road stop from the back

   297

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

   298

		// don't enter road depot from the back

   299

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

   300

	}

   301

   302

	tpf->rd.cur_length++;

   303

   304

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

   305

   306

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

   307

		bits &= _tpfmode1_and[direction];

   308

		bits = bits | (bits>>8);

   309

	}

   310

	bits &= 0xBF;

   311

   312

	if (bits != 0) {

   313

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

   314

			do {

   315

				i = FIND_FIRST_BIT(bits);

   316

				bits = KILL_FIRST_BIT(bits);

   317

   318

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

   319

				rd = tpf->rd;

   320

   321

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

   322

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

   323

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

   324

				}

   325

				tpf->rd = rd;

   326

			} while (bits != 0);

   327

		}

   328

	}

   329

   330

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

   331

	 * seems to go in 2 directions simultaneously */

   332

   333

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

   334

	 * stack space dramatically. */

   335

   336

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

   337

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

   338

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

   339

	if (tpf->hasbit_13)

   340

		return;

   341

   342

	tile = tile_org;

   343

	direction = ReverseDiagDir(direction);

   344

   345

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

   346

	bits |= (bits >> 8);

   347

   348

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

   349

		bits &= _bits_mask[direction];

   350

	}

   351

   352

	bits &= 0xBF;

   353

	if (bits == 0)

   354

		return;

   355

   356

	do {

   357

		i = FIND_FIRST_BIT(bits);

   358

		bits = KILL_FIRST_BIT(bits);

   359

   360

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

   361

		rd = tpf->rd;

   362

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

   363

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

   364

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

   365

		}

   366

		tpf->rd = rd;

   367

	} while (bits != 0);

   368

}

   369

   370

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

   371

{

   372

	TrackPathFinder tpf;

   373

   374

	assert(direction < 4);

   375

   376

	/* initialize path finder variables */

   377

	tpf.userdata = data;

   378

	tpf.enum_proc = enum_proc;

   379

	tpf.new_link = tpf.links;

   380

	tpf.num_links_left = lengthof(tpf.links);

   381

   382

	tpf.rd.cur_length = 0;

   383

	tpf.rd.depth = 0;

   384

	tpf.rd.pft_var6 = 0;

   385

   386

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

   387

   388

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

   389

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

   390

   391

   392

	tpf.tracktype = (byte)flags;

   393

   394

	if (HASBIT(flags, 11)) {

   395

		tpf.rd.pft_var6 = 0xFF;

   396

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

   397

		TPFMode2(&tpf, tile, direction);

   398

	} else {

   399

		/* clear the hash_heads */

   400

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

   401

		TPFMode1(&tpf, tile, direction);

   402

	}

   403

   404

	if (after_proc != NULL)

   405

		after_proc(&tpf);

   406

}

   407

   408

typedef struct {

   409

	TileIndex tile;

   410

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

   411

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

   412

	byte track;

   413

	byte depth;

   414

	byte state;

   415

	byte first_track;

   416

} StackedItem;

   417

   418

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

   419

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

   420

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

   421

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

   422

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

   423

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

   424

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

   425

};

   426

   427

typedef struct HashLink {

   428

	TileIndex tile;

   429

	uint16 typelength;

   430

	uint16 next;

   431

} HashLink;

   432

   433

typedef struct {

   434

	NTPEnumProc *enum_proc;

   435

	void *userdata;

   436

	TileIndex dest;

   437

   438

	TransportType tracktype;

   439

	RailTypeMask railtypes;

   440

	uint maxlength;

   441

   442

	HashLink *new_link;

   443

	uint num_links_left;

   444

   445

	uint nstack;

   446

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

   447

   448

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

   449

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

   450

   451

	HashLink links[0x400]; // hash links

   452

   453

} NewTrackPathFinder;

   454

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

   455

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

   456

   457

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

   458

   459

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

   460

// move it down to the proper position

   461

static inline void HeapifyUp(NewTrackPathFinder *tpf)

   462

{

   463

	StackedItem si;

   464

	int i = ++tpf->nstack;

   465

   466

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

   467

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

   468

		// swap the child item and the parent item.

   469

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

   470

		i>>=1;

   471

	}

   472

}

   473

   474

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

   475

static inline void HeapifyDown(NewTrackPathFinder *tpf)

   476

{

   477

	StackedItem si;

   478

	int i = 1, j;

   479

	int n;

   480

   481

	assert(tpf->nstack > 0);

   482

	n = --tpf->nstack;

   483

   484

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

   485

   486

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

   487

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

   488

   489

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

   490

		// figure out which is smaller of the children.

   491

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

   492

			j++; // right item is smaller

   493

   494

		assert(i <= n && j <= n);

   495

		if (ARR(i).priority <= ARR(j).priority)

   496

			break; // base elem smaller than smallest, done!

   497

   498

		// swap parent with the child

   499

		si = ARR(i); ARR(i) = ARR(j); ARR(j) = si;

   500

		i = j;

   501

	}

   502

}

   503

   504

// mark a tile as visited and store the length of the path.

   505

// if we already had a better path to this tile, return false.

   506

// otherwise return true.

   507

static bool NtpVisit(NewTrackPathFinder* tpf, TileIndex tile, DiagDirection dir, uint length)

   508

{

   509