Update readme and changelog for v1.27.0

[openttd-joker.git] / src / road_cmd.cpp

/* $Id$ */

/*
 * This file is part of OpenTTD.
 * 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.
 * 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.
 * 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/>.
 */

/** @file road_cmd.cpp Commands related to road tiles. */

#include "stdafx.h"
#include "cmd_helper.h"
#include "road_internal.h"
#include "viewport_func.h"
#include "command_func.h"
#include "pathfinder/yapf/yapf_cache.h"
#include "depot_base.h"
#include "newgrf.h"
#include "autoslope.h"
#include "tunnelbridge_map.h"
#include "strings_func.h"
#include "vehicle_func.h"
#include "sound_func.h"
#include "tunnelbridge.h"
#include "cheat_type.h"
#include "effectvehicle_func.h"
#include "effectvehicle_base.h"
#include "elrail_func.h"
#include "roadveh.h"
#include "town.h"
#include "company_base.h"
#include "core/random_func.hpp"
#include "newgrf_debug.h"
#include "newgrf_railtype.h"
#include "newgrf_roadtype.h"
#include "date_func.h"
#include "genworld.h"
#include "company_gui.h"
#include "road.h"
#include "road_func.h"

#include "table/strings.h"
#include "table/roadtypes.h"

#include "safeguards.h"

/** Helper type for lists/vectors of road vehicles */
typedef SmallVector<RoadVehicle *, 16> RoadVehicleList;

RoadtypeInfo _roadtypes[ROADTYPE_END][ROADSUBTYPE_END];
RoadTypeIdentifier _sorted_roadtypes[ROADTYPE_END][ROADSUBTYPE_END];
uint8 _sorted_roadtypes_size[ROADTYPE_END];

/**
 * Reset all road type information to its default values.
 */
void ResetRoadTypes()
{
        static const RoadtypeInfo empty_roadtype = {
                {0,0,0,0,0,0},
                {0,0,0,0,0,0},
                {0,0,0,0,0,0,0,0,0,{},{},0,{},{}},
                ROADSUBTYPES_NONE, ROTFB_NONE, 0, 0, 0, 0,
                RoadTypeLabelList(), 0, 0, ROADSUBTYPES_NONE, ROADSUBTYPES_NONE, 0,
                {}, {} };

        /* Road type */
        assert_compile(lengthof(_original_roadtypes) <= lengthof(_roadtypes[ROADTYPE_ROAD]));
        uint i = 0;
        for (; i < lengthof(_original_roadtypes);       i++) _roadtypes[ROADTYPE_ROAD][i] = _original_roadtypes[i];
        for (; i < lengthof(_roadtypes[ROADTYPE_ROAD]); i++) _roadtypes[ROADTYPE_ROAD][i] = empty_roadtype;

        /* Tram type */
        assert_compile(lengthof(_original_tramtypes) <= lengthof(_roadtypes[ROADTYPE_TRAM]));
        i = 0;
        for (; i < lengthof(_original_tramtypes);       i++) _roadtypes[ROADTYPE_TRAM][i] = _original_tramtypes[i];
        for (; i < lengthof(_roadtypes[ROADTYPE_TRAM]); i++) _roadtypes[ROADTYPE_TRAM][i] = empty_roadtype;
}

void ResolveRoadTypeGUISprites(RoadtypeInfo *rti)
{
        SpriteID cursors_base = GetCustomRoadSprite(rti, INVALID_TILE, ROTSG_CURSORS);
        if (cursors_base != 0) {
                rti->gui_sprites.build_x_road = cursors_base + 0;
                rti->gui_sprites.build_y_road = cursors_base + 1;
                rti->gui_sprites.auto_road = cursors_base + 2;
                rti->gui_sprites.build_depot = cursors_base + 3;
                rti->gui_sprites.build_tunnel = cursors_base + 4;
                rti->gui_sprites.convert_road = cursors_base + 5;
                rti->cursor.road_swne = cursors_base + 6;
                rti->cursor.road_nwse = cursors_base + 7;
                rti->cursor.autoroad = cursors_base + 8;
                rti->cursor.depot = cursors_base + 9;
                rti->cursor.tunnel = cursors_base + 10;
                rti->cursor.convert_road = cursors_base + 11;
        }
}

/**
 * Compare roadtypes based on their sorting order.
 * @param first  The roadtype to compare to.
 * @param second The roadtype to compare.
 * @return True iff the first should be sorted before the second.
 */
static int CDECL CompareRoadTypes(const RoadTypeIdentifier *first, const RoadTypeIdentifier *second)
{
        return GetRoadTypeInfo(*first)->sorting_order - GetRoadTypeInfo(*second)->sorting_order;
}

/**
 * Resolve sprites of custom road types
 */
void InitRoadTypes()
{
        for (RoadType rt = ROADTYPE_BEGIN; rt != ROADTYPE_END; rt++) {
                for (RoadSubType rst = ROADSUBTYPE_BEGIN; rst != ROADSUBTYPE_END; rst++) {
                        RoadtypeInfo *rti = &_roadtypes[rt][rst];
                        ResolveRoadTypeGUISprites(rti);
                }

                _sorted_roadtypes_size[rt] = 0;
                for (RoadSubType rst = ROADSUBTYPE_BEGIN; rst != ROADSUBTYPE_END; rst++) {
                        if (_roadtypes[rt][rst].label != 0) {
                                _sorted_roadtypes[rt][_sorted_roadtypes_size[rt]++] = RoadTypeIdentifier(rt, rst);
                        }
                }
                QSortT(_sorted_roadtypes[rt], _sorted_roadtypes_size[rt], CompareRoadTypes);
        }
}

/**
 * Allocate a new road type label
 */
RoadTypeIdentifier AllocateRoadType(RoadTypeLabel label, RoadType basetype)
{
        RoadTypeIdentifier rtid;

        rtid.basetype = INVALID_ROADTYPE;
        rtid.subtype = INVALID_ROADSUBTYPE;

        for (RoadSubType rt = ROADSUBTYPE_BEGIN; rt != ROADSUBTYPE_END; rt++) {
                RoadtypeInfo *rti = &_roadtypes[basetype][rt];

                if (rti->label == 0) {
                        /* Set up new road type */
                        *rti = (basetype == ROADTYPE_ROAD ? _original_roadtypes[ROADSUBTYPE_NORMAL] : _original_tramtypes[ROADSUBTYPE_NORMAL]);
                        rti->label = label;
                        rti->alternate_labels.Clear();

                        /* Make us compatible with ourself. */
                        rti->powered_roadtypes = (RoadSubTypes)(1 << rt);

                        /* We also introduce ourself. */
                        rti->introduces_roadtypes = (RoadSubTypes)(1 << rt);

                        /* Default sort order; order of allocation, but with some
                         * offsets so it's easier for NewGRF to pick a spot without
                         * changing the order of other (original) road types.
                         * The << is so you can place other roadtypes in between the
                         * other roadtypes, the 7 is to be able to place something
                         * before the first (default) road type. */
                        rti->sorting_order = rt << 4 | 7;

                        rtid.basetype = basetype;
                        rtid.subtype = rt;

                        return rtid;
                }
        }

        return rtid;
}

/**
 * Verify whether a road vehicle is available.
 * @return \c true if at least one road vehicle is available, \c false if not
 */
bool RoadVehiclesAreBuilt()
{
        const RoadVehicle *rv;
        FOR_ALL_ROADVEHICLES(rv) return true;

        return false;
}

/** Invalid RoadBits on slopes.  */
extern const RoadBits _invalid_tileh_slopes_road[2][15] = {
        /* The inverse of the mixable RoadBits on a leveled slope */
        {
                ROAD_NONE,         // SLOPE_FLAT
                ROAD_NE | ROAD_SE, // SLOPE_W
                ROAD_NE | ROAD_NW, // SLOPE_S

                ROAD_NE,           // SLOPE_SW
                ROAD_NW | ROAD_SW, // SLOPE_E
                ROAD_NONE,         // SLOPE_EW

                ROAD_NW,           // SLOPE_SE
                ROAD_NONE,         // SLOPE_WSE
                ROAD_SE | ROAD_SW, // SLOPE_N

                ROAD_SE,           // SLOPE_NW
                ROAD_NONE,         // SLOPE_NS
                ROAD_NONE,         // SLOPE_ENW

                ROAD_SW,           // SLOPE_NE
                ROAD_NONE,         // SLOPE_SEN
                ROAD_NONE          // SLOPE_NWS
        },
        /* The inverse of the allowed straight roads on a slope
         * (with and without a foundation). */
        {
                ROAD_NONE, // SLOPE_FLAT
                ROAD_NONE, // SLOPE_W    Foundation
                ROAD_NONE, // SLOPE_S    Foundation

                ROAD_Y,    // SLOPE_SW
                ROAD_NONE, // SLOPE_E    Foundation
                ROAD_ALL,  // SLOPE_EW

                ROAD_X,    // SLOPE_SE
                ROAD_ALL,  // SLOPE_WSE
                ROAD_NONE, // SLOPE_N    Foundation

                ROAD_X,    // SLOPE_NW
                ROAD_ALL,  // SLOPE_NS
                ROAD_ALL,  // SLOPE_ENW

                ROAD_Y,    // SLOPE_NE
                ROAD_ALL,  // SLOPE_SEN
                ROAD_ALL   // SLOPE_NW
        }
};

static Foundation GetRoadFoundation(Slope tileh, RoadBits bits);

/**
 * Is it allowed to remove the given road bits from the given tile?
 * @param tile      the tile to remove the road from
 * @param remove    the roadbits that are going to be removed
 * @param owner     the actual owner of the roadbits of the tile
 * @param rt        the road type to remove the bits from
 * @param flags     command flags
 * @param town_check Shall the town rating checked/affected
 * @return A succeeded command when it is allowed to remove the road bits, a failed command otherwise.
 */
CommandCost CheckAllowRemoveRoad(TileIndex tile, RoadBits remove, Owner owner, RoadType rt, DoCommandFlag flags, bool town_check)
{
        if (_game_mode == GM_EDITOR || remove == ROAD_NONE) return CommandCost();

        /* Water can always flood and towns can always remove "normal" road pieces.
         * Towns are not be allowed to remove non "normal" road pieces, like tram
         * tracks as that would result in trams that cannot turn. */
        if (_current_company == OWNER_WATER ||
                        (rt == ROADTYPE_ROAD && !Company::IsValidID(_current_company))) return CommandCost();

        /* Only do the special processing if the road is owned
         * by a town */
        if (owner != OWNER_TOWN) {
                if (owner == OWNER_NONE) return CommandCost();
                CommandCost ret = CheckOwnership(owner);
                return ret;
        }

        if (!town_check) return CommandCost();

        if (_cheats.magic_bulldozer.value) return CommandCost();

        Town *t = ClosestTownFromTile(tile, UINT_MAX);
        if (t == nullptr) return CommandCost();

        /* check if you're allowed to remove the street owned by a town
         * removal allowance depends on difficulty setting */
        CommandCost ret = CheckforTownRating(flags, t, ROAD_REMOVE);
        if (ret.Failed()) return ret;

        /* Get a bitmask of which neighbouring roads has a tile */
        RoadBits n = ROAD_NONE;
        RoadBits present = GetAnyRoadBits(tile, rt);
        if ((present & ROAD_NE) && (GetAnyRoadBits(TILE_ADDXY(tile, -1,  0), rt) & ROAD_SW)) n |= ROAD_NE;
        if ((present & ROAD_SE) && (GetAnyRoadBits(TILE_ADDXY(tile,  0,  1), rt) & ROAD_NW)) n |= ROAD_SE;
        if ((present & ROAD_SW) && (GetAnyRoadBits(TILE_ADDXY(tile,  1,  0), rt) & ROAD_NE)) n |= ROAD_SW;
        if ((present & ROAD_NW) && (GetAnyRoadBits(TILE_ADDXY(tile,  0, -1), rt) & ROAD_SE)) n |= ROAD_NW;

        int rating_decrease = RATING_ROAD_DOWN_STEP_EDGE;
        /* If 0 or 1 bits are set in n, or if no bits that match the bits to remove,
         * then allow it */
        if (KillFirstBit(n) != ROAD_NONE && (n & remove) != ROAD_NONE) {
                /* you can remove all kind of roads with extra dynamite */
                if (!_settings_game.construction.extra_dynamite) {
                        SetDParam(0, t->index);
                        return CommandError(STR_ERROR_LOCAL_AUTHORITY_REFUSES_TO_ALLOW_THIS);
                }
                rating_decrease = RATING_ROAD_DOWN_STEP_INNER;
        }
        ChangeTownRating(t, rating_decrease, RATING_ROAD_MINIMUM, flags);

        return CommandCost();
}


/**
 * Delete a piece of road.
 * @param tile tile where to remove road from
 * @param flags operation to perform
 * @param pieces roadbits to remove
 * @param rtid identifyer describing the roadtype to remove
 * @param town_check should we check if the town allows removal?
 */
static CommandCost RemoveRoad(TileIndex tile, DoCommandFlag flags, RoadBits pieces, RoadTypeIdentifier rtid, bool town_check = true)
{
        const RoadType rt = rtid.basetype;
        const RoadTypes rts = GetRoadTypes(tile);

        // The tile doesn't have the given road type.
        if (!HasBit(rts, rtid.basetype)) return CommandError(rt == ROADTYPE_TRAM ? STR_ERROR_THERE_IS_NO_TRAMWAY : STR_ERROR_THERE_IS_NO_ROAD);

        switch (GetTileType(tile)) {
                case MP_ROAD: {
                        CommandCost ret = EnsureNoVehicleOnGround(tile);
                        if (ret.Failed()) return ret;
                        break;
                }

                case MP_STATION: {
                        if (!IsDriveThroughStopTile(tile)) return CommandError();

                        CommandCost ret = EnsureNoVehicleOnGround(tile);
                        if (ret.Failed()) return ret;
                        break;
                }

                case MP_TUNNELBRIDGE: {
                        if (GetTunnelBridgeTransportType(tile) != TRANSPORT_ROAD) return CommandError();
                        CommandCost ret = TunnelBridgeIsFree(tile, GetOtherTunnelBridgeEnd(tile));
                        if (ret.Failed()) return ret;
                        break;
                }

                default:
                        return CommandError();
        }

        CommandCost ret = CheckAllowRemoveRoad(tile, pieces, GetRoadOwner(tile, rt), rt, flags, town_check);
        if (ret.Failed()) return ret;

        if (!IsTileType(tile, MP_ROAD)) {
                const bool custom_bridge_head = IsBridgeTile(tile) &&
                                HasBridgeFlatRamp(GetTileSlope(tile), DiagDirToAxis(GetTunnelBridgeDirection(tile))) &&
                                (_settings_game.construction.road_custom_bridge_heads || IsRoadCustomBridgeHead(tile));

                // If it's the last roadtype, just clear the whole tile.
                if (!custom_bridge_head && rts == RoadTypeToRoadTypes(rt)) return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);

                CommandCost cost(EXPENSES_CONSTRUCTION);
                if (IsTileType(tile, MP_TUNNELBRIDGE)) {
                        const RoadBits entrance_piece = DiagDirToRoadBits(GetTunnelBridgeDirection(tile));
                        const RoadBits axial_pieces = AxisToRoadBits(DiagDirToAxis(GetTunnelBridgeDirection(tile)));
                        const RoadBits existing = IsBridge(tile) ? GetCustomBridgeHeadRoadBits(tile, rt) : axial_pieces;
                        const RoadType other_rt = (rt == ROADTYPE_ROAD) ? ROADTYPE_TRAM : ROADTYPE_ROAD;

                        // Handle case where we would otherwise leave a single bridge entrance piece.
                        if ((existing & ~pieces) == entrance_piece) {
                                pieces |= entrance_piece;
                        }

                        /* Removing any roadbit in the bridge axis removes the roadtype (that's the behaviour remove-long-roads needs) */
                        if ((existing & pieces) == ROAD_NONE) return CommandError(rt == ROADTYPE_TRAM ? STR_ERROR_THERE_IS_NO_TRAMWAY : STR_ERROR_THERE_IS_NO_ROAD);

                        if (!custom_bridge_head) pieces |= axial_pieces;

                        const TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
                        const uint middle_len = GetTunnelBridgeLength(other_end, tile);
                        uint pieces_count = 0;

                        const RoadBits other_end_existing = IsBridge(other_end) ? GetCustomBridgeHeadRoadBits(other_end, rt) : axial_pieces;
                        RoadBits other_end_pieces = ROAD_NONE;
                        if (pieces & entrance_piece) {
                                other_end_pieces |= MirrorRoadBits(entrance_piece);
                                // If removing the other end entrance would only leave one piece, remove that too.
                                if (CountBits(other_end_existing & ~other_end_pieces) == 1) {
                                        other_end_pieces |= other_end_existing;
                                }
                                pieces_count += middle_len * 2;
                                if (custom_bridge_head && ((GetCustomBridgeHeadRoadBits(tile, other_rt) & entrance_piece) == ROAD_NONE)) {
                                        // Can't leave no entrance pieces for any road type.
                                        return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
                                }
                        }
                        pieces_count += CountBits(pieces & existing);
                        pieces_count += CountBits(other_end_pieces & other_end_existing);
                        cost.AddCost(pieces_count * _price[PR_CLEAR_ROAD]);

                        if (flags & DC_EXEC) {
                                SubtractRoadTunnelBridgeInfrastructure(tile, other_end);

                                const RoadBits bits = existing & ~pieces;
                                const RoadBits other_bits = other_end_existing & ~other_end_pieces;

                                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                RoadTypeIdentifiers other_rtids = RoadTypeIdentifiers::FromTile(other_end);
                                rtids.ClearRoadType(rt);
                                other_rtids.ClearRoadType(rt);
                                if (bits == ROAD_NONE) SetRoadTypes(tile, rtids);
                                if (other_bits == ROAD_NONE) SetRoadTypes(other_end, other_rtids);

                                if (IsBridge(tile)) {
                                        SetCustomBridgeHeadRoadBits(tile, rt, bits);
                                        SetCustomBridgeHeadRoadBits(other_end, rt, other_bits);
                                }

                                if (bits == ROAD_NONE && other_bits == ROAD_NONE) {
                                        /* If the owner of the bridge sells all its road, also move the ownership
                                         * to the owner of the other roadtype, unless the bridge owner is a town. */
                                        Owner other_owner = GetRoadOwner(tile, other_rt);
                                        if (!IsTileOwner(tile, other_owner) && !IsTileOwner(tile, OWNER_TOWN)) {
                                                SetTileOwner(tile, other_owner);
                                                SetTileOwner(other_end, other_owner);
                                        }
                                }

                                /* Mark tiles dirty that have been repaved */
                                if (IsBridge(tile)) {
                                        MarkBridgeDirty(tile);
                                } else {
                                        MarkTileDirtyByTile(tile);
                                        MarkTileDirtyByTile(other_end);
                                }

                                AddRoadTunnelBridgeInfrastructure(tile, other_end);
                                DirtyAllCompanyInfrastructureWindows();
                        }
                } else {
                        assert(IsDriveThroughStopTile(tile));
                        cost.AddCost(_price[PR_CLEAR_ROAD] * 2);

                        if (flags & DC_EXEC) {
                                Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
                                if (c != nullptr) {
                                        /* A full diagonal road tile has two road bits. */
                                        c->infrastructure.road[rtid.basetype][rtid.subtype] -= 2;
                                        DirtyCompanyInfrastructureWindows(c->index);
                                }
                                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                rtids.ClearRoadType(rt);
                                SetRoadTypes(tile, rtids);
                                MarkTileDirtyByTile(tile);
                        }
                }
                return cost;
        }

        switch (GetRoadTileType(tile)) {
                case ROAD_TILE_NORMAL: {
                        Slope tileh = GetTileSlope(tile);

                        /* Steep slopes behave the same as slopes with one corner raised. */
                        if (IsSteepSlope(tileh)) {
                                tileh = SlopeWithOneCornerRaised(GetHighestSlopeCorner(tileh));
                        }

                        RoadBits present = GetRoadBits(tile, rt);
                        const RoadBits other = GetOtherRoadBits(tile, rt);
                        const Foundation f = GetRoadFoundation(tileh, present);

                        if (HasRoadWorks(tile) && _current_company != OWNER_WATER) return CommandError(STR_ERROR_ROAD_WORKS_IN_PROGRESS);

                        /* Autocomplete to a straight road
                         * @li if the bits of the other roadtypes result in another foundation
                         * @li if build on slopes is disabled */
                        if ((IsStraightRoad(other) && (other & _invalid_tileh_slopes_road[0][tileh & SLOPE_ELEVATED]) != ROAD_NONE) ||
                                        (tileh != SLOPE_FLAT && !_settings_game.construction.build_on_slopes)) {
                                pieces |= MirrorRoadBits(pieces);
                        }

                        /* limit the bits to delete to the existing bits. */
                        pieces &= present;
                        if (pieces == ROAD_NONE) return CommandError(rt == ROADTYPE_TRAM ? STR_ERROR_THERE_IS_NO_TRAMWAY : STR_ERROR_THERE_IS_NO_ROAD);

                        /* Now set present what it will be after the remove */
                        present ^= pieces;

                        /* Check for invalid RoadBit combinations on slopes */
                        if (tileh != SLOPE_FLAT && present != ROAD_NONE &&
                                        (present & _invalid_tileh_slopes_road[0][tileh & SLOPE_ELEVATED]) == present) {
                                return CommandError();
                        }

                        if (flags & DC_EXEC) {
                                if (HasRoadWorks(tile)) {
                                        /* flooding tile with road works, don't forget to remove the effect vehicle too */
                                        assert(_current_company == OWNER_WATER);
                                        EffectVehicle *v;
                                        FOR_ALL_EFFECTVEHICLES(v) {
                                                if (TileVirtXY(v->x_pos, v->y_pos) == tile) {
                                                        delete v;
                                                }
                                        }
                                }

                                Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
                                if (c != nullptr) {
                                        c->infrastructure.road[rtid.basetype][rtid.subtype] -= CountBits(pieces);
                                        DirtyCompanyInfrastructureWindows(c->index);
                                }

                                if (present == ROAD_NONE) {
                                        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                        rtids.ClearRoadType(rt);
                                        if (rtids.PresentRoadTypes() == ROADTYPES_NONE) {
                                                /* Includes MarkTileDirtyByTile() */
                                                DoClearSquare(tile);
                                        } else {
                                                if (rt == ROADTYPE_ROAD && IsRoadOwner(tile, ROADTYPE_ROAD, OWNER_TOWN)) {
                                                        /* Update nearest-town index */
                                                        const Town *town = CalcClosestTownFromTile(tile);
                                                        SetTownIndex(tile, town == nullptr ? (TownID)INVALID_TOWN : town->index);
                                                }
                                                SetRoadBits(tile, ROAD_NONE, rt);
                                                SetRoadTypes(tile, rtids);
                                                MarkTileDirtyByTile(tile);
                                        }
                                } else {
                                        /* When bits are removed, you *always* end up with something that
                                         * is not a complete straight road tile. However, trams do not have
                                         * onewayness, so they cannot remove it either. */
                                        if (rt != ROADTYPE_TRAM) SetDisallowedRoadDirections(tile, DRD_NONE);
                                        SetRoadBits(tile, present, rt);
                                        MarkTileDirtyByTile(tile);
                                }
                        }

                        CommandCost cost(EXPENSES_CONSTRUCTION, CountBits(pieces) * _price[PR_CLEAR_ROAD]);
                        /* If we build a foundation we have to pay for it. */
                        if (f == FOUNDATION_NONE && GetRoadFoundation(tileh, present) != FOUNDATION_NONE) cost.AddCost(_price[PR_BUILD_FOUNDATION]);

                        return cost;
                }

                case ROAD_TILE_CROSSING: {
                        if (pieces & ComplementRoadBits(GetCrossingRoadBits(tile))) {
                                return CommandError();
                        }

                        if (flags & DC_EXEC) {
                                Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
                                if (c != nullptr) {
                                        /* A full diagonal road tile has two road bits. */
                                        c->infrastructure.road[rtid.basetype][rtid.subtype] -= 2;
                                        DirtyCompanyInfrastructureWindows(c->index);
                                }

                                Track railtrack = GetCrossingRailTrack(tile);
                                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                rtids.ClearRoadType(rt);
                                if (rtids.PresentRoadTypes() == ROADTYPES_NONE) {
                                        TrackBits tracks = GetCrossingRailBits(tile);
                                        bool reserved = HasCrossingReservation(tile);
                                        MakeRailNormal(tile, GetTileOwner(tile), tracks, GetRailType(tile));
                                        if (reserved) SetTrackReservation(tile, tracks);

                                        /* Update rail count for level crossings. The plain track should still be accounted
                                         * for, so only subtract the difference to the level crossing cost. */
                                        c = Company::GetIfValid(GetTileOwner(tile));
                                        if (c != nullptr) {
                                                c->infrastructure.rail[GetRailType(tile)] -= LEVELCROSSING_TRACKBIT_FACTOR - 1;
                                                DirtyCompanyInfrastructureWindows(c->index);
                                        }
                                } else {
                                        SetRoadTypes(tile, rtids);
                                }
                                MarkTileDirtyByTile(tile);
                                YapfNotifyTrackLayoutChange(tile, railtrack);
                        }
                        return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_CLEAR_ROAD] * 2);
                }

                default:
                case ROAD_TILE_DEPOT:
                        return CommandError();
        }
}


/**
 * Calculate the costs for roads on slopes
 *  Aside modify the RoadBits to fit on the slopes
 *
 * @note The RoadBits are modified too!
 * @param tileh The current slope
 * @param pieces The RoadBits we want to add
 * @param existing The existent RoadBits of the current type
 * @param other The other existent RoadBits
 * @return The costs for these RoadBits on this slope
 */
static CommandCost CheckRoadSlope(Slope tileh, RoadBits *pieces, RoadBits existing, RoadBits other)
{
        /* Remove already build pieces */
        CLRBITS(*pieces, existing);

        /* If we can't build anything stop here */
        if (*pieces == ROAD_NONE) return CommandError();

        /* All RoadBit combos are valid on flat land */
        if (tileh == SLOPE_FLAT) return CommandCost();

        /* Steep slopes behave the same as slopes with one corner raised. */
        if (IsSteepSlope(tileh)) {
                tileh = SlopeWithOneCornerRaised(GetHighestSlopeCorner(tileh));
        }

        /* Save the merge of all bits of the current type */
        RoadBits type_bits = existing | *pieces;

        /* Roads on slopes */
        if (_settings_game.construction.build_on_slopes && (_invalid_tileh_slopes_road[0][tileh] & (other | type_bits)) == ROAD_NONE) {

                /* If we add leveling we've got to pay for it */
                if ((other | existing) == ROAD_NONE) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);

                return CommandCost();
        }

        /* Autocomplete uphill roads */
        *pieces |= MirrorRoadBits(*pieces);
        type_bits = existing | *pieces;

        /* Uphill roads */
        if (IsStraightRoad(type_bits) && (other == type_bits || other == ROAD_NONE) &&
                        (_invalid_tileh_slopes_road[1][tileh] & (other | type_bits)) == ROAD_NONE) {

                /* Slopes with foundation ? */
                if (IsSlopeWithOneCornerRaised(tileh)) {

                        /* Prevent build on slopes if it isn't allowed */
                        if (_settings_game.construction.build_on_slopes) {

                                /* If we add foundation we've got to pay for it */
                                if ((other | existing) == ROAD_NONE) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);

                                return CommandCost();
                        }
                } else {
                        if (HasExactlyOneBit(existing) && GetRoadFoundation(tileh, existing) == FOUNDATION_NONE) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
                        return CommandCost();
                }
        }
        return CommandError();
}

/**
 * Build a piece of road.
 * @param tile tile where to build road
 * @param flags operation to perform
 * @param p1 bit  0.. 3 road pieces to build (RoadBits)
 *           bit  4.. 9 road type
 *           bit 10..11 disallowed directions to toggle
 *           bit 12     disable custom bridge heads
 * @param p2 the town that is building the road (0 if not applicable)
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdBuildRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char* text)
{
        CompanyID company = _current_company;
        CommandCost cost(EXPENSES_CONSTRUCTION);

        RoadBits existing_bits = ROAD_NONE;
        RoadBits other_bits = ROAD_NONE;

        // Road pieces are max 4 bitset values (NE, NW, SE, SW) and town can only be non-zero
        // if a non-company is building the road.
        if ((Company::IsValidID(company) && p2 != 0) || (company == OWNER_TOWN && !Town::IsValidID(p2)) || (company == OWNER_DEITY && p2 != 0)) return CommandError();
        if (company != OWNER_TOWN) {
                const Town* town = CalcClosestTownFromTile(tile);
                p2 = (town != nullptr) ? town->index : static_cast<TownID>(INVALID_TOWN);

                if (company == OWNER_DEITY) {
                        company = OWNER_TOWN;

                        // If we are not within a town, we are not owned by the town.
                        if (town == nullptr || DistanceSquare(tile, town->xy) > town->cache.squared_town_zone_radius[HZB_TOWN_EDGE]) {
                                company = OWNER_NONE;
                        }
                }
        }

        auto bits_to_build = Extract<RoadBits, 0, 4>(p1);

        // Do not allow building 'zero' road bits, code wouldn't handle it.
        if (bits_to_build == ROAD_NONE) return CommandError();

        RoadTypeIdentifier rtid;
        if (!rtid.UnpackIfValid(GB(p1, 4, 6))) return CommandError();
        if (!ValParamRoadType(rtid)) return CommandError();

        const auto disallowed_road_directions = Extract<DisallowedRoadDirections, 10, 2>(p1);
        const bool disable_custom_bridge_heads = HasBit(p1, 12);

        const Slope slope = GetTileSlope(tile);

        bool need_to_clear = false;
        switch (GetTileType(tile)) {
                case MP_ROAD:
                        switch (GetRoadTileType(tile)) {
                                case ROAD_TILE_NORMAL: {
                                        if (HasRoadWorks(tile)) return CommandError(STR_ERROR_ROAD_WORKS_IN_PROGRESS);

                                        other_bits = GetOtherRoadBits(tile, rtid.basetype);

                                        if (!HasTileRoadType(tile, rtid.basetype)) break;

                                        existing_bits = GetRoadBits(tile, rtid.basetype);
                                        const bool crossing = !IsStraightRoad(existing_bits | bits_to_build);

                                        if (rtid.IsRoad() && (GetDisallowedRoadDirections(tile) != DRD_NONE || disallowed_road_directions != DRD_NONE) && crossing) {
                                                // Junctions cannot be one-way.
                                                return CommandError(STR_ERROR_ONEWAY_ROADS_CAN_T_HAVE_JUNCTION);
                                        }

                                        if ((existing_bits & bits_to_build) == bits_to_build) {
                                                // We only want to set the (dis)allowed road directions.
                                                if (disallowed_road_directions != DRD_NONE && rtid.IsRoad()) {
                                                        if (crossing) return CommandError(STR_ERROR_ONEWAY_ROADS_CAN_T_HAVE_JUNCTION);

                                                        const Owner owner = GetRoadOwner(tile, ROADTYPE_ROAD);

                                                        if (owner != OWNER_NONE) {
                                                                CommandCost ret = CheckOwnership(owner, tile);
                                                                if (ret.Failed()) return ret;
                                                        }

                                                        const DisallowedRoadDirections dis_existing = GetDisallowedRoadDirections(tile);
                                                        const DisallowedRoadDirections dis_new      = dis_existing ^ disallowed_road_directions;

                                                        // We allow removing disallowed directions to break up
                                                        // deadlocks, but adding them can break articulated
                                                        // vehicles. As such, only when less is disallowed,
                                                        // i.e. bits are removed, we skip the vehicle check.
                                                        if (CountBits(dis_existing) <= CountBits(dis_new)) {
                                                                CommandCost ret = EnsureNoVehicleOnGround(tile);
                                                                if (ret.Failed()) return ret;
                                                        }

                                                        // Ignore half built tiles.
                                                        if ((flags & DC_EXEC) && rtid.IsRoad() && IsStraightRoad(existing_bits)) {
                                                                SetDisallowedRoadDirections(tile, dis_new);
                                                                MarkTileDirtyByTile(tile);
                                                        }

                                                        return CommandCost();
                                                }

                                                return CommandError(STR_ERROR_ALREADY_BUILT);
                                        }

                                        // Disallow breaking end-of-line of someone else
                                        // so trams can still reverse on this tile.
                                        if (rtid.IsTram() && HasExactlyOneBit(existing_bits)) {
                                                const Owner owner = GetRoadOwner(tile, rtid.basetype);

                                                if (Company::IsValidID(owner)) {
                                                        CommandCost ret = CheckOwnership(owner);
                                                        if (ret.Failed()) return ret;
                                                }
                                        }
                                        break;
                                }

                                case ROAD_TILE_CROSSING:
                                        if (RoadNoLevelCrossing(rtid)) {
                                                return CommandError(STR_ERROR_CROSSING_DISALLOWED_ROAD);
                                        }

                                        other_bits = GetCrossingRoadBits(tile);
                                        if (bits_to_build & ComplementRoadBits(other_bits)) goto do_clear;

                                        // We need to pay for both roadbits.
                                        bits_to_build = other_bits; 

                                        if (HasTileRoadType(tile, rtid.basetype)) return CommandError(STR_ERROR_ALREADY_BUILT);
                                        break;

                                case ROAD_TILE_DEPOT:
                                        if ((GetAnyRoadBits(tile, rtid.basetype) & bits_to_build) == bits_to_build) return CommandError(STR_ERROR_ALREADY_BUILT);
                                        goto do_clear;

                                default: NOT_REACHED();
                        }
                        break;

                case MP_RAILWAY: {
                        if (IsSteepSlope(slope)) {
                                return CommandError(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
                        }

                        /* Level crossings may only be built on these slopes */
                        if (!HasBit(VALID_LEVEL_CROSSING_SLOPES, slope)) {
                                return CommandError(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
                        }

                        if (GetRailTileType(tile) != RAIL_TILE_NORMAL) goto do_clear;

                        if (RoadNoLevelCrossing(rtid)) {
                                return CommandError(STR_ERROR_CROSSING_DISALLOWED_ROAD);
                        }

                        if (RailNoLevelCrossings(GetRailType(tile))) {
                                return CommandError(STR_ERROR_CROSSING_DISALLOWED_RAIL);
                        }

                        Axis roaddir;
                        switch (GetTrackBits(tile)) {
                                case TRACK_BIT_X:
                                        if (bits_to_build & ROAD_X) goto do_clear;
                                        roaddir = AXIS_Y;
                                        break;

                                case TRACK_BIT_Y:
                                        if (bits_to_build & ROAD_Y) goto do_clear;
                                        roaddir = AXIS_X;
                                        break;

                                default: goto do_clear;
                        }

                        CommandCost ret = EnsureNoVehicleOnGround(tile);
                        if (ret.Failed()) return ret;

                        if (flags & DC_EXEC) {
                                Track railtrack = AxisToTrack(OtherAxis(roaddir));
                                YapfNotifyTrackLayoutChange(tile, railtrack);
                                /* Update company infrastructure counts. A level crossing has two road bits. */
                                Company *c = Company::GetIfValid(company);
                                if (c != nullptr) {
                                        c->infrastructure.road[rtid.basetype][rtid.subtype] += 2;
                                        DirtyCompanyInfrastructureWindows(company);
                                }
                                /* Update rail count for level crossings. The plain track is already
                                 * counted, so only add the difference to the level crossing cost. */
                                c = Company::GetIfValid(GetTileOwner(tile));
                                if (c != nullptr) {
                                        c->infrastructure.rail[GetRailType(tile)] += LEVELCROSSING_TRACKBIT_FACTOR - 1;
                                        DirtyCompanyInfrastructureWindows(c->index);
                                }

                                /* Always add road to the roadtypes (can't draw without it) */
                                bool reserved = HasBit(GetRailReservationTrackBits(tile), railtrack);
                                MakeRoadCrossing(tile, company, company, GetTileOwner(tile), roaddir, GetRailType(tile), RoadTypeIdentifiers::FromRoadTypeIdentifier(rtid), p2);
                                SetCrossingReservation(tile, reserved);
                                UpdateLevelCrossing(tile, false);
                                MarkTileDirtyByTile(tile);
                        }
                        return CommandCost(EXPENSES_CONSTRUCTION, 2 * RoadBuildCost(rtid));
                }

                case MP_STATION: {
                        if ((GetAnyRoadBits(tile, rtid.basetype) & bits_to_build) == bits_to_build) return CommandError(STR_ERROR_ALREADY_BUILT);
                        if (!IsDriveThroughStopTile(tile)) goto do_clear;

                        RoadBits curbits = AxisToRoadBits(DiagDirToAxis(GetRoadStopDir(tile)));
                        if (bits_to_build & ~curbits) goto do_clear;
                        bits_to_build = curbits; // we need to pay for both roadbits

                        if (HasTileRoadType(tile, rtid.basetype)) return CommandError(STR_ERROR_ALREADY_BUILT);
                        break;
                }

                case MP_TUNNELBRIDGE: {
                        if (GetTunnelBridgeTransportType(tile) != TRANSPORT_ROAD) goto do_clear;

                        const TileIndex other_end = GetOtherTunnelBridgeEnd(tile);

                        if (IsBridge(tile)) {
                                const DiagDirection entrance_dir = GetTunnelBridgeDirection(tile);
                                const RoadBits entrance_piece = DiagDirToRoadBits(entrance_dir);
                                const RoadBits axial_pieces = AxisToRoadBits(DiagDirToAxis(entrance_dir));
                                existing_bits = GetCustomBridgeHeadRoadBits(tile, rtid.basetype);

                                if (!(_settings_game.construction.road_custom_bridge_heads && HasBridgeFlatRamp(slope, DiagDirToAxis(entrance_dir))) || disable_custom_bridge_heads) {
                                        // Ordinary bridge heads only
                                        // Only allow building the outer roadbit, so building long roads stops at existing bridges.
                                        if (MirrorRoadBits(entrance_piece) != bits_to_build) goto do_clear;
                                        bits_to_build = axial_pieces;
                                }

                                if ((existing_bits & bits_to_build) == bits_to_build) return CommandError(STR_ERROR_ALREADY_BUILT);

                                if ((bits_to_build & ~axial_pieces) && !_settings_game.construction.build_on_slopes) {
                                        return CommandError(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
                                }

                                // Steep slopes behave the same as slopes with one corner raised.
                                const Slope normalised_tileh = IsSteepSlope(slope) ? SlopeWithOneCornerRaised(GetHighestSlopeCorner(slope)) : slope;

                                if ((_invalid_tileh_slopes_road[0][normalised_tileh & SLOPE_ELEVATED] & (bits_to_build & ~entrance_piece)) != ROAD_NONE) {
                                        return CommandError(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
                                }

                                // Don't allow adding roadtype to the bridge/tunnel when vehicles are already driving on it.
                                CommandCost ret = TunnelBridgeIsFree(tile, other_end);
                                if (ret.Failed()) return ret;

                                if ((existing_bits | bits_to_build) == entrance_piece) {
                                        // Don't allow the custom bridge head bits to be only the entrance piece
                                        // as this makes road vehicles go haywire
                                        bits_to_build = axial_pieces;
                                }

                                const RoadBits added_pieces = (existing_bits | bits_to_build) & ~existing_bits;
                                uint added_pieces_count = CountBits(added_pieces);
                                RoadBits other_end_added_pieces = ROAD_NONE;
                                RoadBits other_end_existing = ROAD_NONE;

                                if (added_pieces & entrance_piece) {
                                        // adding road to whole bridge.

                                        other_end_added_pieces = MirrorRoadBits(entrance_piece);
                                        added_pieces_count += 1 + (GetTunnelBridgeLength(tile, other_end) * 2);

                                        other_end_existing = GetCustomBridgeHeadRoadBits(other_end, rtid.basetype);
                                        assert((other_end_added_pieces & other_end_existing) == ROAD_NONE);

                                        if (other_end_existing == ROAD_NONE) {
                                                // Don't allow the other end custom bridge head bits to be only the entrance piece
                                                // as this makes road vehicles go haywire
                                                other_end_added_pieces = axial_pieces;
                                                added_pieces_count++;
                                        }
                                }

                                cost.AddCost(added_pieces_count * _price[PR_BUILD_ROAD]);

                                if (flags & DC_EXEC) {
                                        SubtractRoadTunnelBridgeInfrastructure(tile, other_end);

                                        auto tile_rtids = RoadTypeIdentifiers::FromTile(tile);
                                        tile_rtids.MergeRoadType(rtid);
                                        SetRoadTypes(tile, tile_rtids);

                                        if (!existing_bits) {
                                                SetRoadOwner(tile, rtid.basetype, company);
                                        }

                                        SetCustomBridgeHeadRoadBits(tile, rtid.basetype, existing_bits | bits_to_build);

                                        if (other_end_added_pieces) {

                                                auto other_rtids = RoadTypeIdentifiers::FromTile(other_end);
                                                other_rtids.MergeRoadType(rtid);
                                                SetRoadTypes(other_end, other_rtids);

                                                if (!other_end_existing) {
                                                        SetRoadOwner(other_end, rtid.basetype, company);
                                                }

                                                SetCustomBridgeHeadRoadBits(other_end, rtid.basetype, other_end_existing | other_end_added_pieces);
                                        }

                                        MarkBridgeDirty(tile);

                                        AddRoadTunnelBridgeInfrastructure(tile, other_end);
                                        DirtyAllCompanyInfrastructureWindows();
                                }

                                return cost;
                        } else { // IsTunnel(tile)
                                /* Only allow building the outer roadbit, so building long roads stops at existing bridges */
                                if (MirrorRoadBits(DiagDirToRoadBits(GetTunnelBridgeDirection(tile))) != bits_to_build) goto do_clear;
                                if (HasTileRoadType(tile, rtid.basetype)) return CommandError(STR_ERROR_ALREADY_BUILT);
                                /* Don't allow adding roadtype to the bridge/tunnel when vehicles are already driving on it */
                                CommandCost ret = TunnelBridgeIsFree(tile, other_end);
                                if (ret.Failed()) return ret;
                        }
                        break;
                }

                default: {
do_clear:;
                        need_to_clear = true;
                        break;
                }
        }

        if (need_to_clear) {
                CommandCost ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
                if (ret.Failed()) return ret;
                cost.AddCost(ret);
        }

        if (other_bits != bits_to_build) {
                /* Check the foundation/slopes when adding road/tram bits */
                CommandCost ret = CheckRoadSlope(slope, &bits_to_build, existing_bits, other_bits);
                /* Return an error if we need to build a foundation (ret != 0) but the
                 * current setting is turned off */
                if (ret.Failed() || (ret.GetCost() != 0 && !_settings_game.construction.build_on_slopes)) {
                        return CommandError(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
                }
                cost.AddCost(ret);
        }

        if (!need_to_clear) {
                if (IsTileType(tile, MP_ROAD)) {
                        /* Don't put the pieces that already exist */
                        bits_to_build &= ComplementRoadBits(existing_bits);

                        /* Check if new road bits will have the same foundation as other existing road types */
                        if (IsNormalRoad(tile)) {
                                Slope slope = GetTileSlope(tile);
                                Foundation found_new = GetRoadFoundation(slope, bits_to_build | existing_bits);

                                /* Test if all other roadtypes can be built at that foundation */
                                for (RoadType rtest = ROADTYPE_ROAD; rtest < ROADTYPE_END; rtest++) {
                                        if (rtest != rtid.basetype) { // check only other road types
                                                RoadBits bits = GetRoadBits(tile, rtest);
                                                /* do not check if there are not road bits of given type */
                                                if (bits != ROAD_NONE && GetRoadFoundation(slope, bits) != found_new) {
                                                        return CommandError(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
                                                }
                                        }
                                }
                        }
                }

                CommandCost ret = EnsureNoVehicleOnGround(tile);
                if (ret.Failed()) return ret;

                if (IsNormalRoadTile(tile)) {
                        /* If the road types don't match, try to convert only if vehicles of
                         * the new road type are not powered on the present road type and vehicles of
                         * the present road type are powered on the new road type. */
                        RoadTypeIdentifier existing_rtid = GetRoadType(tile, rtid.basetype);
                        if (existing_rtid.IsValid() && existing_rtid != rtid) {
                                if (HasPowerOnRoad(rtid, existing_rtid)) {
                                        rtid = existing_rtid;
                                } else if (HasPowerOnRoad(existing_rtid, rtid)) {
                                        CommandCost ret = DoCommand(tile, tile, rtid.Pack(), flags, CMD_CONVERT_ROAD);
                                        if (ret.Failed()) return ret;
                                        cost.AddCost(ret);
                                } else {
                                        return CommandError();
                                }
                        }
                }
        }

        uint num_pieces = (!need_to_clear && IsTileType(tile, MP_TUNNELBRIDGE)) ?
                        /* There are 2 pieces on *every* tile of the bridge or tunnel */
                        2 * (GetTunnelBridgeLength(GetOtherTunnelBridgeEnd(tile), tile) + 2) :
                        /* Count pieces */
                        CountBits(bits_to_build);

        cost.AddCost(num_pieces * RoadBuildCost(rtid));

        if (flags & DC_EXEC) {
                switch (GetTileType(tile)) {
                        case MP_ROAD: {
                                RoadTileType rtt = GetRoadTileType(tile);
                                if (existing_bits == ROAD_NONE || rtt == ROAD_TILE_CROSSING) {
                                        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                        rtids.MergeRoadType(rtid);
                                        SetRoadTypes(tile, rtids);

                                        SetRoadOwner(tile, rtid.basetype, company);
                                        if (rtid.IsRoad()) SetTownIndex(tile, p2);
                                }
                                if (rtt != ROAD_TILE_CROSSING) SetRoadBits(tile, existing_bits | bits_to_build, rtid.basetype);
                                break;
                        }

                        case MP_TUNNELBRIDGE: {
                                TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
                                
                                RoadTypeIdentifiers other_rtids = RoadTypeIdentifiers::FromTile(other_end);
                                other_rtids.MergeRoadType(rtid);
                                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                rtids.MergeRoadType(rtid);
                                SetRoadTypes(other_end, other_rtids);
                                SetRoadTypes(tile, rtids);
                                SetRoadOwner(other_end, rtid.basetype, company);
                                SetRoadOwner(tile, rtid.basetype, company);

                                /* Mark tiles dirty that have been repaved */
                                if (IsBridge(tile)) {
                                        NOT_REACHED();
                                } else {
                                        MarkTileDirtyByTile(other_end);
                                        MarkTileDirtyByTile(tile);
                                }
                                break;
                        }

                        case MP_STATION: {
                                assert(IsDriveThroughStopTile(tile));
                                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                rtids.MergeRoadType(rtid);
                                SetRoadTypes(tile, rtids);
                                SetRoadOwner(tile, rtid.basetype, company);
                                break;
                        }

                        default:
                                MakeRoadNormal(tile, bits_to_build, RoadTypeIdentifiers::FromRoadTypeIdentifier(rtid), p2, company, company);
                                break;
                }

                /* Update company infrastructure count. */
                Company *c = Company::GetIfValid(GetRoadOwner(tile, rtid.basetype));
                if (c != nullptr) {
                        if (IsTileType(tile, MP_TUNNELBRIDGE)) num_pieces *= TUNNELBRIDGE_TRACKBIT_FACTOR;
                        c->infrastructure.road[rtid.basetype][rtid.subtype] += num_pieces;
                        DirtyCompanyInfrastructureWindows(c->index);
                }

                if (rtid.IsRoad() && IsNormalRoadTile(tile)) {
                        existing_bits |= bits_to_build;
                        SetDisallowedRoadDirections(tile, IsStraightRoad(existing_bits) ?
                                        GetDisallowedRoadDirections(tile) ^ disallowed_road_directions : DRD_NONE);
                }

                MarkTileDirtyByTile(tile);
        }
        return cost;
}

/**
 * Checks whether a road or tram connection can be found when building a new road or tram.
 * @param tile Tile at which the road being built will end.
 * @param rt Roadtype of the road being built.
 * @param dir Direction that the road is following.
 * @return True if the next tile at dir direction is suitable for being connected directly by a second roadbit at the end of the road being built.
 */
static bool CanConnectToRoad(TileIndex tile, RoadType rt, DiagDirection dir)
{
        RoadBits bits = GetAnyRoadBits(tile + TileOffsByDiagDir(dir), rt, false);
        return (bits & DiagDirToRoadBits(ReverseDiagDir(dir))) != 0;
}

/**
 * Build a long piece of road.
 * @param start_tile start tile of drag (the building cost will appear over this tile)
 * @param flags operation to perform
 * @param p1 end tile of drag
 * @param p2 various bitstuffed elements
 * - p2 = (bit 0) - start tile starts in the 2nd half of tile (p2 & 1). Only used if bit 6 is set or if we are building a single tile
 * - p2 = (bit 1) - end tile starts in the 2nd half of tile (p2 & 2). Only used if bit 6 is set or if we are building a single tile
 * - p2 = (bit 2) - direction: 0 = along x-axis, 1 = along y-axis (p2 & 4)
 * - p2 = (bit 3..8) - road type identifier
 * - p2 = (bit 9) - set road direction
 * - p2 = (bit 10) - defines two different behaviors for this command:
 *      - 0 = Build up to an obstacle. Do not build the first and last roadbits unless they can be connected to something, or if we are building a single tile
 *      - 1 = Fail if an obstacle is found. Always take into account bit 0 and 1. Disable custom bridge heads. This behavior is used for scripts
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdBuildLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        DisallowedRoadDirections drd = DRD_NORTHBOUND;

        if (p1 >= MapSize()) return CommandError();

        TileIndex end_tile = p1;
        RoadTypeIdentifier rtid;
        if (!rtid.UnpackIfValid(GB(p2, 3, 6))) return CommandError();
        if (!ValParamRoadType(rtid)) return CommandError();

        Axis axis = Extract<Axis, 2, 1>(p2);
        /* Only drag in X or Y direction dictated by the direction variable */
        if (axis == AXIS_X && TileY(start_tile) != TileY(end_tile)) return CommandError(); // x-axis
        if (axis == AXIS_Y && TileX(start_tile) != TileX(end_tile)) return CommandError(); // y-axis

        DiagDirection dir = AxisToDiagDir(axis);

        /* Swap direction, also the half-tile drag var (bit 0 and 1) */
        if (start_tile > end_tile || (start_tile == end_tile && HasBit(p2, 0))) {
                dir = ReverseDiagDir(dir);
                p2 ^= 3;
                drd = DRD_SOUTHBOUND;
        }

        /* On the X-axis, we have to swap the initial bits, so they
         * will be interpreted correctly in the GTTS. Furthermore
         * when you just 'click' on one tile to build them. */
        if ((axis == AXIS_Y) == (start_tile == end_tile && HasBit(p2, 0) == HasBit(p2, 1))) drd ^= DRD_BOTH;
        /* No disallowed direction bits have to be toggled */
        if (!HasBit(p2, 9)) drd = DRD_NONE;

        CommandCost cost(EXPENSES_CONSTRUCTION);
        CommandCost last_error = CommandError();
        TileIndex tile = start_tile;
        bool had_success = false;
        bool is_ai = HasBit(p2, 10);

        /* Start tile is the first tile clicked by the user. */
        for (;;) {
                RoadBits bits = AxisToRoadBits(axis);

                /* Determine which road parts should be built. */
                if (!is_ai && start_tile != end_tile) {
                        /* Only build the first and last roadbit if they can connect to something. */
                        if (tile == end_tile && !CanConnectToRoad(tile, rtid.basetype, dir)) { // TODO
                                bits = DiagDirToRoadBits(ReverseDiagDir(dir));
                        } else if (tile == start_tile && !CanConnectToRoad(tile, rtid.basetype, ReverseDiagDir(dir))) { // TODO
                                bits = DiagDirToRoadBits(dir);
                        }
                } else {
                        /* Road parts only have to be built at the start tile or at the end tile. */
                        if (tile == end_tile && !HasBit(p2, 1)) bits &= DiagDirToRoadBits(ReverseDiagDir(dir));
                        if (tile == start_tile && HasBit(p2, 0)) bits &= DiagDirToRoadBits(dir);
                }

                CommandCost ret = DoCommand(tile, (is_ai ? 1 << 12 : 0) | drd << 10 | rtid.Pack() << 4 | bits, 0, flags, CMD_BUILD_ROAD);
                if (ret.Failed()) {
                        last_error = ret;
                        if (last_error.GetErrorMessage() != STR_ERROR_ALREADY_BUILT) {
                                if (is_ai) return last_error;
                                break;
                        }
                } else {
                        had_success = true;
                        cost.AddCost(ret);
                }

                /* Do not run into or across bridges/tunnels */
                if (IsTileType(tile, MP_TUNNELBRIDGE)) {
                        if (GetTunnelBridgeDirection(tile) == dir) break;
                }

                if (tile == end_tile) break;

                tile += TileOffsByDiagDir(dir);

                /* Do not run onto a bridge/tunnel tile from below/above */
                if (IsTileType(tile, MP_TUNNELBRIDGE)) {
                        if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(dir)) break;
                }
        }

        return had_success ? cost : last_error;
}

/**
 * Remove a long piece of road.
 * RoadSubType is ignored, each roadtype can remove all its subtypes
 * @param start_tile start tile of drag
 * @param flags operation to perform
 * @param p1 end tile of drag
 * @param p2 various bitstuffed elements
 * - p2 = (bit 0) - start tile starts in the 2nd half of tile (p2 & 1)
 * - p2 = (bit 1) - end tile starts in the 2nd half of tile (p2 & 2)
 * - p2 = (bit 2) - direction: 0 = along x-axis, 1 = along y-axis (p2 & 4)
 * - p2 = (bit 3 - 8) - road type
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdRemoveLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        CommandCost cost(EXPENSES_CONSTRUCTION);

        if (p1 >= MapSize()) return CommandError();

        TileIndex end_tile = p1;
        RoadTypeIdentifier rtid;
        if (!rtid.UnpackIfValid(GB(p2, 3, 6))) return CommandError();

        Axis axis = Extract<Axis, 2, 1>(p2);
        /* Only drag in X or Y direction dictated by the direction variable */
        if (axis == AXIS_X && TileY(start_tile) != TileY(end_tile)) return CommandError(); // x-axis
        if (axis == AXIS_Y && TileX(start_tile) != TileX(end_tile)) return CommandError(); // y-axis

        /* Swap start and ending tile, also the half-tile drag var (bit 0 and 1) */
        if (start_tile > end_tile || (start_tile == end_tile && HasBit(p2, 0))) {
                TileIndex t = start_tile;
                start_tile = end_tile;
                end_tile = t;
                p2 ^= IsInsideMM(p2 & 3, 1, 3) ? 3 : 0;
        }

        Money money = GetAvailableMoneyForCommand();
        TileIndex tile = start_tile;
        CommandCost last_error = CommandError();
        bool had_success = false;
        /* Start tile is the small number. */
        for (;;) {
                RoadBits bits = AxisToRoadBits(axis);

                if (tile == end_tile && !HasBit(p2, 1)) bits &= ROAD_NW | ROAD_NE;
                if (tile == start_tile && HasBit(p2, 0)) bits &= ROAD_SE | ROAD_SW;

                /* try to remove the halves. */
                if (bits != 0) {
                        CommandCost ret = RemoveRoad(tile, flags & ~DC_EXEC, bits, rtid);
                        if (ret.Succeeded()) {
                                if (flags & DC_EXEC) {
                                        money -= ret.GetCost();
                                        if (money < 0) {
                                                _additional_cash_required = DoCommand(start_tile, end_tile, p2, flags & ~DC_EXEC, CMD_REMOVE_LONG_ROAD).GetCost();
                                                return cost;
                                        }
                                        RemoveRoad(tile, flags, bits, rtid, false);
                                }
                                cost.AddCost(ret);
                                had_success = true;
                        } else {
                                /* Ownership errors are more important. */
                                if (last_error.GetErrorMessage() != STR_ERROR_OWNED_BY) last_error = ret;
                        }
                }

                if (tile == end_tile) break;

                tile += (axis == AXIS_Y) ? TileDiffXY(0, 1) : TileDiffXY(1, 0);
        }

        return had_success ? cost : last_error;
}

/**
 * Build a road depot.
 * @param tile tile where to build the depot
 * @param flags operation to perform
 * @param p1 bit 0..1 entrance direction (DiagDirection)
 *           bit 2..7 road type identifier
 * @param p2 unused
 * @param text unused
 * @return the cost of this operation or an error
 *
 * @todo When checking for the tile slope,
 * distinguish between "Flat land required" and "land sloped in wrong direction"
 */
CommandCost CmdBuildRoadDepot(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        DiagDirection dir = Extract<DiagDirection, 0, 2>(p1);

        RoadTypeIdentifier rtid;
        if (!rtid.UnpackIfValid(GB(p1, 2, 6))) return CommandError();
        if (!ValParamRoadType(rtid)) return CommandError();

        Slope tileh = GetTileSlope(tile);
        if (tileh != SLOPE_FLAT && (
                                !_settings_game.construction.build_on_slopes ||
                                !CanBuildDepotByTileh(dir, tileh)
                        )) {
                return CommandError(STR_ERROR_FLAT_LAND_REQUIRED);
        }

        CommandCost cost = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
        if (cost.Failed()) return cost;

        if (IsBridgeAbove(tile)) return CommandError(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);

        if (!Depot::CanAllocateItem()) return CommandError();

        if (flags & DC_EXEC) {
                Depot *dep = new Depot(tile);
                dep->build_date = _date;

                /* A road depot has two road bits. */
                Company::Get(_current_company)->infrastructure.road[rtid.basetype][rtid.subtype] += 2;
                DirtyCompanyInfrastructureWindows(_current_company);

                MakeRoadDepot(tile, _current_company, dep->index, dir, rtid);
                MarkTileDirtyByTile(tile);
                MakeDefaultName(dep);
        }
        cost.AddCost(_price[PR_BUILD_DEPOT_ROAD]);
        return cost;
}

static CommandCost RemoveRoadDepot(TileIndex tile, DoCommandFlag flags)
{
        if (_current_company != OWNER_WATER) {
                CommandCost ret = CheckTileOwnership(tile);
                if (ret.Failed()) return ret;
        }

        CommandCost ret = EnsureNoVehicleOnGround(tile);
        if (ret.Failed()) return ret;

        if (flags & DC_EXEC) {
                Company *c = Company::GetIfValid(GetTileOwner(tile));
                if (c != nullptr) {
                        /* A road depot has two road bits. */
                        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                        RoadTypeIdentifier rtid = rtids.HasRoad() ? rtids.road_identifier : rtids.tram_identifier;
                        c->infrastructure.road[rtid.basetype][rtid.subtype] -= 2;
                        DirtyCompanyInfrastructureWindows(c->index);
                }

                delete Depot::GetByTile(tile);
                DoClearSquare(tile);
        }

        return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_CLEAR_DEPOT_ROAD]);
}

static CommandCost ClearTile_Road(TileIndex tile, DoCommandFlag flags)
{
        switch (GetRoadTileType(tile)) {
                case ROAD_TILE_NORMAL: {
                        RoadBits b = GetAllRoadBits(tile);

                        /* Clear the road if only one piece is on the tile OR we are not using the DC_AUTO flag */
                        if ((HasExactlyOneBit(b) && GetRoadBits(tile, ROADTYPE_TRAM) == ROAD_NONE) || !(flags & DC_AUTO)) {
                                CommandCost ret(EXPENSES_CONSTRUCTION);
                                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                                RoadTypeIdentifier rtid;
                                FOR_EACH_SET_ROADTYPEIDENTIFIER(rtid, rtids) {
                                        CommandCost tmp_ret = RemoveRoad(tile, flags, GetRoadBits(tile, rtid.basetype), rtid);
                                        if (tmp_ret.Failed()) return tmp_ret;
                                        ret.AddCost(tmp_ret);
                                }
                                return ret;
                        }
                        return CommandError(STR_ERROR_MUST_REMOVE_ROAD_FIRST);
                }

                case ROAD_TILE_CROSSING: {
                        RoadTypes rts = GetRoadTypes(tile);
                        CommandCost ret(EXPENSES_CONSTRUCTION);

                        if (flags & DC_AUTO) return CommandError(STR_ERROR_MUST_REMOVE_ROAD_FIRST);

                        /* Must iterate over the roadtypes in a reverse manner because
                         * tram tracks must be removed before the road bits. */
                        RoadType rt = ROADTYPE_TRAM;
                        RoadTypeIdentifier rtid;
                        do {
                                if (HasBit(rts, rt)) {
                                        rtid.basetype = rt;
                                        CommandCost tmp_ret = RemoveRoad(tile, flags, GetCrossingRoadBits(tile), rtid);
                                        if (tmp_ret.Failed()) return tmp_ret;
                                        ret.AddCost(tmp_ret);
                                }
                        } while (rt-- != ROADTYPE_ROAD);

                        if (flags & DC_EXEC) {
                                DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
                        }
                        return ret;
                }

                default:
                case ROAD_TILE_DEPOT:
                        if (flags & DC_AUTO) {
                                return CommandError(STR_ERROR_BUILDING_MUST_BE_DEMOLISHED);
                        }
                        return RemoveRoadDepot(tile, flags);
        }
}


struct DrawRoadTileStruct {
        uint16 image;
        byte subcoord_x;
        byte subcoord_y;
};

#include "table/road_land.h"

/**
 * Get the foundationtype of a RoadBits Slope combination
 *
 * @param tileh The Slope part
 * @param bits The RoadBits part
 * @return The resulting Foundation
 */
static Foundation GetRoadFoundation(Slope tileh, RoadBits bits)
{
        /* Flat land and land without a road doesn't require a foundation */
        if (tileh == SLOPE_FLAT || bits == ROAD_NONE) return FOUNDATION_NONE;

        /* Steep slopes behave the same as slopes with one corner raised. */
        if (IsSteepSlope(tileh)) {
                tileh = SlopeWithOneCornerRaised(GetHighestSlopeCorner(tileh));
        }

        /* Leveled RoadBits on a slope */
        if ((_invalid_tileh_slopes_road[0][tileh] & bits) == ROAD_NONE) return FOUNDATION_LEVELED;

        /* Straight roads without foundation on a slope */
        if (!IsSlopeWithOneCornerRaised(tileh) &&
                        (_invalid_tileh_slopes_road[1][tileh] & bits) == ROAD_NONE)
                return FOUNDATION_NONE;

        /* Roads on steep Slopes or on Slopes with one corner raised */
        return (bits == ROAD_X ? FOUNDATION_INCLINED_X : FOUNDATION_INCLINED_Y);
}

const byte _road_sloped_sprites[14] = {
        0,  0,  2,  0,
        0,  1,  0,  0,
        3,  0,  0,  0,
        0,  0
};

/**
 * Get the sprite offset within a spritegroup.
 * @param slope Slope
 * @param bits Roadbits
 * @return Offset for the sprite within the spritegroup.
 */
static uint GetRoadSpriteOffset(Slope slope, RoadBits bits)
{
        if (slope != SLOPE_FLAT) {
                switch (slope) {
                        case SLOPE_NE: return 11;
                        case SLOPE_SE: return 12;
                        case SLOPE_SW: return 13;
                        case SLOPE_NW: return 14;
                        default: NOT_REACHED();
                }
        } else {
                static const uint offsets[] = {
                        0, 18, 17, 7,
                        16, 0, 10, 5,
                        15, 8, 1, 4,
                        9, 3, 6, 2
                };
                return offsets[bits];
        }
}

/**
 * Should the road be drawn as a unpaved snow/desert road?
 * By default, roads are always drawn as unpaved if they are on desert or
 * above the snow line, but NewGRFs can override this for desert.
 *
 * @param tile The tile the road is on
 * @param roadside What sort of road this is
 * @return True if snow/desert road sprites should be used.
 */
static bool DrawRoadAsSnowDesert(TileIndex tile, Roadside roadside)
{
        return (IsOnSnow(tile) &&
                        !(_settings_game.game_creation.landscape == LT_TROPIC && HasGrfMiscBit(GMB_DESERT_PAVED_ROADS) &&
                                roadside != ROADSIDE_BARREN && roadside != ROADSIDE_GRASS && roadside != ROADSIDE_GRASS_ROAD_WORKS));
}

/**
 * Draws the catenary for the RoadType of the given tile
 * @param ti   information about the tile (slopes, height etc)
 * @param rtid road type to draw catenary for
 * @param rb   the roadbits for the tram
 */
void DrawRoadTypeCatenary(const TileInfo *ti, RoadTypeIdentifier rtid, RoadBits rb)
{
        /* Don't draw the catenary under a low bridge */
        if (IsBridgeAbove(ti->tile) && !IsTransparencySet(TO_CATENARY)) {
                int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));

                if (height <= GetTileMaxZ(ti->tile) + 1) return;
        }

        if (CountBits(rb) > 2) {
                /* On junctions we check whether neighbouring tiles also have catenary, and possibly
                 * do not draw catenary towards those neighbours, which do not have catenary. */
                RoadBits rb_new = ROAD_NONE;
                for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
                        if (rb & DiagDirToRoadBits(dir)) {
                                TileIndex neighbour = TileAddByDiagDir(ti->tile, dir);
                                if (MayHaveRoad(neighbour)) {
                                        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(neighbour);
                                        if ((rtids.HasRoad() && HasRoadCatenary(rtids.road_identifier)) ||
                                                        (rtids.HasTram() && HasRoadCatenary(rtids.tram_identifier))) {
                                                rb_new |= DiagDirToRoadBits(dir);
                                        }
                                }
                        }
                }
                if (CountBits(rb_new) >= 2) rb = rb_new;
        }

        const RoadtypeInfo* rti = GetRoadTypeInfo(rtid);
        SpriteID front = GetCustomRoadSprite(rti, ti->tile, ROTSG_CATENARY_FRONT);
        SpriteID back = GetCustomRoadSprite(rti, ti->tile, ROTSG_CATENARY_BACK);

        if (front != 0 || back != 0) {
                if (front != 0) front += GetRoadSpriteOffset(ti->tileh, rb);
                if (back != 0) back += GetRoadSpriteOffset(ti->tileh, rb);
        } else if (ti->tileh != SLOPE_FLAT) {
                back  = SPR_TRAMWAY_BACK_WIRES_SLOPED  + _road_sloped_sprites[ti->tileh - 1];
                front = SPR_TRAMWAY_FRONT_WIRES_SLOPED + _road_sloped_sprites[ti->tileh - 1];
        } else {
                back  = SPR_TRAMWAY_BASE + _road_backpole_sprites_1[rb];
                front = SPR_TRAMWAY_BASE + _road_frontwire_sprites_1[rb];
        }

    /* Catenary uses 1st company colour to help identify owner.
     * For tiles with OWNER_TOWN or OWNER_NONE, recolour CC to grey as a neutral colour. */
        Owner owner = GetRoadOwner(ti->tile, rtid.basetype);
        PaletteID pal = (owner == OWNER_NONE || owner == OWNER_TOWN ? GENERAL_SPRITE_COLOUR(COLOUR_GREY) : COMPANY_SPRITE_COLOUR(owner));
        if (back != 0) AddSortableSpriteToDraw(back,  pal, ti->x, ti->y, 16, 16, TILE_HEIGHT + BB_HEIGHT_UNDER_BRIDGE, ti->z, IsTransparencySet(TO_CATENARY));
        if (front != 0) AddSortableSpriteToDraw(front, pal, ti->x, ti->y, 16, 16, TILE_HEIGHT + BB_HEIGHT_UNDER_BRIDGE, ti->z, IsTransparencySet(TO_CATENARY));
}

/**
 * Draws the catenary for the given tile
 * @param ti information about the tile (slopes, height etc)
 */
void DrawRoadCatenary(const TileInfo *ti)
{
        RoadBits road;
        RoadBits tram;

        if (IsTileType(ti->tile, MP_ROAD)) {
                if (IsNormalRoad(ti->tile)) {
                        road = GetRoadBits(ti->tile, ROADTYPE_ROAD);
                        tram = GetRoadBits(ti->tile, ROADTYPE_TRAM);
                }
                else if (IsLevelCrossing(ti->tile)) {
                        tram = road = (GetCrossingRailAxis(ti->tile) == AXIS_Y ? ROAD_X : ROAD_Y);
                }
        }
        else if (IsTileType(ti->tile, MP_STATION)) {
                if (IsRoadStop(ti->tile)) {
                        Axis axis = GetRoadStopDir(ti->tile) == DIAGDIR_NE ? AXIS_X : AXIS_Y;
                        tram = road = (axis == AXIS_X ? ROAD_X : ROAD_Y);
                }
        }
        else {
                // No road here, no catenary to draw
                return;
        }

        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(ti->tile);
        const RoadtypeInfo* road_rti = rtids.HasRoad() ? GetRoadTypeInfo(rtids.road_identifier) : NULL;
        const RoadtypeInfo* tram_rti = rtids.HasTram() ? GetRoadTypeInfo(rtids.tram_identifier) : NULL;

        if (road_rti != NULL && HasRoadCatenaryDrawn(rtids.road_identifier)) {
                DrawRoadTypeCatenary(ti, rtids.road_identifier, road);
        }

        if (tram_rti != NULL && HasRoadCatenaryDrawn(rtids.tram_identifier)) {
                DrawRoadTypeCatenary(ti, rtids.tram_identifier, tram);
        }
}

/**
 * Draws details on/around the road
 * @param img the sprite to draw
 * @param ti  the tile to draw on
 * @param dx  the offset from the top of the BB of the tile
 * @param dy  the offset from the top of the BB of the tile
 * @param h   the height of the sprite to draw
 */
static void DrawRoadDetail(SpriteID img, const TileInfo *ti, int dx, int dy, int h)
{
        int x = ti->x | dx;
        int y = ti->y | dy;
        int z = ti->z;
        if (ti->tileh != SLOPE_FLAT) z = GetSlopePixelZ(x, y);
        AddSortableSpriteToDraw(img, PAL_NONE, x, y, 2, 2, h, z);
}

/**
 * Draw ground sprite and road pieces
 * @param ti TileInfo
 */
void DrawRoadBits(TileInfo *ti)
{
        const bool is_bridge = IsTileType(ti->tile, MP_TUNNELBRIDGE);
        RoadBits road = is_bridge ? GetCustomBridgeHeadRoadBits(ti->tile, ROADTYPE_ROAD) : GetRoadBits(ti->tile, ROADTYPE_ROAD);
        RoadBits tram = is_bridge ? GetCustomBridgeHeadRoadBits(ti->tile, ROADTYPE_TRAM) : GetRoadBits(ti->tile, ROADTYPE_TRAM);

        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(ti->tile);
        const RoadtypeInfo* road_rti = rtids.HasRoad() ? GetRoadTypeInfo(rtids.road_identifier) : NULL;
        const RoadtypeInfo* tram_rti = rtids.HasTram() ? GetRoadTypeInfo(rtids.tram_identifier) : NULL;

        if (ti->tileh != SLOPE_FLAT) {
                DrawFoundation(ti, is_bridge ? FOUNDATION_LEVELED : GetRoadFoundation(ti->tileh, road | tram));
                /* DrawFoundation() modifies ti. */
        }

        /* Determine sprite offsets */
        uint road_offset = GetRoadSpriteOffset(ti->tileh, road);
        uint tram_offset = GetRoadSpriteOffset(ti->tileh, tram);

        /* Draw baseset underlay */
        SpriteID image = SPR_ROAD_Y + (road_rti != NULL ? road_offset : tram_offset);
        PaletteID pal = PAL_NONE;

        Roadside roadside = is_bridge ? ROADSIDE_PAVED : GetRoadside(ti->tile);

        if (DrawRoadAsSnowDesert(ti->tile, roadside)) {
                image += 19;
        } else {
                switch (roadside) {
                        case ROADSIDE_BARREN:           pal = PALETTE_TO_BARE_LAND; break;
                        case ROADSIDE_GRASS:            break;
                        case ROADSIDE_GRASS_ROAD_WORKS: break;
                        default:                        image -= 19; break; // Paved
                }
        }

        DrawGroundSprite(image, pal);

        /* Road underlay takes precendence over tram */
        if (road_rti != NULL) {
                if (road_rti->UsesOverlay()) {
                        SpriteID ground = GetCustomRoadSprite(road_rti, ti->tile, ROTSG_GROUND);
                        DrawGroundSprite(ground + road_offset, PAL_NONE);
                }
        } else {
                if (tram_rti->UsesOverlay()) {
                        SpriteID ground = GetCustomRoadSprite(tram_rti, ti->tile, ROTSG_GROUND);
                        DrawGroundSprite(ground + tram_offset, PAL_NONE);
                } else {
                        DrawGroundSprite(SPR_TRAMWAY_TRAM + tram_offset, PAL_NONE);
                }
        }

        /* Draw road overlay */
        if (road_rti != nullptr) {
                if (road_rti->UsesOverlay()) {
                        SpriteID ground = GetCustomRoadSprite(road_rti, ti->tile, ROTSG_OVERLAY);
                        if (ground != 0) DrawGroundSprite(ground + road_offset, PAL_NONE);
                }
        }

        /* Draw tram overlay */
        if (tram_rti != nullptr) {
                if (tram_rti->UsesOverlay()) {
                        SpriteID ground = GetCustomRoadSprite(tram_rti, ti->tile, ROTSG_OVERLAY);
                        if (ground != 0) DrawGroundSprite(ground + tram_offset, PAL_NONE);
                } else if (road_rti != nullptr) {
                        DrawGroundSprite(SPR_TRAMWAY_OVERLAY + tram_offset, PAL_NONE);
                }
        }

        /* Draw one way */
        if (!is_bridge && road_rti != nullptr) {
                DisallowedRoadDirections drd = GetDisallowedRoadDirections(ti->tile);
                if (drd != DRD_NONE) {
                        DrawGroundSpriteAt(SPR_ONEWAY_BASE + drd - 1 + ((road == ROAD_X) ? 0 : 3), PAL_NONE, 8, 8, GetPartialPixelZ(8, 8, ti->tileh));
                }
        }

        if (!is_bridge && HasRoadWorks(ti->tile)) {
                /* Road works */
                DrawGroundSprite((road | tram) & ROAD_X ? SPR_EXCAVATION_X : SPR_EXCAVATION_Y, PAL_NONE);
                return;
        }

        /* Draw road, tram catenary */
        DrawRoadCatenary(ti);

        /* Return if full detail is disabled, or we are zoomed fully out. */
        if (!HasBit(_display_opt, DO_FULL_DETAIL) || _cur_dpi->zoom > ZOOM_LVL_DETAIL) return;

        /* Do not draw details (street lights, trees) under low bridge */
        if (IsBridgeAbove(ti->tile) && (roadside == ROADSIDE_TREES || roadside == ROADSIDE_STREET_LIGHTS)) {
                int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
                int minz = GetTileMaxZ(ti->tile) + 2;

                if (roadside == ROADSIDE_TREES) minz++;

                if (height < minz) return;
        }

        /* If there are no road bits, return, as there is nothing left to do */
        if (HasAtMostOneBit(road)) return;

        /* Draw extra details. */
        for (const DrawRoadTileStruct *drts = _road_display_table[roadside][road | tram]; drts->image != 0; drts++) {
                DrawRoadDetail(drts->image, ti, drts->subcoord_x, drts->subcoord_y, 0x10);
        }
}

/** Tile callback function for rendering a road tile to the screen */
static void DrawTile_Road(TileInfo *ti)
{
        switch (GetRoadTileType(ti->tile)) {
                case ROAD_TILE_NORMAL:
                        DrawRoadBits(ti);
                        DrawOverlay(ti, MP_ROAD);
                        break;

                case ROAD_TILE_CROSSING: {
                        if (ti->tileh != SLOPE_FLAT) DrawFoundation(ti, FOUNDATION_LEVELED);

                        Axis axis = GetCrossingRailAxis(ti->tile);

                        const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(ti->tile));

                        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(ti->tile);
                        const RoadtypeInfo* road_rti = rtids.HasRoad() ? GetRoadTypeInfo(rtids.road_identifier) : NULL;
                        const RoadtypeInfo* tram_rti = rtids.HasTram() ? GetRoadTypeInfo(rtids.tram_identifier) : NULL;

                        /* Draw base ground */
                        if (rti->UsesOverlay()) {
                                PaletteID pal = PAL_NONE;
                                SpriteID image = SPR_ROAD_Y + axis;

                                Roadside roadside = GetRoadside(ti->tile);
                                if (DrawRoadAsSnowDesert(ti->tile, roadside)) {
                                        image += 19;
                                } else {
                                        switch (roadside) {
                                                case ROADSIDE_BARREN: pal = PALETTE_TO_BARE_LAND; break;
                                                case ROADSIDE_GRASS:  break;
                                                default:              image -= 19; break; // Paved
                                        }
                                }

                                DrawGroundSprite(image, pal);
                        } else {
                                PaletteID pal = PAL_NONE;
                                SpriteID image = rti->base_sprites.crossing + axis;
                                if (IsCrossingBarred(ti->tile)) image += 2;

                                Roadside roadside = GetRoadside(ti->tile);
                                if (DrawRoadAsSnowDesert(ti->tile, roadside)) {
                                        image += 8;
                                } else {
                                        switch (roadside) {
                                                case ROADSIDE_BARREN: pal = PALETTE_TO_BARE_LAND; break;
                                                case ROADSIDE_GRASS:  break;
                                                default:              image += 4; break; // Paved
                                        }
                                }

                                DrawGroundSprite(image, pal);
                        }

                        /* Draw road/tram underlay; road underlay takes precendence over tram */
                        if (road_rti != NULL) {
                                if (road_rti->UsesOverlay()) {
                                        SpriteID ground = GetCustomRoadSprite(road_rti, ti->tile, ROTSG_GROUND);
                                        DrawGroundSprite(ground + axis, PAL_NONE);
                                }
                        } else {
                                if (tram_rti->UsesOverlay()) {
                                        SpriteID ground = GetCustomRoadSprite(tram_rti, ti->tile, ROTSG_GROUND);
                                        DrawGroundSprite(ground + axis, PAL_NONE);
                                } else {
                                        DrawGroundSprite(SPR_TRAMWAY_TRAM + axis, PAL_NONE);
                                }
                        }

                        /* Draw road overlay */
                        if (road_rti != NULL) {
                                if (road_rti->UsesOverlay()) {
                                        SpriteID ground = GetCustomRoadSprite(road_rti, ti->tile, ROTSG_OVERLAY);
                                        if (ground != 0) DrawGroundSprite(ground + axis, PAL_NONE);
                                }
                        }

                        /* Draw tram overlay */
                        if (tram_rti != NULL) {
                                if (tram_rti->UsesOverlay()) {
                                        SpriteID ground = GetCustomRoadSprite(tram_rti, ti->tile, ROTSG_OVERLAY);
                                        if (ground != 0) DrawGroundSprite(ground + axis, PAL_NONE);
                                } else if (road_rti != NULL) {
                                        DrawGroundSprite(SPR_TRAMWAY_OVERLAY + axis, PAL_NONE);
                                }
                        }

                        /* Draw rail/PBS overlay */
                        bool draw_pbs = _game_mode != GM_MENU && _settings_client.gui.show_track_reservation && HasCrossingReservation(ti->tile);
                        if (rti->UsesOverlay()) {
                                PaletteID pal = draw_pbs ? PALETTE_CRASH : PAL_NONE;
                                SpriteID rail = GetCustomRailSprite(rti, ti->tile, RTSG_CROSSING) + axis;
                                DrawGroundSprite(rail, pal);

                                DrawRailTileSeq(ti, &_crossing_layout, TO_CATENARY, rail, 0, PAL_NONE);
                        } else if (draw_pbs || tram_rti != NULL || road_rti->UsesOverlay()) {
                                /* Add another rail overlay, unless there is only the base road sprite. */
                                PaletteID pal = draw_pbs ? PALETTE_CRASH : PAL_NONE;
                                SpriteID rail = GetCrossingRoadAxis(ti->tile) == AXIS_Y ? GetRailTypeInfo(GetRailType(ti->tile))->base_sprites.single_x : GetRailTypeInfo(GetRailType(ti->tile))->base_sprites.single_y;
                                DrawGroundSprite(rail, pal);
                        }

                        /* Draw road, tram catenary */
                        DrawRoadCatenary(ti);

                        /* Draw rail catenary */
                        if (HasRailCatenaryDrawn(GetRailType(ti->tile))) DrawRailCatenary(ti);

                        break;
                }

                default:
                case ROAD_TILE_DEPOT: {
                        if (ti->tileh != SLOPE_FLAT) DrawFoundation(ti, FOUNDATION_LEVELED);

                        PaletteID palette = COMPANY_SPRITE_COLOUR(GetTileOwner(ti->tile));
                        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(ti->tile);
                        const RoadtypeInfo* rti = GetRoadTypeInfo(rtids.HasRoad() ? rtids.road_identifier : rtids.tram_identifier);

                        int relocation = GetCustomRoadSprite(rti, ti->tile, ROTSG_DEPOT);
                        bool default_gfx = relocation == 0;
                        if (default_gfx) {
                                if (HasBit(rti->flags, ROTF_CATENARY)) {
                                        if (_loaded_newgrf_features.tram == TRAMWAY_REPLACE_DEPOT_WITH_TRACK && rtids.HasTram() && !rti->UsesOverlay()) {
                                                /* Sprites with track only work for default tram */
                                                relocation = SPR_TRAMWAY_DEPOT_WITH_TRACK - SPR_ROAD_DEPOT;
                                                default_gfx = false;
                                        } else {
                                                /* Sprites without track are always better, if provided */
                                                relocation = SPR_TRAMWAY_DEPOT_NO_TRACK - SPR_ROAD_DEPOT;
                                        }
                                }
                        } else {
                                relocation -= SPR_ROAD_DEPOT;
                        }

                        DiagDirection dir = GetRoadDepotDirection(ti->tile);
                        const DrawTileSprites *dts = &_road_depot[dir];
                        DrawGroundSprite(dts->ground.sprite, PAL_NONE);

                        if (default_gfx) {
                                uint offset = GetRoadSpriteOffset(SLOPE_FLAT, DiagDirToRoadBits(dir));
                                if (rti->UsesOverlay()) {
                                        SpriteID ground = GetCustomRoadSprite(rti, ti->tile, ROTSG_OVERLAY);
                                        if (ground != 0) DrawGroundSprite(ground + offset, PAL_NONE);
                                } else if (rtids.HasTram()) {
                                        DrawGroundSprite(SPR_TRAMWAY_OVERLAY + offset, PAL_NONE);
                                }
                        }

                        DrawRailTileSeq(ti, dts, TO_BUILDINGS, relocation, 0, palette);
                        break;
                }
        }
        DrawBridgeMiddle(ti);
}

/**
 * Draw the road depot sprite.
 * @param x   The x offset to draw at.
 * @param y   The y offset to draw at.
 * @param dir The direction the depot must be facing.
 * @param rtid The road type of the depot to draw.
 */
void DrawRoadDepotSprite(int x, int y, DiagDirection dir, RoadTypeIdentifier rtid)
{
        PaletteID palette = COMPANY_SPRITE_COLOUR(_local_company);

        const RoadtypeInfo* rti = GetRoadTypeInfo(rtid);
        int relocation = GetCustomRoadSprite(rti, INVALID_TILE, ROTSG_DEPOT);
        bool default_gfx = relocation == 0;
        if (default_gfx) {
                if (HasBit(rti->flags, ROTF_CATENARY)) {
                        if (_loaded_newgrf_features.tram == TRAMWAY_REPLACE_DEPOT_WITH_TRACK && rtid.IsTram() && !rti->UsesOverlay()) {
                                /* Sprites with track only work for default tram */
                                relocation = SPR_TRAMWAY_DEPOT_WITH_TRACK - SPR_ROAD_DEPOT;
                                default_gfx = false;
                        } else {
                                /* Sprites without track are always better, if provided */
                                relocation = SPR_TRAMWAY_DEPOT_NO_TRACK - SPR_ROAD_DEPOT;
                        }
                }
        } else {
                relocation -= SPR_ROAD_DEPOT;
        }

        const DrawTileSprites *dts = &_road_depot[dir];
        DrawSprite(dts->ground.sprite, PAL_NONE, x, y);

        if (default_gfx) {
                uint offset = GetRoadSpriteOffset(SLOPE_FLAT, DiagDirToRoadBits(dir));
                if (rti->UsesOverlay()) {
                        SpriteID ground = GetCustomRoadSprite(rti, INVALID_TILE, ROTSG_OVERLAY);
                        if (ground != 0) DrawSprite(ground + offset, PAL_NONE, x, y);
                } else if (rtid.IsTram()) {
                        DrawSprite(SPR_TRAMWAY_OVERLAY + offset, PAL_NONE, x, y);
                }
        }

        DrawRailTileSeqInGUI(x, y, dts, relocation, 0, palette);
}

/**
 * Updates cached nearest town for all road tiles
 * @param invalidate are we just invalidating cached data?
 * @pre invalidate == true implies _generating_world == true
 */
void UpdateNearestTownForRoadTiles(bool invalidate)
{
        assert(!invalidate || _generating_world);

        for (TileIndex t = 0; t < MapSize(); t++) {
                if (IsTileType(t, MP_ROAD) && !IsRoadDepot(t) && !HasTownOwnedRoad(t)) {
                        TownID tid = (TownID)INVALID_TOWN;
                        if (!invalidate) {
                                const Town *town = CalcClosestTownFromTile(t);
                                if (town != nullptr) tid = town->index;
                        }
                        SetTownIndex(t, tid);
                }
        }
}

static int GetSlopePixelZ_Road(TileIndex tile, uint x, uint y)
{

        if (IsNormalRoad(tile)) {
                int z;
                Slope tileh = GetTilePixelSlope(tile, &z);
                if (tileh == SLOPE_FLAT) return z;

                Foundation f = GetRoadFoundation(tileh, GetAllRoadBits(tile));
                z += ApplyPixelFoundationToSlope(f, &tileh);
                return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
        } else {
                return GetTileMaxPixelZ(tile);
        }
}

static Foundation GetFoundation_Road(TileIndex tile, Slope tileh)
{
        if (IsNormalRoad(tile)) {
                return GetRoadFoundation(tileh, GetAllRoadBits(tile));
        } else {
                return FlatteningFoundation(tileh);
        }
}

static const Roadside _town_road_types[][2] = {
        { ROADSIDE_GRASS,         ROADSIDE_GRASS },
        { ROADSIDE_PAVED,         ROADSIDE_PAVED },
        { ROADSIDE_PAVED,         ROADSIDE_PAVED },
        { ROADSIDE_TREES,         ROADSIDE_TREES },
        { ROADSIDE_STREET_LIGHTS, ROADSIDE_PAVED }
};

static const Roadside _town_road_types_2[][2] = {
        { ROADSIDE_GRASS,         ROADSIDE_GRASS },
        { ROADSIDE_PAVED,         ROADSIDE_PAVED },
        { ROADSIDE_STREET_LIGHTS, ROADSIDE_PAVED },
        { ROADSIDE_STREET_LIGHTS, ROADSIDE_PAVED },
        { ROADSIDE_STREET_LIGHTS, ROADSIDE_PAVED }
};


static void TileLoop_Road(TileIndex tile)
{
        switch (_settings_game.game_creation.landscape) {
                case LT_ARCTIC:
                        if (IsOnSnow(tile) != (GetTileMaxZ(tile) > GetSnowLine())) {
                                ToggleSnow(tile);
                                MarkTileDirtyByTile(tile);
                        }
                        break;

                case LT_TROPIC:
                        if (GetTropicZone(tile) == TROPICZONE_DESERT && !IsOnDesert(tile)) {
                                ToggleDesert(tile);
                                MarkTileDirtyByTile(tile);
                        }
                        break;
        }

        if (IsRoadDepot(tile)) return;

        const Town *t = ClosestTownFromTile(tile, UINT_MAX);
        if (!HasRoadWorks(tile)) {
                HouseZonesBits grp = HZB_TOWN_EDGE;

                if (t != nullptr) {
                        grp = GetTownRadiusGroup(t, tile);

                        /* Show an animation to indicate road work */
                        if (t->road_build_months != 0 &&
                                        (DistanceManhattan(t->xy, tile) < 8 || grp != HZB_TOWN_EDGE) &&
                                        IsNormalRoad(tile) && !HasAtMostOneBit(GetAllRoadBits(tile))) {
                                if (GetFoundationSlope(tile) == SLOPE_FLAT && EnsureNoVehicleOnGround(tile).Succeeded() && Chance16(1, 40)) {
                                        StartRoadWorks(tile);

                                        if (_settings_client.sound.ambient) SndPlayTileFx(SND_21_JACKHAMMER, tile);
                                        CreateEffectVehicleAbove(
                                                TileX(tile) * TILE_SIZE + 7,
                                                TileY(tile) * TILE_SIZE + 7,
                                                0,
                                                EV_BULLDOZER);
                                        MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
                                        return;
                                }
                        }
                }

                {
                        /* Adjust road ground type depending on 'grp' (grp is the distance to the center) */
                        const Roadside *new_rs = (_settings_game.game_creation.landscape == LT_TOYLAND) ? _town_road_types_2[grp] : _town_road_types[grp];
                        Roadside cur_rs = GetRoadside(tile);

                        /* We have our desired type, do nothing */
                        if (cur_rs == new_rs[0]) return;

                        /* We have the pre-type of the desired type, switch to the desired type */
                        if (cur_rs == new_rs[1]) {
                                cur_rs = new_rs[0];
                        /* We have barren land, install the pre-type */
                        } else if (cur_rs == ROADSIDE_BARREN) {
                                cur_rs = new_rs[1];
                        /* We're totally off limits, remove any installation and make barren land */
                        } else {
                                cur_rs = ROADSIDE_BARREN;
                        }
                        SetRoadside(tile, cur_rs);
                        MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
                }
        } else if (IncreaseRoadWorksCounter(tile)) {
                TerminateRoadWorks(tile);

                if (_settings_game.economy.mod_road_rebuild) {
                        /* Generate a nicer town surface */
                        const RoadBits old_rb = GetAnyRoadBits(tile, ROADTYPE_ROAD);
                        const RoadBits new_rb = CleanUpRoadBits(tile, old_rb);

                        if (old_rb != new_rb) {
                                RemoveRoad(tile, DC_EXEC | DC_AUTO | DC_NO_WATER, (old_rb ^ new_rb), RoadTypeIdentifier(ROADTYPE_ROAD, ROADSUBTYPE_NORMAL));
                        }
                }

                MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
        }
}

static bool ClickTile_Road(TileIndex tile)
{
        if (!IsRoadDepot(tile)) return false;

        ShowDepotWindow(tile, VEH_ROAD);
        return true;
}

/* Converts RoadBits to TrackBits */
extern const TrackBits _road_trackbits[16] = {
        TRACK_BIT_NONE,                                  // ROAD_NONE
        TRACK_BIT_NONE,                                  // ROAD_NW
        TRACK_BIT_NONE,                                  // ROAD_SW
        TRACK_BIT_LEFT,                                  // ROAD_W
        TRACK_BIT_NONE,                                  // ROAD_SE
        TRACK_BIT_Y,                                     // ROAD_Y
        TRACK_BIT_LOWER,                                 // ROAD_S
        TRACK_BIT_LEFT | TRACK_BIT_LOWER | TRACK_BIT_Y,  // ROAD_Y | ROAD_SW
        TRACK_BIT_NONE,                                  // ROAD_NE
        TRACK_BIT_UPPER,                                 // ROAD_N
        TRACK_BIT_X,                                     // ROAD_X
        TRACK_BIT_LEFT | TRACK_BIT_UPPER | TRACK_BIT_X,  // ROAD_X | ROAD_NW
        TRACK_BIT_RIGHT,                                 // ROAD_E
        TRACK_BIT_RIGHT | TRACK_BIT_UPPER | TRACK_BIT_Y, // ROAD_Y | ROAD_NE
        TRACK_BIT_RIGHT | TRACK_BIT_LOWER | TRACK_BIT_X, // ROAD_X | ROAD_SE
        TRACK_BIT_ALL,                                   // ROAD_ALL
};

static TrackStatus GetTileTrackStatus_Road(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
{
        TrackdirBits trackdirbits = TRACKDIR_BIT_NONE;
        TrackdirBits red_signals = TRACKDIR_BIT_NONE; // crossing barred
        switch (mode) {
                case TRANSPORT_RAIL:
                        if (IsLevelCrossing(tile)) trackdirbits = TrackBitsToTrackdirBits(GetCrossingRailBits(tile));
                        break;

                case TRANSPORT_ROAD: {
                        RoadType rt = (RoadType)sub_mode;
                        if (!HasTileRoadType(tile, rt)) break;
                        switch (GetRoadTileType(tile)) {
                                case ROAD_TILE_NORMAL: {
                                        const uint drd_to_multiplier[DRD_END] = { 0x101, 0x100, 0x1, 0x0 };
                                        RoadBits bits = GetRoadBits(tile, rt);

                                        /* no roadbit at this side of tile, return 0 */
                                        if (side != INVALID_DIAGDIR && (DiagDirToRoadBits(side) & bits) == 0) break;

                                        uint multiplier = drd_to_multiplier[rt == ROADTYPE_TRAM ? DRD_NONE : GetDisallowedRoadDirections(tile)];
                                        if (!HasRoadWorks(tile)) trackdirbits = (TrackdirBits)(_road_trackbits[bits] * multiplier);
                                        break;
                                }

                                case ROAD_TILE_CROSSING: {
                                        Axis axis = GetCrossingRoadAxis(tile);

                                        if (side != INVALID_DIAGDIR && axis != DiagDirToAxis(side)) break;

                                        trackdirbits = TrackBitsToTrackdirBits(AxisToTrackBits(axis));
                                        if (IsCrossingBarred(tile)) red_signals = trackdirbits;
                                        if (IsLevelCrossingTile(TileAddByDiagDir(tile, AxisToDiagDir(axis))) &&
                                                        IsCrossingBarred(TileAddByDiagDir(tile, AxisToDiagDir(axis)))) {
                                                red_signals &= (TrackdirBits)0x0102; // magic value. I think TRACKBIT_X_SW and TRACKBIT_X_NE should be swapped
                                        }
                                        if (IsLevelCrossingTile(TileAddByDiagDir(tile, ReverseDiagDir(AxisToDiagDir(axis)))) &&
                                                        IsCrossingBarred(TileAddByDiagDir(tile, ReverseDiagDir(AxisToDiagDir(axis))))) {
                                                red_signals &= (TrackdirBits)0x0201; // inverse of above magic value
                                        }
                                        break;
                                }

                                default:
                                case ROAD_TILE_DEPOT: {
                                        DiagDirection dir = GetRoadDepotDirection(tile);

                                        if (side != INVALID_DIAGDIR && side != dir) break;

                                        trackdirbits = TrackBitsToTrackdirBits(DiagDirToDiagTrackBits(dir));
                                        break;
                                }
                        }
                        break;
                }

                default: break;
        }
        return CombineTrackStatus(trackdirbits, red_signals);
}

static const StringID _road_tile_strings[] = {
        STR_LAI_ROAD_DESCRIPTION_ROAD,
        STR_LAI_ROAD_DESCRIPTION_ROAD,
        STR_LAI_ROAD_DESCRIPTION_ROAD,
        STR_LAI_ROAD_DESCRIPTION_ROAD_WITH_STREETLIGHTS,
        STR_LAI_ROAD_DESCRIPTION_ROAD,
        STR_LAI_ROAD_DESCRIPTION_TREE_LINED_ROAD,
        STR_LAI_ROAD_DESCRIPTION_ROAD,
        STR_LAI_ROAD_DESCRIPTION_ROAD,
};

static void GetTileDesc_Road(TileIndex tile, TileDesc *td)
{
        Owner rail_owner = INVALID_OWNER;
        Owner road_owner = INVALID_OWNER;
        Owner tram_owner = INVALID_OWNER;

        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
        if (rtids.HasRoad()) {
                const RoadtypeInfo *rti = GetRoadTypeInfo(rtids.road_identifier);
                td->roadtype = rti->strings.name;
                td->road_speed = rti->max_speed / 2;
                road_owner = GetRoadOwner(tile, ROADTYPE_ROAD);
        }
        if (rtids.HasTram()) {
                const RoadtypeInfo *rti = GetRoadTypeInfo(rtids.tram_identifier);
                td->tramtype = rti->strings.name;
                td->tram_speed = rti->max_speed / 2;
                tram_owner = GetRoadOwner(tile, ROADTYPE_TRAM);
        }

        switch (GetRoadTileType(tile)) {
                case ROAD_TILE_CROSSING: {
                        td->str = STR_LAI_ROAD_DESCRIPTION_ROAD_RAIL_LEVEL_CROSSING;
                        rail_owner = GetTileOwner(tile);

                        const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(tile));
                        td->railtype = rti->strings.name;
                        td->rail_speed = rti->max_speed;

                        break;
                }

                case ROAD_TILE_DEPOT:
                        td->str = STR_LAI_ROAD_DESCRIPTION_ROAD_VEHICLE_DEPOT;
                        td->build_date = Depot::GetByTile(tile)->build_date;
                        break;

                default: {
                        td->str = (rtids.HasRoad() ? _road_tile_strings[GetRoadside(tile)] : STR_LAI_ROAD_DESCRIPTION_TRAMWAY);
                        break;
                }
        }

        /* Now we have to discover, if the tile has only one owner or many:
         *   - Find a first_owner of the tile. (Currently road or tram must be present, but this will break when the third type becomes available)
         *   - Compare the found owner with the other owners, and test if they differ.
         * Note: If road exists it will be the first_owner.
         */
        Owner first_owner = (road_owner == INVALID_OWNER ? tram_owner : road_owner);
        bool mixed_owners = (tram_owner != INVALID_OWNER && tram_owner != first_owner) || (rail_owner != INVALID_OWNER && rail_owner != first_owner);

        if (mixed_owners) {
                /* Multiple owners */
                td->owner_type[0] = (rail_owner == INVALID_OWNER ? STR_NULL : STR_LAND_AREA_INFORMATION_RAIL_OWNER);
                td->owner[0] = rail_owner;
                td->owner_type[1] = (road_owner == INVALID_OWNER ? STR_NULL : STR_LAND_AREA_INFORMATION_ROAD_OWNER);
                td->owner[1] = road_owner;
                td->owner_type[2] = (tram_owner == INVALID_OWNER ? STR_NULL : STR_LAND_AREA_INFORMATION_TRAM_OWNER);
                td->owner[2] = tram_owner;
        } else {
                /* One to rule them all */
                td->owner[0] = first_owner;
        }
}

/**
 * Given the direction the road depot is pointing, this is the direction the
 * vehicle should be travelling in in order to enter the depot.
 */
static const byte _roadveh_enter_depot_dir[4] = {
        TRACKDIR_X_SW, TRACKDIR_Y_NW, TRACKDIR_X_NE, TRACKDIR_Y_SE
};

static VehicleEnterTileStatus VehicleEnter_Road(Vehicle *v, TileIndex tile, int x, int y)
{
        switch (GetRoadTileType(tile)) {
                case ROAD_TILE_DEPOT: {
                        if (v->type != VEH_ROAD) break;

                        RoadVehicle *rv = RoadVehicle::From(v);
                        if (rv->frame == RVC_DEPOT_STOP_FRAME &&
                                        _roadveh_enter_depot_dir[GetRoadDepotDirection(tile)] == rv->state) {
                                rv->state = RVSB_IN_DEPOT;
                                rv->vehstatus |= VS_HIDDEN;
                                rv->direction = ReverseDir(rv->direction);
                                if (rv->Next() == nullptr) VehicleEnterDepot(rv->First());
                                rv->tile = tile;

                                InvalidateWindowData(WC_VEHICLE_DEPOT, rv->tile);
                                return VETSB_ENTERED_WORMHOLE;
                        }
                        break;
                }

                default: break;
        }
        return VETSB_CONTINUE;
}


static void ChangeTileOwner_Road(TileIndex tile, Owner old_owner, Owner new_owner)
{
        RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
        if (IsRoadDepot(tile)) {
                if (GetTileOwner(tile) == old_owner) {
                        if (new_owner == INVALID_OWNER) {
                                DoCommand(tile, 0, 0, DC_EXEC | DC_BANKRUPT, CMD_LANDSCAPE_CLEAR);
                        } else {
                                /* A road depot has two road bits. No need to dirty windows here, we'll redraw the whole screen anyway. */
                                RoadTypeIdentifier rtid = rtids.HasRoad() ? rtids.road_identifier : rtids.tram_identifier;
                                Company::Get(old_owner)->infrastructure.road[rtid.basetype][rtid.subtype] -= 2;
                                Company::Get(new_owner)->infrastructure.road[rtid.basetype][rtid.subtype] += 2;

                                SetTileOwner(tile, new_owner);
                                for (RoadType rt = ROADTYPE_ROAD; rt < ROADTYPE_END; rt++) {
                                        if (GetRoadOwner(tile, rt) == old_owner) {
                                                SetRoadOwner(tile, rt, new_owner);
                                        }
                                }
                        }
                }
                return;
        }

        for (RoadType rt = ROADTYPE_ROAD; rt < ROADTYPE_END; rt++) {
                /* Update all roadtypes, no matter if they are present */
                if (GetRoadOwner(tile, rt) == old_owner) {
                        RoadTypeIdentifier rtid = rt == ROADTYPE_ROAD ? rtids.road_identifier : rtids.tram_identifier;
                        if (rtid.IsValid()) {
                                /* A level crossing has two road bits. No need to dirty windows here, we'll redraw the whole screen anyway. */
                                uint num_bits = IsLevelCrossing(tile) ? 2 : CountBits(GetRoadBits(tile, rt));
                                Company::Get(old_owner)->infrastructure.road[rtid.basetype][rtid.subtype] -= num_bits;
                                if (new_owner != INVALID_OWNER) Company::Get(new_owner)->infrastructure.road[rtid.basetype][rtid.subtype] += num_bits;
                        }

                        SetRoadOwner(tile, rt, new_owner == INVALID_OWNER ? OWNER_NONE : new_owner);
                }
        }

        if (IsLevelCrossing(tile)) {
                if (GetTileOwner(tile) == old_owner) {
                        if (new_owner == INVALID_OWNER) {
                                DoCommand(tile, 0, GetCrossingRailTrack(tile), DC_EXEC | DC_BANKRUPT, CMD_REMOVE_SINGLE_RAIL);
                        } else {
                                /* Update infrastructure counts. No need to dirty windows here, we'll redraw the whole screen anyway. */
                                Company::Get(old_owner)->infrastructure.rail[GetRailType(tile)] -= LEVELCROSSING_TRACKBIT_FACTOR;
                                Company::Get(new_owner)->infrastructure.rail[GetRailType(tile)] += LEVELCROSSING_TRACKBIT_FACTOR;

                                SetTileOwner(tile, new_owner);
                        }
                }
        }
}

static CommandCost TerraformTile_Road(TileIndex tile, DoCommandFlag flags, int z_new, Slope tileh_new)
{
        if (_settings_game.construction.build_on_slopes && AutoslopeEnabled()) {
                switch (GetRoadTileType(tile)) {
                        case ROAD_TILE_CROSSING:
                                if (!IsSteepSlope(tileh_new) && (GetTileMaxZ(tile) == z_new + GetSlopeMaxZ(tileh_new)) && HasBit(VALID_LEVEL_CROSSING_SLOPES, tileh_new)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
                                break;

                        case ROAD_TILE_DEPOT:
                                if (AutoslopeCheckForEntranceEdge(tile, z_new, tileh_new, GetRoadDepotDirection(tile))) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
                                break;

                        case ROAD_TILE_NORMAL: {
                                RoadBits bits = GetAllRoadBits(tile);
                                RoadBits bits_copy = bits;
                                /* Check if the slope-road_bits combination is valid at all, i.e. it is safe to call GetRoadFoundation(). */
                                if (CheckRoadSlope(tileh_new, &bits_copy, ROAD_NONE, ROAD_NONE).Succeeded()) {
                                        /* CheckRoadSlope() sometimes changes the road_bits, if it does not agree with them. */
                                        if (bits == bits_copy) {
                                                int z_old;
                                                Slope tileh_old = GetTileSlope(tile, &z_old);

                                                /* Get the slope on top of the foundation */
                                                z_old += ApplyFoundationToSlope(GetRoadFoundation(tileh_old, bits), &tileh_old);
                                                z_new += ApplyFoundationToSlope(GetRoadFoundation(tileh_new, bits), &tileh_new);

                                                /* The surface slope must not be changed */
                                                if ((z_old == z_new) && (tileh_old == tileh_new)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
                                        }
                                }
                                break;
                        }

                        default: NOT_REACHED();
                }
        }

        return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
}

/** Update power of train under which is the railtype being converted */
static Vehicle *UpdateRoadVehPowerProc(Vehicle *v, void *data)
{
        if (v->type != VEH_ROAD) return NULL;

        RoadVehicleList *affected_trains = static_cast<RoadVehicleList*>(data);
        affected_trains->Include(RoadVehicle::From(v)->First());

        return NULL;
}

/**
 * Checks the tile and returns whether the current player is allowed to convert the roadtype to another roadtype
 * @param tile the tile to convert
 * @param to_type the RoadTypeIdentifier to be converted
 * @return whether the road is convertible
 */
static bool CanConvertRoadType(Owner owner, RoadType basetype)
{
        return (owner == OWNER_NONE || (owner == OWNER_TOWN && basetype == ROADTYPE_ROAD));
}

/**
 * Convert the ownership of the RoadType of the tile if applyable
 * @param tile the tile of which convert ownership
 * @param num_pieces the count of the roadbits to assign to the new owner
 * @param owner the current owner of the RoadType
 * @param from_type the old RoadTypeIdentifier
 * @param to_type the new RoadTypeIdentifier
 */
static void ConvertRoadTypeOwner(TileIndex tile, uint num_pieces, Owner owner, RoadTypeIdentifier from_type, RoadTypeIdentifier to_type)
{
        // Scenario editor, maybe? Don't touch the owners when converting roadtypes...
        if (_current_company >= MAX_COMPANIES) return;

        // We can't get a company from invalid owners but we can get ownership of roads without an owner
        if (owner >= MAX_COMPANIES && owner != OWNER_NONE) return;

        Company *c;

        switch (owner) {
        case OWNER_NONE:
                SetRoadOwner(tile, to_type.basetype, (Owner)_current_company);
                c = Company::Get(_current_company);
                c->infrastructure.road[to_type.basetype][to_type.subtype] += num_pieces;
                DirtyCompanyInfrastructureWindows(c->index);
                break;

        default:
                c = Company::Get(owner);
                c->infrastructure.road[from_type.basetype][from_type.subtype] -= num_pieces;
                c->infrastructure.road[to_type.basetype][to_type.subtype] += num_pieces;
                DirtyCompanyInfrastructureWindows(c->index);
                break;
        }
}

/**
 * Convert one road subtype to another.
 * Not meant to convert from road to tram.
 *
 * @param tile end tile of road conversion drag
 * @param flags operation to perform
 * @param p1 start tile of drag
 * @param p2 various bitstuffed elements:
 * - p2 = (bit  0..5) new roadtype to convert to.
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdConvertRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2,  const char *text)
{
        RoadTypeIdentifier to_type;
        if (!to_type.UnpackIfValid(GB(p2, 0, 6))) return CommandError();

        TileIndex area_start = p1;
        TileIndex area_end = tile;

        if (!ValParamRoadType(to_type)) return CommandError();
        if (area_start >= MapSize()) return CommandError();

        RoadVehicleList affected_rvs;

        CommandCost cost(EXPENSES_CONSTRUCTION);
        CommandCost error = CommandCost(to_type.IsRoad() ? STR_ERROR_NO_SUITABLE_ROAD : STR_ERROR_NO_SUITABLE_TRAMWAY); // by default, there is no road to convert.

        TileIterator *iter = new OrthogonalTileIterator(area_start, area_end);
        for (; (tile = *iter) != INVALID_TILE; ++(*iter)) {
                /* Is road present on tile? */
                if (!MayHaveRoad(tile)) continue;
                RoadTypeIdentifiers rtids = RoadTypeIdentifiers::FromTile(tile);
                if (!rtids.HasType(to_type.basetype)) continue;

                /* Converting to the same subtype? */
                RoadTypeIdentifier from_type = rtids.GetType(to_type.basetype);
                if (from_type.subtype == to_type.subtype) continue;

                /* Check if there is any infrastructure on tile */
                TileType tt = GetTileType(tile);
                switch (tt) {
                        case MP_STATION:
                                if (!IsRoadStop(tile)) continue;
                                break;
                        case MP_ROAD:
                                if (IsLevelCrossing(tile) && RoadNoLevelCrossing(to_type)) {
                                        error.MakeError(STR_ERROR_CROSSING_DISALLOWED_ROAD);
                                        continue;
                                }
                                break;
                        case MP_TUNNELBRIDGE:
                                if (GetTunnelBridgeTransportType(tile) != TRANSPORT_ROAD) continue;
                                break;
                        default: continue;
                }

                /* Trying to convert other's road */ // TODO allow upgrade?
                Owner owner = GetRoadOwner(tile, to_type.basetype);
                if (!CanConvertRoadType(owner, to_type.basetype)) {
                        CommandCost ret = CheckOwnership(owner, tile);
                        if (ret.Failed()) {
                                error = ret;
                                continue;
                        }
                }

                /* Vehicle on the tile when not converting normal <-> powered
                 * Tunnels and bridges have special check later */
                if (tt != MP_TUNNELBRIDGE) {
                        if (!HasPowerOnRoad(from_type, to_type)) {
                                CommandCost ret = EnsureNoVehicleOnGround(tile);
                                if (ret.Failed()) {
                                        error = ret;
                                        continue;
                                }

                                if (to_type.basetype == ROADTYPE_ROAD && owner == OWNER_TOWN) {
                                        error.MakeError(STR_ERROR_INCOMPATIBLE_ROAD);
                                        continue;
                                }
                        }

                        uint num_pieces = CountBits(GetAnyRoadBits(tile, from_type.basetype));;
                        cost.AddCost(num_pieces * RoadConvertCost(from_type, to_type));

                        if (flags & DC_EXEC) { // we can safely convert, too
                                /* Update the company infrastructure counters. */
                                if (!IsRoadStopTile(tile) && CanConvertRoadType(owner, to_type.basetype) && owner != OWNER_TOWN) {
                                        ConvertRoadTypeOwner(tile, num_pieces, owner, from_type, to_type);
                                }

                                /* Perform the conversion */
                                rtids.MergeRoadType(to_type);
                                SetRoadTypes(tile, rtids);
                                MarkTileDirtyByTile(tile);

                                /* update power of train on this tile */
                                FindVehicleOnPos(tile, &affected_rvs, &UpdateRoadVehPowerProc);

                                if (IsRoadDepotTile(tile)) {
                                        /* Update build vehicle window related to this depot */
                                        InvalidateWindowData(WC_VEHICLE_DEPOT, tile);
                                        InvalidateWindowData(WC_BUILD_VEHICLE, tile);
                                }
                        }
                } else {
                        TileIndex endtile = GetOtherTunnelBridgeEnd(tile);

                        /* If both ends of tunnel/bridge are in the range, do not try to convert twice -
                         * it would cause assert because of different test and exec runs */
                        if (endtile < tile) {
                                if (OrthogonalTileArea(area_start, area_end).Contains(endtile)) continue;
                        }

                        /* When not converting rail <-> el. rail, any vehicle cannot be in tunnel/bridge */
                        if (!HasPowerOnRoad(from_type, to_type)) {
                                CommandCost ret = TunnelBridgeIsFree(tile, endtile);
                                if (ret.Failed()) {
                                        error = ret;
                                        continue;
                                }

                                if (to_type.basetype == ROADTYPE_ROAD && owner == OWNER_TOWN) {
                                        error.MakeError(STR_ERROR_INCOMPATIBLE_ROAD);
                                        continue;
                                }
                        }

                        /* There are 2 pieces on *every* tile of the bridge or tunnel */
                        uint num_pieces = (GetTunnelBridgeLength(tile, endtile) + 2) * 2;
                        cost.AddCost(num_pieces * RoadConvertCost(from_type, to_type));

                        if (flags & DC_EXEC) {
                                /* Update the company infrastructure counters. */
                                if (CanConvertRoadType(owner, to_type.basetype) && owner != OWNER_TOWN) {
                                        ConvertRoadTypeOwner(tile, num_pieces, owner, from_type, to_type);
                                        ConvertRoadTypeOwner(endtile, num_pieces, owner, from_type, to_type);
                                        SetTunnelBridgeOwner(tile, endtile, _current_company);
                                }

                                /* Perform the conversion */
                                rtids.MergeRoadType(to_type);
                                SetRoadTypes(tile, rtids);
                                SetRoadTypes(endtile, rtids);

                                FindVehicleOnPos(tile, &affected_rvs, &UpdateRoadVehPowerProc);
                                FindVehicleOnPos(endtile, &affected_rvs, &UpdateRoadVehPowerProc);

                                if (IsBridge(tile)) {
                                        MarkBridgeDirty(tile);
                                } else {
                                        MarkTileDirtyByTile(tile);
                                        MarkTileDirtyByTile(endtile);
                                }
                        }
                }
        }

        if (flags & DC_EXEC) {
                /* Roadtype changed, update roadvehicles as when entering different track */
                for (RoadVehicle **v = affected_rvs.Begin(); v != affected_rvs.End(); v++) {
                        (*v)->CargoChanged();
                }
        }

        delete iter;
        return (cost.GetCost() == 0) ? error : cost;
}


/** Tile callback functions for road tiles */
extern const TileTypeProcs _tile_type_road_procs = {
        DrawTile_Road,           // draw_tile_proc
        GetSlopePixelZ_Road,     // get_slope_z_proc
        ClearTile_Road,          // clear_tile_proc
        nullptr,                    // add_accepted_cargo_proc
        GetTileDesc_Road,        // get_tile_desc_proc
        GetTileTrackStatus_Road, // get_tile_track_status_proc
        ClickTile_Road,          // click_tile_proc
        nullptr,                    // animate_tile_proc
        TileLoop_Road,           // tile_loop_proc
        ChangeTileOwner_Road,    // change_tile_owner_proc
        nullptr,                    // add_produced_cargo_proc
        VehicleEnter_Road,       // vehicle_enter_tile_proc
        GetFoundation_Road,      // get_foundation_proc
        TerraformTile_Road,      // terraform_tile_proc
};