Doc: Prepare for 14.0-RC2 release (#12248)

[openttd-github.git] / src / ship_cmd.cpp

/*
 * 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 ship_cmd.cpp Handling of ships. */

#include "stdafx.h"
#include "ship.h"
#include "landscape.h"
#include "timetable.h"
#include "news_func.h"
#include "company_func.h"
#include "pathfinder/npf/npf_func.h"
#include "depot_base.h"
#include "station_base.h"
#include "newgrf_engine.h"
#include "pathfinder/yapf/yapf.h"
#include "pathfinder/yapf/yapf_ship_regions.h"
#include "newgrf_sound.h"
#include "spritecache.h"
#include "strings_func.h"
#include "window_func.h"
#include "timer/timer_game_calendar.h"
#include "timer/timer_game_economy.h"
#include "vehicle_func.h"
#include "sound_func.h"
#include "ai/ai.hpp"
#include "game/game.hpp"
#include "engine_base.h"
#include "company_base.h"
#include "tunnelbridge_map.h"
#include "zoom_func.h"
#include "framerate_type.h"
#include "industry.h"
#include "industry_map.h"
#include "ship_cmd.h"

#include "table/strings.h"

#include <unordered_set>

#include "safeguards.h"

/** Max distance in tiles (as the crow flies) to search for depots when user clicks "go to depot". */
constexpr int MAX_SHIP_DEPOT_SEARCH_DISTANCE = 80;

/**
 * Determine the effective #WaterClass for a ship travelling on a tile.
 * @param tile Tile of interest
 * @return the waterclass to be used by the ship.
 */
WaterClass GetEffectiveWaterClass(TileIndex tile)
{
        if (HasTileWaterClass(tile)) return GetWaterClass(tile);
        if (IsTileType(tile, MP_TUNNELBRIDGE)) {
                assert(GetTunnelBridgeTransportType(tile) == TRANSPORT_WATER);
                return WATER_CLASS_CANAL;
        }
        if (IsTileType(tile, MP_RAILWAY)) {
                assert(GetRailGroundType(tile) == RAIL_GROUND_WATER);
                return WATER_CLASS_SEA;
        }
        NOT_REACHED();
}

static const uint16_t _ship_sprites[] = {0x0E5D, 0x0E55, 0x0E65, 0x0E6D};

template <>
bool IsValidImageIndex<VEH_SHIP>(uint8_t image_index)
{
        return image_index < lengthof(_ship_sprites);
}

static inline TrackBits GetTileShipTrackStatus(TileIndex tile)
{
        return TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_WATER, 0));
}

static void GetShipIcon(EngineID engine, EngineImageType image_type, VehicleSpriteSeq *result)
{
        const Engine *e = Engine::Get(engine);
        uint8_t spritenum = e->u.ship.image_index;

        if (is_custom_sprite(spritenum)) {
                GetCustomVehicleIcon(engine, DIR_W, image_type, result);
                if (result->IsValid()) return;

                spritenum = e->original_image_index;
        }

        assert(IsValidImageIndex<VEH_SHIP>(spritenum));
        result->Set(DIR_W + _ship_sprites[spritenum]);
}

void DrawShipEngine(int left, int right, int preferred_x, int y, EngineID engine, PaletteID pal, EngineImageType image_type)
{
        VehicleSpriteSeq seq;
        GetShipIcon(engine, image_type, &seq);

        Rect rect;
        seq.GetBounds(&rect);
        preferred_x = Clamp(preferred_x,
                        left - UnScaleGUI(rect.left),
                        right - UnScaleGUI(rect.right));

        seq.Draw(preferred_x, y, pal, pal == PALETTE_CRASH);
}

/**
 * Get the size of the sprite of a ship sprite heading west (used for lists).
 * @param engine The engine to get the sprite from.
 * @param[out] width The width of the sprite.
 * @param[out] height The height of the sprite.
 * @param[out] xoffs Number of pixels to shift the sprite to the right.
 * @param[out] yoffs Number of pixels to shift the sprite downwards.
 * @param image_type Context the sprite is used in.
 */
void GetShipSpriteSize(EngineID engine, uint &width, uint &height, int &xoffs, int &yoffs, EngineImageType image_type)
{
        VehicleSpriteSeq seq;
        GetShipIcon(engine, image_type, &seq);

        Rect rect;
        seq.GetBounds(&rect);

        width  = UnScaleGUI(rect.Width());
        height = UnScaleGUI(rect.Height());
        xoffs  = UnScaleGUI(rect.left);
        yoffs  = UnScaleGUI(rect.top);
}

void Ship::GetImage(Direction direction, EngineImageType image_type, VehicleSpriteSeq *result) const
{
        uint8_t spritenum = this->spritenum;

        if (image_type == EIT_ON_MAP) direction = this->rotation;

        if (is_custom_sprite(spritenum)) {
                GetCustomVehicleSprite(this, direction, image_type, result);
                if (result->IsValid()) return;

                spritenum = this->GetEngine()->original_image_index;
        }

        assert(IsValidImageIndex<VEH_SHIP>(spritenum));
        result->Set(_ship_sprites[spritenum] + direction);
}

static const Depot *FindClosestShipDepot(const Vehicle *v, uint max_distance)
{
        const int max_region_distance = (max_distance / WATER_REGION_EDGE_LENGTH) + 1;

        static std::unordered_set<int> visited_patch_hashes;
        static std::deque<WaterRegionPatchDesc> patches_to_search;
        visited_patch_hashes.clear();
        patches_to_search.clear();

        /* Step 1: find a set of reachable Water Region Patches using BFS. */
        const WaterRegionPatchDesc start_patch = GetWaterRegionPatchInfo(v->tile);
        patches_to_search.push_back(start_patch);
        visited_patch_hashes.insert(CalculateWaterRegionPatchHash(start_patch));

        while (!patches_to_search.empty()) {
                /* Remove first patch from the queue and make it the current patch. */
                const WaterRegionPatchDesc current_node = patches_to_search.front();
                patches_to_search.pop_front();

                /* Add neighbors of the current patch to the search queue. */
                TVisitWaterRegionPatchCallBack visitFunc = [&](const WaterRegionPatchDesc &water_region_patch) {
                        /* Note that we check the max distance per axis, not the total distance. */
                        if (std::abs(water_region_patch.x - start_patch.x) > max_region_distance ||
                                        std::abs(water_region_patch.y - start_patch.y) > max_region_distance) return;

                        const int hash = CalculateWaterRegionPatchHash(water_region_patch);
                        if (visited_patch_hashes.count(hash) == 0) {
                                visited_patch_hashes.insert(hash);
                                patches_to_search.push_back(water_region_patch);
                        }
                };

                VisitWaterRegionPatchNeighbors(current_node, visitFunc);
        }

        /* Step 2: Find the closest depot within the reachable Water Region Patches. */
        const Depot *best_depot = nullptr;
        uint best_dist_sq = std::numeric_limits<uint>::max();
        for (const Depot *depot : Depot::Iterate()) {
                const TileIndex tile = depot->xy;
                if (IsShipDepotTile(tile) && IsTileOwner(tile, v->owner)) {
                        const uint dist_sq = DistanceSquare(tile, v->tile);
                        if (dist_sq < best_dist_sq && dist_sq <= max_distance * max_distance &&
                                        visited_patch_hashes.count(CalculateWaterRegionPatchHash(GetWaterRegionPatchInfo(tile))) > 0) {
                                best_dist_sq = dist_sq;
                                best_depot = depot;
                        }
                }
        }

        return best_depot;
}

static void CheckIfShipNeedsService(Vehicle *v)
{
        if (Company::Get(v->owner)->settings.vehicle.servint_ships == 0 || !v->NeedsAutomaticServicing()) return;
        if (v->IsChainInDepot()) {
                VehicleServiceInDepot(v);
                return;
        }

        uint max_distance;
        switch (_settings_game.pf.pathfinder_for_ships) {
                case VPF_NPF:  max_distance = _settings_game.pf.npf.maximum_go_to_depot_penalty  / NPF_TILE_LENGTH;  break;
                case VPF_YAPF: max_distance = _settings_game.pf.yapf.maximum_go_to_depot_penalty / YAPF_TILE_LENGTH; break;
                default: NOT_REACHED();
        }

        const Depot *depot = FindClosestShipDepot(v, max_distance);

        if (depot == nullptr) {
                if (v->current_order.IsType(OT_GOTO_DEPOT)) {
                        v->current_order.MakeDummy();
                        SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
                }
                return;
        }

        v->current_order.MakeGoToDepot(depot->index, ODTFB_SERVICE);
        v->SetDestTile(depot->xy);
        SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
}

/**
 * Update the caches of this ship.
 */
void Ship::UpdateCache()
{
        const ShipVehicleInfo *svi = ShipVehInfo(this->engine_type);

        /* Get speed fraction for the current water type. Aqueducts are always canals. */
        bool is_ocean = GetEffectiveWaterClass(this->tile) == WATER_CLASS_SEA;
        uint raw_speed = GetVehicleProperty(this, PROP_SHIP_SPEED, svi->max_speed);
        this->vcache.cached_max_speed = svi->ApplyWaterClassSpeedFrac(raw_speed, is_ocean);

        /* Update cargo aging period. */
        this->vcache.cached_cargo_age_period = GetVehicleProperty(this, PROP_SHIP_CARGO_AGE_PERIOD, EngInfo(this->engine_type)->cargo_age_period);

        this->UpdateVisualEffect();
}

Money Ship::GetRunningCost() const
{
        const Engine *e = this->GetEngine();
        uint cost_factor = GetVehicleProperty(this, PROP_SHIP_RUNNING_COST_FACTOR, e->u.ship.running_cost);
        return GetPrice(PR_RUNNING_SHIP, cost_factor, e->GetGRF());
}

/** Calendar day handler. */
void Ship::OnNewCalendarDay()
{
        AgeVehicle(this);
}

/** Economy day handler. */
void Ship::OnNewEconomyDay()
{
        EconomyAgeVehicle(this);

        if ((++this->day_counter & 7) == 0) {
                DecreaseVehicleValue(this);
        }

        CheckVehicleBreakdown(this);
        CheckIfShipNeedsService(this);

        CheckOrders(this);

        if (this->running_ticks == 0) return;

        CommandCost cost(EXPENSES_SHIP_RUN, this->GetRunningCost() * this->running_ticks / (CalendarTime::DAYS_IN_YEAR * Ticks::DAY_TICKS));

        this->profit_this_year -= cost.GetCost();
        this->running_ticks = 0;

        SubtractMoneyFromCompanyFract(this->owner, cost);

        SetWindowDirty(WC_VEHICLE_DETAILS, this->index);
        /* we need this for the profit */
        SetWindowClassesDirty(WC_SHIPS_LIST);
}

Trackdir Ship::GetVehicleTrackdir() const
{
        if (this->vehstatus & VS_CRASHED) return INVALID_TRACKDIR;

        if (this->IsInDepot()) {
                /* We'll assume the ship is facing outwards */
                return DiagDirToDiagTrackdir(GetShipDepotDirection(this->tile));
        }

        if (this->state == TRACK_BIT_WORMHOLE) {
                /* ship on aqueduct, so just use its direction and assume a diagonal track */
                return DiagDirToDiagTrackdir(DirToDiagDir(this->direction));
        }

        return TrackDirectionToTrackdir(FindFirstTrack(this->state), this->direction);
}

void Ship::MarkDirty()
{
        this->colourmap = PAL_NONE;
        this->UpdateViewport(true, false);
        this->UpdateCache();
}

void Ship::PlayLeaveStationSound(bool force) const
{
        if (PlayVehicleSound(this, VSE_START, force)) return;
        SndPlayVehicleFx(ShipVehInfo(this->engine_type)->sfx, this);
}

TileIndex Ship::GetOrderStationLocation(StationID station)
{
        if (station == this->last_station_visited) this->last_station_visited = INVALID_STATION;

        const Station *st = Station::Get(station);
        if (CanVehicleUseStation(this, st)) {
                return st->xy;
        } else {
                this->IncrementRealOrderIndex();
                return 0;
        }
}

void Ship::UpdateDeltaXY()
{
        static const int8_t _delta_xy_table[8][4] = {
                /* y_extent, x_extent, y_offs, x_offs */
                { 6,  6,  -3,  -3}, // N
                { 6, 32,  -3, -16}, // NE
                { 6,  6,  -3,  -3}, // E
                {32,  6, -16,  -3}, // SE
                { 6,  6,  -3,  -3}, // S
                { 6, 32,  -3, -16}, // SW
                { 6,  6,  -3,  -3}, // W
                {32,  6, -16,  -3}, // NW
        };

        const int8_t *bb = _delta_xy_table[this->rotation];
        this->x_offs        = bb[3];
        this->y_offs        = bb[2];
        this->x_extent      = bb[1];
        this->y_extent      = bb[0];
        this->z_extent      = 6;

        if (this->direction != this->rotation) {
                /* If we are rotating, then it is possible the ship was moved to its next position. In that
                 * case, because we are still showing the old direction, the ship will appear to glitch sideways
                 * slightly. We can work around this by applying an additional offset to make the ship appear
                 * where it was before it moved. */
                this->x_offs -= this->x_pos - this->rotation_x_pos;
                this->y_offs -= this->y_pos - this->rotation_y_pos;
        }
}

/**
 * Test-procedure for HasVehicleOnPos to check for any ships which are visible and not stopped by the player.
 */
static Vehicle *EnsureNoMovingShipProc(Vehicle *v, void *)
{
        return v->type == VEH_SHIP && (v->vehstatus & (VS_HIDDEN | VS_STOPPED)) == 0 ? v : nullptr;
}

static bool CheckReverseShip(const Ship *v, Trackdir *trackdir = nullptr)
{
        /* Ask pathfinder for best direction */
        bool reverse = false;
        switch (_settings_game.pf.pathfinder_for_ships) {
                case VPF_NPF: reverse = NPFShipCheckReverse(v, trackdir); break;
                case VPF_YAPF: reverse = YapfShipCheckReverse(v, trackdir); break;
                default: NOT_REACHED();
        }
        return reverse;
}

static bool CheckShipLeaveDepot(Ship *v)
{
        if (!v->IsChainInDepot()) return false;

        /* Check if we should wait here for unbunching. */
        if (v->IsWaitingForUnbunching()) return true;

        /* We are leaving a depot, but have to go to the exact same one; re-enter */
        if (v->current_order.IsType(OT_GOTO_DEPOT) &&
                        IsShipDepotTile(v->tile) && GetDepotIndex(v->tile) == v->current_order.GetDestination()) {
                VehicleEnterDepot(v);
                return true;
        }

        /* Don't leave depot if no destination set */
        if (v->dest_tile == 0) return true;

        /* Don't leave depot if another vehicle is already entering/leaving */
        /* This helps avoid CPU load if many ships are set to start at the same time */
        if (HasVehicleOnPos(v->tile, nullptr, &EnsureNoMovingShipProc)) return true;

        TileIndex tile = v->tile;
        Axis axis = GetShipDepotAxis(tile);

        DiagDirection north_dir = ReverseDiagDir(AxisToDiagDir(axis));
        TileIndex north_neighbour = TILE_ADD(tile, TileOffsByDiagDir(north_dir));
        DiagDirection south_dir = AxisToDiagDir(axis);
        TileIndex south_neighbour = TILE_ADD(tile, 2 * TileOffsByDiagDir(south_dir));

        TrackBits north_tracks = DiagdirReachesTracks(north_dir) & GetTileShipTrackStatus(north_neighbour);
        TrackBits south_tracks = DiagdirReachesTracks(south_dir) & GetTileShipTrackStatus(south_neighbour);
        if (north_tracks && south_tracks) {
                if (CheckReverseShip(v)) north_tracks = TRACK_BIT_NONE;
        }

        if (north_tracks) {
                /* Leave towards north */
                v->rotation = v->direction = DiagDirToDir(north_dir);
        } else if (south_tracks) {
                /* Leave towards south */
                v->rotation = v->direction = DiagDirToDir(south_dir);
        } else {
                /* Both ways blocked */
                return false;
        }

        v->state = AxisToTrackBits(axis);
        v->vehstatus &= ~VS_HIDDEN;

        v->cur_speed = 0;
        v->UpdateViewport(true, true);
        SetWindowDirty(WC_VEHICLE_DEPOT, v->tile);

        VehicleServiceInDepot(v);
        v->LeaveUnbunchingDepot();
        v->PlayLeaveStationSound();
        InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
        SetWindowClassesDirty(WC_SHIPS_LIST);

        return false;
}

/**
 * Accelerates the ship towards its target speed.
 * @param v Ship to accelerate.
 * @return Number of steps to move the ship.
 */
static uint ShipAccelerate(Vehicle *v)
{
        uint speed;
        speed = std::min<uint>(v->cur_speed + v->acceleration, v->vcache.cached_max_speed);
        speed = std::min<uint>(speed, v->current_order.GetMaxSpeed() * 2);

        /* updates statusbar only if speed have changed to save CPU time */
        if (speed != v->cur_speed) {
                v->cur_speed = speed;
                SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
        }

        const uint advance_speed = v->GetAdvanceSpeed(speed);
        const uint number_of_steps = (advance_speed + v->progress) / v->GetAdvanceDistance();
        const uint remainder = (advance_speed + v->progress) % v->GetAdvanceDistance();
        assert(remainder <= std::numeric_limits<byte>::max());
        v->progress = static_cast<byte>(remainder);
        return number_of_steps;
}

/**
 * Ship arrives at a dock. If it is the first time, send out a news item.
 * @param v  Ship that arrived.
 * @param st Station being visited.
 */
static void ShipArrivesAt(const Vehicle *v, Station *st)
{
        /* Check if station was ever visited before */
        if (!(st->had_vehicle_of_type & HVOT_SHIP)) {
                st->had_vehicle_of_type |= HVOT_SHIP;

                SetDParam(0, st->index);
                AddVehicleNewsItem(
                        STR_NEWS_FIRST_SHIP_ARRIVAL,
                        (v->owner == _local_company) ? NT_ARRIVAL_COMPANY : NT_ARRIVAL_OTHER,
                        v->index,
                        st->index
                );
                AI::NewEvent(v->owner, new ScriptEventStationFirstVehicle(st->index, v->index));
                Game::NewEvent(new ScriptEventStationFirstVehicle(st->index, v->index));
        }
}


/**
 * Runs the pathfinder to choose a track to continue along.
 *
 * @param v Ship to navigate
 * @param tile Tile, the ship is about to enter
 * @param enterdir Direction of entering
 * @param tracks Available track choices on \a tile
 * @return Track to choose, or INVALID_TRACK when to reverse.
 */
static Track ChooseShipTrack(Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks)
{
        assert(IsValidDiagDirection(enterdir));

        bool path_found = true;
        Track track;

        if (v->dest_tile == 0) {
                /* No destination, don't invoke pathfinder. */
                track = TrackBitsToTrack(v->state);
                if (!IsDiagonalTrack(track)) track = TrackToOppositeTrack(track);
                if (!HasBit(tracks, track)) track = FindFirstTrack(tracks);
                path_found = false;
        } else {
                /* Attempt to follow cached path. */
                if (!v->path.empty()) {
                        track = TrackdirToTrack(v->path.front());

                        if (HasBit(tracks, track)) {
                                v->path.pop_front();
                                /* HandlePathfindResult() is not called here because this is not a new pathfinder result. */
                                return track;
                        }

                        /* Cached path is invalid so continue with pathfinder. */
                        v->path.clear();
                }

                switch (_settings_game.pf.pathfinder_for_ships) {
                        case VPF_NPF: track = NPFShipChooseTrack(v, path_found); break;
                        case VPF_YAPF: track = YapfShipChooseTrack(v, tile, enterdir, tracks, path_found, v->path); break;
                        default: NOT_REACHED();
                }
        }

        v->HandlePathfindingResult(path_found);
        return track;
}

/**
 * Get the available water tracks on a tile for a ship entering a tile.
 * @param tile The tile about to enter.
 * @param dir The entry direction.
 * @return The available trackbits on the next tile.
 */
static inline TrackBits GetAvailShipTracks(TileIndex tile, DiagDirection dir)
{
        TrackBits tracks = GetTileShipTrackStatus(tile) & DiagdirReachesTracks(dir);

        return tracks;
}

/** Structure for ship sub-coordinate data for moving into a new tile via a Diagdir onto a Track. */
struct ShipSubcoordData {
        byte x_subcoord; ///< New X sub-coordinate on the new tile
        byte y_subcoord; ///< New Y sub-coordinate on the new tile
        Direction dir;   ///< New Direction to move in on the new track
};
/** Ship sub-coordinate data for moving into a new tile via a Diagdir onto a Track.
 * Array indexes are Diagdir, Track.
 * There will always be three possible tracks going into an adjacent tile via a Diagdir,
 * so each Diagdir sub-array will have three valid and three invalid structures per Track.
 */
static const ShipSubcoordData _ship_subcoord[DIAGDIR_END][TRACK_END] = {
        // DIAGDIR_NE
        {
                {15,  8, DIR_NE},      // TRACK_X
                { 0,  0, INVALID_DIR}, // TRACK_Y
                { 0,  0, INVALID_DIR}, // TRACK_UPPER
                {15,  8, DIR_E},       // TRACK_LOWER
                {15,  7, DIR_N},       // TRACK_LEFT
                { 0,  0, INVALID_DIR}, // TRACK_RIGHT
        },
        // DIAGDIR_SE
        {
                { 0,  0, INVALID_DIR}, // TRACK_X
                { 8,  0, DIR_SE},      // TRACK_Y
                { 7,  0, DIR_E},       // TRACK_UPPER
                { 0,  0, INVALID_DIR}, // TRACK_LOWER
                { 8,  0, DIR_S},       // TRACK_LEFT
                { 0,  0, INVALID_DIR}, // TRACK_RIGHT
        },
        // DIAGDIR_SW
        {
                { 0,  8, DIR_SW},      // TRACK_X
                { 0,  0, INVALID_DIR}, // TRACK_Y
                { 0,  7, DIR_W},       // TRACK_UPPER
                { 0,  0, INVALID_DIR}, // TRACK_LOWER
                { 0,  0, INVALID_DIR}, // TRACK_LEFT
                { 0,  8, DIR_S},       // TRACK_RIGHT
        },
        // DIAGDIR_NW
        {
                { 0,  0, INVALID_DIR}, // TRACK_X
                { 8, 15, DIR_NW},      // TRACK_Y
                { 0,  0, INVALID_DIR}, // TRACK_UPPER
                { 8, 15, DIR_W},       // TRACK_LOWER
                { 0,  0, INVALID_DIR}, // TRACK_LEFT
                { 7, 15, DIR_N},       // TRACK_RIGHT
        }
};

/**
 * Test if a ship is in the centre of a lock and should move up or down.
 * @param v Ship being tested.
 * @return 0 if ship is not moving in lock, or -1 to move down, 1 to move up.
 */
static int ShipTestUpDownOnLock(const Ship *v)
{
        /* Suitable tile? */
        if (!IsTileType(v->tile, MP_WATER) || !IsLock(v->tile) || GetLockPart(v->tile) != LOCK_PART_MIDDLE) return 0;

        /* Must be at the centre of the lock */
        if ((v->x_pos & 0xF) != 8 || (v->y_pos & 0xF) != 8) return 0;

        DiagDirection diagdir = GetInclinedSlopeDirection(GetTileSlope(v->tile));
        assert(IsValidDiagDirection(diagdir));

        if (DirToDiagDir(v->direction) == diagdir) {
                /* Move up */
                return (v->z_pos < GetTileMaxZ(v->tile) * (int)TILE_HEIGHT) ? 1 : 0;
        } else {
                /* Move down */
                return (v->z_pos > GetTileZ(v->tile) * (int)TILE_HEIGHT) ? -1 : 0;
        }
}

/**
 * Test and move a ship up or down in a lock.
 * @param v Ship to move.
 * @return true iff ship is moving up or down in a lock.
 */
static bool ShipMoveUpDownOnLock(Ship *v)
{
        /* Moving up/down through lock */
        int dz = ShipTestUpDownOnLock(v);
        if (dz == 0) return false;

        if (v->cur_speed != 0) {
                v->cur_speed = 0;
                SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
        }

        if ((v->tick_counter & 7) == 0) {
                v->z_pos += dz;
                v->UpdatePosition();
                v->UpdateViewport(true, true);
        }

        return true;
}

/**
 * Test if a tile is a docking tile for the given station.
 * @param tile Docking tile to test.
 * @param station Destination station.
 * @return true iff docking tile is next to station.
 */
bool IsShipDestinationTile(TileIndex tile, StationID station)
{
        assert(IsDockingTile(tile));
        /* Check each tile adjacent to docking tile. */
        for (DiagDirection d = DIAGDIR_BEGIN; d != DIAGDIR_END; d++) {
                TileIndex t = tile + TileOffsByDiagDir(d);
                if (!IsValidTile(t)) continue;
                if (IsDockTile(t) && GetStationIndex(t) == station && IsDockWaterPart(t)) return true;
                if (IsTileType(t, MP_INDUSTRY)) {
                        const Industry *i = Industry::GetByTile(t);
                        if (i->neutral_station != nullptr && i->neutral_station->index == station) return true;
                }
                if (IsTileType(t, MP_STATION) && IsOilRig(t) && GetStationIndex(t) == station) return true;
        }
        return false;
}

static void ReverseShipIntoTrackdir(Ship *v, Trackdir trackdir)
{
        static constexpr Direction _trackdir_to_direction[] = {
                DIR_NE, DIR_SE, DIR_E, DIR_E, DIR_S, DIR_S, INVALID_DIR, INVALID_DIR,
                DIR_SW, DIR_NW, DIR_W, DIR_W, DIR_N, DIR_N, INVALID_DIR, INVALID_DIR,
        };

        v->direction = _trackdir_to_direction[trackdir];
        assert(v->direction != INVALID_DIR);
        v->state = TrackdirBitsToTrackBits(TrackdirToTrackdirBits(trackdir));

        /* Remember our current location to avoid movement glitch */
        v->rotation_x_pos = v->x_pos;
        v->rotation_y_pos = v->y_pos;
        v->cur_speed = 0;
        v->path.clear();

        v->UpdatePosition();
        v->UpdateViewport(true, true);
}

static void ReverseShip(Ship *v)
{
        v->direction = ReverseDir(v->direction);

        /* Remember our current location to avoid movement glitch */
        v->rotation_x_pos = v->x_pos;
        v->rotation_y_pos = v->y_pos;
        v->cur_speed = 0;
        v->path.clear();

        v->UpdatePosition();
        v->UpdateViewport(true, true);
}

static void ShipController(Ship *v)
{
        v->tick_counter++;
        v->current_order_time++;

        if (v->HandleBreakdown()) return;

        if (v->vehstatus & VS_STOPPED) return;

        if (ProcessOrders(v) && CheckReverseShip(v)) return ReverseShip(v);

        v->HandleLoading();

        if (v->current_order.IsType(OT_LOADING)) return;

        if (CheckShipLeaveDepot(v)) return;

        v->ShowVisualEffect();

        /* Rotating on spot */
        if (v->direction != v->rotation) {
                if ((v->tick_counter & 7) == 0) {
                        DirDiff diff = DirDifference(v->direction, v->rotation);
                        v->rotation = ChangeDir(v->rotation, diff > DIRDIFF_REVERSE ? DIRDIFF_45LEFT : DIRDIFF_45RIGHT);
                        /* Invalidate the sprite cache direction to force recalculation of viewport */
                        v->sprite_cache.last_direction = INVALID_DIR;
                        v->UpdateViewport(true, true);
                }
                return;
        }

        if (ShipMoveUpDownOnLock(v)) return;

        const uint number_of_steps = ShipAccelerate(v);
        for (uint i = 0; i < number_of_steps; ++i) {
                if (ShipMoveUpDownOnLock(v)) return;

                GetNewVehiclePosResult gp = GetNewVehiclePos(v);
                if (v->state != TRACK_BIT_WORMHOLE) {
                        /* Not on a bridge */
                        if (gp.old_tile == gp.new_tile) {
                                /* Staying in tile */
                                if (v->IsInDepot()) {
                                        gp.x = v->x_pos;
                                        gp.y = v->y_pos;
                                } else {
                                        /* Not inside depot */
                                        const VehicleEnterTileStatus r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
                                        if (HasBit(r, VETS_CANNOT_ENTER)) return ReverseShip(v);

                                        /* A leave station order only needs one tick to get processed, so we can
                                         * always skip ahead. */
                                        if (v->current_order.IsType(OT_LEAVESTATION)) {
                                                v->current_order.Free();
                                                SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
                                                /* Test if continuing forward would lead to a dead-end, moving into the dock. */
                                                const DiagDirection exitdir = VehicleExitDir(v->direction, v->state);
                                                const TileIndex tile = TileAddByDiagDir(v->tile, exitdir);
                                                if (TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_WATER, 0, exitdir)) == TRACK_BIT_NONE) return ReverseShip(v);
                                        } else if (v->dest_tile != 0) {
                                                /* We have a target, let's see if we reached it... */
                                                if (v->current_order.IsType(OT_GOTO_WAYPOINT) &&
                                                                DistanceManhattan(v->dest_tile, gp.new_tile) <= 3) {
                                                        /* We got within 3 tiles of our target buoy, so let's skip to our
                                                         * next order */
                                                        UpdateVehicleTimetable(v, true);
                                                        v->IncrementRealOrderIndex();
                                                        v->current_order.MakeDummy();
                                                } else if (v->current_order.IsType(OT_GOTO_DEPOT) &&
                                                        v->dest_tile == gp.new_tile) {
                                                        /* Depot orders really need to reach the tile */
                                                        if ((gp.x & 0xF) == 8 && (gp.y & 0xF) == 8) {
                                                                VehicleEnterDepot(v);
                                                                return;
                                                        }
                                                } else if (v->current_order.IsType(OT_GOTO_STATION) && IsDockingTile(gp.new_tile)) {
                                                        /* Process station in the orderlist. */
                                                        Station *st = Station::Get(v->current_order.GetDestination());
                                                        if (st->docking_station.Contains(gp.new_tile) && IsShipDestinationTile(gp.new_tile, st->index)) {
                                                                v->last_station_visited = st->index;
                                                                if (st->facilities & FACIL_DOCK) { // ugly, ugly workaround for problem with ships able to drop off cargo at wrong stations
                                                                        ShipArrivesAt(v, st);
                                                                        v->BeginLoading();
                                                                } else { // leave stations without docks right away
                                                                        v->current_order.MakeLeaveStation();
                                                                        v->IncrementRealOrderIndex();
                                                                }
                                                        }
                                                }
                                        }
                                }
                        } else {
                                /* New tile */
                                if (!IsValidTile(gp.new_tile)) return ReverseShip(v);

                                const DiagDirection diagdir = DiagdirBetweenTiles(gp.old_tile, gp.new_tile);
                                assert(diagdir != INVALID_DIAGDIR);
                                const TrackBits tracks = GetAvailShipTracks(gp.new_tile, diagdir);
                                if (tracks == TRACK_BIT_NONE) {
                                        Trackdir trackdir = INVALID_TRACKDIR;
                                        CheckReverseShip(v, &trackdir);
                                        if (trackdir == INVALID_TRACKDIR) return ReverseShip(v);
                                        return ReverseShipIntoTrackdir(v, trackdir);
                                }

                                /* Choose a direction, and continue if we find one */
                                const Track track = ChooseShipTrack(v, gp.new_tile, diagdir, tracks);
                                if (track == INVALID_TRACK) return ReverseShip(v);

                                const ShipSubcoordData &b = _ship_subcoord[diagdir][track];

                                gp.x = (gp.x & ~0xF) | b.x_subcoord;
                                gp.y = (gp.y & ~0xF) | b.y_subcoord;

                                /* Call the landscape function and tell it that the vehicle entered the tile */
                                const VehicleEnterTileStatus r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
                                if (HasBit(r, VETS_CANNOT_ENTER)) return ReverseShip(v);

                                if (!HasBit(r, VETS_ENTERED_WORMHOLE)) {
                                        v->tile = gp.new_tile;
                                        v->state = TrackToTrackBits(track);

                                        /* Update ship cache when the water class changes. Aqueducts are always canals. */
                                        if (GetEffectiveWaterClass(gp.old_tile) != GetEffectiveWaterClass(gp.new_tile)) v->UpdateCache();
                                }

                                const Direction new_direction = b.dir;
                                const DirDiff diff = DirDifference(new_direction, v->direction);
                                switch (diff) {
                                        case DIRDIFF_SAME:
                                        case DIRDIFF_45RIGHT:
                                        case DIRDIFF_45LEFT:
                                                /* Continue at speed */
                                                v->rotation = v->direction = new_direction;
                                                break;

                                        default:
                                                /* Stop for rotation */
                                                v->cur_speed = 0;
                                                v->direction = new_direction;
                                                /* Remember our current location to avoid movement glitch */
                                                v->rotation_x_pos = v->x_pos;
                                                v->rotation_y_pos = v->y_pos;
                                                break;
                                }
                        }
                } else {
                        /* On a bridge */
                        if (!IsTileType(gp.new_tile, MP_TUNNELBRIDGE) || !HasBit(VehicleEnterTile(v, gp.new_tile, gp.x, gp.y), VETS_ENTERED_WORMHOLE)) {
                                v->x_pos = gp.x;
                                v->y_pos = gp.y;
                                v->UpdatePosition();
                                if ((v->vehstatus & VS_HIDDEN) == 0) v->Vehicle::UpdateViewport(true);
                                return;
                        }

                        /* Ship is back on the bridge head, we need to consume its path
                         * cache entry here as we didn't have to choose a ship track. */
                        if (!v->path.empty()) v->path.pop_front();
                }

                /* update image of ship, as well as delta XY */
                v->x_pos = gp.x;
                v->y_pos = gp.y;

                v->UpdatePosition();
                v->UpdateViewport(true, true);
        }
}

bool Ship::Tick()
{
        PerformanceAccumulator framerate(PFE_GL_SHIPS);

        if (!(this->vehstatus & VS_STOPPED)) this->running_ticks++;

        ShipController(this);

        return true;
}

void Ship::SetDestTile(TileIndex tile)
{
        if (tile == this->dest_tile) return;
        this->path.clear();
        this->dest_tile = tile;
}

/**
 * Build a ship.
 * @param flags    type of operation.
 * @param tile     tile of the depot where ship is built.
 * @param e        the engine to build.
 * @param[out] ret the vehicle that has been built.
 * @return the cost of this operation or an error.
 */
CommandCost CmdBuildShip(DoCommandFlag flags, TileIndex tile, const Engine *e, Vehicle **ret)
{
        tile = GetShipDepotNorthTile(tile);
        if (flags & DC_EXEC) {
                int x;
                int y;

                const ShipVehicleInfo *svi = &e->u.ship;

                Ship *v = new Ship();
                *ret = v;

                v->owner = _current_company;
                v->tile = tile;
                x = TileX(tile) * TILE_SIZE + TILE_SIZE / 2;
                y = TileY(tile) * TILE_SIZE + TILE_SIZE / 2;
                v->x_pos = x;
                v->y_pos = y;
                v->z_pos = GetSlopePixelZ(x, y);

                v->UpdateDeltaXY();
                v->vehstatus = VS_HIDDEN | VS_STOPPED | VS_DEFPAL;

                v->spritenum = svi->image_index;
                v->cargo_type = e->GetDefaultCargoType();
                assert(IsValidCargoID(v->cargo_type));
                v->cargo_cap = svi->capacity;
                v->refit_cap = 0;

                v->last_station_visited = INVALID_STATION;
                v->last_loading_station = INVALID_STATION;
                v->engine_type = e->index;

                v->reliability = e->reliability;
                v->reliability_spd_dec = e->reliability_spd_dec;
                v->max_age = e->GetLifeLengthInDays();

                v->state = TRACK_BIT_DEPOT;

                v->SetServiceInterval(Company::Get(_current_company)->settings.vehicle.servint_ships);
                v->date_of_last_service = TimerGameEconomy::date;
                v->date_of_last_service_newgrf = TimerGameCalendar::date;
                v->build_year = TimerGameCalendar::year;
                v->sprite_cache.sprite_seq.Set(SPR_IMG_QUERY);
                v->random_bits = Random();

                v->acceleration = svi->acceleration;
                v->UpdateCache();

                if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) SetBit(v->vehicle_flags, VF_BUILT_AS_PROTOTYPE);
                v->SetServiceIntervalIsPercent(Company::Get(_current_company)->settings.vehicle.servint_ispercent);

                v->InvalidateNewGRFCacheOfChain();

                v->cargo_cap = e->DetermineCapacity(v);

                v->InvalidateNewGRFCacheOfChain();

                v->UpdatePosition();
        }

        return CommandCost();
}

ClosestDepot Ship::FindClosestDepot()
{
        const Depot *depot = FindClosestShipDepot(this, MAX_SHIP_DEPOT_SEARCH_DISTANCE);
        if (depot == nullptr) return ClosestDepot();

        return ClosestDepot(depot->xy, depot->index);
}