roadveh_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 "roadveh.h"
#include "command_func.h"
#include "error_func.h"
#include "news_func.h"
#include "station_base.h"
#include "company_func.h"
#include "articulated_vehicles.h"
#include "newgrf_sound.h"
#include "pathfinder/yapf/yapf.h"
#include "strings_func.h"
#include "tunnelbridge_map.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 "depot_map.h"
#include "effectvehicle_func.h"
#include "roadstop_base.h"
#include "spritecache.h"
#include "core/random_func.hpp"
#include "company_base.h"
#include "core/backup_type.hpp"
#include "newgrf.h"
#include "zoom_func.h"
#include "framerate_type.h"
#include "roadveh_cmd.h"
#include "road_cmd.h"
#include "newgrf_roadstop.h"
 
#include "table/strings.h"
 
#include "safeguards.h"
 
static const uint16_t _roadveh_images[] = {
  0xCD4, 0xCDC, 0xCE4, 0xCEC, 0xCF4, 0xCFC, 0xD0C, 0xD14,
  0xD24, 0xD1C, 0xD2C, 0xD04, 0xD1C, 0xD24, 0xD6C, 0xD74,
  0xD7C, 0xC14, 0xC1C, 0xC24, 0xC2C, 0xC34, 0xC3C, 0xC4C,
  0xC54, 0xC64, 0xC5C, 0xC6C, 0xC44, 0xC5C, 0xC64, 0xCAC,
  0xCB4, 0xCBC, 0xD94, 0xD9C, 0xDA4, 0xDAC, 0xDB4, 0xDBC,
  0xDCC, 0xDD4, 0xDE4, 0xDDC, 0xDEC, 0xDC4, 0xDDC, 0xDE4,
  0xE2C, 0xE34, 0xE3C, 0xC14, 0xC1C, 0xC2C, 0xC3C, 0xC4C,
  0xC5C, 0xC64, 0xC6C, 0xC74, 0xC84, 0xC94, 0xCA4
};
 
static const uint16_t _roadveh_full_adder[] = {
   0,  88,   0,   0,   0,   0,  48,  48,
  48,  48,   0,   0,  64,  64,   0,  16,
  16,   0,  88,   0,   0,   0,   0,  48,
  48,  48,  48,   0,   0,  64,  64,   0,
  16,  16,   0,  88,   0,   0,   0,   0,
  48,  48,  48,  48,   0,   0,  64,  64,
   0,  16,  16,   0,   8,   8,   8,   8,
   0,   0,   0,   8,   8,   8,   8
};
static_assert(lengthof(_roadveh_images) == lengthof(_roadveh_full_adder));
 
template <>
bool IsValidImageIndex<VEH_ROAD>(uint8_t image_index)
{
  return image_index < lengthof(_roadveh_images);
}
 
static const Trackdir _road_reverse_table[DIAGDIR_END] = {
  TRACKDIR_RVREV_NE, TRACKDIR_RVREV_SE, TRACKDIR_RVREV_SW, TRACKDIR_RVREV_NW
};
 
bool RoadVehicle::IsBus() const
{
  assert(this->IsFrontEngine());
  return IsCargoInClass(this->cargo_type, CargoClass::Passengers);
}
bool RoadVehicle::IsBus() const {…}
 
int RoadVehicle::GetDisplayImageWidth(Point *offset) const
{
  int reference_width = ROADVEHINFO_DEFAULT_VEHICLE_WIDTH;
 
  if (offset != nullptr) {
    offset->x = ScaleSpriteTrad(reference_width) / 2;
    offset->y = 0;
  }
  return ScaleSpriteTrad(this->gcache.cached_veh_length * reference_width / VEHICLE_LENGTH);
}
int RoadVehicle::GetDisplayImageWidth(Point *offset) const {…}
 
static void GetRoadVehIcon(EngineID engine, EngineImageType image_type, VehicleSpriteSeq *result)
{
  const Engine *e = Engine::Get(engine);
  uint8_t spritenum = e->u.road.image_index;
 
  if (IsCustomVehicleSpriteNum(spritenum)) {
    GetCustomVehicleIcon(engine, DIR_W, image_type, result);
    if (result->IsValid()) return;
 
    spritenum = e->original_image_index;
  }
 
  assert(IsValidImageIndex<VEH_ROAD>(spritenum));
  result->Set(DIR_W + _roadveh_images[spritenum]);
}
 
void RoadVehicle::GetImage(Direction direction, EngineImageType image_type, VehicleSpriteSeq *result) const
{
  uint8_t spritenum = this->spritenum;
 
  if (IsCustomVehicleSpriteNum(spritenum)) {
    if (spritenum == CUSTOM_VEHICLE_SPRITENUM_REVERSED) direction = ReverseDir(direction);
    GetCustomVehicleSprite(this, direction, image_type, result);
    if (result->IsValid()) return;
 
    spritenum = this->GetEngine()->original_image_index;
  }
 
  assert(IsValidImageIndex<VEH_ROAD>(spritenum));
  SpriteID sprite = direction + _roadveh_images[spritenum];
 
  if (this->cargo.StoredCount() >= this->cargo_cap / 2U) sprite += _roadveh_full_adder[spritenum];
 
  result->Set(sprite);
}
void RoadVehicle::GetImage(Direction direction, EngineImageType image_type, VehicleSpriteSeq *result) const {…}
 
void DrawRoadVehEngine(int left, int right, int preferred_x, int y, EngineID engine, PaletteID pal, EngineImageType image_type)
{
  VehicleSpriteSeq seq;
  GetRoadVehIcon(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 DrawRoadVehEngine(int left, int right, int preferred_x, int y, EngineID engine, PaletteID pal, EngineImageType image_type) {…}
 
void GetRoadVehSpriteSize(EngineID engine, uint &width, uint &height, int &xoffs, int &yoffs, EngineImageType image_type)
{
  VehicleSpriteSeq seq;
  GetRoadVehIcon(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 GetRoadVehSpriteSize(EngineID engine, uint &width, uint &height, int &xoffs, int &yoffs, EngineImageType image_type) {…}
 
static uint GetRoadVehLength(const RoadVehicle *v)
{
  const Engine *e = v->GetEngine();
  uint length = VEHICLE_LENGTH;
 
  uint16_t veh_len = CALLBACK_FAILED;
  if (e->GetGRF() != nullptr && e->GetGRF()->grf_version >= 8) {
    /* Use callback 36 */
    veh_len = GetVehicleProperty(v, PROP_ROADVEH_SHORTEN_FACTOR, CALLBACK_FAILED);
    if (veh_len != CALLBACK_FAILED && veh_len >= VEHICLE_LENGTH) ErrorUnknownCallbackResult(e->GetGRFID(), CBID_VEHICLE_LENGTH, veh_len);
  } else {
    /* Use callback 11 */
    veh_len = GetVehicleCallback(CBID_VEHICLE_LENGTH, 0, 0, v->engine_type, v);
  }
  if (veh_len == CALLBACK_FAILED) veh_len = e->u.road.shorten_factor;
  if (veh_len != 0) {
    length -= Clamp(veh_len, 0, VEHICLE_LENGTH - 1);
  }
 
  return length;
}
static uint GetRoadVehLength(const RoadVehicle *v) {…}
 
void RoadVehUpdateCache(RoadVehicle *v, bool same_length)
{
  assert(v->type == VEH_ROAD);
  assert(v->IsFrontEngine());
 
  v->InvalidateNewGRFCacheOfChain();
 
  v->gcache.cached_total_length = 0;
 
  for (RoadVehicle *u = v; u != nullptr; u = u->Next()) {
    /* Check the v->first cache. */
    assert(u->First() == v);
 
    /* Update the 'first engine' */
    u->gcache.first_engine = (v == u) ? EngineID::Invalid() : v->engine_type;
 
    /* Update the length of the vehicle. */
    uint veh_len = GetRoadVehLength(u);
    /* Verify length hasn't changed. */
    if (same_length && veh_len != u->gcache.cached_veh_length) VehicleLengthChanged(u);
 
    u->gcache.cached_veh_length = veh_len;
    v->gcache.cached_total_length += u->gcache.cached_veh_length;
 
    /* Update visual effect */
    u->UpdateVisualEffect();
 
    /* Update cargo aging period. */
    u->vcache.cached_cargo_age_period = GetVehicleProperty(u, PROP_ROADVEH_CARGO_AGE_PERIOD, EngInfo(u->engine_type)->cargo_age_period);
  }
 
  uint max_speed = GetVehicleProperty(v, PROP_ROADVEH_SPEED, 0);
  v->vcache.cached_max_speed = (max_speed != 0) ? max_speed * 4 : RoadVehInfo(v->engine_type)->max_speed;
}
void RoadVehUpdateCache(RoadVehicle *v, bool same_length) {…}
 
CommandCost CmdBuildRoadVehicle(DoCommandFlags flags, TileIndex tile, const Engine *e, Vehicle **ret)
{
  /* Check that the vehicle can drive on the road in question */
  RoadType rt = e->u.road.roadtype;
  const RoadTypeInfo *rti = GetRoadTypeInfo(rt);
  if (!HasTileAnyRoadType(tile, rti->powered_roadtypes)) return CommandCost(STR_ERROR_DEPOT_WRONG_DEPOT_TYPE);
 
  if (flags.Test(DoCommandFlag::Execute)) {
    const RoadVehicleInfo *rvi = &e->u.road;
 
    RoadVehicle *v = new RoadVehicle();
    *ret = v;
    v->direction = DiagDirToDir(GetRoadDepotDirection(tile));
    v->owner = _current_company;
 
    v->tile = tile;
    int x = TileX(tile) * TILE_SIZE + TILE_SIZE / 2;
    int y = TileY(tile) * TILE_SIZE + TILE_SIZE / 2;
    v->x_pos = x;
    v->y_pos = y;
    v->z_pos = GetSlopePixelZ(x, y, true);
 
    v->state = RVSB_IN_DEPOT;
    v->vehstatus = {VehState::Hidden, VehState::Stopped, VehState::DefaultPalette};
 
    v->spritenum = rvi->image_index;
    v->cargo_type = e->GetDefaultCargoType();
    assert(IsValidCargoType(v->cargo_type));
    v->cargo_cap = rvi->capacity;
    v->refit_cap = 0;
 
    v->last_station_visited = StationID::Invalid();
    v->last_loading_station = StationID::Invalid();
    v->engine_type = e->index;
    v->gcache.first_engine = EngineID::Invalid(); // needs to be set before first callback
 
    v->reliability = e->reliability;
    v->reliability_spd_dec = e->reliability_spd_dec;
    v->max_age = e->GetLifeLengthInDays();
 
    v->SetServiceInterval(Company::Get(v->owner)->settings.vehicle.servint_roadveh);
 
    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->SetFrontEngine();
 
    v->roadtype = rt;
    v->compatible_roadtypes = rti->powered_roadtypes;
    v->gcache.cached_veh_length = VEHICLE_LENGTH;
 
    if (e->flags.Test(EngineFlag::ExclusivePreview)) v->vehicle_flags.Set(VehicleFlag::BuiltAsPrototype);
    v->SetServiceIntervalIsPercent(Company::Get(_current_company)->settings.vehicle.servint_ispercent);
 
    AddArticulatedParts(v);
    v->InvalidateNewGRFCacheOfChain();
 
    /* Call various callbacks after the whole consist has been constructed */
    for (RoadVehicle *u = v; u != nullptr; u = u->Next()) {
      u->cargo_cap = u->GetEngine()->DetermineCapacity(u);
      u->refit_cap = 0;
      v->InvalidateNewGRFCache();
      u->InvalidateNewGRFCache();
    }
    RoadVehUpdateCache(v);
    /* Initialize cached values for realistic acceleration. */
    if (_settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) v->CargoChanged();
 
    v->UpdatePosition();
 
    CheckConsistencyOfArticulatedVehicle(v);
  }
 
  return CommandCost();
}
CommandCost CmdBuildRoadVehicle(DoCommandFlags flags, TileIndex tile, const Engine *e, Vehicle **ret) {…}
 
static FindDepotData FindClosestRoadDepot(const RoadVehicle *v, int max_distance)
{
  if (IsRoadDepotTile(v->tile)) return FindDepotData(v->tile, 0);
 
  return YapfRoadVehicleFindNearestDepot(v, max_distance);
}
 
ClosestDepot RoadVehicle::FindClosestDepot()
{
  FindDepotData rfdd = FindClosestRoadDepot(this, 0);
  if (rfdd.best_length == UINT_MAX) return ClosestDepot();
 
  return ClosestDepot(rfdd.tile, GetDepotIndex(rfdd.tile));
}
ClosestDepot RoadVehicle::FindClosestDepot() {…}
 
CommandCost CmdTurnRoadVeh(DoCommandFlags flags, VehicleID veh_id)
{
  RoadVehicle *v = RoadVehicle::GetIfValid(veh_id);
  if (v == nullptr) return CMD_ERROR;
 
  if (!v->IsPrimaryVehicle()) return CMD_ERROR;
 
  CommandCost ret = CheckOwnership(v->owner);
  if (ret.Failed()) return ret;
 
  if (v->vehstatus.Any({VehState::Stopped, VehState::Crashed}) ||
      v->breakdown_ctr != 0 ||
      v->overtaking != 0 ||
      v->state == RVSB_WORMHOLE ||
      v->IsInDepot() ||
      v->current_order.IsType(OT_LOADING)) {
    return CMD_ERROR;
  }
 
  if (IsNormalRoadTile(v->tile) && GetDisallowedRoadDirections(v->tile) != DRD_NONE) return CMD_ERROR;
 
  if (IsTileType(v->tile, MP_TUNNELBRIDGE) && DirToDiagDir(v->direction) == GetTunnelBridgeDirection(v->tile)) return CMD_ERROR;
 
  if (flags.Test(DoCommandFlag::Execute)) {
    v->reverse_ctr = 180;
 
    /* Unbunching data is no longer valid. */
    v->ResetDepotUnbunching();
  }
 
  return CommandCost();
}
CommandCost CmdTurnRoadVeh(DoCommandFlags flags, VehicleID veh_id) {…}
 
 
void RoadVehicle::MarkDirty()
{
  for (RoadVehicle *v = this; v != nullptr; v = v->Next()) {
    v->colourmap = PAL_NONE;
    v->UpdateViewport(true, false);
  }
  this->CargoChanged();
}
void RoadVehicle::MarkDirty() {…}
 
void RoadVehicle::UpdateDeltaXY()
{
  static const int8_t _delta_xy_table[8][10] = {
    /* y_extent, x_extent, y_offs, x_offs, y_bb_offs, x_bb_offs, y_extent_shorten, x_extent_shorten, y_bb_offs_shorten, x_bb_offs_shorten */
    {3, 3, -1, -1,  0,  0, -1, -1, -1, -1}, // N
    {3, 7, -1, -3,  0, -1,  0, -1,  0,  0}, // NE
    {3, 3, -1, -1,  0,  0,  1, -1,  1, -1}, // E
    {7, 3, -3, -1, -1,  0,  0,  0,  1,  0}, // SE
    {3, 3, -1, -1,  0,  0,  1,  1,  1,  1}, // S
    {3, 7, -1, -3,  0, -1,  0,  0,  0,  1}, // SW
    {3, 3, -1, -1,  0,  0, -1,  1, -1,  1}, // W
    {7, 3, -3, -1, -1,  0, -1,  0,  0,  0}, // NW
  };
 
  int shorten = VEHICLE_LENGTH - this->gcache.cached_veh_length;
  if (!IsDiagonalDirection(this->direction)) shorten >>= 1;
 
  const int8_t *bb = _delta_xy_table[this->direction];
  this->x_bb_offs     = bb[5] + bb[9] * shorten;
  this->y_bb_offs     = bb[4] + bb[8] * shorten;;
  this->x_offs        = bb[3];
  this->y_offs        = bb[2];
  this->x_extent      = bb[1] + bb[7] * shorten;
  this->y_extent      = bb[0] + bb[6] * shorten;
  this->z_extent      = 6;
}
void RoadVehicle::UpdateDeltaXY() {…}
 
inline int RoadVehicle::GetCurrentMaxSpeed() const
{
  int max_speed = this->gcache.cached_max_track_speed;
 
  /* Limit speed to 50% while reversing, 75% in curves. */
  for (const RoadVehicle *u = this; u != nullptr; u = u->Next()) {
    if (_settings_game.vehicle.roadveh_acceleration_model == AM_REALISTIC) {
      if (this->state <= RVSB_TRACKDIR_MASK && IsReversingRoadTrackdir((Trackdir)this->state)) {
        max_speed = this->gcache.cached_max_track_speed / 2;
        break;
      } else if ((u->direction & 1) == 0) {
        max_speed = this->gcache.cached_max_track_speed * 3 / 4;
      }
    }
 
    /* Vehicle is on the middle part of a bridge. */
    if (u->state == RVSB_WORMHOLE && !u->vehstatus.Test(VehState::Hidden)) {
      max_speed = std::min(max_speed, GetBridgeSpec(GetBridgeType(u->tile))->speed * 2);
    }
  }
 
  return std::min(max_speed, this->current_order.GetMaxSpeed() * 2);
}
inline int RoadVehicle::GetCurrentMaxSpeed() const {…}
 
static void DeleteLastRoadVeh(RoadVehicle *v)
{
  RoadVehicle *first = v->First();
  Vehicle *u = v;
  for (; v->Next() != nullptr; v = v->Next()) u = v;
  u->SetNext(nullptr);
  v->last_station_visited = first->last_station_visited; // for PreDestructor
 
  /* Only leave the road stop when we're really gone. */
  if (IsInsideMM(v->state, RVSB_IN_ROAD_STOP, RVSB_IN_ROAD_STOP_END)) RoadStop::GetByTile(v->tile, GetRoadStopType(v->tile))->Leave(v);
 
  delete v;
}
static void DeleteLastRoadVeh(RoadVehicle *v) {…}
 
static void RoadVehSetRandomDirection(RoadVehicle *v)
{
  static const DirDiff delta[] = {
    DIRDIFF_45LEFT, DIRDIFF_SAME, DIRDIFF_SAME, DIRDIFF_45RIGHT
  };
 
  do {
    uint32_t r = Random();
 
    v->direction = ChangeDir(v->direction, delta[r & 3]);
    v->UpdateViewport(true, true);
  } while ((v = v->Next()) != nullptr);
}
 
static bool RoadVehIsCrashed(RoadVehicle *v)
{
  v->crashed_ctr++;
  if (v->crashed_ctr == 2) {
    CreateEffectVehicleRel(v, 4, 4, 8, EV_EXPLOSION_LARGE);
  } else if (v->crashed_ctr <= 45) {
    if ((v->tick_counter & 7) == 0) RoadVehSetRandomDirection(v);
  } else if (v->crashed_ctr >= 2220 && !(v->tick_counter & 0x1F)) {
    bool ret = v->Next() != nullptr;
    DeleteLastRoadVeh(v);
    return ret;
  }
 
  return true;
}
static bool RoadVehIsCrashed(RoadVehicle *v) {…}
 
uint RoadVehicle::Crash(bool flooded)
{
  uint victims = this->GroundVehicleBase::Crash(flooded);
  if (this->IsFrontEngine()) {
    victims += 1; // driver
 
    /* If we're in a drive through road stop we ought to leave it */
    if (IsInsideMM(this->state, RVSB_IN_DT_ROAD_STOP, RVSB_IN_DT_ROAD_STOP_END)) {
      RoadStop::GetByTile(this->tile, GetRoadStopType(this->tile))->Leave(this);
    }
  }
  this->crashed_ctr = flooded ? 2000 : 1; // max 2220, disappear pretty fast when flooded
  return victims;
}
uint RoadVehicle::Crash(bool flooded) {…}
 
static void RoadVehCrash(RoadVehicle *v)
{
  uint victims = v->Crash();
 
  AI::NewEvent(v->owner, new ScriptEventVehicleCrashed(v->index, v->tile, ScriptEventVehicleCrashed::CRASH_RV_LEVEL_CROSSING, victims, v->owner));
  Game::NewEvent(new ScriptEventVehicleCrashed(v->index, v->tile, ScriptEventVehicleCrashed::CRASH_RV_LEVEL_CROSSING, victims, v->owner));
 
  EncodedString headline = (victims == 1)
    ? GetEncodedString(STR_NEWS_ROAD_VEHICLE_CRASH_DRIVER)
    : GetEncodedString(STR_NEWS_ROAD_VEHICLE_CRASH, victims);
  NewsType newstype = v->owner == _local_company ? NewsType::Accident : NewsType::AccidentOther;
 
  AddTileNewsItem(std::move(headline), newstype, v->tile);
 
  ModifyStationRatingAround(v->tile, v->owner, -160, 22);
  if (_settings_client.sound.disaster) SndPlayVehicleFx(SND_12_EXPLOSION, v);
}
 
static bool RoadVehCheckTrainCrash(RoadVehicle *v)
{
  for (RoadVehicle *u = v; u != nullptr; u = u->Next()) {
    if (u->state == RVSB_WORMHOLE) continue;
 
    TileIndex tile = u->tile;
 
    if (!IsLevelCrossingTile(tile)) continue;
 
    if (HasVehicleNearTileXY(v->x_pos, v->y_pos, 4, [&u](const Vehicle *t) {
        return t->type == VEH_TRAIN && abs(t->z_pos - u->z_pos) <= 6;
      })) {
      RoadVehCrash(v);
      return true;
    }
  }
 
  return false;
}
 
TileIndex RoadVehicle::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)) {
    /* There is no stop left at the station, so don't even TRY to go there */
    this->IncrementRealOrderIndex();
    return TileIndex{};
  }
 
  return st->xy;
}
TileIndex RoadVehicle::GetOrderStationLocation(StationID station) {…}
 
static void StartRoadVehSound(const RoadVehicle *v)
{
  if (!PlayVehicleSound(v, VSE_START)) {
    SoundID s = RoadVehInfo(v->engine_type)->sfx;
    if (s == SND_19_DEPARTURE_OLD_RV_1 && (v->tick_counter & 3) == 0) {
      s = SND_1A_DEPARTURE_OLD_RV_2;
    }
    SndPlayVehicleFx(s, v);
  }
}
 
struct RoadVehFindData {
  int x;
  int y;
  const Vehicle *veh;
  Vehicle *best;
  uint best_diff;
  Direction dir;
};
struct RoadVehFindData {…};
 
static void FindClosestBlockingRoadVeh(Vehicle *v, RoadVehFindData *rvf)
{
  static const int8_t dist_x[] = { -4, -8, -4, -1, 4, 8, 4, 1 };
  static const int8_t dist_y[] = { -4, -1, 4, 8, 4, 1, -4, -8 };
 
  int x_diff = v->x_pos - rvf->x;
  int y_diff = v->y_pos - rvf->y;
 
  /* Not a close Road vehicle when it's not a road vehicle, in the depot, or ourself. */
  if (v->type != VEH_ROAD || v->IsInDepot() || rvf->veh->First() == v->First()) return;
 
  /* Not close when at a different height or when going in a different direction. */
  if (abs(v->z_pos - rvf->veh->z_pos) >= 6 || v->direction != rvf->dir) return;
 
  /* We 'return' the closest vehicle, in distance and then VehicleID as tie-breaker. */
  uint diff = abs(x_diff) + abs(y_diff);
  if (diff > rvf->best_diff || (diff == rvf->best_diff && v->index > rvf->best->index)) return;
 
  auto IsCloseOnAxis = [](int dist, int diff) {
    if (dist < 0) return diff > dist && diff <= 0;
    return diff < dist && diff >= 0;
  };
 
  if (IsCloseOnAxis(dist_x[v->direction], x_diff) && IsCloseOnAxis(dist_y[v->direction], y_diff)) {
    rvf->best = v;
    rvf->best_diff = diff;
  }
}
 
static RoadVehicle *RoadVehFindCloseTo(RoadVehicle *v, int x, int y, Direction dir, bool update_blocked_ctr = true)
{
  RoadVehFindData rvf;
  RoadVehicle *front = v->First();
 
  if (front->reverse_ctr != 0) return nullptr;
 
  rvf.x = x;
  rvf.y = y;
  rvf.dir = dir;
  rvf.veh = v;
  rvf.best_diff = UINT_MAX;
 
  if (front->state == RVSB_WORMHOLE) {
    for (Vehicle *u : VehiclesOnTile(v->tile)) {
      FindClosestBlockingRoadVeh(u, &rvf);
    }
    for (Vehicle *u : VehiclesOnTile(GetOtherTunnelBridgeEnd(v->tile))) {
      FindClosestBlockingRoadVeh(u, &rvf);
    }
  } else {
    for (Vehicle *u : VehiclesNearTileXY(x, y, 8)) {
      FindClosestBlockingRoadVeh(u, &rvf);
    }
  }
 
  /* This code protects a roadvehicle from being blocked for ever
   * If more than 1480 / 74 days a road vehicle is blocked, it will
   * drive just through it. The ultimate backup-code of TTD.
   * It can be disabled. */
  if (rvf.best_diff == UINT_MAX) {
    front->blocked_ctr = 0;
    return nullptr;
  }
 
  if (update_blocked_ctr && ++front->blocked_ctr > 1480) return nullptr;
 
  return RoadVehicle::From(rvf.best);
}
 
static void RoadVehArrivesAt(const RoadVehicle *v, Station *st)
{
  if (v->IsBus()) {
    /* Check if station was ever visited before */
    if (!(st->had_vehicle_of_type & HVOT_BUS)) {
      st->had_vehicle_of_type |= HVOT_BUS;
      AddVehicleNewsItem(
        GetEncodedString(RoadTypeIsRoad(v->roadtype) ? STR_NEWS_FIRST_BUS_ARRIVAL : STR_NEWS_FIRST_PASSENGER_TRAM_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));
    }
  } else {
    /* Check if station was ever visited before */
    if (!(st->had_vehicle_of_type & HVOT_TRUCK)) {
      st->had_vehicle_of_type |= HVOT_TRUCK;
      AddVehicleNewsItem(
        GetEncodedString(RoadTypeIsRoad(v->roadtype) ? STR_NEWS_FIRST_TRUCK_ARRIVAL : STR_NEWS_FIRST_CARGO_TRAM_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 void RoadVehArrivesAt(const RoadVehicle *v, Station *st) {…}
 
int RoadVehicle::UpdateSpeed()
{
  switch (_settings_game.vehicle.roadveh_acceleration_model) {
    default: NOT_REACHED();
    case AM_ORIGINAL:
      return this->DoUpdateSpeed(this->overtaking != 0 ? 512 : 256, 0, this->GetCurrentMaxSpeed());
 
    case AM_REALISTIC:
      return this->DoUpdateSpeed(this->GetAcceleration() + (this->overtaking != 0 ? 256 : 0), this->GetAccelerationStatus() == AS_BRAKE ? 0 : 4, this->GetCurrentMaxSpeed());
  }
}
int RoadVehicle::UpdateSpeed() {…}
 
static Direction RoadVehGetNewDirection(const RoadVehicle *v, int x, int y)
{
  static const Direction _roadveh_new_dir[] = {
    DIR_N , DIR_NW, DIR_W , INVALID_DIR,
    DIR_NE, DIR_N , DIR_SW, INVALID_DIR,
    DIR_E , DIR_SE, DIR_S
  };
 
  x = x - v->x_pos + 1;
  y = y - v->y_pos + 1;
 
  if ((uint)x > 2 || (uint)y > 2) return v->direction;
  return _roadveh_new_dir[y * 4 + x];
}
 
static Direction RoadVehGetSlidingDirection(const RoadVehicle *v, int x, int y)
{
  Direction new_dir = RoadVehGetNewDirection(v, x, y);
  Direction old_dir = v->direction;
  DirDiff delta;
 
  if (new_dir == old_dir) return old_dir;
  delta = (DirDifference(new_dir, old_dir) > DIRDIFF_REVERSE ? DIRDIFF_45LEFT : DIRDIFF_45RIGHT);
  return ChangeDir(old_dir, delta);
}
 
struct OvertakeData {
  const RoadVehicle *u;
  const RoadVehicle *v;
  TileIndex tile;
  Trackdir trackdir;
};
struct OvertakeData {…};
 
static bool CheckRoadBlockedForOvertaking(OvertakeData *od)
{
  if (!HasTileAnyRoadType(od->tile, od->v->compatible_roadtypes)) return true;
  TrackStatus ts = GetTileTrackStatus(od->tile, TRANSPORT_ROAD, GetRoadTramType(od->v->roadtype));
  TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts);
  TrackdirBits red_signals = TrackStatusToRedSignals(ts); // barred level crossing
  TrackBits trackbits = TrackdirBitsToTrackBits(trackdirbits);
 
  /* Track does not continue along overtaking direction || track has junction || levelcrossing is barred */
  if (!HasBit(trackdirbits, od->trackdir) || (trackbits & ~TRACK_BIT_CROSS) || (red_signals != TRACKDIR_BIT_NONE)) return true;
 
  /* Are there more vehicles on the tile except the two vehicles involved in overtaking */
  return HasVehicleOnTile(od->tile, [&](const Vehicle *v) {
    return v->type == VEH_ROAD && v->First() == v && v != od->u && v != od->v;
  });
}
static bool CheckRoadBlockedForOvertaking(OvertakeData *od) {…}
 
static void RoadVehCheckOvertake(RoadVehicle *v, RoadVehicle *u)
{
  OvertakeData od;
 
  od.v = v;
  od.u = u;
 
  /* Trams can't overtake other trams */
  if (RoadTypeIsTram(v->roadtype)) return;
 
  /* Don't overtake in stations */
  if (IsTileType(v->tile, MP_STATION) || IsTileType(u->tile, MP_STATION)) return;
 
  /* For now, articulated road vehicles can't overtake anything. */
  if (v->HasArticulatedPart()) return;
 
  /* Vehicles are not driving in same direction || direction is not a diagonal direction */
  if (v->direction != u->direction || !(v->direction & 1)) return;
 
  /* Check if vehicle is in a road stop, depot, tunnel or bridge or not on a straight road */
  if (v->state >= RVSB_IN_ROAD_STOP || !IsStraightRoadTrackdir((Trackdir)(v->state & RVSB_TRACKDIR_MASK))) return;
 
  /* Can't overtake a vehicle that is moving faster than us. If the vehicle in front is
   * accelerating, take the maximum speed for the comparison, else the current speed.
   * Original acceleration always accelerates, so always use the maximum speed. */
  int u_speed = (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL || u->GetAcceleration() > 0) ? u->GetCurrentMaxSpeed() : u->cur_speed;
  if (u_speed >= v->GetCurrentMaxSpeed() &&
      !u->vehstatus.Test(VehState::Stopped) &&
      u->cur_speed != 0) {
    return;
  }
 
  od.trackdir = DiagDirToDiagTrackdir(DirToDiagDir(v->direction));
 
  /* Are the current and the next tile suitable for overtaking?
   *  - Does the track continue along od.trackdir
   *  - No junctions
   *  - No barred levelcrossing
   *  - No other vehicles in the way
   */
  od.tile = v->tile;
  if (CheckRoadBlockedForOvertaking(&od)) return;
 
  od.tile = v->tile + TileOffsByDiagDir(DirToDiagDir(v->direction));
  if (CheckRoadBlockedForOvertaking(&od)) return;
 
  /* When the vehicle in front of us is stopped we may only take
   * half the time to pass it than when the vehicle is moving. */
  v->overtaking_ctr = (od.u->cur_speed == 0 || od.u->vehstatus.Test(VehState::Stopped)) ? RV_OVERTAKE_TIMEOUT / 2 : 0;
  v->overtaking = RVSB_DRIVE_SIDE;
}
 
static void RoadZPosAffectSpeed(RoadVehicle *v, int old_z)
{
  if (old_z == v->z_pos || _settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) return;
 
  if (old_z < v->z_pos) {
    v->cur_speed = v->cur_speed * 232 / 256; // slow down by ~10%
  } else {
    uint16_t spd = v->cur_speed + 2;
    if (spd <= v->gcache.cached_max_track_speed) v->cur_speed = spd;
  }
}
 
static int PickRandomBit(uint bits)
{
  uint i;
  uint num = RandomRange(CountBits(bits));
 
  for (i = 0; !(bits & 1) || (int)--num >= 0; bits >>= 1, i++) {}
  return i;
}
 
static Trackdir RoadFindPathToDest(RoadVehicle *v, TileIndex tile, DiagDirection enterdir)
{
#define return_track(x) { best_track = (Trackdir)x; goto found_best_track; }
 
  TileIndex desttile;
  Trackdir best_track;
  bool path_found = true;
 
  TrackStatus ts = GetTileTrackStatus(tile, TRANSPORT_ROAD, GetRoadTramType(v->roadtype));
  TrackdirBits red_signals = TrackStatusToRedSignals(ts); // crossing
  TrackdirBits trackdirs = TrackStatusToTrackdirBits(ts);
 
  if (IsTileType(tile, MP_ROAD)) {
    if (IsRoadDepot(tile) && (!IsTileOwner(tile, v->owner) || GetRoadDepotDirection(tile) == enterdir)) {
      /* Road depot owned by another company or with the wrong orientation */
      trackdirs = TRACKDIR_BIT_NONE;
    }
  } else if (IsTileType(tile, MP_STATION) && IsBayRoadStopTile(tile)) {
    /* Standard road stop (drive-through stops are treated as normal road) */
 
    if (!IsTileOwner(tile, v->owner) || GetBayRoadStopDir(tile) == enterdir || v->HasArticulatedPart()) {
      /* different station owner or wrong orientation or the vehicle has articulated parts */
      trackdirs = TRACKDIR_BIT_NONE;
    } else {
      /* Our station */
      RoadStopType rstype = v->IsBus() ? RoadStopType::Bus : RoadStopType::Truck;
 
      if (GetRoadStopType(tile) != rstype) {
        /* Wrong station type */
        trackdirs = TRACKDIR_BIT_NONE;
      } else {
        /* Proper station type, check if there is free loading bay */
        if (!_settings_game.pf.roadveh_queue && IsBayRoadStopTile(tile) &&
            !RoadStop::GetByTile(tile, rstype)->HasFreeBay()) {
          /* Station is full and RV queuing is off */
          trackdirs = TRACKDIR_BIT_NONE;
        }
      }
    }
  }
  /* The above lookups should be moved to GetTileTrackStatus in the
   * future, but that requires more changes to the pathfinder and other
   * stuff, probably even more arguments to GTTS.
   */
 
  /* Remove tracks unreachable from the enter dir */
  trackdirs &= DiagdirReachesTrackdirs(enterdir);
  if (trackdirs == TRACKDIR_BIT_NONE) {
    /* If vehicle expected a path, it no longer exists, so invalidate it. */
    if (!v->path.empty()) v->path.clear();
    /* No reachable tracks, so we'll reverse */
    return_track(_road_reverse_table[enterdir]);
  }
 
  if (v->reverse_ctr != 0) {
    bool reverse = true;
    if (RoadTypeIsTram(v->roadtype)) {
      /* Trams may only reverse on a tile if it contains at least the straight
       * trackbits or when it is a valid turning tile (i.e. one roadbit) */
      RoadBits rb = GetAnyRoadBits(tile, RTT_TRAM);
      RoadBits straight = AxisToRoadBits(DiagDirToAxis(enterdir));
      reverse = ((rb & straight) == straight) ||
                (rb == DiagDirToRoadBits(enterdir));
    }
    if (reverse) {
      v->reverse_ctr = 0;
      if (v->tile != tile) {
        return_track(_road_reverse_table[enterdir]);
      }
    }
  }
 
  desttile = v->dest_tile;
  if (desttile == 0) {
    /* We've got no destination, pick a random track */
    return_track(PickRandomBit(trackdirs));
  }
 
  /* Only one track to choose between? */
  if (KillFirstBit(trackdirs) == TRACKDIR_BIT_NONE) {
    if (!v->path.empty() && v->path.back().tile == tile) {
      /* Vehicle expected a choice here, invalidate its path. */
      v->path.clear();
    }
    return_track(FindFirstBit(trackdirs));
  }
 
  /* Attempt to follow cached path. */
  if (!v->path.empty()) {
    if (v->path.back().tile != tile) {
      /* Vehicle didn't expect a choice here, invalidate its path. */
      v->path.clear();
    } else {
      Trackdir trackdir = v->path.back().trackdir;
 
      if (HasBit(trackdirs, trackdir)) {
        v->path.pop_back();
        return_track(trackdir);
      }
 
      /* Vehicle expected a choice which is no longer available. */
      v->path.clear();
    }
  }
 
  best_track = YapfRoadVehicleChooseTrack(v, tile, enterdir, trackdirs, path_found, v->path);
 
  v->HandlePathfindingResult(path_found);
 
found_best_track:;
 
  if (HasBit(red_signals, best_track)) return INVALID_TRACKDIR;
 
  return best_track;
}
static Trackdir RoadFindPathToDest(RoadVehicle *v, TileIndex tile, DiagDirection enterdir) {…}
 
struct RoadDriveEntry {
  uint8_t x, y;
};
struct RoadDriveEntry {…};
 
#include "table/roadveh_movement.h"
 
bool RoadVehLeaveDepot(RoadVehicle *v, bool first)
{
  /* Don't leave unless v and following wagons are in the depot. */
  for (const RoadVehicle *u = v; u != nullptr; u = u->Next()) {
    if (u->state != RVSB_IN_DEPOT || u->tile != v->tile) return false;
  }
 
  DiagDirection dir = GetRoadDepotDirection(v->tile);
  v->direction = DiagDirToDir(dir);
 
  Trackdir tdir = DiagDirToDiagTrackdir(dir);
  const RoadDriveEntry *rdp = _road_drive_data[GetRoadTramType(v->roadtype)][(_settings_game.vehicle.road_side << RVS_DRIVE_SIDE) + tdir];
 
  int x = TileX(v->tile) * TILE_SIZE + (rdp[RVC_DEPOT_START_FRAME].x & 0xF);
  int y = TileY(v->tile) * TILE_SIZE + (rdp[RVC_DEPOT_START_FRAME].y & 0xF);
 
  if (first) {
    /* We are leaving a depot, but have to go to the exact same one; re-enter */
    if (v->current_order.IsType(OT_GOTO_DEPOT) && v->tile == v->dest_tile) {
      VehicleEnterDepot(v);
      return true;
    }
 
    if (RoadVehFindCloseTo(v, x, y, v->direction, false) != nullptr) return true;
 
    VehicleServiceInDepot(v);
    v->LeaveUnbunchingDepot();
 
    StartRoadVehSound(v);
 
    /* Vehicle is about to leave a depot */
    v->cur_speed = 0;
  }
 
  v->vehstatus.Reset(VehState::Hidden);
  v->state = tdir;
  v->frame = RVC_DEPOT_START_FRAME;
 
  v->x_pos = x;
  v->y_pos = y;
  v->UpdatePosition();
  v->UpdateInclination(true, true);
 
  InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
 
  return true;
}
 
static Trackdir FollowPreviousRoadVehicle(const RoadVehicle *v, const RoadVehicle *prev, TileIndex tile, DiagDirection entry_dir, bool already_reversed)
{
  if (prev->tile == v->tile && !already_reversed) {
    /* If the previous vehicle is on the same tile as this vehicle is
     * then it must have reversed. */
    return _road_reverse_table[entry_dir];
  }
 
  uint8_t prev_state = prev->state;
  Trackdir dir;
 
  if (prev_state == RVSB_WORMHOLE || prev_state == RVSB_IN_DEPOT) {
    DiagDirection diag_dir = INVALID_DIAGDIR;
 
    if (IsTileType(tile, MP_TUNNELBRIDGE)) {
      diag_dir = GetTunnelBridgeDirection(tile);
    } else if (IsRoadDepotTile(tile)) {
      diag_dir = ReverseDiagDir(GetRoadDepotDirection(tile));
    }
 
    if (diag_dir == INVALID_DIAGDIR) return INVALID_TRACKDIR;
    dir = DiagDirToDiagTrackdir(diag_dir);
  } else {
    if (already_reversed && prev->tile != tile) {
      /*
       * The vehicle has reversed, but did not go straight back.
       * It immediately turn onto another tile. This means that
       * the roadstate of the previous vehicle cannot be used
       * as the direction we have to go with this vehicle.
       *
       * Next table is build in the following way:
       *  - first row for when the vehicle in front went to the northern or
       *    western tile, second for southern and eastern.
       *  - columns represent the entry direction.
       *  - cell values are determined by the Trackdir one has to take from
       *    the entry dir (column) to the tile in north or south by only
       *    going over the trackdirs used for turning 90 degrees, i.e.
       *    TRACKDIR_{UPPER,RIGHT,LOWER,LEFT}_{N,E,S,W}.
       */
      static const Trackdir reversed_turn_lookup[2][DIAGDIR_END] = {
        { TRACKDIR_UPPER_W, TRACKDIR_RIGHT_N, TRACKDIR_LEFT_N,  TRACKDIR_UPPER_E },
        { TRACKDIR_RIGHT_S, TRACKDIR_LOWER_W, TRACKDIR_LOWER_E, TRACKDIR_LEFT_S  }};
      dir = reversed_turn_lookup[prev->tile < tile ? 0 : 1][ReverseDiagDir(entry_dir)];
    } else if (HasBit(prev_state, RVS_IN_DT_ROAD_STOP)) {
      dir = (Trackdir)(prev_state & RVSB_ROAD_STOP_TRACKDIR_MASK);
    } else if (prev_state < TRACKDIR_END) {
      dir = (Trackdir)prev_state;
    } else {
      return INVALID_TRACKDIR;
    }
  }
 
  /* Do some sanity checking. */
  static const RoadBits required_roadbits[] = {
    ROAD_X,            ROAD_Y,            ROAD_NW | ROAD_NE, ROAD_SW | ROAD_SE,
    ROAD_NW | ROAD_SW, ROAD_NE | ROAD_SE, ROAD_X,            ROAD_Y
  };
  RoadBits required = required_roadbits[dir & 0x07];
 
  if ((required & GetAnyRoadBits(tile, GetRoadTramType(v->roadtype), true)) == ROAD_NONE) {
    dir = INVALID_TRACKDIR;
  }
 
  return dir;
}
 
static bool CanBuildTramTrackOnTile(CompanyID c, TileIndex t, RoadType rt, RoadBits r)
{
  /* The 'current' company is not necessarily the owner of the vehicle. */
  Backup<CompanyID> cur_company(_current_company, c);
 
  CommandCost ret = Command<CMD_BUILD_ROAD>::Do(DoCommandFlag::NoWater, t, r, rt, DRD_NONE, TownID::Invalid());
 
  cur_company.Restore();
  return ret.Succeeded();
}
static bool CanBuildTramTrackOnTile(CompanyID c, TileIndex t, RoadType rt, RoadBits r) {…}
 
bool IndividualRoadVehicleController(RoadVehicle *v, const RoadVehicle *prev)
{
  if (v->overtaking != 0)  {
    if (IsTileType(v->tile, MP_STATION)) {
      /* Force us to be not overtaking! */
      v->overtaking = 0;
    } else if (++v->overtaking_ctr >= RV_OVERTAKE_TIMEOUT) {
      /* If overtaking just aborts at a random moment, we can have a out-of-bound problem,
       *  if the vehicle started a corner. To protect that, only allow an abort of
       *  overtake if we are on straight roads */
      if (v->state < RVSB_IN_ROAD_STOP && IsStraightRoadTrackdir((Trackdir)v->state)) {
        v->overtaking = 0;
      }
    }
  }
 
  /* If this vehicle is in a depot and we've reached this point it must be
   * one of the articulated parts. It will stay in the depot until activated
   * by the previous vehicle in the chain when it gets to the right place. */
  if (v->IsInDepot()) return true;
 
  if (v->state == RVSB_WORMHOLE) {
    /* Vehicle is entering a depot or is on a bridge or in a tunnel */
    GetNewVehiclePosResult gp = GetNewVehiclePos(v);
 
    if (v->IsFrontEngine()) {
      const Vehicle *u = RoadVehFindCloseTo(v, gp.x, gp.y, v->direction);
      if (u != nullptr) {
        v->cur_speed = u->First()->cur_speed;
        return false;
      }
    }
 
    if (IsTileType(gp.new_tile, MP_TUNNELBRIDGE) && VehicleEnterTile(v, gp.new_tile, gp.x, gp.y).Test(VehicleEnterTileState::EnteredWormhole)) {
      /* Vehicle has just entered a bridge or tunnel */
      v->x_pos = gp.x;
      v->y_pos = gp.y;
      v->UpdatePosition();
      v->UpdateInclination(true, true);
      return true;
    }
 
    v->x_pos = gp.x;
    v->y_pos = gp.y;
    v->UpdatePosition();
    if (!v->vehstatus.Test(VehState::Hidden)) v->Vehicle::UpdateViewport(true);
    return true;
  }
 
  /* Get move position data for next frame.
   * For a drive-through road stop use 'straight road' move data.
   * In this case v->state is masked to give the road stop entry direction. */
  RoadDriveEntry rd = _road_drive_data[GetRoadTramType(v->roadtype)][(
    (HasBit(v->state, RVS_IN_DT_ROAD_STOP) ? v->state & RVSB_ROAD_STOP_TRACKDIR_MASK : v->state) +
    (_settings_game.vehicle.road_side << RVS_DRIVE_SIDE)) ^ v->overtaking][v->frame + 1];
 
  if (rd.x & RDE_NEXT_TILE) {
    TileIndex tile = v->tile + TileOffsByDiagDir((DiagDirection)(rd.x & 3));
    Trackdir dir;
 
    if (v->IsFrontEngine()) {
      /* If this is the front engine, look for the right path. */
      if (HasTileAnyRoadType(tile, v->compatible_roadtypes)) {
        dir = RoadFindPathToDest(v, tile, (DiagDirection)(rd.x & 3));
      } else {
        dir = _road_reverse_table[(DiagDirection)(rd.x & 3)];
      }
    } else {
      dir = FollowPreviousRoadVehicle(v, prev, tile, (DiagDirection)(rd.x & 3), false);
    }
 
    if (dir == INVALID_TRACKDIR) {
      if (!v->IsFrontEngine()) FatalError("Disconnecting road vehicle.");
      v->cur_speed = 0;
      return false;
    }
 
again:
    uint start_frame = RVC_DEFAULT_START_FRAME;
    if (IsReversingRoadTrackdir(dir)) {
      /* When turning around we can't be overtaking. */
      v->overtaking = 0;
 
      /* Turning around */
      if (RoadTypeIsTram(v->roadtype)) {
        /* Determine the road bits the tram needs to be able to turn around
         * using the 'big' corner loop. */
        RoadBits needed;
        switch (dir) {
          default: NOT_REACHED();
          case TRACKDIR_RVREV_NE: needed = ROAD_SW; break;
          case TRACKDIR_RVREV_SE: needed = ROAD_NW; break;
          case TRACKDIR_RVREV_SW: needed = ROAD_NE; break;
          case TRACKDIR_RVREV_NW: needed = ROAD_SE; break;
        }
        if ((v->Previous() != nullptr && v->Previous()->tile == tile) ||
            (v->IsFrontEngine() && IsNormalRoadTile(tile) && !HasRoadWorks(tile) &&
              HasTileAnyRoadType(tile, v->compatible_roadtypes) &&
              (needed & GetRoadBits(tile, RTT_TRAM)) != ROAD_NONE)) {
          /*
           * Taking the 'big' corner for trams only happens when:
           * - The previous vehicle in this (articulated) tram chain is
           *   already on the 'next' tile, we just follow them regardless of
           *   anything. When it is NOT on the 'next' tile, the tram started
           *   doing a reversing turn when the piece of tram track on the next
           *   tile did not exist yet. Do not use the big tram loop as that is
           *   going to cause the tram to split up.
           * - Or the front of the tram can drive over the next tile.
           */
        } else if (!v->IsFrontEngine() || !CanBuildTramTrackOnTile(v->owner, tile, v->roadtype, needed) || ((~needed & GetAnyRoadBits(v->tile, RTT_TRAM, false)) == ROAD_NONE)) {
          /*
           * Taking the 'small' corner for trams only happens when:
           * - We are not the from vehicle of an articulated tram.
           * - Or when the company cannot build on the next tile.
           *
           * The 'small' corner means that the vehicle is on the end of a
           * tram track and needs to start turning there. To do this properly
           * the tram needs to start at an offset in the tram turning 'code'
           * for 'big' corners. It furthermore does not go to the next tile,
           * so that needs to be fixed too.
           */
          tile = v->tile;
          start_frame = RVC_TURN_AROUND_START_FRAME_SHORT_TRAM;
        } else {
          /* The company can build on the next tile, so wait till they do. */
          v->cur_speed = 0;
          return false;
        }
      } else if (IsNormalRoadTile(v->tile) && GetDisallowedRoadDirections(v->tile) != DRD_NONE) {
        v->cur_speed = 0;
        return false;
      } else {
        tile = v->tile;
      }
    }
 
    /* Get position data for first frame on the new tile */
    const RoadDriveEntry *rdp = _road_drive_data[GetRoadTramType(v->roadtype)][(dir + (_settings_game.vehicle.road_side << RVS_DRIVE_SIDE)) ^ v->overtaking];
 
    int x = TileX(tile) * TILE_SIZE + rdp[start_frame].x;
    int y = TileY(tile) * TILE_SIZE + rdp[start_frame].y;
 
    Direction new_dir = RoadVehGetSlidingDirection(v, x, y);
    if (v->IsFrontEngine()) {
      const Vehicle *u = RoadVehFindCloseTo(v, x, y, new_dir);
      if (u != nullptr) {
        v->cur_speed = u->First()->cur_speed;
        /* We might be blocked, prevent pathfinding rerun as we already know where we are heading to. */
        v->path.emplace_back(dir, tile);
        return false;
      }
    }
 
    auto vets = VehicleEnterTile(v, tile, x, y);
    if (vets.Test(VehicleEnterTileState::CannotEnter)) {
      if (!IsTileType(tile, MP_TUNNELBRIDGE)) {
        v->cur_speed = 0;
        return false;
      }
      /* Try an about turn to re-enter the previous tile */
      dir = _road_reverse_table[rd.x & 3];
      goto again;
    }
 
    if (IsInsideMM(v->state, RVSB_IN_ROAD_STOP, RVSB_IN_DT_ROAD_STOP_END) && IsTileType(v->tile, MP_STATION)) {
      if (IsReversingRoadTrackdir(dir) && IsInsideMM(v->state, RVSB_IN_ROAD_STOP, RVSB_IN_ROAD_STOP_END)) {
        /* New direction is trying to turn vehicle around.
         * We can't turn at the exit of a road stop so wait.*/
        v->cur_speed = 0;
        return false;
      }
 
      /* If we are a drive through road stop and the next tile is of
       * the same road stop and the next tile isn't this one (i.e. we
       * are not reversing), then keep the reservation and state.
       * This way we will not be shortly unregister from the road
       * stop. It also makes it possible to load when on the edge of
       * two road stops; otherwise you could get vehicles that should
       * be loading but are not actually loading. */
      if (IsDriveThroughStopTile(v->tile) &&
          RoadStop::IsDriveThroughRoadStopContinuation(v->tile, tile) &&
          v->tile != tile) {
        /* So, keep 'our' state */
        dir = (Trackdir)v->state;
      } else if (IsStationRoadStop(v->tile)) {
        /* We're not continuing our drive through road stop, so leave. */
        RoadStop::GetByTile(v->tile, GetRoadStopType(v->tile))->Leave(v);
      }
    }
 
    if (!vets.Test(VehicleEnterTileState::EnteredWormhole)) {
      TileIndex old_tile = v->tile;
 
      v->tile = tile;
      v->state = (uint8_t)dir;
      v->frame = start_frame;
      RoadTramType rtt = GetRoadTramType(v->roadtype);
      if (GetRoadType(old_tile, rtt) != GetRoadType(tile, rtt)) {
        if (v->IsFrontEngine()) {
          RoadVehUpdateCache(v);
        }
        v->First()->CargoChanged();
      }
    }
    if (new_dir != v->direction) {
      v->direction = new_dir;
      if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
    }
    v->x_pos = x;
    v->y_pos = y;
    v->UpdatePosition();
    RoadZPosAffectSpeed(v, v->UpdateInclination(true, true));
    return true;
  }
 
  if (rd.x & RDE_TURNED) {
    /* Vehicle has finished turning around, it will now head back onto the same tile */
    Trackdir dir;
    uint turn_around_start_frame = RVC_TURN_AROUND_START_FRAME;
 
    if (RoadTypeIsTram(v->roadtype) && !IsRoadDepotTile(v->tile) && HasExactlyOneBit(GetAnyRoadBits(v->tile, RTT_TRAM, true))) {
      /*
       * The tram is turning around with one tram 'roadbit'. This means that
       * it is using the 'big' corner 'drive data'. However, to support the
       * trams to take a small corner, there is a 'turned' marker in the middle
       * of the turning 'drive data'. When the tram took the long corner, we
       * will still use the 'big' corner drive data, but we advance it one
       * frame. We furthermore set the driving direction so the turning is
       * going to be properly shown.
       */
      turn_around_start_frame = RVC_START_FRAME_AFTER_LONG_TRAM;
      switch (rd.x & 0x3) {
        default: NOT_REACHED();
        case DIAGDIR_NW: dir = TRACKDIR_RVREV_SE; break;
        case DIAGDIR_NE: dir = TRACKDIR_RVREV_SW; break;
        case DIAGDIR_SE: dir = TRACKDIR_RVREV_NW; break;
        case DIAGDIR_SW: dir = TRACKDIR_RVREV_NE; break;
      }
    } else {
      if (v->IsFrontEngine()) {
        /* If this is the front engine, look for the right path. */
        dir = RoadFindPathToDest(v, v->tile, (DiagDirection)(rd.x & 3));
      } else {
        dir = FollowPreviousRoadVehicle(v, prev, v->tile, (DiagDirection)(rd.x & 3), true);
      }
    }
 
    if (dir == INVALID_TRACKDIR) {
      v->cur_speed = 0;
      return false;
    }
 
    const RoadDriveEntry *rdp = _road_drive_data[GetRoadTramType(v->roadtype)][(_settings_game.vehicle.road_side << RVS_DRIVE_SIDE) + dir];
 
    int x = TileX(v->tile) * TILE_SIZE + rdp[turn_around_start_frame].x;
    int y = TileY(v->tile) * TILE_SIZE + rdp[turn_around_start_frame].y;
 
    Direction new_dir = RoadVehGetSlidingDirection(v, x, y);
    if (v->IsFrontEngine()) {
      const Vehicle *u = RoadVehFindCloseTo(v, x, y, new_dir);
      if (u != nullptr) {
        v->cur_speed = u->First()->cur_speed;
        /* We might be blocked, prevent pathfinding rerun as we already know where we are heading to. */
        v->path.emplace_back(dir, v->tile);
        return false;
      }
    }
 
    auto vets = VehicleEnterTile(v, v->tile, x, y);
    if (vets.Test(VehicleEnterTileState::CannotEnter)) {
      v->cur_speed = 0;
      return false;
    }
 
    v->state = dir;
    v->frame = turn_around_start_frame;
 
    if (new_dir != v->direction) {
      v->direction = new_dir;
      if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
    }
 
    v->x_pos = x;
    v->y_pos = y;
    v->UpdatePosition();
    RoadZPosAffectSpeed(v, v->UpdateInclination(true, true));
    return true;
  }
 
  /* This vehicle is not in a wormhole and it hasn't entered a new tile. If
   * it's on a depot tile, check if it's time to activate the next vehicle in
   * the chain yet. */
  if (v->Next() != nullptr && IsRoadDepotTile(v->tile)) {
    if (v->frame == v->gcache.cached_veh_length + RVC_DEPOT_START_FRAME) {
      RoadVehLeaveDepot(v->Next(), false);
    }
  }
 
  /* Calculate new position for the vehicle */
  int x = (v->x_pos & ~15) + (rd.x & 15);
  int y = (v->y_pos & ~15) + (rd.y & 15);
 
  Direction new_dir = RoadVehGetSlidingDirection(v, x, y);
 
  if (v->IsFrontEngine() && !IsInsideMM(v->state, RVSB_IN_ROAD_STOP, RVSB_IN_ROAD_STOP_END)) {
    /* Vehicle is not in a road stop.
     * Check for another vehicle to overtake */
    RoadVehicle *u = RoadVehFindCloseTo(v, x, y, new_dir);
 
    if (u != nullptr) {
      u = u->First();
      /* There is a vehicle in front overtake it if possible */
      if (v->overtaking == 0) RoadVehCheckOvertake(v, u);
      if (v->overtaking == 0) v->cur_speed = u->cur_speed;
 
      /* In case an RV is stopped in a road stop, why not try to load? */
      if (v->cur_speed == 0 && IsInsideMM(v->state, RVSB_IN_DT_ROAD_STOP, RVSB_IN_DT_ROAD_STOP_END) &&
          v->current_order.ShouldStopAtStation(v, GetStationIndex(v->tile)) &&
          v->owner == GetTileOwner(v->tile) && !v->current_order.IsType(OT_LEAVESTATION) &&
          GetRoadStopType(v->tile) == (v->IsBus() ? RoadStopType::Bus : RoadStopType::Truck)) {
        Station *st = Station::GetByTile(v->tile);
        v->last_station_visited = st->index;
        RoadVehArrivesAt(v, st);
        v->BeginLoading();
        TriggerRoadStopRandomisation(st, v->tile, StationRandomTrigger::VehicleArrives);
        TriggerRoadStopAnimation(st, v->tile, StationAnimationTrigger::VehicleArrives);
      }
      return false;
    }
  }
 
  Direction old_dir = v->direction;
  if (new_dir != old_dir) {
    v->direction = new_dir;
    if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
 
    /* Delay the vehicle in curves by making it require one additional frame per turning direction (two in total).
     * A vehicle has to spend at least 9 frames on a tile, so the following articulated part can follow.
     * (The following part may only be one tile behind, and the front part is moved before the following ones.)
     * The short (inner) curve has 8 frames, this elongates it to 10. */
    v->UpdateViewport(true, true);
    return true;
  }
 
  /* If the vehicle is in a normal road stop and the frame equals the stop frame OR
   * if the vehicle is in a drive-through road stop and this is the destination station
   * and it's the correct type of stop (bus or truck) and the frame equals the stop frame...
   * (the station test and stop type test ensure that other vehicles, using the road stop as
   * a through route, do not stop) */
  if (v->IsFrontEngine() && ((IsInsideMM(v->state, RVSB_IN_ROAD_STOP, RVSB_IN_ROAD_STOP_END) &&
      _road_stop_stop_frame[v->state - RVSB_IN_ROAD_STOP + (_settings_game.vehicle.road_side << RVS_DRIVE_SIDE)] == v->frame) ||
      (IsInsideMM(v->state, RVSB_IN_DT_ROAD_STOP, RVSB_IN_DT_ROAD_STOP_END) &&
      v->current_order.ShouldStopAtStation(v, GetStationIndex(v->tile)) &&
      v->owner == GetTileOwner(v->tile) &&
      GetRoadStopType(v->tile) == (v->IsBus() ? RoadStopType::Bus : RoadStopType::Truck) &&
      v->frame == RVC_DRIVE_THROUGH_STOP_FRAME))) {
 
    RoadStop *rs = RoadStop::GetByTile(v->tile, GetRoadStopType(v->tile));
    Station *st = Station::GetByTile(v->tile);
 
    /* Vehicle is at the stop position (at a bay) in a road stop.
     * Note, if vehicle is loading/unloading it has already been handled,
     * so if we get here the vehicle has just arrived or is just ready to leave. */
    if (!HasBit(v->state, RVS_ENTERED_STOP)) {
      /* Vehicle has arrived at a bay in a road stop */
 
      if (IsDriveThroughStopTile(v->tile)) {
        TileIndex next_tile = TileAddByDir(v->tile, v->direction);
 
        /* Check if next inline bay is free and has compatible road. */
        if (RoadStop::IsDriveThroughRoadStopContinuation(v->tile, next_tile) && HasTileAnyRoadType(next_tile, v->compatible_roadtypes)) {
          v->frame++;
          v->x_pos = x;
          v->y_pos = y;
          v->UpdatePosition();
          RoadZPosAffectSpeed(v, v->UpdateInclination(true, false));
          return true;
        }
      }
 
      rs->SetEntranceBusy(false);
      SetBit(v->state, RVS_ENTERED_STOP);
 
      v->last_station_visited = st->index;
 
      if (IsDriveThroughStopTile(v->tile) || (v->current_order.IsType(OT_GOTO_STATION) && v->current_order.GetDestination() == st->index)) {
        RoadVehArrivesAt(v, st);
        v->BeginLoading();
        TriggerRoadStopRandomisation(st, v->tile, StationRandomTrigger::VehicleArrives);
        TriggerRoadStopAnimation(st, v->tile, StationAnimationTrigger::VehicleArrives);
        return false;
      }
    } else {
      /* Vehicle is ready to leave a bay in a road stop */
      if (rs->IsEntranceBusy()) {
        /* Road stop entrance is busy, so wait as there is nowhere else to go */
        v->cur_speed = 0;
        return false;
      }
      if (v->current_order.IsType(OT_LEAVESTATION)) v->current_order.Free();
    }
 
    if (IsBayRoadStopTile(v->tile)) rs->SetEntranceBusy(true);
 
    StartRoadVehSound(v);
    SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
  }
 
  /* Check tile position conditions - i.e. stop position in depot,
   * entry onto bridge or into tunnel */
  auto vets = VehicleEnterTile(v, v->tile, x, y);
  if (vets.Test(VehicleEnterTileState::CannotEnter)) {
    v->cur_speed = 0;
    return false;
  }
 
  if (v->current_order.IsType(OT_LEAVESTATION) && IsDriveThroughStopTile(v->tile)) {
    v->current_order.Free();
  }
 
  /* Move to next frame unless vehicle arrived at a stop position
   * in a depot or entered a tunnel/bridge */
  if (!vets.Test(VehicleEnterTileState::EnteredWormhole)) v->frame++;
  v->x_pos = x;
  v->y_pos = y;
  v->UpdatePosition();
  RoadZPosAffectSpeed(v, v->UpdateInclination(false, true));
  return true;
}
 
static bool RoadVehController(RoadVehicle *v)
{
  /* decrease counters */
  v->current_order_time++;
  if (v->reverse_ctr != 0) v->reverse_ctr--;
 
  /* handle crashed */
  if (v->vehstatus.Test(VehState::Crashed) || RoadVehCheckTrainCrash(v)) {
    return RoadVehIsCrashed(v);
  }
 
  /* road vehicle has broken down? */
  if (v->HandleBreakdown()) return true;
  if (v->vehstatus.Test(VehState::Stopped)) {
    v->SetLastSpeed();
    return true;
  }
 
  ProcessOrders(v);
  v->HandleLoading();
 
  if (v->current_order.IsType(OT_LOADING)) return true;
 
  if (v->IsInDepot()) {
    /* Check if we should wait here for unbunching. */
    if (v->IsWaitingForUnbunching()) return true;
    if (RoadVehLeaveDepot(v, true)) return true;
  }
 
  v->ShowVisualEffect();
 
  /* Check how far the vehicle needs to proceed */
  int j = v->UpdateSpeed();
 
  int adv_spd = v->GetAdvanceDistance();
  bool blocked = false;
  while (j >= adv_spd) {
    j -= adv_spd;
 
    RoadVehicle *u = v;
    for (RoadVehicle *prev = nullptr; u != nullptr; prev = u, u = u->Next()) {
      if (!IndividualRoadVehicleController(u, prev)) {
        blocked = true;
        break;
      }
    }
    if (blocked) break;
 
    /* Determine distance to next map position */
    adv_spd = v->GetAdvanceDistance();
 
    /* Test for a collision, but only if another movement will occur. */
    if (j >= adv_spd && RoadVehCheckTrainCrash(v)) break;
  }
 
  v->SetLastSpeed();
 
  for (RoadVehicle *u = v; u != nullptr; u = u->Next()) {
    if (u->vehstatus.Test(VehState::Hidden)) continue;
 
    u->UpdateViewport(false, false);
  }
 
  /* If movement is blocked, set 'progress' to its maximum, so the roadvehicle does
   * not accelerate again before it can actually move. I.e. make sure it tries to advance again
   * on next tick to discover whether it is still blocked. */
  if (v->progress == 0) v->progress = blocked ? adv_spd - 1 : j;
 
  return true;
}
 
Money RoadVehicle::GetRunningCost() const
{
  const Engine *e = this->GetEngine();
  if (e->u.road.running_cost_class == INVALID_PRICE) return 0;
 
  uint cost_factor = GetVehicleProperty(this, PROP_ROADVEH_RUNNING_COST_FACTOR, e->u.road.running_cost);
  if (cost_factor == 0) return 0;
 
  return GetPrice(e->u.road.running_cost_class, cost_factor, e->GetGRF());
}
Money RoadVehicle::GetRunningCost() const {…}
 
bool RoadVehicle::Tick()
{
  PerformanceAccumulator framerate(PFE_GL_ROADVEHS);
 
  this->tick_counter++;
 
  if (this->IsFrontEngine()) {
    if (!this->vehstatus.Test(VehState::Stopped)) this->running_ticks++;
    return RoadVehController(this);
  }
 
  return true;
}
bool RoadVehicle::Tick() {…}
 
void RoadVehicle::SetDestTile(TileIndex tile)
{
  if (tile == this->dest_tile) return;
  this->path.clear();
  this->dest_tile = tile;
}
 
static void CheckIfRoadVehNeedsService(RoadVehicle *v)
{
  /* If we already got a slot at a stop, use that FIRST, and go to a depot later */
  if (Company::Get(v->owner)->settings.vehicle.servint_roadveh == 0 || !v->NeedsAutomaticServicing()) return;
  if (v->IsChainInDepot()) {
    VehicleServiceInDepot(v);
    return;
  }
 
  uint max_penalty = _settings_game.pf.yapf.maximum_go_to_depot_penalty;
 
  FindDepotData rfdd = FindClosestRoadDepot(v, max_penalty);
  /* Only go to the depot if it is not too far out of our way. */
  if (rfdd.best_length == UINT_MAX || rfdd.best_length > max_penalty) {
    if (v->current_order.IsType(OT_GOTO_DEPOT)) {
      /* If we were already heading for a depot but it has
       * suddenly moved farther away, we continue our normal
       * schedule? */
      v->current_order.MakeDummy();
      SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
    }
    return;
  }
 
  DepotID depot = GetDepotIndex(rfdd.tile);
 
  if (v->current_order.IsType(OT_GOTO_DEPOT) &&
      v->current_order.GetNonStopType() & ONSF_NO_STOP_AT_INTERMEDIATE_STATIONS &&
      !Chance16(1, 20)) {
    return;
  }
 
  SetBit(v->gv_flags, GVF_SUPPRESS_IMPLICIT_ORDERS);
  v->current_order.MakeGoToDepot(depot, ODTFB_SERVICE);
  v->SetDestTile(rfdd.tile);
  SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
}
 
void RoadVehicle::OnNewCalendarDay()
{
  if (!this->IsFrontEngine()) return;
  AgeVehicle(this);
}
void RoadVehicle::OnNewCalendarDay() {…}
 
void RoadVehicle::OnNewEconomyDay()
{
  if (!this->IsFrontEngine()) return;
  EconomyAgeVehicle(this);
 
  if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
  if (this->blocked_ctr == 0) CheckVehicleBreakdown(this);
 
  CheckIfRoadVehNeedsService(this);
 
  CheckOrders(this);
 
  if (this->running_ticks == 0) return;
 
  CommandCost cost(EXPENSES_ROADVEH_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);
  SetWindowClassesDirty(WC_ROADVEH_LIST);
}
void RoadVehicle::OnNewEconomyDay() {…}
 
Trackdir RoadVehicle::GetVehicleTrackdir() const
{
  if (this->vehstatus.Test(VehState::Crashed)) return INVALID_TRACKDIR;
 
  if (this->IsInDepot()) {
    /* We'll assume the road vehicle is facing outwards */
    return DiagDirToDiagTrackdir(GetRoadDepotDirection(this->tile));
  }
 
  if (IsBayRoadStopTile(this->tile)) {
    /* We'll assume the road vehicle is facing outwards */
    return DiagDirToDiagTrackdir(GetBayRoadStopDir(this->tile)); // Road vehicle in a station
  }
 
  /* Drive through road stops / wormholes (tunnels) */
  if (this->state > RVSB_TRACKDIR_MASK) return DiagDirToDiagTrackdir(DirToDiagDir(this->direction));
 
  /* If vehicle's state is a valid track direction (vehicle is not turning around) return it,
   * otherwise transform it into a valid track direction */
  return (Trackdir)((IsReversingRoadTrackdir((Trackdir)this->state)) ? (this->state - 6) : this->state);
}
Trackdir RoadVehicle::GetVehicleTrackdir() const {…}
 
uint16_t RoadVehicle::GetMaxWeight() const
{
  uint16_t weight = CargoSpec::Get(this->cargo_type)->WeightOfNUnits(this->GetEngine()->DetermineCapacity(this));
 
  /* Vehicle weight is not added for articulated parts. */
  if (!this->IsArticulatedPart()) {
    /* Road vehicle weight is in units of 1/4 t. */
    weight += GetVehicleProperty(this, PROP_ROADVEH_WEIGHT, RoadVehInfo(this->engine_type)->weight) / 4;
  }
 
  return weight;
}
uint16_t RoadVehicle::GetMaxWeight() const {…}