ship_cmd.cpp

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/*
 * 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/>.
 */
 
#include "stdafx.h"
#include "ship.h"
#include "landscape.h"
#include "timetable.h"
#include "news_func.h"
#include "company_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 "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"
 
constexpr int MAX_SHIP_DEPOT_SEARCH_DISTANCE = 80;
 
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->VehInfo<ShipVehicleInfo>().image_index;
 
  if (IsCustomVehicleSpriteNum(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);
}
 
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 (IsCustomVehicleSpriteNum(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 neighbours of the current patch to the search queue. */
    VisitWaterRegionPatchCallback visit_func = [&](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);
      }
    };
 
    VisitWaterRegionPatchNeighbours(current_node, visit_func);
  }
 
  /* 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 = _settings_game.pf.yapf.maximum_go_to_depot_penalty / YAPF_TILE_LENGTH;
 
  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);
}
 
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->VehInfo<ShipVehicleInfo>().running_cost);
  return GetPrice(PR_RUNNING_SHIP, cost_factor, e->GetGRF());
}
 
void Ship::OnNewCalendarDay()
{
  AgeVehicle(this);
}
 
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.Test(VehState::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 = StationID::Invalid();
 
  const Station *st = Station::Get(station);
  if (CanVehicleUseStation(this, st)) {
    return st->xy;
  } else {
    this->IncrementRealOrderIndex();
    return TileIndex{};
  }
}
 
void Ship::UpdateDeltaXY()
{
  static constexpr SpriteBounds ship_bounds[DIR_END] = {
    {{ -3,  -3, 0}, { 6,  6, 6}, {}}, // N
    {{-16,  -3, 0}, {32,  6, 6}, {}}, // NE
    {{ -3,  -3, 0}, { 6,  6, 6}, {}}, // E
    {{ -3, -16, 0}, { 6, 32, 6}, {}}, // SE
    {{ -3,  -3, 0}, { 6,  6, 6}, {}}, // S
    {{-16,  -3, 0}, {32,  6, 6}, {}}, // SW
    {{ -3,  -3, 0}, { 6,  6, 6}, {}}, // W
    {{ -3, -16, 0}, { 6, 32, 6}, {}}, // NW
  };
 
  this->bounds = ship_bounds[this->rotation];
 
  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->bounds.origin.x -= this->x_pos - this->rotation_x_pos;
    this->bounds.origin.y -= this->y_pos - this->rotation_y_pos;
  }
}
 
static bool CheckReverseShip(const Ship *v, Trackdir *trackdir = nullptr)
{
  /* Ask pathfinder for best direction */
  return YapfShipCheckReverse(v, trackdir);
}
 
static bool CheckShipStayInDepot(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 (HasVehicleOnTile(v->tile, [](const Vehicle *u) {
      return u->type == VEH_SHIP && u->cur_speed != 0;
    })) return true;
 
  assert(v->GetVehicleTrackdir() == TRACKDIR_X_NE || v->GetVehicleTrackdir() == TRACKDIR_Y_NW);
  v->direction = DiagDirToDir(TrackdirToExitdir(v->GetVehicleTrackdir()));
  if (CheckReverseShip(v)) v->direction = ReverseDir(v->direction);
 
  v->state = AxisToTrackBits(GetShipDepotAxis(v->tile));
  v->rotation = v->direction;
  v->vehstatus.Reset(VehState::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;
}
 
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<uint8_t>::max());
  v->progress = static_cast<uint8_t>(remainder);
  return number_of_steps;
}
 
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;
 
    AddVehicleNewsItem(
      GetEncodedString(STR_NEWS_FIRST_SHIP_ARRIVAL, st->index),
      (v->owner == _local_company) ? NewsType::ArrivalCompany : NewsType::ArrivalOther,
      v->index,
      st->index
    );
    AI::NewEvent(v->owner, new ScriptEventStationFirstVehicle(st->index, v->index));
    Game::NewEvent(new ScriptEventStationFirstVehicle(st->index, v->index));
  }
}
 
 
static Track ChooseShipTrack(Ship *v, TileIndex tile, TrackBits tracks)
{
  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.back().trackdir);
 
      if (HasBit(tracks, track)) {
        v->path.pop_back();
        /* 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();
    }
 
    track = YapfShipChooseTrack(v, tile, path_found, v->path);
  }
 
  v->HandlePathfindingResult(path_found);
  return track;
}
 
static inline TrackBits GetAvailShipTracks(TileIndex tile, DiagDirection dir)
{
  TrackBits tracks = GetTileShipTrackStatus(tile) & DiagdirReachesTracks(dir);
 
  return tracks;
}
 
struct ShipSubcoordData {
  uint8_t x_subcoord; 
  uint8_t y_subcoord; 
  Direction dir;   
};
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
  }
};
 
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;
  }
}
 
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;
}
 
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.Test(VehState::Stopped)) return;
 
  if (ProcessOrders(v) && CheckReverseShip(v)) return ReverseShip(v);
 
  v->HandleLoading();
 
  if (v->current_order.IsType(OT_LOADING)) return;
 
  if (CheckShipStayInDepot(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 */
          auto vets = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
          if (vets.Test(VehicleEnterTileState::CannotEnter)) 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().ToStationID());
              if (st->docking_station.Contains(gp.new_tile) && IsShipDestinationTile(gp.new_tile, st->index)) {
                v->last_station_visited = st->index;
                if (st->facilities.Test(StationFacility::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, 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 */
        auto vets = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
        if (vets.Test(VehicleEnterTileState::CannotEnter)) return ReverseShip(v);
 
        if (!vets.Test(VehicleEnterTileState::EnteredWormhole)) {
          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) || !VehicleEnterTile(v, gp.new_tile, gp.x, gp.y).Test(VehicleEnterTileState::EnteredWormhole)) {
        v->x_pos = gp.x;
        v->y_pos = gp.y;
        v->UpdatePosition();
        if (!v->vehstatus.Test(VehState::Hidden)) v->Vehicle::UpdateViewport(true);
        continue;
      }
 
      /* 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_back();
    }
 
    /* 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.Test(VehState::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;
}
 
CommandCost CmdBuildShip(DoCommandFlags flags, TileIndex tile, const Engine *e, Vehicle **ret)
{
  tile = GetShipDepotNorthTile(tile);
  if (flags.Test(DoCommandFlag::Execute)) {
    int x;
    int y;
 
    const ShipVehicleInfo *svi = &e->VehInfo<ShipVehicleInfo>();
 
    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->direction = DiagDirToDir(GetShipDepotDirection(tile));
 
    /* UpdateDeltaXY() requires rotation to be initialised as well. */
    v->rotation = v->direction;
    v->UpdateDeltaXY();
 
    v->vehstatus = {VehState::Hidden, VehState::Stopped, VehState::DefaultPalette};
 
    v->spritenum = svi->image_index;
    v->cargo_type = e->GetDefaultCargoType();
    assert(IsValidCargoType(v->cargo_type));
    v->cargo_cap = svi->capacity;
    v->refit_cap = 0;
 
    v->last_station_visited = StationID::Invalid();
    v->last_loading_station = StationID::Invalid();
    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.Test(EngineFlag::ExclusivePreview)) v->vehicle_flags.Set(VehicleFlag::BuiltAsPrototype);
    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);
}