1

#include "stdafx.h"

     2

#include "ttd.h"

     3

#include "map.h"

     4

#include "command.h"

     5

#include "ai.h"

     6

     7

#define TEST_STATION_NO_DIR 0xFF

     8

     9

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

    10

// TODO: make it train compatible

    11

bool TestCanBuildStationHere(uint tile, byte dir) {

    12

    Player *p = DEREF_PLAYER(_current_player);

    13

    if (dir == TEST_STATION_NO_DIR) {

    14

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

    15

        //  should be fixed!!!

    16

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

    17

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

    18

            if (res != CMD_ERROR)

    19

            	return true;

    20

        }

    21

        return false;

    22

    } else {

    23

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

    24

        if (res == CMD_ERROR)

    25

        	return false;

    26

    }

    27

    return true;

    28

}

    29

    30

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

    31

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

    32

    33

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

    34

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

    35

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

    36

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

    37

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

    38

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

    39

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

    40

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

    41

    			return AYSTAR_FOUND_END_NODE;

    42

    43

	return AYSTAR_DONE;

    44

}

    45

    46

// Calculates the hash

    47

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

    48

uint AiPathFinder_Hash(uint key1, uint key2) {

    49

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

    50

}

    51

    52

// Clear the memory of all the things

    53

void AyStar_AiPathFinder_Free(AyStar *aystar) {

    54

	AyStarMain_Free(aystar);

    55

	free(aystar);

    56

}

    57

    58

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

    59

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

    60

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

    61

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

    62

    63

// This creates the AiPathFinder

    64

AyStar *new_AyStar_AiPathFinder(int max_tiles_around, Ai_PathFinderInfo *PathFinderInfo) {

    65

	PathNode start_node;

    66

	uint x,y;

    67

	// Create AyStar

    68

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

    69

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

    70

	// Set the function pointers

    71

	result->CalculateG = AyStar_AiPathFinder_CalculateG;

    72

	result->CalculateH = AyStar_AiPathFinder_CalculateH;

    73

	result->EndNodeCheck = AyStar_AiPathFinder_EndNodeCheck;

    74

	result->FoundEndNode = AyStar_AiPathFinder_FoundEndNode;

    75

	result->GetNeighbours = AyStar_AiPathFinder_GetNeighbours;

    76

    77

	result->free = AyStar_AiPathFinder_Free;

    78

    79

	// Set some information

    80

	result->loops_per_tick = AI_PATHFINDER_LOOPS_PER_TICK;

    81

	result->max_path_cost = 0;

    82

	result->max_search_nodes = AI_PATHFINDER_MAX_SEARCH_NODES;

    83

    84

	// Set the user_data to the PathFinderInfo

    85

	result->user_target = PathFinderInfo;

    86

    87

	// Set the start node

    88

	start_node.parent = NULL;

    89

	start_node.node.direction = 0;

    90

	start_node.node.user_data[0] = 0;

    91

    92

	// Now we add all the starting tiles

    93

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

    94

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

    95

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

    96

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

    97

		}

    98

	}

    99

   100

	return result;

   101

}

   102

   103

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

   104

void clean_AyStar_AiPathFinder(AyStar *aystar, Ai_PathFinderInfo *PathFinderInfo) {

   105

	PathNode start_node;

   106

	uint x,y;

   107

   108

	aystar->clear(aystar);

   109

   110

	// Set the user_data to the PathFinderInfo

   111

	aystar->user_target = PathFinderInfo;

   112

   113

	// Set the start node

   114

	start_node.parent = NULL;

   115

	start_node.node.direction = 0;

   116

	start_node.node.user_data[0] = 0;

   117

	start_node.node.tile = PathFinderInfo->start_tile_tl;

   118

   119

	// Now we add all the starting tiles

   120

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

   121

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

   122

			if (!(IS_TILETYPE(TILE_XY(x,y), MP_CLEAR) || IS_TILETYPE(TILE_XY(x,y), MP_TREES))) continue;

   123

			if (!TestCanBuildStationHere(TILE_XY(x,y),TEST_STATION_NO_DIR)) continue;

   124

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

   125

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

   126

		}

   127

	}

   128

}

   129

   130

// The h-value, simple calculation

   131

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

   132

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

   133

	int r, r2;

   134

	if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION) {

   135

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

   136

		r = GetTileDist(current->tile, PathFinderInfo->end_tile_tl + TileOffsByDir(PathFinderInfo->end_direction));

   137

		r2 = GetTileDist(current->tile, PathFinderInfo->end_tile_br + TileOffsByDir(PathFinderInfo->end_direction));

   138

	} else {

   139

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

   140

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

   141

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

   142

	}

   143

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

   144

	if (r2 < r) r = r2;

   145

	return r * AI_PATHFINDER_H_MULTIPLER;

   146

}

   147

   148

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

   149

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

   150

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

   151

	uint i = 0;

   152

	PathNode *parent = &current->path;

   153

   154

	do {

   155

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

   156

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

   157

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

   158

			// We ran out of space for the PathFinder

   159

			DEBUG(ai,0)("[AiPathFinder] Ran out of spacein the route[] array!!!");

   160

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

   161

			return;

   162

		}

   163

		parent = parent->parent;

   164

	} while (parent != NULL);

   165

	PathFinderInfo->route_length = i;

   166

	DEBUG(ai,1)("[Ai-PathFinding] Found route of %d nodes long in %d nodes of searching",i,Hash_Size(&aystar->ClosedListHash));

   167

}

   168

   169

// What tiles are around us.

   170

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

   171

		uint i;

   172

		int r;

   173

		int dir;

   174

   175

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

   176

   177

    aystar->num_neighbours = 0;

   178

   179

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

   180

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

   181

   		if (TileX(TileOffsByDir(i) + current->path.node.tile) > 1 &&

   182

					TileX(TileOffsByDir(i) + current->path.node.tile) < MapMaxX() - 1 &&

   183

       		TileY(TileOffsByDir(i) + current->path.node.tile) > 1 &&

   184

					TileY(TileOffsByDir(i) + current->path.node.tile) < MapMaxY() - 1) {

   185

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

   186

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

   187

   188

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

   189

       		if (!PathFinderInfo->rail_or_road && AI_PATHFINDER_IS_ROAD(current->path.node.tile + TileOffsByDir(i))) {

   190

       			if (IS_TILETYPE(current->path.node.tile + TileOffsByDir(i), MP_TUNNELBRIDGE)) {

   191

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

   192

       				if ((_map5[current->path.node.tile + TileOffsByDir(i)] & 1U) != (i & 1)) continue;

   193

   					// This problem only is valid for tunnels:

   194

       				// When the last tile was not yet a tunnel, check if we enter from the right side..

   195

       				if (!IS_TILETYPE(current->path.node.tile, MP_TUNNELBRIDGE) && (_map5[current->path.node.tile + TileOffsByDir(i)] & 0x80) == 0) {

   196

       					if (i != (_map5[current->path.node.tile + TileOffsByDir(i)] & 3U)) continue;

   197

       				}

   198

       			}

   199

       		}

   200

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

   201

       		if (!PathFinderInfo->rail_or_road && AI_PATHFINDER_IS_ROAD(current->path.node.tile)) {

   202

       			if (IS_TILETYPE(current->path.node.tile, MP_TUNNELBRIDGE)) {

   203

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

   204

       				if ((_map5[current->path.node.tile] & 1U) != (i & 1)) continue;

   205

       			}

   206

       		}

   207

   208

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

   209

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

   210

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

   211

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

   212

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

   213

       		}

   214

       		dir = 0;

   215

   216

       		// First, check if we have a parent

   217

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

   218

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

   219

       			if (PathFinderInfo->start_direction != AI_PATHFINDER_NO_DIRECTION) {

   220

		       		// We do need a direction?

   221

		       		if (AiNew_GetDirection(current->path.node.tile, current->path.node.tile + TileOffsByDir(i)) != PathFinderInfo->start_direction)

   222

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

   223

		       			continue;

   224

		       	}

   225

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

   226

       			if (PathFinderInfo->rail_or_road) {

   227

       				// Rail check

   228

       				dir = AiNew_GetRailDirection(current->path.parent->node.tile, current->path.node.tile, current->path.node.tile + TileOffsByDir(i));

   229

       				r = DoCommandByTile(current->path.node.tile, 0, dir, DC_AUTO | DC_NO_WATER, CMD_BUILD_SINGLE_RAIL);

   230

       				if (r == CMD_ERROR) continue;

   231

#ifdef AI_PATHFINDER_NO_90DEGREES_TURN

   232

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

   233

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

   234

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

   235

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

   236

       						continue;

   237

       					}

   238

       				}

   239

#endif

   240

       			} else {

   241

       				// Road check

   242

       				dir = AiNew_GetRoadDirection(current->path.parent->node.tile, current->path.node.tile, current->path.node.tile + TileOffsByDir(i));

   243

       				if (AI_PATHFINDER_IS_ROAD(current->path.node.tile)) {

   244

       					if (IS_TILETYPE(current->path.node.tile, MP_TUNNELBRIDGE)) {

   245

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

   246

       						dir = 0;

   247

       					} else {

   248

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

   249

	       					if ((_map5[current->path.node.tile] & dir) != dir) {

   250

	       						// We do miss some pieces :(

   251

	       						dir &= ~_map5[current->path.node.tile];

   252

	       					} else {

   253

	       						dir = 0;

   254

    	   					}

   255

    	   				}

   256

       				}

   257

       				// Only destruct things if it is MP_CLEAR of MP_TREES

   258

       				if (dir != 0) {

   259

       					r = DoCommandByTile(current->path.node.tile, dir, 0, DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD);

   260

       					if (r == CMD_ERROR) continue;

   261

       				}

   262

       			}

   263

   264

       		}

   265

   266

			// The tile can be connected

   267

   			aystar->neighbours[aystar->num_neighbours].tile = TileOffsByDir(i) + current->path.node.tile;

   268

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

   269

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

   270

       	}

   271

    }

   272

   273

    // Next step, check for bridges and tunnels

   274

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

   275

   276

        TileInfo ti;

   277

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

   278

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

   279

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

   280

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

   281

    	TileIndex new_tile = tile;

   282

   283

    	FindLandscapeHeightByTile(&ti, tile);

   284

   285

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

   286

   		//  And if there is a road or rail blocking

   287

   		if (ti.tileh != 0 ||

   288

     		(PathFinderInfo->rail_or_road && IS_TILETYPE(tile + TileOffsByDir(dir), MP_STREET)) ||

   289

       		(!PathFinderInfo->rail_or_road && IS_TILETYPE(tile + TileOffsByDir(dir), MP_RAILWAY))) {

   290

   291

    		for (;;) {

   292

    			new_tile += TileOffsByDir(dir);

   293

   294

    	    	// Precheck, is the length allowed?

   295

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

   296

   297

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

   298

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

   299

   300

    	    	// Try building the bridge..

   301

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

   302

	    	   	if (r == CMD_ERROR) continue;

   303

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

   304

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

   305

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

   306

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

   307

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

   308

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

   309

			}

   310

    	}

   311

   312

    	// Next, check for tunnels!

   313

    	// Tunnels can only be build with tileh of 3, 6, 9 or 12, depending on the direction

   314

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

   315

    	if ((dir == 0 && ti.tileh == 12) ||

   316

    		(dir == 1 && ti.tileh == 6) ||

   317

    		(dir == 2 && ti.tileh == 3) ||

   318

    		(dir == 3 && ti.tileh == 9)) {

   319

    		// Now simply check if a tunnel can be build

   320

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

   321

    		FindLandscapeHeightByTile(&ti, _build_tunnel_endtile);

   322

    		if (r != CMD_ERROR && (ti.tileh == 3 || ti.tileh == 6 || ti.tileh == 9 || ti.tileh == 12)) {

   323

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

   324

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

   325

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

   326

    		}

   327

    	}

   328

  	}

   329

}

   330

   331

extern uint GetRailFoundation(uint tileh, uint bits);

   332

extern uint GetRoadFoundation(uint tileh, uint bits);

   333

extern uint GetBridgeFoundation(uint tileh, byte direction);

   334

enum {

   335

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

   336

};

   337

   338

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

   339

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

   340

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

   341

	int r, res = 0;

   342

	TileInfo ti, parent_ti;

   343

   344

	// Gather some information about the tile..

   345

	FindLandscapeHeightByTile(&ti, current->tile);

   346

	FindLandscapeHeightByTile(&parent_ti, parent->path.node.tile);

   347

   348

	// Check if we hit the end-tile

   349

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

   350

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

   351

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

   352

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

   353

			return AYSTAR_INVALID_NODE;

   354

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

   355

		return 0;

   356

	}

   357

   358

	// Give everything a small penalty

   359

	res += AI_PATHFINDER_PENALTY;

   360

   361

	if (!PathFinderInfo->rail_or_road) {

   362

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

   363

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

   364

		if (AI_PATHFINDER_IS_ROAD(current->tile)) {

   365

			res -= AI_PATHFINDER_ROAD_ALREADY_EXISTS_BONUS;

   366

		}

   367

	}

   368

   369

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

   370

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

   371

	if (parent_ti.tileh != 0 && parent->path.parent != NULL) {

   372

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

   373

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

   374

			if (PathFinderInfo->rail_or_road) {

   375

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

   376

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

   377

				if (r >= 15 || (r == 0 && (BRIDGE_NO_FOUNDATION & (1 << ti.tileh)))) {

   378

					res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;

   379

				}

   380

			} else {

   381

				if (!(AI_PATHFINDER_IS_ROAD(parent->path.node.tile) && IS_TILETYPE(parent->path.node.tile, MP_TUNNELBRIDGE))) {

   382

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

   383

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

   384

						res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;

   385

				}

   386

			}

   387

		}

   388

	}

   389

   390

	// Are we part of a tunnel?

   391

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

   392

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

   393

		// Ironicly, we are using BridgeCode here ;)

   394

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

   395

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

   396

	}

   397

   398

	// Are we part of a bridge?

   399

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

   400

		// That means for every length a penalty

   401

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

   402

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

   403

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

   404

		if (!(BRIDGE_NO_FOUNDATION & (1 << parent_ti.tileh))) {

   405

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

   406

				res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   407

		}

   408

		// Second for the end point

   409

		if (!(BRIDGE_NO_FOUNDATION & (1 << ti.tileh))) {

   410

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

   411

				res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   412

		}

   413

		if (parent_ti.tileh == 0)

   414

			res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   415

		if (ti.tileh == 0)

   416

			res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;

   417

	}

   418

   419

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

   420

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

   421

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

   422

	if (!PathFinderInfo->rail_or_road) {

   423

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

   424

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

   425

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

   426

			if (AI_PATHFINDER_IS_ROAD(parent->path.node.tile))

   427

				res += AI_PATHFINDER_DIRECTION_CHANGE_ON_EXISTING_ROAD_PENALTY;

   428

			else

   429

				res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;

   430

		}

   431

	} else {

   432

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

   433

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

   434

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

   435

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

   436

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

   437

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

   438

			if (dir1 > 1) { res -= AI_PATHFINDER_DIAGONAL_BONUS; }

   439

   440

			// First see if they are different

   441

			if (dir1 != dir2) {

   442

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

   443

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

   444

					// It is not, so we changed of direction

   445

					res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;

   446

				}

   447

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

   448

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

   449

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

   450

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

   451

						res += AI_PATHFINDER_CURVE_PENALTY;

   452

					}

   453

				}

   454

			}

   455

		}

   456

	}

   457

   458

	// Res should never be below zero.. if so, make it zero!

   459

	if (res < 0) { res = 0; }

   460

   461

	// Return our value

   462

	return res;

   463

}