1

/* $Id$ */

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#include "../../stdafx.h"

     4

#include "../../openttd.h"

     5

#include "../../bridge_map.h"

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#include "../../debug.h"

     7

#include "../../functions.h"

     8

#include "../../map.h"

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#include "../../tile.h"

    10

#include "../../command.h"

    11

#include "trolly.h"

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#include "../../depot.h"

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#include "../../tunnel_map.h"

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#include "../../bridge.h"

    15

#include "../ai.h"

    16

    17

#define TEST_STATION_NO_DIR 0xFF

    18

    19

// Tests if a station can be build on the given spot

    20

// TODO: make it train compatible

    21

static bool TestCanBuildStationHere(TileIndex tile, byte dir)

    22

{

    23

	Player *p = GetPlayer(_current_player);

    24

    25

	if (dir == TEST_STATION_NO_DIR) {

    26

		int32 ret;

    27

		// TODO: currently we only allow spots that can be access from al 4 directions...

    28

		//  should be fixed!!!

    29

		for (dir = 0; dir < 4; dir++) {

    30

			ret = AiNew_Build_Station(p, p->ainew.tbt, tile, 1, 1, dir, DC_QUERY_COST);

    31

			if (!CmdFailed(ret)) return true;

    32

		}

    33

		return false;

    34

	}

    35

    36

	// return true if command succeeded, so the inverse of CmdFailed()

    37

	return !CmdFailed(AiNew_Build_Station(p, p->ainew.tbt, tile, 1, 1, dir, DC_QUERY_COST));

    38

}

    39

    40

    41

static bool IsRoad(TileIndex tile)

    42

{

    43

	return

    44

		// MP_STREET, but not a road depot?

    45

		(IsTileType(tile, MP_STREET) && !IsTileDepotType(tile, TRANSPORT_ROAD)) ||

    46

		(IsTileType(tile, MP_TUNNELBRIDGE) && (

    47

			(IsTunnel(tile) && GetTunnelTransportType(tile) == TRANSPORT_ROAD) ||

    48

			(IsBridge(tile) && GetBridgeTransportType(tile) == TRANSPORT_ROAD)

    49

		));

    50

}

    51

    52

    53

// Checks if a tile 'a' is between the tiles 'b' and 'c'

    54

#define TILES_BETWEEN(a, b, c) (TileX(a) >= TileX(b) && TileX(a) <= TileX(c) && TileY(a) >= TileY(b) && TileY(a) <= TileY(c))

    55

    56

    57

// Check if the current tile is in our end-area

    58

static int32 AyStar_AiPathFinder_EndNodeCheck(AyStar *aystar, OpenListNode *current)

    59

{

    60

	const Ai_PathFinderInfo* PathFinderInfo = aystar->user_target;

    61

    62

	// It is not allowed to have a station on the end of a bridge or tunnel ;)

    63

	if (current->path.node.user_data[0] != 0) return AYSTAR_DONE;

    64

	if (TILES_BETWEEN(current->path.node.tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br))

    65

		if (IsTileType(current->path.node.tile, MP_CLEAR) || IsTileType(current->path.node.tile, MP_TREES))

    66

			if (current->path.parent == NULL || TestCanBuildStationHere(current->path.node.tile, AiNew_GetDirection(current->path.parent->node.tile, current->path.node.tile)))

    67

				return AYSTAR_FOUND_END_NODE;

    68

    69

	return AYSTAR_DONE;

    70

}

    71

    72

    73

// Calculates the hash

    74

//   Currently it is a 10 bit hash, so the hash array has a max depth of 6 bits (so 64)

    75

static uint AiPathFinder_Hash(uint key1, uint key2)

    76

{

    77

	return (TileX(key1) & 0x1F) + ((TileY(key1) & 0x1F) << 5);

    78

}

    79

    80

    81

// Clear the memory of all the things

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static void AyStar_AiPathFinder_Free(AyStar *aystar)

    83

{

    84

	AyStarMain_Free(aystar);

    85

	free(aystar);

    86

}

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    88

    89

static int32 AyStar_AiPathFinder_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent);

    90

static int32 AyStar_AiPathFinder_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent);

    91

static void AyStar_AiPathFinder_FoundEndNode(AyStar *aystar, OpenListNode *current);

    92

static void AyStar_AiPathFinder_GetNeighbours(AyStar *aystar, OpenListNode *current);

    93

    94

    95

// This creates the AiPathFinder

    96

AyStar *new_AyStar_AiPathFinder(int max_tiles_around, Ai_PathFinderInfo *PathFinderInfo)

    97

{

    98

	PathNode start_node;

    99

	uint x;

   100

	uint y;

   101

	// Create AyStar

   102

	AyStar *result = malloc(sizeof(AyStar));

   103

	init_AyStar(result, AiPathFinder_Hash, 1 << 10);

   104

	// Set the function pointers

   105

	result->CalculateG = AyStar_AiPathFinder_CalculateG;

   106

	result->CalculateH = AyStar_AiPathFinder_CalculateH;

   107

	result->EndNodeCheck = AyStar_AiPathFinder_EndNodeCheck;

   108

	result->FoundEndNode = AyStar_AiPathFinder_FoundEndNode;

   109

	result->GetNeighbours = AyStar_AiPathFinder_GetNeighbours;

   110

   111

	result->free = AyStar_AiPathFinder_Free;

   112

   113

	// Set some information

   114

	result->loops_per_tick = AI_PATHFINDER_LOOPS_PER_TICK;

   115

	result->max_path_cost = 0;

   116

	result->max_search_nodes = AI_PATHFINDER_MAX_SEARCH_NODES;

   117

   118

	// Set the user_data to the PathFinderInfo

   119

	result->user_target = PathFinderInfo;

   120

   121

	// Set the start node

   122

	start_node.parent = NULL;

   123

	start_node.node.direction = 0;

   124

	start_node.node.user_data[0] = 0;

   125

   126

	// Now we add all the starting tiles

   127

	for (x = TileX(PathFinderInfo->start_tile_tl); x <= TileX(PathFinderInfo->start_tile_br); x++) {

   128

		for (y = TileY(PathFinderInfo->start_tile_tl); y <= TileY(PathFinderInfo->start_tile_br); y++) {

   129

			start_node.node.tile = TileXY(x, y);

   130

			result->addstart(result, &start_node.node, 0);

   131

		}

   132

	}

   133

   134

	return result;

   135

}

   136

   137

   138

// To reuse AyStar we sometimes have to clean all the memory

   139

void clean_AyStar_AiPathFinder(AyStar *aystar, Ai_PathFinderInfo *PathFinderInfo)

   140

{

   141

	PathNode start_node;

   142

	uint x;

   143

	uint y;

   144

   145

	aystar->clear(aystar);

   146

   147

	// Set the user_data to the PathFinderInfo

   148

	aystar->user_target = PathFinderInfo;

   149

   150

	// Set the start node

   151

	start_node.parent = NULL;

   152

	start_node.node.direction = 0;

   153

	start_node.node.user_data[0] = 0;

   154

	start_node.node.tile = PathFinderInfo->start_tile_tl;

   155

   156

	// Now we add all the starting tiles

   157

	for (x = TileX(PathFinderInfo->start_tile_tl); x <= TileX(PathFinderInfo->start_tile_br); x++) {

   158

		for (y = TileY(PathFinderInfo->start_tile_tl); y <= TileY(PathFinderInfo->start_tile_br); y++) {

   159

			TileIndex tile = TileXY(x, y);

   160

   161

			if (!IsTileType(tile, MP_CLEAR) && !IsTileType(tile, MP_TREES)) continue;

   162

			if (!TestCanBuildStationHere(tile, TEST_STATION_NO_DIR)) continue;

   163

			start_node.node.tile = tile;

   164

			aystar->addstart(aystar, &start_node.node, 0);

   165

		}

   166

	}

   167

}

   168

   169

   170

// The h-value, simple calculation

   171

static int32 AyStar_AiPathFinder_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent)

   172

{

   173

	const Ai_PathFinderInfo* PathFinderInfo = aystar->user_target;

   174

	int r, r2;

   175

   176

	if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION) {

   177

		// The station is pointing to a direction, add a tile towards that direction, so the H-value is more accurate

   178

		r = DistanceManhattan(current->tile, PathFinderInfo->end_tile_tl + TileOffsByDiagDir(PathFinderInfo->end_direction));

   179

		r2 = DistanceManhattan(current->tile, PathFinderInfo->end_tile_br + TileOffsByDiagDir(PathFinderInfo->end_direction));

   180

	} else {

   181

		// No direction, so just get the fastest route to the station

   182

		r = DistanceManhattan(current->tile, PathFinderInfo->end_tile_tl);

   183

		r2 = DistanceManhattan(current->tile, PathFinderInfo->end_tile_br);

   184

	}

   185

	// See if the bottomright is faster than the topleft..

   186

	if (r2 < r) r = r2;

   187

	return r * AI_PATHFINDER_H_MULTIPLER;

   188

}

   189

   190

   191

// We found the end.. let's get the route back and put it in an array

   192

static void AyStar_AiPathFinder_FoundEndNode(AyStar *aystar, OpenListNode *current)

   193

{

   194

	Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;

   195

	uint i = 0;

   196

	PathNode *parent = &current->path;

   197

   198

	do {

   199

		PathFinderInfo->route_extra[i] = parent->node.user_data[0];

   200

		PathFinderInfo->route[i++] = parent->node.tile;

   201

		if (i > lengthof(PathFinderInfo->route)) {

   202

			// We ran out of space for the PathFinder

   204

			PathFinderInfo->route_length = -1; // -1 indicates out of space

   205

			return;

   206

		}

   207

		parent = parent->parent;

   208

	} while (parent != NULL);

   209

	PathFinderInfo->route_length = i;

   211

}

   212

   213

   214

// What tiles are around us.

   215

static void AyStar_AiPathFinder_GetNeighbours(AyStar *aystar, OpenListNode *current)

   216

{

   217

	uint i;

   218

	int ret;

   219

	int dir;

   220

   221

	Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;

   222

   223

	aystar->num_neighbours = 0;

   224

   225

	// Go through all surrounding tiles and check if they are within the limits

   226

	for (i = 0; i < 4; i++) {

   227

		TileIndex ctile = current->path.node.tile; // Current tile

   228

		TileIndex atile = ctile + TileOffsByDiagDir(i); // Adjacent tile

   229

   230

		if (TileX(atile) > 1 && TileX(atile) < MapMaxX() - 1 &&

   231

				TileY(atile) > 1 && TileY(atile) < MapMaxY() - 1) {

   232

			// We also directly test if the current tile can connect to this tile..

   233

			//  We do this simply by just building the tile!

   234

   235

			// If the next step is a bridge, we have to enter it the right way

   236

			if (!PathFinderInfo->rail_or_road && IsRoad(atile)) {

   237

				if (IsTileType(atile, MP_TUNNELBRIDGE)) {

   238

					if (IsTunnel(atile)) {

   239

						if (GetTunnelDirection(atile) != i) continue;

   240

					} else {

   241

						if ((_m[atile].m5 & 1U) != DiagDirToAxis(i)) continue;

   242

					}

   243

				}

   244

			}

   245

			// But also if we are on a bridge, we can only move a certain direction

   246

			if (!PathFinderInfo->rail_or_road && IsRoad(ctile)) {

   247

				if (IsTileType(ctile, MP_TUNNELBRIDGE)) {

   248

					// An existing bridge/tunnel... let's test the direction ;)

   249

					if ((_m[ctile].m5 & 1U) != (i & 1)) continue;

   250

				}

   251

			}

   252

   253

			if ((AI_PATHFINDER_FLAG_BRIDGE & current->path.node.user_data[0]) != 0 ||

   254

					(AI_PATHFINDER_FLAG_TUNNEL & current->path.node.user_data[0]) != 0) {

   255

				// We are a bridge/tunnel, how cool!!

   256

				//  This means we can only point forward.. get the direction from the user_data

   257

				if (i != (current->path.node.user_data[0] >> 8)) continue;

   258

			}

   259

			dir = 0;

   260

   261

			// First, check if we have a parent

   262

			if (current->path.parent == NULL && current->path.node.user_data[0] == 0) {

   263

				// If not, this means we are at the starting station

   264

				if (PathFinderInfo->start_direction != AI_PATHFINDER_NO_DIRECTION) {

   265

					// We do need a direction?

   266

					if (AiNew_GetDirection(ctile, atile) != PathFinderInfo->start_direction) {

   267

						// We are not pointing the right way, invalid tile

   268

						continue;

   269

					}

   270

				}

   271

			} else if (current->path.node.user_data[0] == 0) {

   272

				if (PathFinderInfo->rail_or_road) {

   273

					// Rail check

   274

					dir = AiNew_GetRailDirection(current->path.parent->node.tile, ctile, atile);

   275

					ret = AI_DoCommand(ctile, 0, dir, DC_AUTO | DC_NO_WATER, CMD_BUILD_SINGLE_RAIL);

   276

					if (CmdFailed(ret)) continue;

   277

#ifdef AI_PATHFINDER_NO_90DEGREES_TURN

   278

					if (current->path.parent->parent != NULL) {

   279

						// Check if we don't make a 90degree curve

   280

						int dir1 = AiNew_GetRailDirection(current->path.parent->parent->node.tile, current->path.parent->node.tile, ctile);

   281

						if (_illegal_curves[dir1] == dir || _illegal_curves[dir] == dir1) {

   282

							continue;

   283

						}

   284

					}

   285

#endif

   286

				} else {

   287

					// Road check

   288

					dir = AiNew_GetRoadDirection(current->path.parent->node.tile, ctile, atile);

   289

					if (IsRoad(ctile)) {

   290

						if (IsTileType(ctile, MP_TUNNELBRIDGE)) {

   291

							// We have a bridge, how nicely! We should mark it...

   292

							dir = 0;

   293

						} else {

   294

							// It already has road.. check if we miss any bits!

   295

							if ((_m[ctile].m5 & dir) != dir) {

   296

								// We do miss some pieces :(

   297

								dir &= ~_m[ctile].m5;

   298

							} else {

   299

								dir = 0;

   300

							}

   301

						}

   302

					}

   303

					// Only destruct things if it is MP_CLEAR of MP_TREES

   304

					if (dir != 0) {

   305

						ret = AI_DoCommand(ctile, dir, 0, DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD);

   306

						if (CmdFailed(ret)) continue;

   307

					}

   308

				}

   309

			}

   310

   311

			// The tile can be connected

   312

			aystar->neighbours[aystar->num_neighbours].tile = atile;

   313

			aystar->neighbours[aystar->num_neighbours].user_data[0] = 0;

   314

			aystar->neighbours[aystar->num_neighbours++].direction = 0;

   315

		}

   316

	}

   317

   318

	// Next step, check for bridges and tunnels

   319

	if (current->path.parent != NULL && current->path.node.user_data[0] == 0) {

   320

		// First we get the dir from this tile and his parent

   321

		DiagDirection dir = AiNew_GetDirection(current->path.parent->node.tile, current->path.node.tile);

   322

		// It means we can only walk with the track, so the bridge has to be in the same direction

   323

		TileIndex tile = current->path.node.tile;

   324

		TileIndex new_tile = tile;

   325

		Slope tileh = GetTileSlope(tile, NULL);

   326

   327

		// Bridges can only be build on land that is not flat

   328

		//  And if there is a road or rail blocking

   329

		if (tileh != SLOPE_FLAT ||

   330

				(PathFinderInfo->rail_or_road && IsTileType(tile + TileOffsByDiagDir(dir), MP_STREET)) ||

   331

				(!PathFinderInfo->rail_or_road && IsTileType(tile + TileOffsByDiagDir(dir), MP_RAILWAY))) {

   332

			for (;;) {

   333

				new_tile += TileOffsByDiagDir(dir);

   334

   335

				// Precheck, is the length allowed?

   336

				if (!CheckBridge_Stuff(0, GetBridgeLength(tile, new_tile))) break;

   337

   338

				// Check if we hit the station-tile.. we don't like that!

   339

				if (TILES_BETWEEN(new_tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br)) break;

   340

   341

				// Try building the bridge..

   342

				ret = AI_DoCommand(tile, new_tile, (0 << 8) + (MAX_BRIDGES / 2), DC_AUTO, CMD_BUILD_BRIDGE);

   343

				if (CmdFailed(ret)) continue;

   344

				// We can build a bridge here.. add him to the neighbours

   345

				aystar->neighbours[aystar->num_neighbours].tile = new_tile;

   346

				aystar->neighbours[aystar->num_neighbours].user_data[0] = AI_PATHFINDER_FLAG_BRIDGE + (dir << 8);

   347

				aystar->neighbours[aystar->num_neighbours++].direction = 0;

   348

				// We can only have 12 neighbours, and we need 1 left for tunnels

   349

				if (aystar->num_neighbours == 11) break;

   350

			}

   351

		}

   352

   353

		// Next, check for tunnels!

   354

		// Tunnels can only be built on slopes corresponding to the direction

   355

		//  For now, we check both sides for this tile.. terraforming gives fuzzy result

   356

		if ((dir == DIAGDIR_NE && tileh == SLOPE_NE) ||

   357

				(dir == DIAGDIR_SE && tileh == SLOPE_SE) ||

   358

				(dir == DIAGDIR_SW && tileh == SLOPE_SW) ||

   359

				(dir == DIAGDIR_NW && tileh == SLOPE_NW)) {

   360

			// Now simply check if a tunnel can be build

   361

			ret = AI_DoCommand(tile, (PathFinderInfo->rail_or_road?0:0x200), 0, DC_AUTO, CMD_BUILD_TUNNEL);

   362

			tileh = GetTileSlope(_build_tunnel_endtile, NULL);

   363

			if (!CmdFailed(ret) && (tileh == SLOPE_SW || tileh == SLOPE_SE || tileh == SLOPE_NW || tileh == SLOPE_NE)) {

   364

				aystar->neighbours[aystar->num_neighbours].tile = _build_tunnel_endtile;

   365

				aystar->neighbours[aystar->num_neighbours].user_data[0] = AI_PATHFINDER_FLAG_TUNNEL + (dir << 8);

   366

				aystar->neighbours[aystar->num_neighbours++].direction = 0;

   367

			}

   368

		}

   369

	}

   370

}

   371

   372

   373

extern uint GetRailFoundation(Slope tileh, TrackBits bits); // XXX function declaration in .c

   374

extern uint GetRoadFoundation(Slope tileh, uint bits); // XXX function declaration in .c

   375

extern uint GetBridgeFoundation(Slope tileh, Axis); // XXX function declaration in .c

   376

enum {

   377

	BRIDGE_NO_FOUNDATION = 1 << 0 | 1 << 3 | 1 << 6 | 1 << 9 | 1 << 12,

   378

};

   379

   380

// The most important function: it calculates the g-value

   381

static int32 AyStar_AiPathFinder_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent)

   382

{

   383

	Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;

   384

	int r, res = 0;

   385

	Slope tileh = GetTileSlope(current->tile, NULL);

   386

	Slope parent_tileh = GetTileSlope(parent->path.node.tile, NULL);

   387

   388

	// Check if we hit the end-tile

   389

	if (TILES_BETWEEN(current->tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br)) {

   390

		// We are at the end-tile, check if we had a direction or something...

   391

		if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION && AiNew_GetDirection(current->tile, parent->path.node.tile) != PathFinderInfo->end_direction) {

   392

			// We are not pointing the right way, invalid tile

   393

			return AYSTAR_INVALID_NODE;

   394

		}

   395

		// If it was valid, drop out.. we don't build on the endtile

   396

		return 0;

   397

	}

   398

   399

	// Give everything a small penalty

   400

	res += AI_PATHFINDER_PENALTY;

   401

   402

	if (!PathFinderInfo->rail_or_road) {

   403

		// Road has the lovely advantage it can use other road... check if

   404

		//  the current tile is road, and if so, give a good bonus

   405

		if (IsRoad(current->tile)) {

   406

			res -= AI_PATHFINDER_ROAD_ALREADY_EXISTS_BONUS;

   407

		}

   408

	}

   409

   410

	// We should give a penalty when the tile is going up or down.. this is one way to do so!

   411

	//  Too bad we have to count it from the parent.. but that is not so bad.

   412

	// We also dislike long routes on slopes, since they do not look too realistic

   413

	//  when there is a flat land all around, they are more expensive to build, and

   414

	//  especially they essentially block the ability to connect or cross the road

   415

	//  from one side.

   416

	if (parent_tileh != SLOPE_FLAT && parent->path.parent != NULL) {

   417

		// Skip if the tile was from a bridge or tunnel

   418

		if (parent->path.node.user_data[0] == 0 && current->user_data[0] == 0) {

   419

			if (PathFinderInfo->rail_or_road) {

   420

				r = GetRailFoundation(parent_tileh, 1 << AiNew_GetRailDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile));

   421

				// Maybe is BRIDGE_NO_FOUNDATION a bit strange here, but it contains just the right information..

   422

				if (r >= 15 || (r == 0 && HASBIT(BRIDGE_NO_FOUNDATION, tileh))) {

   423

					res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;

   424

				} else {

   425

					res += AI_PATHFINDER_FOUNDATION_PENALTY;

   426

				}

   427

			} else {

   428

				if (!IsRoad(parent->path.node.tile) || !IsTileType(parent->path.node.tile, MP_TUNNELBRIDGE)) {

   429

					r = GetRoadFoundation(parent_tileh, AiNew_GetRoadDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile));

   430

					if (r >= 15 || r == 0) {

   431

						res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;

   432

					} else {

   433

						res += AI_PATHFINDER_FOUNDATION_PENALTY;

   434

					}

   435

				}

   436

			}

   437

		}

   438

	}

   439

   440

	// Are we part of a tunnel?

   441

	if ((AI_PATHFINDER_FLAG_TUNNEL & current->user_data[0]) != 0) {

   442

		// Tunnels are very expensive when build on long routes..

   443

		// Ironicly, we are using BridgeCode here ;)

   444

		r = AI_PATHFINDER_TUNNEL_PENALTY * GetBridgeLength(current->tile, parent->path.node.tile);

   445

		res += r + (r >> 8);

   446

	}

   447

   448

	// Are we part of a bridge?

   449

	if ((AI_PATHFINDER_FLAG_BRIDGE & current->user_data[0]) != 0) {

   450

		// That means for every length a penalty

   451

		res += AI_PATHFINDER_BRIDGE_PENALTY * GetBridgeLength(current->tile, parent->path.node.tile);

   452

		// Check if we are going up or down, first for the starting point

   453

		// In user_data[0] is at the 8th bit the direction

   454

		if (!HASBIT(BRIDGE_NO_FOUNDATION, parent_tileh)) {

   455

			if (GetBridgeFoundation(parent_tileh, (current->user_data[0] >> 8) & 1) < 15) {

   456

				res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   457

			}

   458

		}

   459

		// Second for the end point

   460

		if (!HASBIT(BRIDGE_NO_FOUNDATION, tileh)) {

   461

			if (GetBridgeFoundation(tileh, (current->user_data[0] >> 8) & 1) < 15) {

   462

				res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   463

			}

   464

		}

   465

		if (parent_tileh == SLOPE_FLAT) res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   466

		if (tileh == SLOPE_FLAT) res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   467

	}

   468

   469

	//  To prevent the AI from taking the fastest way in tiles, but not the fastest way

   470

	//    in speed, we have to give a good penalty to direction changing

   471

	//  This way, we get almost the fastest way in tiles, and a very good speed on the track

   472

	if (!PathFinderInfo->rail_or_road) {

   473

		if (parent->path.parent != NULL &&

   474

				AiNew_GetDirection(current->tile, parent->path.node.tile) != AiNew_GetDirection(parent->path.node.tile, parent->path.parent->node.tile)) {

   475

			// When road exists, we don't like turning, but its free, so don't be to piggy about it

   476

			if (IsRoad(parent->path.node.tile)) {

   477

				res += AI_PATHFINDER_DIRECTION_CHANGE_ON_EXISTING_ROAD_PENALTY;

   478

			} else {

   479

				res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;

   480

			}

   481

		}

   482

	} else {

   483

		// For rail we have 1 exeption: diagonal rail..

   484

		// So we fetch 2 raildirection. That of the current one, and of the one before that

   485

		if (parent->path.parent != NULL && parent->path.parent->parent != NULL) {

   486

			int dir1 = AiNew_GetRailDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile);

   487

			int dir2 = AiNew_GetRailDirection(parent->path.parent->parent->node.tile, parent->path.parent->node.tile, parent->path.node.tile);

   488

			// First, see if we are on diagonal path, that is better than straight path

   489

			if (dir1 > 1) res -= AI_PATHFINDER_DIAGONAL_BONUS;

   490

   491

			// First see if they are different

   492

			if (dir1 != dir2) {

   493

				// dir 2 and 3 are 1 diagonal track, and 4 and 5.

   494

				if (!(((dir1 == 2 || dir1 == 3) && (dir2 == 2 || dir2 == 3)) || ((dir1 == 4 || dir1 == 5) && (dir2 == 4 || dir2 == 5)))) {

   495

					// It is not, so we changed of direction

   496

					res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;

   497

				}

   498

				if (parent->path.parent->parent->parent != NULL) {

   499

					int dir3 = AiNew_GetRailDirection(parent->path.parent->parent->parent->node.tile, parent->path.parent->parent->node.tile, parent->path.parent->node.tile);

   500

					// Check if we changed 3 tiles of direction in 3 tiles.. bad!!!

   501

					if ((dir1 == 0 || dir1 == 1) && dir2 > 1 && (dir3 == 0 || dir3 == 1)) {

   502

						res += AI_PATHFINDER_CURVE_PENALTY;

   503

					}

   504

				}

   505

			}

   506

		}

   507

	}

   508

   509

	return (res < 0) ? 0 : res;

   510

}