src/tunnelbridge_cmd.cpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /**
  11  * @file tunnelbridge_cmd.cpp
  12  * This file deals with tunnels and bridges (non-gui stuff)
  13  * @todo separate this file into two
  14  */
  15
  16 #include "stdafx.h"
  17 #include "newgrf_object.h"
  18 #include "viewport_func.h"
  19 #include "cmd_helper.h"
  20 #include "command_func.h"
  21 #include "town.h"
  22 #include "train.h"
  23 #include "ship.h"
  24 #include "roadveh.h"
  25 #include "pathfinder/yapf/yapf_cache.h"
  26 #include "newgrf_sound.h"
  27 #include "autoslope.h"
  28 #include "tunnelbridge_map.h"
  29 #include "strings_func.h"
  30 #include "date_func.h"
  31 #include "clear_func.h"
  32 #include "vehicle_func.h"
  33 #include "sound_func.h"
  34 #include "tunnelbridge.h"
  35 #include "cheat_type.h"
  36 #include "elrail_func.h"
  37 #include "pbs.h"
  38 #include "company_base.h"
  39 #include "newgrf_railtype.h"
  40 #include "object_base.h"
  41 #include "water.h"
  42 #include "company_gui.h"
  43
  44 #include "table/strings.h"
  45 #include "table/bridge_land.h"
  46
  47 #include "safeguards.h"
  48
  49 BridgeSpec _bridge[MAX_BRIDGES]; ///< The specification of all bridges.
  50 TileIndex _build_tunnel_endtile; ///< The end of a tunnel; as hidden return from the tunnel build command for GUI purposes.
  51
  52 /** Z position of the bridge sprites relative to bridge height (downwards) */
  53 static const int BRIDGE_Z_START = 3;
  54
  55
  56 /**
  57  * Mark bridge tiles dirty.
  58  * Note: The bridge does not need to exist, everything is passed via parameters.
  59  * @param begin Start tile.
  60  * @param end End tile.
  61  * @param direction Direction from \a begin to \a end.
  62  * @param bridge_height Bridge height level.
  63  */
  64 void MarkBridgeDirty(TileIndex begin, TileIndex end, DiagDirection direction, uint bridge_height)
  65 {
  66         TileIndexDiff delta = TileOffsByDiagDir(direction);
  67         for (TileIndex t = begin; t != end; t += delta) {
  68                 MarkTileDirtyByTile(t, bridge_height - TileHeight(t));
  69         }
  70         MarkTileDirtyByTile(end);
  71 }
  72
  73 /**
  74  * Mark bridge tiles dirty.
  75  * @param tile Bridge head.
  76  */
  77 void MarkBridgeDirty(TileIndex tile)
  78 {
  79         MarkBridgeDirty(tile, GetOtherTunnelBridgeEnd(tile), GetTunnelBridgeDirection(tile), GetBridgeHeight(tile));
  80 }
  81
  82 /** Reset the data been eventually changed by the grf loaded. */
  83 void ResetBridges()
  84 {
  85         /* First, free sprite table data */
  86         for (BridgeType i = 0; i < MAX_BRIDGES; i++) {
  87                 if (_bridge[i].sprite_table != NULL) {
  88                         for (BridgePieces j = BRIDGE_PIECE_NORTH; j < BRIDGE_PIECE_INVALID; j++) free(_bridge[i].sprite_table[j]);
  89                         free(_bridge[i].sprite_table);
  90                 }
  91         }
  92
  93         /* Then, wipe out current bridges */
  94         memset(&_bridge, 0, sizeof(_bridge));
  95         /* And finally, reinstall default data */
  96         memcpy(&_bridge, &_orig_bridge, sizeof(_orig_bridge));
  97 }
  98
  99 /**
 100  * Calculate the price factor for building a long bridge.
 101  * Basically the cost delta is 1,1, 1, 2,2, 3,3,3, 4,4,4,4, 5,5,5,5,5, 6,6,6,6,6,6,  7,7,7,7,7,7,7,  8,8,8,8,8,8,8,8,
 102  * @param length Length of the bridge.
 103  * @return Price factor for the bridge.
 104  */
 105 int CalcBridgeLenCostFactor(int length)
 106 {
 107         if (length < 2) return length;
 108
 109         length -= 2;
 110         int sum = 2;
 111         for (int delta = 1;; delta++) {
 112                 for (int count = 0; count < delta; count++) {
 113                         if (length == 0) return sum;
 114                         sum += delta;
 115                         length--;
 116                 }
 117         }
 118 }
 119
 120 /**
 121  * Get the foundation for a bridge.
 122  * @param tileh The slope to build the bridge on.
 123  * @param axis The axis of the bridge entrance.
 124  * @return The foundation required.
 125  */
 126 Foundation GetBridgeFoundation(Slope tileh, Axis axis)
 127 {
 128         if (tileh == SLOPE_FLAT ||
 129                         ((tileh == SLOPE_NE || tileh == SLOPE_SW) && axis == AXIS_X) ||
 130                         ((tileh == SLOPE_NW || tileh == SLOPE_SE) && axis == AXIS_Y)) return FOUNDATION_NONE;
 131
 132         return (HasSlopeHighestCorner(tileh) ? InclinedFoundation(axis) : FlatteningFoundation(tileh));
 133 }
 134
 135 /**
 136  * Determines if the track on a bridge ramp is flat or goes up/down.
 137  *
 138  * @param tileh Slope of the tile under the bridge head
 139  * @param axis Orientation of bridge
 140  * @return true iff the track is flat.
 141  */
 142 bool HasBridgeFlatRamp(Slope tileh, Axis axis)
 143 {
 144         ApplyFoundationToSlope(GetBridgeFoundation(tileh, axis), &tileh);
 145         /* If the foundation slope is flat the bridge has a non-flat ramp and vice versa. */
 146         return (tileh != SLOPE_FLAT);
 147 }
 148
 149 static inline const PalSpriteID *GetBridgeSpriteTable(int index, BridgePieces table)
 150 {
 151         const BridgeSpec *bridge = GetBridgeSpec(index);
 152         assert(table < BRIDGE_PIECE_INVALID);
 153         if (bridge->sprite_table == NULL || bridge->sprite_table[table] == NULL) {
 154                 return _bridge_sprite_table[index][table];
 155         } else {
 156                 return bridge->sprite_table[table];
 157         }
 158 }
 159
 160
 161 /**
 162  * Determines the foundation for the north bridge head, and tests if the resulting slope is valid.
 163  *
 164  * @param axis Axis of the bridge
 165  * @param tileh Slope of the tile under the north bridge head; returns slope on top of foundation
 166  * @param z TileZ corresponding to tileh, gets modified as well
 167  * @return Error or cost for bridge foundation
 168  */
 169 static CommandCost CheckBridgeSlopeNorth(Axis axis, Slope *tileh, int *z)
 170 {
 171         Foundation f = GetBridgeFoundation(*tileh, axis);
 172         *z += ApplyFoundationToSlope(f, tileh);
 173
 174         Slope valid_inclined = (axis == AXIS_X ? SLOPE_NE : SLOPE_NW);
 175         if ((*tileh != SLOPE_FLAT) && (*tileh != valid_inclined)) return CMD_ERROR;
 176
 177         if (f == FOUNDATION_NONE) return CommandCost();
 178
 179         return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
 180 }
 181
 182 /**
 183  * Determines the foundation for the south bridge head, and tests if the resulting slope is valid.
 184  *
 185  * @param axis Axis of the bridge
 186  * @param tileh Slope of the tile under the south bridge head; returns slope on top of foundation
 187  * @param z TileZ corresponding to tileh, gets modified as well
 188  * @return Error or cost for bridge foundation
 189  */
 190 static CommandCost CheckBridgeSlopeSouth(Axis axis, Slope *tileh, int *z)
 191 {
 192         Foundation f = GetBridgeFoundation(*tileh, axis);
 193         *z += ApplyFoundationToSlope(f, tileh);
 194
 195         Slope valid_inclined = (axis == AXIS_X ? SLOPE_SW : SLOPE_SE);
 196         if ((*tileh != SLOPE_FLAT) && (*tileh != valid_inclined)) return CMD_ERROR;
 197
 198         if (f == FOUNDATION_NONE) return CommandCost();
 199
 200         return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
 201 }
 202
 203 /**
 204  * Is a bridge of the specified type and length available?
 205  * @param bridge_type Wanted type of bridge.
 206  * @param bridge_len  Wanted length of the bridge.
 207  * @return A succeeded (the requested bridge is available) or failed (it cannot be built) command.
 208  */
 209 CommandCost CheckBridgeAvailability(BridgeType bridge_type, uint bridge_len, DoCommandFlag flags)
 210 {
 211         if (flags & DC_QUERY_COST) {
 212                 if (bridge_len <= _settings_game.construction.max_bridge_length) return CommandCost();
 213                 return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 214         }
 215
 216         if (bridge_type >= MAX_BRIDGES) return CMD_ERROR;
 217
 218         const BridgeSpec *b = GetBridgeSpec(bridge_type);
 219         if (b->avail_year > _cur_year) return CMD_ERROR;
 220
 221         uint max = min(b->max_length, _settings_game.construction.max_bridge_length);
 222
 223         if (b->min_length > bridge_len) return CMD_ERROR;
 224         if (bridge_len <= max) return CommandCost();
 225         return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 226 }
 227
 228 /**
 229  * Build a Bridge
 230  * @param end_tile end tile
 231  * @param flags type of operation
 232  * @param p1 packed start tile coords (~ dx)
 233  * @param p2 various bitstuffed elements
 234  * - p2 = (bit  0- 7) - bridge type (hi bh)
 235  * - p2 = (bit  8-11) - rail type or road types.
 236  * - p2 = (bit 15-16) - transport type.
 237  * @param text unused
 238  * @return the cost of this operation or an error
 239  */
 240 CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 241 {
 242         CompanyID company = _current_company;
 243
 244         RailType railtype = INVALID_RAILTYPE;
 245         RoadTypes roadtypes = ROADTYPES_NONE;
 246
 247         /* unpack parameters */
 248         BridgeType bridge_type = GB(p2, 0, 8);
 249
 250         if (!IsValidTile(p1)) return_cmd_error(STR_ERROR_BRIDGE_THROUGH_MAP_BORDER);
 251
 252         TransportType transport_type = Extract<TransportType, 15, 2>(p2);
 253
 254         /* type of bridge */
 255         switch (transport_type) {
 256                 case TRANSPORT_ROAD:
 257                         roadtypes = Extract<RoadTypes, 8, 2>(p2);
 258                         if (!HasExactlyOneBit(roadtypes) || !HasRoadTypesAvail(company, roadtypes)) return CMD_ERROR;
 259                         break;
 260
 261                 case TRANSPORT_RAIL:
 262                         railtype = Extract<RailType, 8, 4>(p2);
 263                         if (!ValParamRailtype(railtype)) return CMD_ERROR;
 264                         break;
 265
 266                 case TRANSPORT_WATER:
 267                         break;
 268
 269                 default:
 270                         /* Airports don't have bridges. */
 271                         return CMD_ERROR;
 272         }
 273         TileIndex tile_start = p1;
 274         TileIndex tile_end = end_tile;
 275
 276         if (company == OWNER_DEITY) {
 277                 if (transport_type != TRANSPORT_ROAD) return CMD_ERROR;
 278                 const Town *town = CalcClosestTownFromTile(tile_start);
 279
 280                 company = OWNER_TOWN;
 281
 282                 /* If we are not within a town, we are not owned by the town */
 283                 if (town == NULL || DistanceSquare(tile_start, town->xy) > town->cache.squared_town_zone_radius[HZB_TOWN_EDGE]) {
 284                         company = OWNER_NONE;
 285                 }
 286         }
 287
 288         if (tile_start == tile_end) {
 289                 return_cmd_error(STR_ERROR_CAN_T_START_AND_END_ON);
 290         }
 291
 292         Axis direction;
 293         if (TileX(tile_start) == TileX(tile_end)) {
 294                 direction = AXIS_Y;
 295         } else if (TileY(tile_start) == TileY(tile_end)) {
 296                 direction = AXIS_X;
 297         } else {
 298                 return_cmd_error(STR_ERROR_START_AND_END_MUST_BE_IN);
 299         }
 300
 301         if (tile_end < tile_start) Swap(tile_start, tile_end);
 302
 303         uint bridge_len = GetTunnelBridgeLength(tile_start, tile_end);
 304         if (transport_type != TRANSPORT_WATER) {
 305                 /* set and test bridge length, availability */
 306                 CommandCost ret = CheckBridgeAvailability(bridge_type, bridge_len, flags);
 307                 if (ret.Failed()) return ret;
 308         } else {
 309                 if (bridge_len > _settings_game.construction.max_bridge_length) return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 310         }
 311
 312         int z_start;
 313         int z_end;
 314         Slope tileh_start = GetTileSlope(tile_start, &z_start);
 315         Slope tileh_end = GetTileSlope(tile_end, &z_end);
 316         bool pbs_reservation = false;
 317
 318         CommandCost terraform_cost_north = CheckBridgeSlopeNorth(direction, &tileh_start, &z_start);
 319         CommandCost terraform_cost_south = CheckBridgeSlopeSouth(direction, &tileh_end,   &z_end);
 320
 321         /* Aqueducts can't be built of flat land. */
 322         if (transport_type == TRANSPORT_WATER && (tileh_start == SLOPE_FLAT || tileh_end == SLOPE_FLAT)) return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
 323         if (z_start != z_end) return_cmd_error(STR_ERROR_BRIDGEHEADS_NOT_SAME_HEIGHT);
 324
 325         CommandCost cost(EXPENSES_CONSTRUCTION);
 326         Owner owner;
 327         bool is_new_owner;
 328         if (IsBridgeTile(tile_start) && IsBridgeTile(tile_end) &&
 329                         GetOtherBridgeEnd(tile_start) == tile_end &&
 330                         GetTunnelBridgeTransportType(tile_start) == transport_type) {
 331                 /* Replace a current bridge. */
 332
 333                 /* If this is a railway bridge, make sure the railtypes match. */
 334                 if (transport_type == TRANSPORT_RAIL && GetRailType(tile_start) != railtype) {
 335                         return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
 336                 }
 337
 338                 /* Do not replace town bridges with lower speed bridges, unless in scenario editor. */
 339                 if (!(flags & DC_QUERY_COST) && IsTileOwner(tile_start, OWNER_TOWN) &&
 340                                 GetBridgeSpec(bridge_type)->speed < GetBridgeSpec(GetBridgeType(tile_start))->speed &&
 341                                 _game_mode != GM_EDITOR) {
 342                         Town *t = ClosestTownFromTile(tile_start, UINT_MAX);
 343
 344                         if (t == NULL) {
 345                                 return CMD_ERROR;
 346                         } else {
 347                                 SetDParam(0, t->index);
 348                                 return_cmd_error(STR_ERROR_LOCAL_AUTHORITY_REFUSES_TO_ALLOW_THIS);
 349                         }
 350                 }
 351
 352                 /* Do not replace the bridge with the same bridge type. */
 353                 if (!(flags & DC_QUERY_COST) && (bridge_type == GetBridgeType(tile_start)) && (transport_type != TRANSPORT_ROAD || (roadtypes & ~GetRoadTypes(tile_start)) == 0)) {
 354                         return_cmd_error(STR_ERROR_ALREADY_BUILT);
 355                 }
 356
 357                 /* Do not allow replacing another company's bridges. */
 358                 if (!IsTileOwner(tile_start, company) && !IsTileOwner(tile_start, OWNER_TOWN) && !IsTileOwner(tile_start, OWNER_NONE)) {
 359                         return_cmd_error(STR_ERROR_AREA_IS_OWNED_BY_ANOTHER);
 360                 }
 361
 362                 cost.AddCost((bridge_len + 1) * _price[PR_CLEAR_BRIDGE]); // The cost of clearing the current bridge.
 363                 owner = GetTileOwner(tile_start);
 364
 365                 /* If bridge belonged to bankrupt company, it has a new owner now */
 366                 is_new_owner = (owner == OWNER_NONE);
 367                 if (is_new_owner) owner = company;
 368
 369                 switch (transport_type) {
 370                         case TRANSPORT_RAIL:
 371                                 /* Keep the reservation, the path stays valid. */
 372                                 pbs_reservation = HasTunnelBridgeReservation(tile_start);
 373                                 break;
 374
 375                         case TRANSPORT_ROAD:
 376                                 /* Do not remove road types when upgrading a bridge */
 377                                 roadtypes |= GetRoadTypes(tile_start);
 378                                 break;
 379
 380                         default: break;
 381                 }
 382         } else {
 383                 /* Build a new bridge. */
 384
 385                 bool allow_on_slopes = (_settings_game.construction.build_on_slopes && transport_type != TRANSPORT_WATER);
 386
 387                 /* Try and clear the start landscape */
 388                 CommandCost ret = DoCommand(tile_start, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 389                 if (ret.Failed()) return ret;
 390                 cost = ret;
 391
 392                 if (terraform_cost_north.Failed() || (terraform_cost_north.GetCost() != 0 && !allow_on_slopes)) return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
 393                 cost.AddCost(terraform_cost_north);
 394
 395                 /* Try and clear the end landscape */
 396                 ret = DoCommand(tile_end, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 397                 if (ret.Failed()) return ret;
 398                 cost.AddCost(ret);
 399
 400                 /* false - end tile slope check */
 401                 if (terraform_cost_south.Failed() || (terraform_cost_south.GetCost() != 0 && !allow_on_slopes)) return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
 402                 cost.AddCost(terraform_cost_south);
 403
 404                 const TileIndex heads[] = {tile_start, tile_end};
 405                 for (int i = 0; i < 2; i++) {
 406                         if (IsBridgeAbove(heads[i])) {
 407                                 TileIndex north_head = GetNorthernBridgeEnd(heads[i]);
 408
 409                                 if (direction == GetBridgeAxis(heads[i])) return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
 410
 411                                 if (z_start + 1 == GetBridgeHeight(north_head)) {
 412                                         return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
 413                                 }
 414                         }
 415                 }
 416
 417                 TileIndexDiff delta = (direction == AXIS_X ? TileDiffXY(1, 0) : TileDiffXY(0, 1));
 418                 for (TileIndex tile = tile_start + delta; tile != tile_end; tile += delta) {
 419                         if (GetTileMaxZ(tile) > z_start) return_cmd_error(STR_ERROR_BRIDGE_TOO_LOW_FOR_TERRAIN);
 420
 421                         if (z_start >= (GetTileZ(tile) + _settings_game.construction.max_bridge_height)) {
 422                                 /*
 423                                  * Disallow too high bridges.
 424                                  * Properly rendering a map where very high bridges (might) exist is expensive.
 425                                  * See http://www.tt-forums.net/viewtopic.php?f=33&t=40844&start=980#p1131762
 426                                  * for a detailed discussion. z_start here is one heightlevel below the bridge level.
 427                                  */
 428                                 return_cmd_error(STR_ERROR_BRIDGE_TOO_HIGH_FOR_TERRAIN);
 429                         }
 430
 431                         if (IsBridgeAbove(tile)) {
 432                                 /* Disallow crossing bridges for the time being */
 433                                 return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
 434                         }
 435
 436                         switch (GetTileType(tile)) {
 437                                 case MP_WATER:
 438                                         if (!IsWater(tile) && !IsCoast(tile)) goto not_valid_below;
 439                                         break;
 440
 441                                 case MP_RAILWAY:
 442                                         if (!IsPlainRail(tile)) goto not_valid_below;
 443                                         break;
 444
 445                                 case MP_ROAD:
 446                                         if (IsRoadDepot(tile)) goto not_valid_below;
 447                                         break;
 448
 449                                 case MP_TUNNELBRIDGE:
 450                                         if (IsTunnel(tile)) break;
 451                                         if (direction == DiagDirToAxis(GetTunnelBridgeDirection(tile))) goto not_valid_below;
 452                                         if (z_start < GetBridgeHeight(tile)) goto not_valid_below;
 453                                         break;
 454
 455                                 case MP_OBJECT: {
 456                                         const ObjectSpec *spec = ObjectSpec::GetByTile(tile);
 457                                         if ((spec->flags & OBJECT_FLAG_ALLOW_UNDER_BRIDGE) == 0) goto not_valid_below;
 458                                         if (GetTileMaxZ(tile) + spec->height > z_start) goto not_valid_below;
 459                                         break;
 460                                 }
 461
 462                                 case MP_CLEAR:
 463                                         break;
 464
 465                                 default:
 466         not_valid_below:;
 467                                         /* try and clear the middle landscape */
 468                                         ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 469                                         if (ret.Failed()) return ret;
 470                                         cost.AddCost(ret);
 471                                         break;
 472                         }
 473
 474                         if (flags & DC_EXEC) {
 475                                 /* We do this here because when replacing a bridge with another
 476                                  * type calling SetBridgeMiddle isn't needed. After all, the
 477                                  * tile already has the has_bridge_above bits set. */
 478                                 SetBridgeMiddle(tile, direction);
 479                         }
 480                 }
 481
 482                 owner = company;
 483                 is_new_owner = true;
 484         }
 485
 486         /* do the drill? */
 487         if (flags & DC_EXEC) {
 488                 DiagDirection dir = AxisToDiagDir(direction);
 489
 490                 Company *c = Company::GetIfValid(company);
 491                 switch (transport_type) {
 492                         case TRANSPORT_RAIL:
 493                                 /* Add to company infrastructure count if required. */
 494                                 if (is_new_owner && c != NULL) c->infrastructure.rail[railtype] += (bridge_len + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR;
 495                                 MakeRailBridgeRamp(tile_start, owner, bridge_type, dir,                 railtype);
 496                                 MakeRailBridgeRamp(tile_end,   owner, bridge_type, ReverseDiagDir(dir), railtype);
 497                                 SetTunnelBridgeReservation(tile_start, pbs_reservation);
 498                                 SetTunnelBridgeReservation(tile_end,   pbs_reservation);
 499                                 break;
 500
 501                         case TRANSPORT_ROAD: {
 502                                 RoadTypes prev_roadtypes = IsBridgeTile(tile_start) ? GetRoadTypes(tile_start) : ROADTYPES_NONE;
 503                                 if (is_new_owner) {
 504                                         /* Also give unowned present roadtypes to new owner */
 505                                         if (HasBit(prev_roadtypes, ROADTYPE_ROAD) && GetRoadOwner(tile_start, ROADTYPE_ROAD) == OWNER_NONE) ClrBit(prev_roadtypes, ROADTYPE_ROAD);
 506                                         if (HasBit(prev_roadtypes, ROADTYPE_TRAM) && GetRoadOwner(tile_start, ROADTYPE_TRAM) == OWNER_NONE) ClrBit(prev_roadtypes, ROADTYPE_TRAM);
 507                                 }
 508                                 if (c != NULL) {
 509                                         /* Add all new road types to the company infrastructure counter. */
 510                                         RoadType new_rt;
 511                                         FOR_EACH_SET_ROADTYPE(new_rt, roadtypes ^ prev_roadtypes) {
 512                                                 /* A full diagonal road tile has two road bits. */
 513                                                 c->infrastructure.road[new_rt] += (bridge_len + 2) * 2 * TUNNELBRIDGE_TRACKBIT_FACTOR;
 514                                         }
 515                                 }
 516                                 Owner owner_road = HasBit(prev_roadtypes, ROADTYPE_ROAD) ? GetRoadOwner(tile_start, ROADTYPE_ROAD) : company;
 517                                 Owner owner_tram = HasBit(prev_roadtypes, ROADTYPE_TRAM) ? GetRoadOwner(tile_start, ROADTYPE_TRAM) : company;
 518                                 MakeRoadBridgeRamp(tile_start, owner, owner_road, owner_tram, bridge_type, dir,                 roadtypes);
 519                                 MakeRoadBridgeRamp(tile_end,   owner, owner_road, owner_tram, bridge_type, ReverseDiagDir(dir), roadtypes);
 520                                 break;
 521                         }
 522
 523                         case TRANSPORT_WATER:
 524                                 if (is_new_owner && c != NULL) c->infrastructure.water += (bridge_len + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR;
 525                                 MakeAqueductBridgeRamp(tile_start, owner, dir);
 526                                 MakeAqueductBridgeRamp(tile_end,   owner, ReverseDiagDir(dir));
 527                                 break;
 528
 529                         default:
 530                                 NOT_REACHED();
 531                 }
 532
 533                 /* Mark all tiles dirty */
 534                 MarkBridgeDirty(tile_start, tile_end, AxisToDiagDir(direction), z_start);
 535                 DirtyCompanyInfrastructureWindows(company);
 536         }
 537
 538         if ((flags & DC_EXEC) && transport_type == TRANSPORT_RAIL) {
 539                 Track track = AxisToTrack(direction);
 540                 AddSideToSignalBuffer(tile_start, INVALID_DIAGDIR, company);
 541                 YapfNotifyTrackLayoutChange(tile_start, track);
 542         }
 543
 544         /* for human player that builds the bridge he gets a selection to choose from bridges (DC_QUERY_COST)
 545          * It's unnecessary to execute this command every time for every bridge. So it is done only
 546          * and cost is computed in "bridge_gui.c". For AI, Towns this has to be of course calculated
 547          */
 548         Company *c = Company::GetIfValid(company);
 549         if (!(flags & DC_QUERY_COST) || (c != NULL && c->is_ai)) {
 550                 bridge_len += 2; // begin and end tiles/ramps
 551
 552                 switch (transport_type) {
 553                         case TRANSPORT_ROAD: cost.AddCost(bridge_len * _price[PR_BUILD_ROAD] * 2 * CountBits(roadtypes)); break;
 554                         case TRANSPORT_RAIL: cost.AddCost(bridge_len * RailBuildCost(railtype)); break;
 555                         default: break;
 556                 }
 557
 558                 if (c != NULL) bridge_len = CalcBridgeLenCostFactor(bridge_len);
 559
 560                 if (transport_type != TRANSPORT_WATER) {
 561                         cost.AddCost((int64)bridge_len * _price[PR_BUILD_BRIDGE] * GetBridgeSpec(bridge_type)->price >> 8);
 562                 } else {
 563                         /* Aqueducts use a separate base cost. */
 564                         cost.AddCost((int64)bridge_len * _price[PR_BUILD_AQUEDUCT]);
 565                 }
 566
 567         }
 568
 569         return cost;
 570 }
 571
 572
 573 /**
 574  * Build Tunnel.
 575  * @param start_tile start tile of tunnel
 576  * @param flags type of operation
 577  * @param p1 bit 0-3 railtype or roadtypes
 578  *           bit 8-9 transport type
 579  * @param p2 unused
 580  * @param text unused
 581  * @return the cost of this operation or an error
 582  */
 583 CommandCost CmdBuildTunnel(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 584 {
 585         CompanyID company = _current_company;
 586
 587         TransportType transport_type = Extract<TransportType, 8, 2>(p1);
 588
 589         RailType railtype = INVALID_RAILTYPE;
 590         RoadTypes rts = ROADTYPES_NONE;
 591         _build_tunnel_endtile = 0;
 592         switch (transport_type) {
 593                 case TRANSPORT_RAIL:
 594                         railtype = Extract<RailType, 0, 4>(p1);
 595                         if (!ValParamRailtype(railtype)) return CMD_ERROR;
 596                         break;
 597
 598                 case TRANSPORT_ROAD:
 599                         rts = Extract<RoadTypes, 0, 2>(p1);
 600                         if (!HasExactlyOneBit(rts) || !HasRoadTypesAvail(company, rts)) return CMD_ERROR;
 601                         break;
 602
 603                 default: return CMD_ERROR;
 604         }
 605
 606         if (company == OWNER_DEITY) {
 607                 if (transport_type != TRANSPORT_ROAD) return CMD_ERROR;
 608                 const Town *town = CalcClosestTownFromTile(start_tile);
 609
 610                 company = OWNER_TOWN;
 611
 612                 /* If we are not within a town, we are not owned by the town */
 613                 if (town == NULL || DistanceSquare(start_tile, town->xy) > town->cache.squared_town_zone_radius[HZB_TOWN_EDGE]) {
 614                         company = OWNER_NONE;
 615                 }
 616         }
 617
 618         int start_z;
 619         int end_z;
 620         Slope start_tileh = GetTileSlope(start_tile, &start_z);
 621         DiagDirection direction = GetInclinedSlopeDirection(start_tileh);
 622         if (direction == INVALID_DIAGDIR) return_cmd_error(STR_ERROR_SITE_UNSUITABLE_FOR_TUNNEL);
 623
 624         if (HasTileWaterGround(start_tile)) return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);
 625
 626         CommandCost ret = DoCommand(start_tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 627         if (ret.Failed()) return ret;
 628
 629         /* XXX - do NOT change 'ret' in the loop, as it is used as the price
 630          * for the clearing of the entrance of the tunnel. Assigning it to
 631          * cost before the loop will yield different costs depending on start-
 632          * position, because of increased-cost-by-length: 'cost += cost >> 3' */
 633
 634         TileIndexDiff delta = TileOffsByDiagDir(direction);
 635         DiagDirection tunnel_in_way_dir;
 636         if (DiagDirToAxis(direction) == AXIS_Y) {
 637                 tunnel_in_way_dir = (TileX(start_tile) < (MapMaxX() / 2)) ? DIAGDIR_SW : DIAGDIR_NE;
 638         } else {
 639                 tunnel_in_way_dir = (TileY(start_tile) < (MapMaxX() / 2)) ? DIAGDIR_SE : DIAGDIR_NW;
 640         }
 641
 642         TileIndex end_tile = start_tile;
 643
 644         /* Tile shift coefficient. Will decrease for very long tunnels to avoid exponential growth of price*/
 645         int tiles_coef = 3;
 646         /* Number of tiles from start of tunnel */
 647         int tiles = 0;
 648         /* Number of tiles at which the cost increase coefficient per tile is halved */
 649         int tiles_bump = 25;
 650
 651         CommandCost cost(EXPENSES_CONSTRUCTION);
 652         Slope end_tileh;
 653         for (;;) {
 654                 end_tile += delta;
 655                 if (!IsValidTile(end_tile)) return_cmd_error(STR_ERROR_TUNNEL_THROUGH_MAP_BORDER);
 656                 end_tileh = GetTileSlope(end_tile, &end_z);
 657
 658                 if (start_z == end_z) break;
 659
 660                 if (!_cheats.crossing_tunnels.value && IsTunnelInWayDir(end_tile, start_z, tunnel_in_way_dir)) {
 661                         return_cmd_error(STR_ERROR_ANOTHER_TUNNEL_IN_THE_WAY);
 662                 }
 663
 664                 tiles++;
 665                 if (tiles == tiles_bump) {
 666                         tiles_coef++;
 667                         tiles_bump *= 2;
 668                 }
 669
 670                 cost.AddCost(_price[PR_BUILD_TUNNEL]);
 671                 cost.AddCost(cost.GetCost() >> tiles_coef); // add a multiplier for longer tunnels
 672         }
 673
 674         /* Add the cost of the entrance */
 675         cost.AddCost(_price[PR_BUILD_TUNNEL]);
 676         cost.AddCost(ret);
 677
 678         /* if the command fails from here on we want the end tile to be highlighted */
 679         _build_tunnel_endtile = end_tile;
 680
 681         if (tiles > _settings_game.construction.max_tunnel_length) return_cmd_error(STR_ERROR_TUNNEL_TOO_LONG);
 682
 683         if (HasTileWaterGround(end_tile)) return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);
 684
 685         /* Clear the tile in any case */
 686         ret = DoCommand(end_tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 687         if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
 688         cost.AddCost(ret);
 689
 690         /* slope of end tile must be complementary to the slope of the start tile */
 691         if (end_tileh != ComplementSlope(start_tileh)) {
 692                 /* Mark the tile as already cleared for the terraform command.
 693                  * Do this for all tiles (like trees), not only objects. */
 694                 ClearedObjectArea *coa = FindClearedObject(end_tile);
 695                 if (coa == NULL) {
 696                         coa = _cleared_object_areas.Append();
 697                         coa->first_tile = end_tile;
 698                         coa->area = TileArea(end_tile, 1, 1);
 699                 }
 700
 701                 /* Hide the tile from the terraforming command */
 702                 TileIndex old_first_tile = coa->first_tile;
 703                 coa->first_tile = INVALID_TILE;
 704                 ret = DoCommand(end_tile, end_tileh & start_tileh, 0, flags, CMD_TERRAFORM_LAND);
 705                 coa->first_tile = old_first_tile;
 706                 if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
 707                 cost.AddCost(ret);
 708         }
 709         cost.AddCost(_price[PR_BUILD_TUNNEL]);
 710
 711         /* Pay for the rail/road in the tunnel including entrances */
 712         switch (transport_type) {
 713                 case TRANSPORT_ROAD: cost.AddCost((tiles + 2) * _price[PR_BUILD_ROAD] * 2); break;
 714                 case TRANSPORT_RAIL: cost.AddCost((tiles + 2) * RailBuildCost(railtype)); break;
 715                 default: NOT_REACHED();
 716         }
 717
 718         if (flags & DC_EXEC) {
 719                 Company *c = Company::GetIfValid(company);
 720                 uint num_pieces = (tiles + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR;
 721                 if (transport_type == TRANSPORT_RAIL) {
 722                         if (!IsTunnelTile(start_tile) && c != NULL) c->infrastructure.rail[railtype] += num_pieces;
 723                         MakeRailTunnel(start_tile, company, direction,                 railtype);
 724                         MakeRailTunnel(end_tile,   company, ReverseDiagDir(direction), railtype);
 725                         AddSideToSignalBuffer(start_tile, INVALID_DIAGDIR, company);
 726                         YapfNotifyTrackLayoutChange(start_tile, DiagDirToDiagTrack(direction));
 727                 } else {
 728                         if (c != NULL) {
 729                                 RoadType rt;
 730                                 FOR_EACH_SET_ROADTYPE(rt, rts ^ (IsTunnelTile(start_tile) ? GetRoadTypes(start_tile) : ROADTYPES_NONE)) {
 731                                         c->infrastructure.road[rt] += num_pieces * 2; // A full diagonal road has two road bits.
 732                                 }
 733                         }
 734                         MakeRoadTunnel(start_tile, company, direction,                 rts);
 735                         MakeRoadTunnel(end_tile,   company, ReverseDiagDir(direction), rts);
 736                 }
 737                 DirtyCompanyInfrastructureWindows(company);
 738         }
 739
 740         return cost;
 741 }
 742
 743
 744 /**
 745  * Are we allowed to remove the tunnel or bridge at \a tile?
 746  * @param tile End point of the tunnel or bridge.
 747  * @return A succeeded command if the tunnel or bridge may be removed, a failed command otherwise.
 748  */
 749 static inline CommandCost CheckAllowRemoveTunnelBridge(TileIndex tile)
 750 {
 751         /* Floods can remove anything as well as the scenario editor */
 752         if (_current_company == OWNER_WATER || _game_mode == GM_EDITOR) return CommandCost();
 753
 754         switch (GetTunnelBridgeTransportType(tile)) {
 755                 case TRANSPORT_ROAD: {
 756                         RoadTypes rts = GetRoadTypes(tile);
 757                         Owner road_owner = _current_company;
 758                         Owner tram_owner = _current_company;
 759
 760                         if (HasBit(rts, ROADTYPE_ROAD)) road_owner = GetRoadOwner(tile, ROADTYPE_ROAD);
 761                         if (HasBit(rts, ROADTYPE_TRAM)) tram_owner = GetRoadOwner(tile, ROADTYPE_TRAM);
 762
 763                         /* We can remove unowned road and if the town allows it */
 764                         if (road_owner == OWNER_TOWN && _current_company != OWNER_TOWN && !(_settings_game.construction.extra_dynamite || _cheats.magic_bulldozer.value)) {
 765                                 /* Town does not allow */
 766                                 return CheckTileOwnership(tile);
 767                         }
 768                         if (road_owner == OWNER_NONE || road_owner == OWNER_TOWN) road_owner = _current_company;
 769                         if (tram_owner == OWNER_NONE) tram_owner = _current_company;
 770
 771                         CommandCost ret = CheckOwnership(road_owner, tile);
 772                         if (ret.Succeeded()) ret = CheckOwnership(tram_owner, tile);
 773                         return ret;
 774                 }
 775
 776                 case TRANSPORT_RAIL:
 777                         return CheckOwnership(GetTileOwner(tile));
 778
 779                 case TRANSPORT_WATER: {
 780                         /* Always allow to remove aqueducts without owner. */
 781                         Owner aqueduct_owner = GetTileOwner(tile);
 782                         if (aqueduct_owner == OWNER_NONE) aqueduct_owner = _current_company;
 783                         return CheckOwnership(aqueduct_owner);
 784                 }
 785
 786                 default: NOT_REACHED();
 787         }
 788 }
 789
 790 /**
 791  * Remove a tunnel from the game, update town rating, etc.
 792  * @param tile Tile containing one of the endpoints of the tunnel.
 793  * @param flags Command flags.
 794  * @return Succeeded or failed command.
 795  */
 796 static CommandCost DoClearTunnel(TileIndex tile, DoCommandFlag flags)
 797 {
 798         CommandCost ret = CheckAllowRemoveTunnelBridge(tile);
 799         if (ret.Failed()) return ret;
 800
 801         TileIndex endtile = GetOtherTunnelEnd(tile);
 802
 803         ret = TunnelBridgeIsFree(tile, endtile);
 804         if (ret.Failed()) return ret;
 805
 806         _build_tunnel_endtile = endtile;
 807
 808         Town *t = NULL;
 809         if (IsTileOwner(tile, OWNER_TOWN) && _game_mode != GM_EDITOR) {
 810                 t = ClosestTownFromTile(tile, UINT_MAX); // town penalty rating
 811
 812                 /* Check if you are allowed to remove the tunnel owned by a town
 813                  * Removal depends on difficulty settings */
 814                 CommandCost ret = CheckforTownRating(flags, t, TUNNELBRIDGE_REMOVE);
 815                 if (ret.Failed()) return ret;
 816         }
 817
 818         /* checks if the owner is town then decrease town rating by RATING_TUNNEL_BRIDGE_DOWN_STEP until
 819          * you have a "Poor" (0) town rating */
 820         if (IsTileOwner(tile, OWNER_TOWN) && _game_mode != GM_EDITOR) {
 821                 ChangeTownRating(t, RATING_TUNNEL_BRIDGE_DOWN_STEP, RATING_TUNNEL_BRIDGE_MINIMUM, flags);
 822         }
 823
 824         uint len = GetTunnelBridgeLength(tile, endtile) + 2; // Don't forget the end tiles.
 825
 826         if (flags & DC_EXEC) {
 827                 if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) {
 828                         /* We first need to request values before calling DoClearSquare */
 829                         DiagDirection dir = GetTunnelBridgeDirection(tile);
 830                         Track track = DiagDirToDiagTrack(dir);
 831                         Owner owner = GetTileOwner(tile);
 832
 833                         Train *v = NULL;
 834                         if (HasTunnelBridgeReservation(tile)) {
 835                                 v = GetTrainForReservation(tile, track);
 836                                 if (v != NULL) FreeTrainTrackReservation(v);
 837                         }
 838
 839                         if (Company::IsValidID(owner)) {
 840                                 Company::Get(owner)->infrastructure.rail[GetRailType(tile)] -= len * TUNNELBRIDGE_TRACKBIT_FACTOR;
 841                                 DirtyCompanyInfrastructureWindows(owner);
 842                         }
 843
 844                         DoClearSquare(tile);
 845                         DoClearSquare(endtile);
 846
 847                         /* cannot use INVALID_DIAGDIR for signal update because the tunnel doesn't exist anymore */
 848                         AddSideToSignalBuffer(tile,    ReverseDiagDir(dir), owner);
 849                         AddSideToSignalBuffer(endtile, dir,                 owner);
 850
 851                         YapfNotifyTrackLayoutChange(tile,    track);
 852                         YapfNotifyTrackLayoutChange(endtile, track);
 853
 854                         if (v != NULL) TryPathReserve(v);
 855                 } else {
 856                         RoadType rt;
 857                         FOR_EACH_SET_ROADTYPE(rt, GetRoadTypes(tile)) {
 858                                 /* A full diagonal road tile has two road bits. */
 859                                 Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
 860                                 if (c != NULL) {
 861                                         c->infrastructure.road[rt] -= len * 2 * TUNNELBRIDGE_TRACKBIT_FACTOR;
 862                                         DirtyCompanyInfrastructureWindows(c->index);
 863                                 }
 864                         }
 865
 866                         DoClearSquare(tile);
 867                         DoClearSquare(endtile);
 868                 }
 869         }
 870         return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_CLEAR_TUNNEL] * len);
 871 }
 872
 873
 874 /**
 875  * Remove a bridge from the game, update town rating, etc.
 876  * @param tile Tile containing one of the endpoints of the bridge.
 877  * @param flags Command flags.
 878  * @return Succeeded or failed command.
 879  */
 880 static CommandCost DoClearBridge(TileIndex tile, DoCommandFlag flags)
 881 {
 882         CommandCost ret = CheckAllowRemoveTunnelBridge(tile);
 883         if (ret.Failed()) return ret;
 884
 885         TileIndex endtile = GetOtherBridgeEnd(tile);
 886
 887         ret = TunnelBridgeIsFree(tile, endtile);
 888         if (ret.Failed()) return ret;
 889
 890         DiagDirection direction = GetTunnelBridgeDirection(tile);
 891         TileIndexDiff delta = TileOffsByDiagDir(direction);
 892
 893         Town *t = NULL;
 894         if (IsTileOwner(tile, OWNER_TOWN) && _game_mode != GM_EDITOR) {
 895                 t = ClosestTownFromTile(tile, UINT_MAX); // town penalty rating
 896
 897                 /* Check if you are allowed to remove the bridge owned by a town
 898                  * Removal depends on difficulty settings */
 899                 CommandCost ret = CheckforTownRating(flags, t, TUNNELBRIDGE_REMOVE);
 900                 if (ret.Failed()) return ret;
 901         }
 902
 903         /* checks if the owner is town then decrease town rating by RATING_TUNNEL_BRIDGE_DOWN_STEP until
 904          * you have a "Poor" (0) town rating */
 905         if (IsTileOwner(tile, OWNER_TOWN) && _game_mode != GM_EDITOR) {
 906                 ChangeTownRating(t, RATING_TUNNEL_BRIDGE_DOWN_STEP, RATING_TUNNEL_BRIDGE_MINIMUM, flags);
 907         }
 908
 909         Money base_cost = (GetTunnelBridgeTransportType(tile) != TRANSPORT_WATER) ? _price[PR_CLEAR_BRIDGE] : _price[PR_CLEAR_AQUEDUCT];
 910         uint len = GetTunnelBridgeLength(tile, endtile) + 2; // Don't forget the end tiles.
 911
 912         if (flags & DC_EXEC) {
 913                 /* read this value before actual removal of bridge */
 914                 bool rail = GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL;
 915                 Owner owner = GetTileOwner(tile);
 916                 int height = GetBridgeHeight(tile);
 917                 Train *v = NULL;
 918
 919                 if (rail && HasTunnelBridgeReservation(tile)) {
 920                         v = GetTrainForReservation(tile, DiagDirToDiagTrack(direction));
 921                         if (v != NULL) FreeTrainTrackReservation(v);
 922                 }
 923
 924                 /* Update company infrastructure counts. */
 925                 if (rail) {
 926                         if (Company::IsValidID(owner)) Company::Get(owner)->infrastructure.rail[GetRailType(tile)] -= len * TUNNELBRIDGE_TRACKBIT_FACTOR;
 927                 } else if (GetTunnelBridgeTransportType(tile) == TRANSPORT_ROAD) {
 928                         RoadType rt;
 929                         FOR_EACH_SET_ROADTYPE(rt, GetRoadTypes(tile)) {
 930                                 Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
 931                                 if (c != NULL) {
 932                                         /* A full diagonal road tile has two road bits. */
 933                                         c->infrastructure.road[rt] -= len * 2 * TUNNELBRIDGE_TRACKBIT_FACTOR;
 934                                         DirtyCompanyInfrastructureWindows(c->index);
 935                                 }
 936                         }
 937                 } else { // Aqueduct
 938                         if (Company::IsValidID(owner)) Company::Get(owner)->infrastructure.water -= len * TUNNELBRIDGE_TRACKBIT_FACTOR;
 939                 }
 940                 DirtyCompanyInfrastructureWindows(owner);
 941
 942                 DoClearSquare(tile);
 943                 DoClearSquare(endtile);
 944                 for (TileIndex c = tile + delta; c != endtile; c += delta) {
 945                         /* do not let trees appear from 'nowhere' after removing bridge */
 946                         if (IsNormalRoadTile(c) && GetRoadside(c) == ROADSIDE_TREES) {
 947                                 int minz = GetTileMaxZ(c) + 3;
 948                                 if (height < minz) SetRoadside(c, ROADSIDE_PAVED);
 949                         }
 950                         ClearBridgeMiddle(c);
 951                         MarkTileDirtyByTile(c, height - TileHeight(c));
 952                 }
 953
 954                 if (rail) {
 955                         /* cannot use INVALID_DIAGDIR for signal update because the bridge doesn't exist anymore */
 956                         AddSideToSignalBuffer(tile,    ReverseDiagDir(direction), owner);
 957                         AddSideToSignalBuffer(endtile, direction,                 owner);
 958
 959                         Track track = DiagDirToDiagTrack(direction);
 960                         YapfNotifyTrackLayoutChange(tile,    track);
 961                         YapfNotifyTrackLayoutChange(endtile, track);
 962
 963                         if (v != NULL) TryPathReserve(v, true);
 964                 }
 965         }
 966
 967         return CommandCost(EXPENSES_CONSTRUCTION, len * base_cost);
 968 }
 969
 970 /**
 971  * Remove a tunnel or a bridge from the game.
 972  * @param tile Tile containing one of the endpoints.
 973  * @param flags Command flags.
 974  * @return Succeeded or failed command.
 975  */
 976 static CommandCost ClearTile_TunnelBridge(TileIndex tile, DoCommandFlag flags)
 977 {
 978         if (IsTunnel(tile)) {
 979                 if (flags & DC_AUTO) return_cmd_error(STR_ERROR_MUST_DEMOLISH_TUNNEL_FIRST);
 980                 return DoClearTunnel(tile, flags);
 981         } else { // IsBridge(tile)
 982                 if (flags & DC_AUTO) return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
 983                 return DoClearBridge(tile, flags);
 984         }
 985 }
 986
 987 /**
 988  * Draw a single pillar sprite.
 989  * @param psid      Pillarsprite
 990  * @param x         Pillar X
 991  * @param y         Pillar Y
 992  * @param z         Pillar Z
 993  * @param w         Bounding box size in X direction
 994  * @param h         Bounding box size in Y direction
 995  * @param subsprite Optional subsprite for drawing halfpillars
 996  */
 997 static inline void DrawPillar(const PalSpriteID *psid, int x, int y, int z, int w, int h, const SubSprite *subsprite)
 998 {
 999         static const int PILLAR_Z_OFFSET = TILE_HEIGHT - BRIDGE_Z_START; ///< Start offset of pillar wrt. bridge (downwards)
1000         AddSortableSpriteToDraw(psid->sprite, psid->pal, x, y, w, h, BB_HEIGHT_UNDER_BRIDGE - PILLAR_Z_OFFSET, z, IsTransparencySet(TO_BRIDGES), 0, 0, -PILLAR_Z_OFFSET, subsprite);
1001 }
1002
1003 /**
1004  * Draw two bridge pillars (north and south).
1005  * @param z_bottom Bottom Z
1006  * @param z_top    Top Z
1007  * @param psid     Pillarsprite
1008  * @param x        Pillar X
1009  * @param y        Pillar Y
1010  * @param w        Bounding box size in X direction
1011  * @param h        Bounding box size in Y direction
1012  * @return Reached Z at the bottom
1013  */
1014 static int DrawPillarColumn(int z_bottom, int z_top, const PalSpriteID *psid, int x, int y, int w, int h)
1015 {
1016         int cur_z;
1017         for (cur_z = z_top; cur_z >= z_bottom; cur_z -= TILE_HEIGHT) {
1018                 DrawPillar(psid, x, y, cur_z, w, h, NULL);
1019         }
1020         return cur_z;
1021 }
1022
1023 /**
1024  * Draws the pillars under high bridges.
1025  *
1026  * @param psid Image and palette of a bridge pillar.
1027  * @param ti #TileInfo of current bridge-middle-tile.
1028  * @param axis Orientation of bridge.
1029  * @param drawfarpillar Whether to draw the pillar at the back
1030  * @param x Sprite X position of front pillar.
1031  * @param y Sprite Y position of front pillar.
1032  * @param z_bridge Absolute height of bridge bottom.
1033  */
1034 static void DrawBridgePillars(const PalSpriteID *psid, const TileInfo *ti, Axis axis, bool drawfarpillar, int x, int y, int z_bridge)
1035 {
1036         static const int bounding_box_size[2]  = {16, 2}; ///< bounding box size of pillars along bridge direction
1037         static const int back_pillar_offset[2] = { 0, 9}; ///< sprite position offset of back facing pillar
1038
1039         static const int INF = 1000; ///< big number compared to sprite size
1040         static const SubSprite half_pillar_sub_sprite[2][2] = {
1041                 { {  -14, -INF, INF, INF }, { -INF, -INF, -15, INF } }, // X axis, north and south
1042                 { { -INF, -INF,  15, INF }, {   16, -INF, INF, INF } }, // Y axis, north and south
1043         };
1044
1045         if (psid->sprite == 0) return;
1046
1047         /* Determine ground height under pillars */
1048         DiagDirection south_dir = AxisToDiagDir(axis);
1049         int z_front_north = ti->z;
1050         int z_back_north = ti->z;
1051         int z_front_south = ti->z;
1052         int z_back_south = ti->z;
1053         GetSlopePixelZOnEdge(ti->tileh, south_dir, &z_front_south, &z_back_south);
1054         GetSlopePixelZOnEdge(ti->tileh, ReverseDiagDir(south_dir), &z_front_north, &z_back_north);
1055
1056         /* Shared height of pillars */
1057         int z_front = max(z_front_north, z_front_south);
1058         int z_back = max(z_back_north, z_back_south);
1059
1060         /* x and y size of bounding-box of pillars */
1061         int w = bounding_box_size[axis];
1062         int h = bounding_box_size[OtherAxis(axis)];
1063         /* sprite position of back facing pillar */
1064         int x_back = x - back_pillar_offset[axis];
1065         int y_back = y - back_pillar_offset[OtherAxis(axis)];
1066
1067         /* Draw front pillars */
1068         int bottom_z = DrawPillarColumn(z_front, z_bridge, psid, x, y, w, h);
1069         if (z_front_north < z_front) DrawPillar(psid, x, y, bottom_z, w, h, &half_pillar_sub_sprite[axis][0]);
1070         if (z_front_south < z_front) DrawPillar(psid, x, y, bottom_z, w, h, &half_pillar_sub_sprite[axis][1]);
1071
1072         /* Draw back pillars, skip top two parts, which are hidden by the bridge */
1073         int z_bridge_back = z_bridge - 2 * (int)TILE_HEIGHT;
1074         if (drawfarpillar && (z_back_north <= z_bridge_back || z_back_south <= z_bridge_back)) {
1075                 bottom_z = DrawPillarColumn(z_back, z_bridge_back, psid, x_back, y_back, w, h);
1076                 if (z_back_north < z_back) DrawPillar(psid, x_back, y_back, bottom_z, w, h, &half_pillar_sub_sprite[axis][0]);
1077                 if (z_back_south < z_back) DrawPillar(psid, x_back, y_back, bottom_z, w, h, &half_pillar_sub_sprite[axis][1]);
1078         }
1079 }
1080
1081 /**
1082  * Draws the trambits over an already drawn (lower end) of a bridge.
1083  * @param x       the x of the bridge
1084  * @param y       the y of the bridge
1085  * @param z       the z of the bridge
1086  * @param offset  number representing whether to level or sloped and the direction
1087  * @param overlay do we want to still see the road?
1088  * @param head    are we drawing bridge head?
1089  */
1090 static void DrawBridgeTramBits(int x, int y, int z, int offset, bool overlay, bool head)
1091 {
1092         static const SpriteID tram_offsets[2][6] = { { 107, 108, 109, 110, 111, 112 }, { 4, 5, 15, 16, 17, 18 } };
1093         static const SpriteID back_offsets[6]    =   {  95,  96,  99, 102, 100, 101 };
1094         static const SpriteID front_offsets[6]   =   {  97,  98, 103, 106, 104, 105 };
1095
1096         static const uint size_x[6] = {  1, 16, 16,  1, 16,  1 };
1097         static const uint size_y[6] = { 16,  1,  1, 16,  1, 16 };
1098         static const uint front_bb_offset_x[6] = { 15,  0,  0, 15,  0, 15 };
1099         static const uint front_bb_offset_y[6] = {  0, 15, 15,  0, 15,  0 };
1100
1101         /* The sprites under the vehicles are drawn as SpriteCombine. StartSpriteCombine() has already been called
1102          * The bounding boxes here are the same as for bridge front/roof */
1103         if (head || !IsInvisibilitySet(TO_BRIDGES)) {
1104                 AddSortableSpriteToDraw(SPR_TRAMWAY_BASE + tram_offsets[overlay][offset], PAL_NONE,
1105                         x, y, size_x[offset], size_y[offset], 0x28, z,
1106                         !head && IsTransparencySet(TO_BRIDGES));
1107         }
1108
1109         /* Do not draw catenary if it is set invisible */
1110         if (!IsInvisibilitySet(TO_CATENARY)) {
1111                 AddSortableSpriteToDraw(SPR_TRAMWAY_BASE + back_offsets[offset], PAL_NONE,
1112                         x, y, size_x[offset], size_y[offset], 0x28, z,
1113                         IsTransparencySet(TO_CATENARY));
1114         }
1115
1116         /* Start a new SpriteCombine for the front part */
1117         EndSpriteCombine();
1118         StartSpriteCombine();
1119
1120         /* For sloped sprites the bounding box needs to be higher, as the pylons stop on a higher point */
1121         if (!IsInvisibilitySet(TO_CATENARY)) {
1122                 AddSortableSpriteToDraw(SPR_TRAMWAY_BASE + front_offsets[offset], PAL_NONE,
1123                         x, y, size_x[offset] + front_bb_offset_x[offset], size_y[offset] + front_bb_offset_y[offset], 0x28, z,
1124                         IsTransparencySet(TO_CATENARY), front_bb_offset_x[offset], front_bb_offset_y[offset]);
1125         }
1126 }
1127
1128 /**
1129  * Draws a tunnel of bridge tile.
1130  * For tunnels, this is rather simple, as you only need to draw the entrance.
1131  * Bridges are a bit more complex. base_offset is where the sprite selection comes into play
1132  * and it works a bit like a bitmask.<p> For bridge heads:
1133  * @param ti TileInfo of the structure to draw
1134  * <ul><li>Bit 0: direction</li>
1135  * <li>Bit 1: northern or southern heads</li>
1136  * <li>Bit 2: Set if the bridge head is sloped</li>
1137  * <li>Bit 3 and more: Railtype Specific subset</li>
1138  * </ul>
1139  * Please note that in this code, "roads" are treated as railtype 1, whilst the real railtypes are 0, 2 and 3
1140  */
1141 static void DrawTile_TunnelBridge(TileInfo *ti)
1142 {
1143         TransportType transport_type = GetTunnelBridgeTransportType(ti->tile);
1144         DiagDirection tunnelbridge_direction = GetTunnelBridgeDirection(ti->tile);
1145
1146         if (IsTunnel(ti->tile)) {
1147                 /* Front view of tunnel bounding boxes:
1148                  *
1149                  *   122223  <- BB_Z_SEPARATOR
1150                  *   1    3
1151                  *   1    3                1,3 = empty helper BB
1152                  *   1    3                  2 = SpriteCombine of tunnel-roof and catenary (tram & elrail)
1153                  *
1154                  */
1155
1156                 static const int _tunnel_BB[4][12] = {
1157                         /*  tunnnel-roof  |  Z-separator  | tram-catenary
1158                          * w  h  bb_x bb_y| x   y   w   h |bb_x bb_y w h */
1159                         {  1,  0, -15, -14,  0, 15, 16,  1, 0, 1, 16, 15 }, // NE
1160                         {  0,  1, -14, -15, 15,  0,  1, 16, 1, 0, 15, 16 }, // SE
1161                         {  1,  0, -15, -14,  0, 15, 16,  1, 0, 1, 16, 15 }, // SW
1162                         {  0,  1, -14, -15, 15,  0,  1, 16, 1, 0, 15, 16 }, // NW
1163                 };
1164                 const int *BB_data = _tunnel_BB[tunnelbridge_direction];
1165
1166                 bool catenary = false;
1167
1168                 SpriteID image;
1169                 SpriteID railtype_overlay = 0;
1170                 if (transport_type == TRANSPORT_RAIL) {
1171                         const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(ti->tile));
1172                         image = rti->base_sprites.tunnel;
1173                         if (rti->UsesOverlay()) {
1174                                 /* Check if the railtype has custom tunnel portals. */
1175                                 railtype_overlay = GetCustomRailSprite(rti, ti->tile, RTSG_TUNNEL_PORTAL);
1176                                 if (railtype_overlay != 0) image = SPR_RAILTYPE_TUNNEL_BASE; // Draw blank grass tunnel base.
1177                         }
1178                 } else {
1179                         image = SPR_TUNNEL_ENTRY_REAR_ROAD;
1180                 }
1181
1182                 if (HasTunnelBridgeSnowOrDesert(ti->tile)) image += railtype_overlay != 0 ? 8 : 32;
1183
1184                 image += tunnelbridge_direction * 2;
1185                 DrawGroundSprite(image, PAL_NONE);
1186
1187                 if (transport_type == TRANSPORT_ROAD) {
1188                         RoadTypes rts = GetRoadTypes(ti->tile);
1189
1190                         if (HasBit(rts, ROADTYPE_TRAM)) {
1191                                 static const SpriteID tunnel_sprites[2][4] = { { 28, 78, 79, 27 }, {  5, 76, 77,  4 } };
1192
1193                                 DrawGroundSprite(SPR_TRAMWAY_BASE + tunnel_sprites[rts - ROADTYPES_TRAM][tunnelbridge_direction], PAL_NONE);
1194
1195                                 /* Do not draw wires if they are invisible */
1196                                 if (!IsInvisibilitySet(TO_CATENARY)) {
1197                                         catenary = true;
1198                                         StartSpriteCombine();
1199                                         AddSortableSpriteToDraw(SPR_TRAMWAY_TUNNEL_WIRES + tunnelbridge_direction, PAL_NONE, ti->x, ti->y, BB_data[10], BB_data[11], TILE_HEIGHT, ti->z, IsTransparencySet(TO_CATENARY), BB_data[8], BB_data[9], BB_Z_SEPARATOR);
1200                                 }
1201                         }
1202                 } else {
1203                         const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(ti->tile));
1204                         if (rti->UsesOverlay()) {
1205                                 SpriteID surface = GetCustomRailSprite(rti, ti->tile, RTSG_TUNNEL);
1206                                 if (surface != 0) DrawGroundSprite(surface + tunnelbridge_direction, PAL_NONE);
1207                         }
1208
1209                         /* PBS debugging, draw reserved tracks darker */
1210                         if (_game_mode != GM_MENU && _settings_client.gui.show_track_reservation && HasTunnelBridgeReservation(ti->tile)) {
1211                                 if (rti->UsesOverlay()) {
1212                                         SpriteID overlay = GetCustomRailSprite(rti, ti->tile, RTSG_OVERLAY);
1213                                         DrawGroundSprite(overlay + RTO_X + DiagDirToAxis(tunnelbridge_direction), PALETTE_CRASH);
1214                                 } else {
1215                                         DrawGroundSprite(DiagDirToAxis(tunnelbridge_direction) == AXIS_X ? rti->base_sprites.single_x : rti->base_sprites.single_y, PALETTE_CRASH);
1216                                 }
1217                         }
1218
1219                         if (HasRailCatenaryDrawn(GetRailType(ti->tile))) {
1220                                 /* Maybe draw pylons on the entry side */
1221                                 DrawRailCatenary(ti);
1222
1223                                 catenary = true;
1224                                 StartSpriteCombine();
1225                                 /* Draw wire above the ramp */
1226                                 DrawRailCatenaryOnTunnel(ti);
1227                         }
1228                 }
1229
1230                 if (railtype_overlay != 0 && !catenary) StartSpriteCombine();
1231
1232                 AddSortableSpriteToDraw(image + 1, PAL_NONE, ti->x + TILE_SIZE - 1, ti->y + TILE_SIZE - 1, BB_data[0], BB_data[1], TILE_HEIGHT, ti->z, false, BB_data[2], BB_data[3], BB_Z_SEPARATOR);
1233                 /* Draw railtype tunnel portal overlay if defined. */
1234                 if (railtype_overlay != 0) AddSortableSpriteToDraw(railtype_overlay + tunnelbridge_direction, PAL_NONE, ti->x + TILE_SIZE - 1, ti->y + TILE_SIZE - 1, BB_data[0], BB_data[1], TILE_HEIGHT, ti->z, false, BB_data[2], BB_data[3], BB_Z_SEPARATOR);
1235
1236                 if (catenary || railtype_overlay != 0) EndSpriteCombine();
1237
1238                 /* Add helper BB for sprite sorting that separates the tunnel from things beside of it. */
1239                 AddSortableSpriteToDraw(SPR_EMPTY_BOUNDING_BOX, PAL_NONE, ti->x,              ti->y,              BB_data[6], BB_data[7], TILE_HEIGHT, ti->z);
1240                 AddSortableSpriteToDraw(SPR_EMPTY_BOUNDING_BOX, PAL_NONE, ti->x + BB_data[4], ti->y + BB_data[5], BB_data[6], BB_data[7], TILE_HEIGHT, ti->z);
1241
1242                 DrawBridgeMiddle(ti);
1243         } else { // IsBridge(ti->tile)
1244                 const PalSpriteID *psid;
1245                 int base_offset;
1246                 bool ice = HasTunnelBridgeSnowOrDesert(ti->tile);
1247
1248                 if (transport_type == TRANSPORT_RAIL) {
1249                         base_offset = GetRailTypeInfo(GetRailType(ti->tile))->bridge_offset;
1250                         assert(base_offset != 8); // This one is used for roads
1251                 } else {
1252                         base_offset = 8;
1253                 }
1254
1255                 /* as the lower 3 bits are used for other stuff, make sure they are clear */
1256                 assert( (base_offset & 0x07) == 0x00);
1257
1258                 DrawFoundation(ti, GetBridgeFoundation(ti->tileh, DiagDirToAxis(tunnelbridge_direction)));
1259
1260                 /* HACK Wizardry to convert the bridge ramp direction into a sprite offset */
1261                 base_offset += (6 - tunnelbridge_direction) % 4;
1262
1263                 /* Table number BRIDGE_PIECE_HEAD always refers to the bridge heads for any bridge type */
1264                 if (transport_type != TRANSPORT_WATER) {
1265                         if (ti->tileh == SLOPE_FLAT) base_offset += 4; // sloped bridge head
1266                         psid = &GetBridgeSpriteTable(GetBridgeType(ti->tile), BRIDGE_PIECE_HEAD)[base_offset];
1267                 } else {
1268                         psid = _aqueduct_sprites + base_offset;
1269                 }
1270
1271                 if (!ice) {
1272                         TileIndex next = ti->tile + TileOffsByDiagDir(tunnelbridge_direction);
1273                         if (ti->tileh != SLOPE_FLAT && ti->z == 0 && HasTileWaterClass(next) && GetWaterClass(next) == WATER_CLASS_SEA) {
1274                                 DrawShoreTile(ti->tileh);
1275                         } else {
1276                                 DrawClearLandTile(ti, 3);
1277                         }
1278                 } else {
1279                         DrawGroundSprite(SPR_FLAT_SNOW_DESERT_TILE + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
1280                 }
1281
1282                 /* draw ramp */
1283
1284                 /* Draw Trambits and PBS Reservation as SpriteCombine */
1285                 if (transport_type == TRANSPORT_ROAD || transport_type == TRANSPORT_RAIL) StartSpriteCombine();
1286
1287                 /* HACK set the height of the BB of a sloped ramp to 1 so a vehicle on
1288                  * it doesn't disappear behind it
1289                  */
1290                 /* Bridge heads are drawn solid no matter how invisibility/transparency is set */
1291                 AddSortableSpriteToDraw(psid->sprite, psid->pal, ti->x, ti->y, 16, 16, ti->tileh == SLOPE_FLAT ? 0 : 8, ti->z);
1292
1293                 if (transport_type == TRANSPORT_ROAD) {
1294                         RoadTypes rts = GetRoadTypes(ti->tile);
1295
1296                         if (HasBit(rts, ROADTYPE_TRAM)) {
1297                                 uint offset = tunnelbridge_direction;
1298                                 int z = ti->z;
1299                                 if (ti->tileh != SLOPE_FLAT) {
1300                                         offset = (offset + 1) & 1;
1301                                         z += TILE_HEIGHT;
1302                                 } else {
1303                                         offset += 2;
1304                                 }
1305                                 /* DrawBridgeTramBits() calls EndSpriteCombine() and StartSpriteCombine() */
1306                                 DrawBridgeTramBits(ti->x, ti->y, z, offset, HasBit(rts, ROADTYPE_ROAD), true);
1307                         }
1308                         EndSpriteCombine();
1309                 } else if (transport_type == TRANSPORT_RAIL) {
1310                         const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(ti->tile));
1311                         if (rti->UsesOverlay()) {
1312                                 SpriteID surface = GetCustomRailSprite(rti, ti->tile, RTSG_BRIDGE);
1313                                 if (surface != 0) {
1314                                         if (HasBridgeFlatRamp(ti->tileh, DiagDirToAxis(tunnelbridge_direction))) {
1315                                                 AddSortableSpriteToDraw(surface + ((DiagDirToAxis(tunnelbridge_direction) == AXIS_X) ? RTBO_X : RTBO_Y), PAL_NONE, ti->x, ti->y, 16, 16, 0, ti->z + 8);
1316                                         } else {
1317                                                 AddSortableSpriteToDraw(surface + RTBO_SLOPE + tunnelbridge_direction, PAL_NONE, ti->x, ti->y, 16, 16, 8, ti->z);
1318                                         }
1319                                 }
1320                                 /* Don't fallback to non-overlay sprite -- the spec states that
1321                                  * if an overlay is present then the bridge surface must be
1322                                  * present. */
1323                         }
1324
1325                         /* PBS debugging, draw reserved tracks darker */
1326                         if (_game_mode != GM_MENU && _settings_client.gui.show_track_reservation && HasTunnelBridgeReservation(ti->tile)) {
1327                                 if (rti->UsesOverlay()) {
1328                                         SpriteID overlay = GetCustomRailSprite(rti, ti->tile, RTSG_OVERLAY);
1329                                         if (HasBridgeFlatRamp(ti->tileh, DiagDirToAxis(tunnelbridge_direction))) {
1330                                                 AddSortableSpriteToDraw(overlay + RTO_X + DiagDirToAxis(tunnelbridge_direction), PALETTE_CRASH, ti->x, ti->y, 16, 16, 0, ti->z + 8);
1331                                         } else {
1332                                                 AddSortableSpriteToDraw(overlay + RTO_SLOPE_NE + tunnelbridge_direction, PALETTE_CRASH, ti->x, ti->y, 16, 16, 8, ti->z);
1333                                         }
1334                                 } else {
1335                                         if (HasBridgeFlatRamp(ti->tileh, DiagDirToAxis(tunnelbridge_direction))) {
1336                                                 AddSortableSpriteToDraw(DiagDirToAxis(tunnelbridge_direction) == AXIS_X ? rti->base_sprites.single_x : rti->base_sprites.single_y, PALETTE_CRASH, ti->x, ti->y, 16, 16, 0, ti->z + 8);
1337                                         } else {
1338                                                 AddSortableSpriteToDraw(rti->base_sprites.single_sloped + tunnelbridge_direction, PALETTE_CRASH, ti->x, ti->y, 16, 16, 8, ti->z);
1339                                         }
1340                                 }
1341                         }
1342
1343                         EndSpriteCombine();
1344                         if (HasRailCatenaryDrawn(GetRailType(ti->tile))) {
1345                                 DrawRailCatenary(ti);
1346                         }
1347                 }
1348
1349                 DrawBridgeMiddle(ti);
1350         }
1351 }
1352
1353
1354 /**
1355  * Compute bridge piece. Computes the bridge piece to display depending on the position inside the bridge.
1356  * bridges pieces sequence (middle parts).
1357  * Note that it is not covering the bridge heads, which are always referenced by the same sprite table.
1358  * bridge len 1: BRIDGE_PIECE_NORTH
1359  * bridge len 2: BRIDGE_PIECE_NORTH  BRIDGE_PIECE_SOUTH
1360  * bridge len 3: BRIDGE_PIECE_NORTH  BRIDGE_PIECE_MIDDLE_ODD   BRIDGE_PIECE_SOUTH
1361  * bridge len 4: BRIDGE_PIECE_NORTH  BRIDGE_PIECE_INNER_NORTH  BRIDGE_PIECE_INNER_SOUTH  BRIDGE_PIECE_SOUTH
1362  * bridge len 5: BRIDGE_PIECE_NORTH  BRIDGE_PIECE_INNER_NORTH  BRIDGE_PIECE_MIDDLE_EVEN  BRIDGE_PIECE_INNER_SOUTH  BRIDGE_PIECE_SOUTH
1363  * bridge len 6: BRIDGE_PIECE_NORTH  BRIDGE_PIECE_INNER_NORTH  BRIDGE_PIECE_INNER_SOUTH  BRIDGE_PIECE_INNER_NORTH  BRIDGE_PIECE_INNER_SOUTH  BRIDGE_PIECE_SOUTH
1364  * bridge len 7: BRIDGE_PIECE_NORTH  BRIDGE_PIECE_INNER_NORTH  BRIDGE_PIECE_INNER_SOUTH  BRIDGE_PIECE_MIDDLE_ODD   BRIDGE_PIECE_INNER_NORTH  BRIDGE_PIECE_INNER_SOUTH  BRIDGE_PIECE_SOUTH
1365  * #0 - always as first, #1 - always as last (if len>1)
1366  * #2,#3 are to pair in order
1367  * for odd bridges: #5 is going in the bridge middle if on even position, #4 on odd (counting from 0)
1368  * @param north Northernmost tile of bridge
1369  * @param south Southernmost tile of bridge
1370  * @return Index of bridge piece
1371  */
1372 static BridgePieces CalcBridgePiece(uint north, uint south)
1373 {
1374         if (north == 1) {
1375                 return BRIDGE_PIECE_NORTH;
1376         } else if (south == 1) {
1377                 return BRIDGE_PIECE_SOUTH;
1378         } else if (north < south) {
1379                 return north & 1 ? BRIDGE_PIECE_INNER_SOUTH : BRIDGE_PIECE_INNER_NORTH;
1380         } else if (north > south) {
1381                 return south & 1 ? BRIDGE_PIECE_INNER_NORTH : BRIDGE_PIECE_INNER_SOUTH;
1382         } else {
1383                 return north & 1 ? BRIDGE_PIECE_MIDDLE_EVEN : BRIDGE_PIECE_MIDDLE_ODD;
1384         }
1385 }
1386
1387 /**
1388  * Draw the middle bits of a bridge.
1389  * @param ti Tile information of the tile to draw it on.
1390  */
1391 void DrawBridgeMiddle(const TileInfo *ti)
1392 {
1393         /* Sectional view of bridge bounding boxes:
1394          *
1395          *  1           2                                1,2 = SpriteCombine of Bridge front/(back&floor) and RoadCatenary
1396          *  1           2                                  3 = empty helper BB
1397          *  1     7     2                                4,5 = pillars under higher bridges
1398          *  1 6 88888 6 2                                  6 = elrail-pylons
1399          *  1 6 88888 6 2                                  7 = elrail-wire
1400          *  1 6 88888 6 2  <- TILE_HEIGHT                  8 = rail-vehicle on bridge
1401          *  3333333333333  <- BB_Z_SEPARATOR
1402          *                 <- unused
1403          *    4       5    <- BB_HEIGHT_UNDER_BRIDGE
1404          *    4       5
1405          *    4       5
1406          *
1407          */
1408
1409         if (!IsBridgeAbove(ti->tile)) return;
1410
1411         TileIndex rampnorth = GetNorthernBridgeEnd(ti->tile);
1412         TileIndex rampsouth = GetSouthernBridgeEnd(ti->tile);
1413         TransportType transport_type = GetTunnelBridgeTransportType(rampsouth);
1414
1415         Axis axis = GetBridgeAxis(ti->tile);
1416         BridgePieces piece = CalcBridgePiece(
1417                 GetTunnelBridgeLength(ti->tile, rampnorth) + 1,
1418                 GetTunnelBridgeLength(ti->tile, rampsouth) + 1
1419         );
1420
1421         const PalSpriteID *psid;
1422         bool drawfarpillar;
1423         if (transport_type != TRANSPORT_WATER) {
1424                 BridgeType type =  GetBridgeType(rampsouth);
1425                 drawfarpillar = !HasBit(GetBridgeSpec(type)->flags, 0);
1426
1427                 uint base_offset;
1428                 if (transport_type == TRANSPORT_RAIL) {
1429                         base_offset = GetRailTypeInfo(GetRailType(rampsouth))->bridge_offset;
1430                 } else {
1431                         base_offset = 8;
1432                 }
1433
1434                 psid = base_offset + GetBridgeSpriteTable(type, piece);
1435         } else {
1436                 drawfarpillar = true;
1437                 psid = _aqueduct_sprites;
1438         }
1439
1440         if (axis != AXIS_X) psid += 4;
1441
1442         int x = ti->x;
1443         int y = ti->y;
1444         uint bridge_z = GetBridgePixelHeight(rampsouth);
1445         int z = bridge_z - BRIDGE_Z_START;
1446
1447         /* Add a bounding box that separates the bridge from things below it. */
1448         AddSortableSpriteToDraw(SPR_EMPTY_BOUNDING_BOX, PAL_NONE, x, y, 16, 16, 1, bridge_z - TILE_HEIGHT + BB_Z_SEPARATOR);
1449
1450         /* Draw Trambits as SpriteCombine */
1451         if (transport_type == TRANSPORT_ROAD || transport_type == TRANSPORT_RAIL) StartSpriteCombine();
1452
1453         /* Draw floor and far part of bridge*/
1454         if (!IsInvisibilitySet(TO_BRIDGES)) {
1455                 if (axis == AXIS_X) {
1456                         AddSortableSpriteToDraw(psid->sprite, psid->pal, x, y, 16, 1, 0x28, z, IsTransparencySet(TO_BRIDGES), 0, 0, BRIDGE_Z_START);
1457                 } else {
1458                         AddSortableSpriteToDraw(psid->sprite, psid->pal, x, y, 1, 16, 0x28, z, IsTransparencySet(TO_BRIDGES), 0, 0, BRIDGE_Z_START);
1459                 }
1460         }
1461
1462         psid++;
1463
1464         if (transport_type == TRANSPORT_ROAD) {
1465                 RoadTypes rts = GetRoadTypes(rampsouth);
1466
1467                 if (HasBit(rts, ROADTYPE_TRAM)) {
1468                         /* DrawBridgeTramBits() calls EndSpriteCombine() and StartSpriteCombine() */
1469                         DrawBridgeTramBits(x, y, bridge_z, axis ^ 1, HasBit(rts, ROADTYPE_ROAD), false);
1470                 } else {
1471                         EndSpriteCombine();
1472                         StartSpriteCombine();
1473                 }
1474         } else if (transport_type == TRANSPORT_RAIL) {
1475                 const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(rampsouth));
1476                 if (rti->UsesOverlay() && !IsInvisibilitySet(TO_BRIDGES)) {
1477                         SpriteID surface = GetCustomRailSprite(rti, rampsouth, RTSG_BRIDGE, TCX_ON_BRIDGE);
1478                         if (surface != 0) {
1479                                 AddSortableSpriteToDraw(surface + axis, PAL_NONE, x, y, 16, 16, 0, bridge_z, IsTransparencySet(TO_BRIDGES));
1480                         }
1481                 }
1482
1483                 if (_game_mode != GM_MENU && _settings_client.gui.show_track_reservation && !IsInvisibilitySet(TO_BRIDGES) && HasTunnelBridgeReservation(rampnorth)) {
1484                         if (rti->UsesOverlay()) {
1485                                 SpriteID overlay = GetCustomRailSprite(rti, ti->tile, RTSG_OVERLAY);
1486                                 AddSortableSpriteToDraw(overlay + RTO_X + axis, PALETTE_CRASH, ti->x, ti->y, 16, 16, 0, bridge_z, IsTransparencySet(TO_BRIDGES));
1487                         } else {
1488                                 AddSortableSpriteToDraw(axis == AXIS_X ? rti->base_sprites.single_x : rti->base_sprites.single_y, PALETTE_CRASH, ti->x, ti->y, 16, 16, 0, bridge_z, IsTransparencySet(TO_BRIDGES));
1489                         }
1490                 }
1491
1492                 EndSpriteCombine();
1493
1494                 if (HasRailCatenaryDrawn(GetRailType(rampsouth))) {
1495                         DrawRailCatenaryOnBridge(ti);
1496                 }
1497         }
1498
1499         /* draw roof, the component of the bridge which is logically between the vehicle and the camera */
1500         if (!IsInvisibilitySet(TO_BRIDGES)) {
1501                 if (axis == AXIS_X) {
1502                         y += 12;
1503                         if (psid->sprite & SPRITE_MASK) AddSortableSpriteToDraw(psid->sprite, psid->pal, x, y, 16, 4, 0x28, z, IsTransparencySet(TO_BRIDGES), 0, 3, BRIDGE_Z_START);
1504                 } else {
1505                         x += 12;
1506                         if (psid->sprite & SPRITE_MASK) AddSortableSpriteToDraw(psid->sprite, psid->pal, x, y, 4, 16, 0x28, z, IsTransparencySet(TO_BRIDGES), 3, 0, BRIDGE_Z_START);
1507                 }
1508         }
1509
1510         /* Draw TramFront as SpriteCombine */
1511         if (transport_type == TRANSPORT_ROAD) EndSpriteCombine();
1512
1513         /* Do not draw anything more if bridges are invisible */
1514         if (IsInvisibilitySet(TO_BRIDGES)) return;
1515
1516         psid++;
1517         if (ti->z + 5 == z) {
1518                 /* draw poles below for small bridges */
1519                 if (psid->sprite != 0) {
1520                         SpriteID image = psid->sprite;
1521                         SpriteID pal   = psid->pal;
1522                         if (IsTransparencySet(TO_BRIDGES)) {
1523                                 SetBit(image, PALETTE_MODIFIER_TRANSPARENT);
1524                                 pal = PALETTE_TO_TRANSPARENT;
1525                         }
1526
1527                         DrawGroundSpriteAt(image, pal, x - ti->x, y - ti->y, z - ti->z);
1528                 }
1529         } else {
1530                 /* draw pillars below for high bridges */
1531                 DrawBridgePillars(psid, ti, axis, drawfarpillar, x, y, z);
1532         }
1533 }
1534
1535
1536 static int GetSlopePixelZ_TunnelBridge(TileIndex tile, uint x, uint y)
1537 {
1538         int z;
1539         Slope tileh = GetTilePixelSlope(tile, &z);
1540
1541         x &= 0xF;
1542         y &= 0xF;
1543
1544         if (IsTunnel(tile)) {
1545                 uint pos = (DiagDirToAxis(GetTunnelBridgeDirection(tile)) == AXIS_X ? y : x);
1546
1547                 /* In the tunnel entrance? */
1548                 if (5 <= pos && pos <= 10) return z;
1549         } else { // IsBridge(tile)
1550                 DiagDirection dir = GetTunnelBridgeDirection(tile);
1551                 uint pos = (DiagDirToAxis(dir) == AXIS_X ? y : x);
1552
1553                 z += ApplyPixelFoundationToSlope(GetBridgeFoundation(tileh, DiagDirToAxis(dir)), &tileh);
1554
1555                 /* On the bridge ramp? */
1556                 if (5 <= pos && pos <= 10) {
1557                         int delta;
1558
1559                         if (tileh != SLOPE_FLAT) return z + TILE_HEIGHT;
1560
1561                         switch (dir) {
1562                                 default: NOT_REACHED();
1563                                 case DIAGDIR_NE: delta = (TILE_SIZE - 1 - x) / 2; break;
1564                                 case DIAGDIR_SE: delta = y / 2; break;
1565                                 case DIAGDIR_SW: delta = x / 2; break;
1566                                 case DIAGDIR_NW: delta = (TILE_SIZE - 1 - y) / 2; break;
1567                         }
1568                         return z + 1 + delta;
1569                 }
1570         }
1571
1572         return z + GetPartialPixelZ(x, y, tileh);
1573 }
1574
1575 static Foundation GetFoundation_TunnelBridge(TileIndex tile, Slope tileh)
1576 {
1577         return IsTunnel(tile) ? FOUNDATION_NONE : GetBridgeFoundation(tileh, DiagDirToAxis(GetTunnelBridgeDirection(tile)));
1578 }
1579
1580 static void GetTileDesc_TunnelBridge(TileIndex tile, TileDesc *td)
1581 {
1582         TransportType tt = GetTunnelBridgeTransportType(tile);
1583
1584         if (IsTunnel(tile)) {
1585                 td->str = (tt == TRANSPORT_RAIL) ? STR_LAI_TUNNEL_DESCRIPTION_RAILROAD : STR_LAI_TUNNEL_DESCRIPTION_ROAD;
1586         } else { // IsBridge(tile)
1587                 td->str = (tt == TRANSPORT_WATER) ? STR_LAI_BRIDGE_DESCRIPTION_AQUEDUCT : GetBridgeSpec(GetBridgeType(tile))->transport_name[tt];
1588         }
1589         td->owner[0] = GetTileOwner(tile);
1590
1591         Owner road_owner = INVALID_OWNER;
1592         Owner tram_owner = INVALID_OWNER;
1593         RoadTypes rts = GetRoadTypes(tile);
1594         if (HasBit(rts, ROADTYPE_ROAD)) road_owner = GetRoadOwner(tile, ROADTYPE_ROAD);
1595         if (HasBit(rts, ROADTYPE_TRAM)) tram_owner = GetRoadOwner(tile, ROADTYPE_TRAM);
1596
1597         /* Is there a mix of owners? */
1598         if ((tram_owner != INVALID_OWNER && tram_owner != td->owner[0]) ||
1599                         (road_owner != INVALID_OWNER && road_owner != td->owner[0])) {
1600                 uint i = 1;
1601                 if (road_owner != INVALID_OWNER) {
1602                         td->owner_type[i] = STR_LAND_AREA_INFORMATION_ROAD_OWNER;
1603                         td->owner[i] = road_owner;
1604                         i++;
1605                 }
1606                 if (tram_owner != INVALID_OWNER) {
1607                         td->owner_type[i] = STR_LAND_AREA_INFORMATION_TRAM_OWNER;
1608                         td->owner[i] = tram_owner;
1609                 }
1610         }
1611
1612         if (tt == TRANSPORT_RAIL) {
1613                 const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(tile));
1614                 td->rail_speed = rti->max_speed;
1615                 td->railtype = rti->strings.name;
1616
1617                 if (!IsTunnel(tile)) {
1618                         uint16 spd = GetBridgeSpec(GetBridgeType(tile))->speed;
1619                         if (td->rail_speed == 0 || spd < td->rail_speed) {
1620                                 td->rail_speed = spd;
1621                         }
1622                 }
1623         } else if (tt == TRANSPORT_ROAD && !IsTunnel(tile)) {
1624                 td->road_speed = GetBridgeSpec(GetBridgeType(tile))->speed;
1625         }
1626 }
1627
1628
1629 static void TileLoop_TunnelBridge(TileIndex tile)
1630 {
1631         bool snow_or_desert = HasTunnelBridgeSnowOrDesert(tile);
1632         switch (_settings_game.game_creation.landscape) {
1633                 case LT_ARCTIC: {
1634                         /* As long as we do not have a snow density, we want to use the density
1635                          * from the entry edge. For tunnels this is the lowest point for bridges the highest point.
1636                          * (Independent of foundations) */
1637                         int z = IsBridge(tile) ? GetTileMaxZ(tile) : GetTileZ(tile);
1638                         if (snow_or_desert != (z > GetSnowLine())) {
1639                                 SetTunnelBridgeSnowOrDesert(tile, !snow_or_desert);
1640                                 MarkTileDirtyByTile(tile);
1641                         }
1642                         break;
1643                 }
1644
1645                 case LT_TROPIC:
1646                         if (GetTropicZone(tile) == TROPICZONE_DESERT && !snow_or_desert) {
1647                                 SetTunnelBridgeSnowOrDesert(tile, true);
1648                                 MarkTileDirtyByTile(tile);
1649                         }
1650                         break;
1651
1652                 default:
1653                         break;
1654         }
1655 }
1656
1657 static TrackStatus GetTileTrackStatus_TunnelBridge(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
1658 {
1659         TransportType transport_type = GetTunnelBridgeTransportType(tile);
1660         if (transport_type != mode || (transport_type == TRANSPORT_ROAD && (GetRoadTypes(tile) & sub_mode) == 0)) return 0;
1661
1662         DiagDirection dir = GetTunnelBridgeDirection(tile);
1663         if (side != INVALID_DIAGDIR && side != ReverseDiagDir(dir)) return 0;
1664         return CombineTrackStatus(TrackBitsToTrackdirBits(DiagDirToDiagTrackBits(dir)), TRACKDIR_BIT_NONE);
1665 }
1666
1667 static void ChangeTileOwner_TunnelBridge(TileIndex tile, Owner old_owner, Owner new_owner)
1668 {
1669         TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
1670         /* Set number of pieces to zero if it's the southern tile as we
1671          * don't want to update the infrastructure counts twice. */
1672         uint num_pieces = tile < other_end ? (GetTunnelBridgeLength(tile, other_end) + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR : 0;
1673
1674         for (RoadType rt = ROADTYPE_ROAD; rt < ROADTYPE_END; rt++) {
1675                 /* Update all roadtypes, no matter if they are present */
1676                 if (GetRoadOwner(tile, rt) == old_owner) {
1677                         if (HasBit(GetRoadTypes(tile), rt)) {
1678                                 /* Update company infrastructure counts. A full diagonal road tile has two road bits.
1679                                  * No need to dirty windows here, we'll redraw the whole screen anyway. */
1680                                 Company::Get(old_owner)->infrastructure.road[rt] -= num_pieces * 2;
1681                                 if (new_owner != INVALID_OWNER) Company::Get(new_owner)->infrastructure.road[rt] += num_pieces * 2;
1682                         }
1683
1684                         SetRoadOwner(tile, rt, new_owner == INVALID_OWNER ? OWNER_NONE : new_owner);
1685                 }
1686         }
1687
1688         if (!IsTileOwner(tile, old_owner)) return;
1689
1690         /* Update company infrastructure counts for rail and water as well.
1691          * No need to dirty windows here, we'll redraw the whole screen anyway. */
1692         TransportType tt = GetTunnelBridgeTransportType(tile);
1693         Company *old = Company::Get(old_owner);
1694         if (tt == TRANSPORT_RAIL) {
1695                 old->infrastructure.rail[GetRailType(tile)] -= num_pieces;
1696                 if (new_owner != INVALID_OWNER) Company::Get(new_owner)->infrastructure.rail[GetRailType(tile)] += num_pieces;
1697         } else if (tt == TRANSPORT_WATER) {
1698                 old->infrastructure.water -= num_pieces;
1699                 if (new_owner != INVALID_OWNER) Company::Get(new_owner)->infrastructure.water += num_pieces;
1700         }
1701
1702         if (new_owner != INVALID_OWNER) {
1703                 SetTileOwner(tile, new_owner);
1704         } else {
1705                 if (tt == TRANSPORT_RAIL) {
1706                         /* Since all of our vehicles have been removed, it is safe to remove the rail
1707                          * bridge / tunnel. */
1708                         CommandCost ret = DoCommand(tile, 0, 0, DC_EXEC | DC_BANKRUPT, CMD_LANDSCAPE_CLEAR);
1709                         assert(ret.Succeeded());
1710                 } else {
1711                         /* In any other case, we can safely reassign the ownership to OWNER_NONE. */
1712                         SetTileOwner(tile, OWNER_NONE);
1713                 }
1714         }
1715 }
1716
1717 /**
1718  * Frame when the 'enter tunnel' sound should be played. This is the second
1719  * frame on a tile, so the sound is played shortly after entering the tunnel
1720  * tile, while the vehicle is still visible.
1721  */
1722 static const byte TUNNEL_SOUND_FRAME = 1;
1723
1724 /**
1725  * Frame when a vehicle should be hidden in a tunnel with a certain direction.
1726  * This differs per direction, because of visibility / bounding box issues.
1727  * Note that direction, in this case, is the direction leading into the tunnel.
1728  * When entering a tunnel, hide the vehicle when it reaches the given frame.
1729  * When leaving a tunnel, show the vehicle when it is one frame further
1730  * to the 'outside', i.e. at (TILE_SIZE-1) - (frame) + 1
1731  */
1732 extern const byte _tunnel_visibility_frame[DIAGDIR_END] = {12, 8, 8, 12};
1733
1734 static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex tile, int x, int y)
1735 {
1736         int z = GetSlopePixelZ(x, y) - v->z_pos;
1737
1738         if (abs(z) > 2) return VETSB_CANNOT_ENTER;
1739         /* Direction into the wormhole */
1740         const DiagDirection dir = GetTunnelBridgeDirection(tile);
1741         /* Direction of the vehicle */
1742         const DiagDirection vdir = DirToDiagDir(v->direction);
1743         /* New position of the vehicle on the tile */
1744         byte pos = (DiagDirToAxis(vdir) == AXIS_X ? x : y) & TILE_UNIT_MASK;
1745         /* Number of units moved by the vehicle since entering the tile */
1746         byte frame = (vdir == DIAGDIR_NE || vdir == DIAGDIR_NW) ? TILE_SIZE - 1 - pos : pos;
1747
1748         if (IsTunnel(tile)) {
1749                 if (v->type == VEH_TRAIN) {
1750                         Train *t = Train::From(v);
1751
1752                         if (t->track != TRACK_BIT_WORMHOLE && dir == vdir) {
1753                                 if (t->IsFrontEngine() && frame == TUNNEL_SOUND_FRAME) {
1754                                         if (!PlayVehicleSound(t, VSE_TUNNEL) && RailVehInfo(t->engine_type)->engclass == 0) {
1755                                                 SndPlayVehicleFx(SND_05_TRAIN_THROUGH_TUNNEL, v);
1756                                         }
1757                                         return VETSB_CONTINUE;
1758                                 }
1759                                 if (frame == _tunnel_visibility_frame[dir]) {
1760                                         t->tile = tile;
1761                                         t->track = TRACK_BIT_WORMHOLE;
1762                                         t->vehstatus |= VS_HIDDEN;
1763                                         return VETSB_ENTERED_WORMHOLE;
1764                                 }
1765                         }
1766
1767                         if (dir == ReverseDiagDir(vdir) && frame == TILE_SIZE - _tunnel_visibility_frame[dir] && z == 0) {
1768                                 /* We're at the tunnel exit ?? */
1769                                 t->tile = tile;
1770                                 t->track = DiagDirToDiagTrackBits(vdir);
1771                                 assert(t->track);
1772                                 t->vehstatus &= ~VS_HIDDEN;
1773                                 return VETSB_ENTERED_WORMHOLE;
1774                         }
1775                 } else if (v->type == VEH_ROAD) {
1776                         RoadVehicle *rv = RoadVehicle::From(v);
1777
1778                         /* Enter tunnel? */
1779                         if (rv->state != RVSB_WORMHOLE && dir == vdir) {
1780                                 if (frame == _tunnel_visibility_frame[dir]) {
1781                                         /* Frame should be equal to the next frame number in the RV's movement */
1782                                         assert(frame == rv->frame + 1);
1783                                         rv->tile = tile;
1784                                         rv->state = RVSB_WORMHOLE;
1785                                         rv->vehstatus |= VS_HIDDEN;
1786                                         return VETSB_ENTERED_WORMHOLE;
1787                                 } else {
1788                                         return VETSB_CONTINUE;
1789                                 }
1790                         }
1791
1792                         /* We're at the tunnel exit ?? */
1793                         if (dir == ReverseDiagDir(vdir) && frame == TILE_SIZE - _tunnel_visibility_frame[dir] && z == 0) {
1794                                 rv->tile = tile;
1795                                 rv->state = DiagDirToDiagTrackdir(vdir);
1796                                 rv->frame = frame;
1797                                 rv->vehstatus &= ~VS_HIDDEN;
1798                                 return VETSB_ENTERED_WORMHOLE;
1799                         }
1800                 }
1801         } else { // IsBridge(tile)
1802                 if (v->type != VEH_SHIP) {
1803                         /* modify speed of vehicle */
1804                         uint16 spd = GetBridgeSpec(GetBridgeType(tile))->speed;
1805
1806                         if (v->type == VEH_ROAD) spd *= 2;
1807                         Vehicle *first = v->First();
1808                         first->cur_speed = min(first->cur_speed, spd);
1809                 }
1810
1811                 if (vdir == dir) {
1812                         /* Vehicle enters bridge at the last frame inside this tile. */
1813                         if (frame != TILE_SIZE - 1) return VETSB_CONTINUE;
1814                         switch (v->type) {
1815                                 case VEH_TRAIN: {
1816                                         Train *t = Train::From(v);
1817                                         t->track = TRACK_BIT_WORMHOLE;
1818                                         ClrBit(t->gv_flags, GVF_GOINGUP_BIT);
1819                                         ClrBit(t->gv_flags, GVF_GOINGDOWN_BIT);
1820                                         break;
1821                                 }
1822
1823                                 case VEH_ROAD: {
1824                                         RoadVehicle *rv = RoadVehicle::From(v);
1825                                         rv->state = RVSB_WORMHOLE;
1826                                         /* There are no slopes inside bridges / tunnels. */
1827                                         ClrBit(rv->gv_flags, GVF_GOINGUP_BIT);
1828                                         ClrBit(rv->gv_flags, GVF_GOINGDOWN_BIT);
1829                                         break;
1830                                 }
1831
1832                                 case VEH_SHIP:
1833                                         Ship::From(v)->state = TRACK_BIT_WORMHOLE;
1834                                         break;
1835
1836                                 default: NOT_REACHED();
1837                         }
1838                         return VETSB_ENTERED_WORMHOLE;
1839                 } else if (vdir == ReverseDiagDir(dir)) {
1840                         v->tile = tile;
1841                         switch (v->type) {
1842                                 case VEH_TRAIN: {
1843                                         Train *t = Train::From(v);
1844                                         if (t->track == TRACK_BIT_WORMHOLE) {
1845                                                 t->track = DiagDirToDiagTrackBits(vdir);
1846                                                 return VETSB_ENTERED_WORMHOLE;
1847                                         }
1848                                         break;
1849                                 }
1850
1851                                 case VEH_ROAD: {
1852                                         RoadVehicle *rv = RoadVehicle::From(v);
1853                                         if (rv->state == RVSB_WORMHOLE) {
1854                                                 rv->state = DiagDirToDiagTrackdir(vdir);
1855                                                 rv->frame = 0;
1856                                                 return VETSB_ENTERED_WORMHOLE;
1857                                         }
1858                                         break;
1859                                 }
1860
1861                                 case VEH_SHIP: {
1862                                         Ship *ship = Ship::From(v);
1863                                         if (ship->state == TRACK_BIT_WORMHOLE) {
1864                                                 ship->state = DiagDirToDiagTrackBits(vdir);
1865                                                 return VETSB_ENTERED_WORMHOLE;
1866                                         }
1867                                         break;
1868                                 }
1869
1870                                 default: NOT_REACHED();
1871                         }
1872                 }
1873         }
1874         return VETSB_CONTINUE;
1875 }
1876
1877 static CommandCost TerraformTile_TunnelBridge(TileIndex tile, DoCommandFlag flags, int z_new, Slope tileh_new)
1878 {
1879         if (_settings_game.construction.build_on_slopes && AutoslopeEnabled() && IsBridge(tile) && GetTunnelBridgeTransportType(tile) != TRANSPORT_WATER) {
1880                 DiagDirection direction = GetTunnelBridgeDirection(tile);
1881                 Axis axis = DiagDirToAxis(direction);
1882                 CommandCost res;
1883                 int z_old;
1884                 Slope tileh_old = GetTileSlope(tile, &z_old);
1885
1886                 /* Check if new slope is valid for bridges in general (so we can safely call GetBridgeFoundation()) */
1887                 if ((direction == DIAGDIR_NW) || (direction == DIAGDIR_NE)) {
1888                         CheckBridgeSlopeSouth(axis, &tileh_old, &z_old);
1889                         res = CheckBridgeSlopeSouth(axis, &tileh_new, &z_new);
1890                 } else {
1891                         CheckBridgeSlopeNorth(axis, &tileh_old, &z_old);
1892                         res = CheckBridgeSlopeNorth(axis, &tileh_new, &z_new);
1893                 }
1894
1895                 /* Surface slope is valid and remains unchanged? */
1896                 if (res.Succeeded() && (z_old == z_new) && (tileh_old == tileh_new)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
1897         }
1898
1899         return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
1900 }
1901
1902 extern const TileTypeProcs _tile_type_tunnelbridge_procs = {
1903         DrawTile_TunnelBridge,           // draw_tile_proc
1904         GetSlopePixelZ_TunnelBridge,     // get_slope_z_proc
1905         ClearTile_TunnelBridge,          // clear_tile_proc
1906         NULL,                            // add_accepted_cargo_proc
1907         GetTileDesc_TunnelBridge,        // get_tile_desc_proc
1908         GetTileTrackStatus_TunnelBridge, // get_tile_track_status_proc
1909         NULL,                            // click_tile_proc
1910         NULL,                            // animate_tile_proc
1911         TileLoop_TunnelBridge,           // tile_loop_proc
1912         ChangeTileOwner_TunnelBridge,    // change_tile_owner_proc
1913         NULL,                            // add_produced_cargo_proc
1914         VehicleEnter_TunnelBridge,       // vehicle_enter_tile_proc
1915         GetFoundation_TunnelBridge,      // get_foundation_proc
1916         TerraformTile_TunnelBridge,      // terraform_tile_proc
1917 };