water_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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */

 
#include "stdafx.h"
#include "landscape.h"
#include "viewport_func.h"
#include "command_func.h"
#include "town.h"
#include "news_func.h"
#include "depot_base.h"
#include "depot_func.h"
#include "water.h"
#include "industry_map.h"
#include "newgrf_canal.h"
#include "strings_func.h"
#include "vehicle_func.h"
#include "sound_func.h"
#include "company_func.h"
#include "clear_map.h"
#include "tree_map.h"
#include "aircraft.h"
#include "effectvehicle_func.h"
#include "tunnelbridge_map.h"
#include "station_base.h"
#include "ai/ai.hpp"
#include "game/game.hpp"
#include "core/random_func.hpp"
#include "core/backup_type.hpp"
#include "timer/timer_game_calendar.h"
#include "company_base.h"
#include "company_gui.h"
#include "newgrf_generic.h"
#include "industry.h"
#include "water_cmd.h"
#include "landscape_cmd.h"
#include "pathfinder/water_regions.h"
#include "town_type.h"
 
#include "table/strings.h"
 
#include "safeguards.h"

static const Directions _flood_from_dirs[] = {
  {DIR_NW, DIR_SW, DIR_SE, DIR_NE}, // SLOPE_FLAT
  {DIR_NE, DIR_SE},                 // SLOPE_W
  {DIR_NW, DIR_NE},                 // SLOPE_S
  {DIR_NE},                         // SLOPE_SW
  {DIR_NW, DIR_SW},                 // SLOPE_E
  {},                               // SLOPE_EW
  {DIR_NW},                         // SLOPE_SE
  {DIR_N, DIR_NW, DIR_NE},          // SLOPE_WSE, SLOPE_STEEP_S
  {DIR_SW, DIR_SE},                 // SLOPE_N
  {DIR_SE},                         // SLOPE_NW
  {},                               // SLOPE_NS
  {DIR_E, DIR_NE, DIR_SE},          // SLOPE_NWS, SLOPE_STEEP_W
  {DIR_SW},                         // SLOPE_NE
  {DIR_S, DIR_SW, DIR_SE},          // SLOPE_ENW, SLOPE_STEEP_N
  {DIR_W, DIR_SW, DIR_NW},          // SLOPE_SEN, SLOPE_STEEP_E
};

static inline void MarkTileDirtyIfCanalOrRiver(TileIndex tile)
{
  if (IsValidTile(tile) && IsTileType(tile, TileType::Water) && (IsCanal(tile) || IsRiver(tile))) MarkTileDirtyByTile(tile);
}

static void MarkCanalsAndRiversAroundDirty(TileIndex tile)
{
  for (Direction dir = DIR_BEGIN; dir < DIR_END; dir++) {
    MarkTileDirtyIfCanalOrRiver(tile + TileOffsByDir(dir));
  }
}

void ClearNeighbourNonFloodingStates(TileIndex tile)
{
  for (Direction dir = DIR_BEGIN; dir != DIR_END; dir++) {
    TileIndex dest = tile + TileOffsByDir(dir);
    if (IsValidTile(dest) && IsTileType(dest, TileType::Water)) SetNonFloodingWaterTile(dest, false);
  }
}

CommandCost CmdBuildShipDepot(DoCommandFlags flags, TileIndex tile, Axis axis)
{
  if (!IsValidAxis(axis)) return CMD_ERROR;
  TileIndex tile2 = tile + TileOffsByAxis(axis);
 
  if (!HasTileWaterGround(tile) || !HasTileWaterGround(tile2)) {
    return CommandCost(STR_ERROR_MUST_BE_BUILT_ON_WATER);
  }
 
  if (IsBridgeAbove(tile) || IsBridgeAbove(tile2)) return CommandCost(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
 
  if (!IsTileFlat(tile) || !IsTileFlat(tile2)) {
    /* Prevent depots on rapids */
    return CommandCost(STR_ERROR_SITE_UNSUITABLE);
  }
 
  if (!Depot::CanAllocateItem()) return CMD_ERROR;
 
  WaterClass wc1 = GetWaterClass(tile);
  WaterClass wc2 = GetWaterClass(tile2);
  CommandCost cost = CommandCost(EXPENSES_CONSTRUCTION, _price[Price::BuildDepotShip]);
 
  bool add_cost = !IsWaterTile(tile);
  CommandCost ret = Command<Commands::LandscapeClear>::Do(flags | DoCommandFlag::Auto, tile);
  if (ret.Failed()) return ret;
  if (add_cost) {
    cost.AddCost(ret.GetCost());
  }
  add_cost = !IsWaterTile(tile2);
  ret = Command<Commands::LandscapeClear>::Do(flags | DoCommandFlag::Auto, tile2);
  if (ret.Failed()) return ret;
  if (add_cost) {
    cost.AddCost(ret.GetCost());
  }
 
  if (flags.Test(DoCommandFlag::Execute)) {
    Depot *depot = Depot::Create(tile);
 
    uint new_water_infra = 2 * LOCK_DEPOT_TILE_FACTOR;
    /* Update infrastructure counts after the tile clears earlier.
     * Clearing object tiles may result in water tiles which are already accounted for in the water infrastructure total.
     * See: MakeWaterKeepingClass() */
    if (wc1 == WaterClass::Canal && !(HasTileWaterClass(tile) && GetWaterClass(tile) == WaterClass::Canal && IsTileOwner(tile, _current_company))) new_water_infra++;
    if (wc2 == WaterClass::Canal && !(HasTileWaterClass(tile2) && GetWaterClass(tile2) == WaterClass::Canal && IsTileOwner(tile2, _current_company))) new_water_infra++;
 
    Company::Get(_current_company)->infrastructure.water += new_water_infra;
    DirtyCompanyInfrastructureWindows(_current_company);
 
    MakeShipDepot(tile,  _current_company, depot->index, DepotPart::North, axis, wc1);
    MakeShipDepot(tile2, _current_company, depot->index, DepotPart::South, axis, wc2);
    CheckForDockingTile(tile);
    CheckForDockingTile(tile2);
    MarkTileDirtyByTile(tile);
    MarkTileDirtyByTile(tile2);
    MakeDefaultName(depot);
  }
 
  return cost;
}
 
bool IsPossibleDockingTile(Tile t)
{
  assert(IsValidTile(t));
  switch (GetTileType(t)) {
    case TileType::Water:
      if (IsLock(t) && GetLockPart(t) == LockPart::Middle) return false;
      [[fallthrough]];
    case TileType::Railway:
    case TileType::Station:
    case TileType::TunnelBridge:
      return TrackStatusToTrackBits(GetTileTrackStatus(t, TRANSPORT_WATER, 0)) != TRACK_BIT_NONE;
 
    default:
      return false;
  }
}

void CheckForDockingTile(TileIndex t)
{
  for (DiagDirection d = DIAGDIR_BEGIN; d != DIAGDIR_END; d++) {
    TileIndex tile = t + TileOffsByDiagDir(d);
    if (!IsValidTile(tile)) continue;
 
    if (IsDockTile(tile) && IsDockWaterPart(tile)) {
      Station::GetByTile(tile)->docking_station.Add(t);
      SetDockingTile(t, true);
    }
    if (IsTileType(tile, TileType::Industry)) {
      Station *st = Industry::GetByTile(tile)->neutral_station;
      if (st != nullptr) {
        st->docking_station.Add(t);
        SetDockingTile(t, true);
      }
    }
    if (IsTileType(tile, TileType::Station) && IsOilRig(tile)) {
      Station::GetByTile(tile)->docking_station.Add(t);
      SetDockingTile(t, true);
    }
  }
}
 
void MakeWaterKeepingClass(TileIndex tile, Owner o)
{
  WaterClass wc = GetWaterClass(tile);
 
  /* Autoslope might turn an originally canal or river tile into land */
  auto [slope, z] = GetTileSlopeZ(tile);
 
  if (slope != SLOPE_FLAT) {
    if (wc == WaterClass::Canal) {
      /* If we clear the canal, we have to remove it from the infrastructure count as well. */
      Company *c = Company::GetIfValid(o);
      if (c != nullptr) {
        c->infrastructure.water--;
        DirtyCompanyInfrastructureWindows(c->index);
      }
      /* Sloped canals are locks and no natural water remains whatever the slope direction */
      wc = WaterClass::Invalid;
    }
 
    /* Only river water should be restored on appropriate slopes. Other water would be invalid on slopes */
    if (wc != WaterClass::River || GetInclinedSlopeDirection(slope) == INVALID_DIAGDIR) {
      wc = WaterClass::Invalid;
    }
  }
 
  if (wc == WaterClass::Sea && z > 0) {
    /* Update company infrastructure count. */
    Company *c = Company::GetIfValid(o);
    if (c != nullptr) {
      c->infrastructure.water++;
      DirtyCompanyInfrastructureWindows(c->index);
    }
 
    wc = WaterClass::Canal;
  }
 
  /* Zero map array and terminate animation */
  DoClearSquare(tile);
 
  /* Maybe change to water */
  switch (wc) {
    case WaterClass::Sea:   MakeSea(tile);                break;
    case WaterClass::Canal: MakeCanal(tile, o, Random()); break;
    case WaterClass::River: MakeRiver(tile, Random());    break;
    default: break;
  }
 
  if (wc != WaterClass::Invalid) CheckForDockingTile(tile);
  MarkTileDirtyByTile(tile);
}
 
static CommandCost RemoveShipDepot(TileIndex tile, DoCommandFlags flags)
{
  if (!IsShipDepot(tile)) return CMD_ERROR;
 
  CommandCost ret = CheckTileOwnership(tile);
  if (ret.Failed()) return ret;
 
  TileIndex tile2 = GetOtherShipDepotTile(tile);
 
  /* do not check for ship on tile when company goes bankrupt */
  if (!flags.Test(DoCommandFlag::Bankrupt)) {
    ret = EnsureNoVehicleOnGround(tile);
    if (ret.Succeeded()) ret = EnsureNoVehicleOnGround(tile2);
    if (ret.Failed()) return ret;
  }
 
  bool do_clear = flags.Test(DoCommandFlag::ForceClearTile);
 
  if (flags.Test(DoCommandFlag::Execute)) {
    delete Depot::GetByTile(tile);
 
    Company *c = Company::GetIfValid(GetTileOwner(tile));
    if (c != nullptr) {
      c->infrastructure.water -= 2 * LOCK_DEPOT_TILE_FACTOR;
      if (do_clear && GetWaterClass(tile) == WaterClass::Canal) c->infrastructure.water--;
      DirtyCompanyInfrastructureWindows(c->index);
    }
 
    if (!do_clear) MakeWaterKeepingClass(tile,  GetTileOwner(tile));
    MakeWaterKeepingClass(tile2, GetTileOwner(tile2));
  }
 
  return CommandCost(EXPENSES_CONSTRUCTION, _price[Price::ClearDepotShip]);
}

static uint8_t GetLockPartMinimalBridgeHeight(LockPart lock_part)
{
  static constexpr uint8_t MINIMAL_BRIDGE_HEIGHT[to_underlying(LockPart::End)] = {
    2, // LockPart::Middle
    3, // LockPart::Lower
    2, // LockPart::Upper
  };
  return MINIMAL_BRIDGE_HEIGHT[to_underlying(lock_part)];
}

static CommandCost DoBuildLock(TileIndex tile, DiagDirection dir, DoCommandFlags flags)
{
  CommandCost cost(EXPENSES_CONSTRUCTION);
 
  TileIndexDiff delta = TileOffsByDiagDir(dir);
  CommandCost ret = EnsureNoVehicleOnGround(tile);
  if (ret.Succeeded()) ret = EnsureNoVehicleOnGround(tile + delta);
  if (ret.Succeeded()) ret = EnsureNoVehicleOnGround(tile - delta);
  if (ret.Failed()) return ret;
 
  /* middle tile */
  WaterClass wc_middle = HasTileWaterGround(tile) ? GetWaterClass(tile) : WaterClass::Canal;
  ret = Command<Commands::LandscapeClear>::Do(flags, tile);
  if (ret.Failed()) return ret;
  cost.AddCost(ret.GetCost());
 
  /* lower tile */
  if (!IsWaterTile(tile - delta)) {
    ret = Command<Commands::LandscapeClear>::Do(flags, tile - delta);
    if (ret.Failed()) return ret;
    cost.AddCost(ret.GetCost());
    cost.AddCost(_price[Price::BuildCanal]);
  }
  if (!IsTileFlat(tile - delta)) {
    return CommandCost(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
  }
  WaterClass wc_lower = IsWaterTile(tile - delta) ? GetWaterClass(tile - delta) : WaterClass::Canal;
 
  /* upper tile */
  if (!IsWaterTile(tile + delta)) {
    ret = Command<Commands::LandscapeClear>::Do(flags, tile + delta);
    if (ret.Failed()) return ret;
    cost.AddCost(ret.GetCost());
    cost.AddCost(_price[Price::BuildCanal]);
  }
  if (!IsTileFlat(tile + delta)) {
    return CommandCost(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
  }
  WaterClass wc_upper = IsWaterTile(tile + delta) ? GetWaterClass(tile + delta) : WaterClass::Canal;
 
  for (LockPart lock_part = LockPart::Middle; TileIndex t : {tile, tile - delta, tile + delta}) {
    if (IsBridgeAbove(t) && GetBridgeHeight(GetSouthernBridgeEnd(t)) < GetTileMaxZ(t) + GetLockPartMinimalBridgeHeight(lock_part)) {
      int height_diff = (GetTileMaxZ(tile) + GetLockPartMinimalBridgeHeight(lock_part) - GetBridgeHeight(GetSouthernBridgeEnd(t))) * TILE_HEIGHT_STEP;
      return CommandCostWithParam(STR_ERROR_BRIDGE_TOO_LOW_FOR_LOCK, height_diff);
    }
    ++lock_part;
  }
 
  if (flags.Test(DoCommandFlag::Execute)) {
    /* Update company infrastructure counts. */
    Company *c = Company::GetIfValid(_current_company);
    if (c != nullptr) {
      /* Counts for the water. */
      if (!IsWaterTile(tile - delta)) c->infrastructure.water++;
      if (!IsWaterTile(tile + delta)) c->infrastructure.water++;
      /* Count for the lock itself. */
      c->infrastructure.water += 3 * LOCK_DEPOT_TILE_FACTOR; // Lock is three tiles.
      DirtyCompanyInfrastructureWindows(_current_company);
    }
 
    MakeLock(tile, _current_company, dir, wc_lower, wc_upper, wc_middle);
    CheckForDockingTile(tile - delta);
    CheckForDockingTile(tile + delta);
    MarkTileDirtyByTile(tile);
    MarkTileDirtyByTile(tile - delta);
    MarkTileDirtyByTile(tile + delta);
    MarkCanalsAndRiversAroundDirty(tile - delta);
    MarkCanalsAndRiversAroundDirty(tile + delta);
    InvalidateWaterRegion(tile - delta);
    InvalidateWaterRegion(tile + delta);
  }
  cost.AddCost(_price[Price::BuildLock]);
 
  return cost;
}

static CommandCost RemoveLock(TileIndex tile, DoCommandFlags flags)
{
  if (GetTileOwner(tile) != OWNER_NONE) {
    CommandCost ret = CheckTileOwnership(tile);
    if (ret.Failed()) return ret;
  }
 
  TileIndexDiff delta = TileOffsByDiagDir(GetLockDirection(tile));
 
  /* make sure no vehicle is on the tile. */
  CommandCost ret = EnsureNoVehicleOnGround(tile);
  if (ret.Succeeded()) ret = EnsureNoVehicleOnGround(tile + delta);
  if (ret.Succeeded()) ret = EnsureNoVehicleOnGround(tile - delta);
  if (ret.Failed()) return ret;
 
  if (flags.Test(DoCommandFlag::Execute)) {
    /* Remove middle part from company infrastructure count. */
    Company *c = Company::GetIfValid(GetTileOwner(tile));
    if (c != nullptr) {
      c->infrastructure.water -= 3 * LOCK_DEPOT_TILE_FACTOR; // three parts of the lock.
      DirtyCompanyInfrastructureWindows(c->index);
    }
 
    if (GetWaterClass(tile) == WaterClass::River) {
      MakeRiver(tile, Random());
    } else {
      DoClearSquare(tile);
      ClearNeighbourNonFloodingStates(tile);
    }
    MakeWaterKeepingClass(tile + delta, GetTileOwner(tile + delta));
    MakeWaterKeepingClass(tile - delta, GetTileOwner(tile - delta));
    MarkCanalsAndRiversAroundDirty(tile);
    MarkCanalsAndRiversAroundDirty(tile - delta);
    MarkCanalsAndRiversAroundDirty(tile + delta);
  }
 
  return CommandCost(EXPENSES_CONSTRUCTION, _price[Price::ClearLock]);
}

CommandCost CmdBuildLock(DoCommandFlags flags, TileIndex tile)
{
  DiagDirection dir = GetInclinedSlopeDirection(GetTileSlope(tile));
  if (dir == INVALID_DIAGDIR) return CommandCost(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
 
  TileIndex lower_tile = TileAddByDiagDir(tile, ReverseDiagDir(dir));
 
  /* If freeform edges are disabled, don't allow building on edge tiles. */
  if (!_settings_game.construction.freeform_edges && (!IsInsideMM(TileX(lower_tile), 1, Map::MaxX() - 1) || !IsInsideMM(TileY(lower_tile), 1, Map::MaxY() - 1))) {
    return CommandCost(STR_ERROR_TOO_CLOSE_TO_EDGE_OF_MAP);
  }
 
  return DoBuildLock(tile, dir, flags);
}

void MakeRiverAndModifyDesertZoneAround(TileIndex tile)
{
  MakeRiver(tile, Random());
  MarkTileDirtyByTile(tile);
 
  /* Remove desert directly around the river tile. */
  for (auto t : SpiralTileSequence(tile, RIVER_OFFSET_DESERT_DISTANCE)) {
    if (GetTropicZone(t) == TROPICZONE_DESERT) SetTropicZone(t, TROPICZONE_NORMAL);
  }
}

CommandCost CmdBuildCanal(DoCommandFlags flags, TileIndex tile, TileIndex start_tile, WaterClass wc, bool diagonal)
{
  if (start_tile >= Map::Size() || !IsValidWaterClass(wc)) return CMD_ERROR;
 
  /* Outside of the editor you can only build canals, not oceans */
  if (wc != WaterClass::Canal && _game_mode != GM_EDITOR) return CMD_ERROR;
 
  CommandCost cost(EXPENSES_CONSTRUCTION);
 
  std::unique_ptr<TileIterator> iter = TileIterator::Create(tile, start_tile, diagonal);
  for (; *iter != INVALID_TILE; ++(*iter)) {
    TileIndex current_tile = *iter;
    CommandCost ret;
 
    Slope slope = GetTileSlope(current_tile);
    if (slope != SLOPE_FLAT && (wc != WaterClass::River || !IsInclinedSlope(slope))) {
      return CommandCost(STR_ERROR_FLAT_LAND_REQUIRED);
    }
 
    bool water = IsWaterTile(current_tile);
 
    /* Outside the editor, prevent building canals over your own or OWNER_NONE owned canals */
    if (water && IsCanal(current_tile) && _game_mode != GM_EDITOR && (IsTileOwner(current_tile, _current_company) || IsTileOwner(current_tile, OWNER_NONE))) continue;
 
    ret = Command<Commands::LandscapeClear>::Do(flags, current_tile);
    if (ret.Failed()) return ret;
 
    if (!water) cost.AddCost(ret.GetCost());
 
    if (flags.Test(DoCommandFlag::Execute)) {
      if (IsTileType(current_tile, TileType::Water) && IsCanal(current_tile)) {
        Owner owner = GetTileOwner(current_tile);
        if (Company::IsValidID(owner)) {
          Company::Get(owner)->infrastructure.water--;
          DirtyCompanyInfrastructureWindows(owner);
        }
      }
 
      switch (wc) {
        case WaterClass::River:
          MakeRiver(current_tile, Random());
          if (_game_mode == GM_EDITOR) {
            /* Remove desert directly around the river tile. */
            for (auto t : SpiralTileSequence(current_tile, RIVER_OFFSET_DESERT_DISTANCE)) {
              if (GetTropicZone(t) == TROPICZONE_DESERT) SetTropicZone(t, TROPICZONE_NORMAL);
            }
          }
          break;
 
        case WaterClass::Sea:
          if (TileHeight(current_tile) == 0) {
            MakeSea(current_tile);
            break;
          }
          [[fallthrough]];
 
        default:
          MakeCanal(current_tile, _current_company, Random());
          if (Company::IsValidID(_current_company)) {
            Company::Get(_current_company)->infrastructure.water++;
            DirtyCompanyInfrastructureWindows(_current_company);
          }
          break;
      }
      MarkTileDirtyByTile(current_tile);
      MarkCanalsAndRiversAroundDirty(current_tile);
      CheckForDockingTile(current_tile);
    }
 
    cost.AddCost(_price[Price::BuildCanal]);
  }
 
  if (cost.GetCost() == 0) {
    return CommandCost(STR_ERROR_ALREADY_BUILT);
  } else {
    return cost;
  }
}
 
 
static CommandCost ClearTile_Water(TileIndex tile, DoCommandFlags flags)
{
  switch (GetWaterTileType(tile)) {
    case WaterTileType::Clear: {
      if (flags.Test(DoCommandFlag::NoWater)) return CommandCost(STR_ERROR_CAN_T_BUILD_ON_WATER);
 
      Money base_cost = IsCanal(tile) ? _price[Price::ClearCanal] : _price[Price::ClearWater];
      /* Make sure freeform edges are allowed or it's not an edge tile. */
      if (!_settings_game.construction.freeform_edges && (!IsInsideMM(TileX(tile), 1, Map::MaxX() - 1) ||
          !IsInsideMM(TileY(tile), 1, Map::MaxY() - 1))) {
        return CommandCost(STR_ERROR_TOO_CLOSE_TO_EDGE_OF_MAP);
      }
 
      /* Make sure no vehicle is on the tile */
      CommandCost ret = EnsureNoVehicleOnGround(tile);
      if (ret.Failed()) return ret;
 
      Owner owner = GetTileOwner(tile);
      if (owner != OWNER_WATER && owner != OWNER_NONE) {
        ret = CheckTileOwnership(tile);
        if (ret.Failed()) return ret;
      }
 
      if (flags.Test(DoCommandFlag::Execute)) {
        if (IsCanal(tile) && Company::IsValidID(owner)) {
          Company::Get(owner)->infrastructure.water--;
          DirtyCompanyInfrastructureWindows(owner);
        }
 
        /* Handle local authority impact */
        if (IsRiver(tile)) {
          if (Company::IsValidID(_current_company)) {
            Town *town = ClosestTownFromTile(tile, _settings_game.economy.dist_local_authority);
            if (town != nullptr) ChangeTownRating(town, RATING_WATER_RIVER_DOWN_STEP, RATING_WATER_MINIMUM, flags);
          }
        }
 
        DoClearSquare(tile);
        MarkCanalsAndRiversAroundDirty(tile);
        ClearNeighbourNonFloodingStates(tile);
      }
 
      return CommandCost(EXPENSES_CONSTRUCTION, base_cost);
    }
 
    case WaterTileType::Coast: {
      Slope slope = GetTileSlope(tile);
 
      /* Make sure no vehicle is on the tile */
      CommandCost ret = EnsureNoVehicleOnGround(tile);
      if (ret.Failed()) return ret;
 
      if (flags.Test(DoCommandFlag::Execute)) {
        DoClearSquare(tile);
        MarkCanalsAndRiversAroundDirty(tile);
        ClearNeighbourNonFloodingStates(tile);
      }
      if (IsSlopeWithOneCornerRaised(slope)) {
        return CommandCost(EXPENSES_CONSTRUCTION, _price[Price::ClearWater]);
      } else {
        return CommandCost(EXPENSES_CONSTRUCTION, _price[Price::ClearRough]);
      }
    }
 
    case WaterTileType::Lock: {
      static const TileIndexDiffC _lock_tomiddle_offs[to_underlying(LockPart::End)][DIAGDIR_END] = {
        /*   NE       SE        SW      NW       */
        { { 0,  0}, {0,  0}, { 0, 0}, {0,  0} }, // LockPart::Middle
        { {-1,  0}, {0,  1}, { 1, 0}, {0, -1} }, // LockPart::Lower
        { { 1,  0}, {0, -1}, {-1, 0}, {0,  1} }, // LockPart::Upper
      };
 
      if (flags.Test(DoCommandFlag::Auto)) return CommandCost(STR_ERROR_BUILDING_MUST_BE_DEMOLISHED);
      if (_current_company == OWNER_WATER) return CMD_ERROR;
      /* move to the middle tile.. */
      return RemoveLock(tile + ToTileIndexDiff(_lock_tomiddle_offs[to_underlying(GetLockPart(tile))][GetLockDirection(tile)]), flags);
    }
 
    case WaterTileType::Depot:
      if (flags.Test(DoCommandFlag::Auto)) return CommandCost(STR_ERROR_BUILDING_MUST_BE_DEMOLISHED);
      return RemoveShipDepot(tile, flags);
 
    default:
      NOT_REACHED();
  }
}

bool IsWateredTile(TileIndex tile, Direction from)
{
  switch (GetTileType(tile)) {
    case TileType::Water:
      switch (GetWaterTileType(tile)) {
        default: NOT_REACHED();
        case WaterTileType::Depot: case WaterTileType::Clear: return true;
        case WaterTileType::Lock: return DiagDirToAxis(GetLockDirection(tile)) == DiagDirToAxis(DirToDiagDir(from));
 
        case WaterTileType::Coast:
          switch (GetTileSlope(tile)) {
            case SLOPE_W: return (from == DIR_SE) || (from == DIR_E) || (from == DIR_NE);
            case SLOPE_S: return (from == DIR_NE) || (from == DIR_N) || (from == DIR_NW);
            case SLOPE_E: return (from == DIR_NW) || (from == DIR_W) || (from == DIR_SW);
            case SLOPE_N: return (from == DIR_SW) || (from == DIR_S) || (from == DIR_SE);
            default: return false;
          }
      }
 
    case TileType::Railway:
      if (GetRailGroundType(tile) == RailGroundType::HalfTileWater) {
        assert(IsPlainRail(tile));
        switch (GetTileSlope(tile)) {
          case SLOPE_W: return (from == DIR_SE) || (from == DIR_E) || (from == DIR_NE);
          case SLOPE_S: return (from == DIR_NE) || (from == DIR_N) || (from == DIR_NW);
          case SLOPE_E: return (from == DIR_NW) || (from == DIR_W) || (from == DIR_SW);
          case SLOPE_N: return (from == DIR_SW) || (from == DIR_S) || (from == DIR_SE);
          default: return false;
        }
      }
      return false;
 
    case TileType::Station:
      if (IsOilRig(tile)) {
        /* Do not draw waterborders inside of industries.
         * Note: There is no easy way to detect the industry of an oilrig tile. */
        TileIndex src_tile = tile + TileOffsByDir(from);
        if ((IsTileType(src_tile, TileType::Station) && IsOilRig(src_tile)) ||
            (IsTileType(src_tile, TileType::Industry))) return true;
 
        return IsTileOnWater(tile);
      }
      return (IsDock(tile) && IsTileFlat(tile)) || IsBuoy(tile);
 
    case TileType::Industry: {
      /* Do not draw waterborders inside of industries.
       * Note: There is no easy way to detect the industry of an oilrig tile. */
      TileIndex src_tile = tile + TileOffsByDir(from);
      if ((IsTileType(src_tile, TileType::Station) && IsOilRig(src_tile)) ||
          (IsTileType(src_tile, TileType::Industry) && GetIndustryIndex(src_tile) == GetIndustryIndex(tile))) return true;
 
      return IsTileOnWater(tile);
    }
 
    case TileType::Object: return IsTileOnWater(tile);
 
    case TileType::TunnelBridge: return GetTunnelBridgeTransportType(tile) == TRANSPORT_WATER && ReverseDiagDir(GetTunnelBridgeDirection(tile)) == DirToDiagDir(from);
 
    case TileType::Void: return true; // consider map border as water, esp. for rivers
 
    default:          return false;
  }
}

static void DrawWaterSprite(SpriteID base, uint offset, CanalFeature feature, TileIndex tile)
{
  if (base != SPR_FLAT_WATER_TILE) {
    /* Only call offset callback if the sprite is NewGRF-provided. */
    offset = GetCanalSpriteOffset(feature, tile, offset);
  }
  DrawGroundSprite(base + offset, PAL_NONE);
}

static void DrawWaterEdges(bool canal, uint offset, TileIndex tile)
{
  CanalFeature feature;
  SpriteID base = 0;
  if (canal) {
    feature = CF_DIKES;
    base = GetCanalSprite(CF_DIKES, tile);
    if (base == 0) base = SPR_CANAL_DIKES_BASE;
  } else {
    feature = CF_RIVER_EDGE;
    base = GetCanalSprite(CF_RIVER_EDGE, tile);
    if (base == 0) return; // Don't draw if no sprites provided.
  }
 
  uint wa;
 
  /* determine the edges around with water. */
  wa  = IsWateredTile(TileAddXY(tile, -1,  0), DIR_SW) << 0;
  wa += IsWateredTile(TileAddXY(tile,  0,  1), DIR_NW) << 1;
  wa += IsWateredTile(TileAddXY(tile,  1,  0), DIR_NE) << 2;
  wa += IsWateredTile(TileAddXY(tile,  0, -1), DIR_SE) << 3;
 
  if (!(wa & 1)) DrawWaterSprite(base, offset,     feature, tile);
  if (!(wa & 2)) DrawWaterSprite(base, offset + 1, feature, tile);
  if (!(wa & 4)) DrawWaterSprite(base, offset + 2, feature, tile);
  if (!(wa & 8)) DrawWaterSprite(base, offset + 3, feature, tile);
 
  /* right corner */
  switch (wa & 0x03) {
    case 0: DrawWaterSprite(base, offset + 4, feature, tile); break;
    case 3: if (!IsWateredTile(TileAddXY(tile, -1, 1), DIR_W)) DrawWaterSprite(base, offset + 8, feature, tile); break;
  }
 
  /* bottom corner */
  switch (wa & 0x06) {
    case 0: DrawWaterSprite(base, offset + 5, feature, tile); break;
    case 6: if (!IsWateredTile(TileAddXY(tile, 1, 1), DIR_N)) DrawWaterSprite(base, offset + 9, feature, tile); break;
  }
 
  /* left corner */
  switch (wa & 0x0C) {
    case  0: DrawWaterSprite(base, offset + 6, feature, tile); break;
    case 12: if (!IsWateredTile(TileAddXY(tile, 1, -1), DIR_E)) DrawWaterSprite(base, offset + 10, feature, tile); break;
  }
 
  /* upper corner */
  switch (wa & 0x09) {
    case 0: DrawWaterSprite(base, offset + 7, feature, tile); break;
    case 9: if (!IsWateredTile(TileAddXY(tile, -1, -1), DIR_S)) DrawWaterSprite(base, offset + 11, feature, tile); break;
  }
}

static void DrawSeaWater(TileIndex)
{
  DrawGroundSprite(SPR_FLAT_WATER_TILE, PAL_NONE);
}

static void DrawCanalWater(TileIndex tile)
{
  SpriteID image = SPR_FLAT_WATER_TILE;
  if (HasBit(_water_feature[CF_WATERSLOPE].flags, CFF_HAS_FLAT_SPRITE)) {
    /* First water slope sprite is flat water. */
    image = GetCanalSprite(CF_WATERSLOPE, tile);
    if (image == 0) image = SPR_FLAT_WATER_TILE;
  }
  DrawWaterSprite(image, 0, CF_WATERSLOPE, tile);
 
  DrawWaterEdges(true, 0, tile);
}
 
#include "table/water_land.h"

static void DrawWaterTileStruct(const TileInfo *ti, std::span<const DrawTileSeqStruct> seq, SpriteID base, uint offset, PaletteID palette, CanalFeature feature)
{
  /* Don't draw if buildings are invisible. */
  if (IsInvisibilitySet(TO_BUILDINGS)) return;
 
  for (const DrawTileSeqStruct &dtss : seq) {
    uint tile_offs = offset + dtss.image.sprite;
    if (feature < CF_END) tile_offs = GetCanalSpriteOffset(feature, ti->tile, tile_offs);
    AddSortableSpriteToDraw(base + tile_offs, palette, *ti, dtss, IsTransparencySet(TO_BUILDINGS));
  }
}

static void DrawWaterLock(const TileInfo *ti)
{
  LockPart part = GetLockPart(ti->tile);
  const DrawTileSprites &dts = _lock_display_data[to_underlying(part)][GetLockDirection(ti->tile)];
 
  /* Draw ground sprite. */
  SpriteID image = dts.ground.sprite;
 
  SpriteID water_base = GetCanalSprite(CF_WATERSLOPE, ti->tile);
  if (water_base == 0) {
    /* Use default sprites. */
    water_base = SPR_CANALS_BASE;
  } else if (HasBit(_water_feature[CF_WATERSLOPE].flags, CFF_HAS_FLAT_SPRITE)) {
    /* NewGRF supplies a flat sprite as first sprite. */
    if (image == SPR_FLAT_WATER_TILE) {
      image = water_base;
    } else {
      image++;
    }
  }
 
  if (image < 5) image += water_base;
  DrawGroundSprite(image, PAL_NONE);
 
  /* Draw structures. */
  uint     zoffs = 0;
  SpriteID base  = GetCanalSprite(CF_LOCKS, ti->tile);
 
  if (base == 0) {
    /* If no custom graphics, use defaults. */
    base = SPR_LOCK_BASE;
    uint8_t z_threshold = part == LockPart::Upper ? 8 : 0;
    zoffs = ti->z > z_threshold ? 24 : 0;
  }
 
  DrawWaterTileStruct(ti, dts.GetSequence(), base, zoffs, PAL_NONE, CF_LOCKS);
}

static void DrawWaterDepot(const TileInfo *ti)
{
  DrawWaterClassGround(ti);
  DrawWaterTileStruct(ti, _shipdepot_display_data[GetShipDepotAxis(ti->tile)][to_underlying(GetShipDepotPart(ti->tile))].seq, 0, 0, GetCompanyPalette(GetTileOwner(ti->tile)), CF_END);
}
 
static void DrawRiverWater(const TileInfo *ti)
{
  SpriteID image = SPR_FLAT_WATER_TILE;
  uint     offset = 0;
  uint     edges_offset = 0;
 
  if (ti->tileh != SLOPE_FLAT || HasBit(_water_feature[CF_RIVER_SLOPE].flags, CFF_HAS_FLAT_SPRITE)) {
    image = GetCanalSprite(CF_RIVER_SLOPE, ti->tile);
    if (image == 0) {
      switch (ti->tileh) {
        case SLOPE_NW: image = SPR_WATER_SLOPE_Y_DOWN; break;
        case SLOPE_SW: image = SPR_WATER_SLOPE_X_UP;   break;
        case SLOPE_SE: image = SPR_WATER_SLOPE_Y_UP;   break;
        case SLOPE_NE: image = SPR_WATER_SLOPE_X_DOWN; break;
        default:       image = SPR_FLAT_WATER_TILE;    break;
      }
    } else {
      /* Flag bit 0 indicates that the first sprite is flat water. */
      offset = HasBit(_water_feature[CF_RIVER_SLOPE].flags, CFF_HAS_FLAT_SPRITE) ? 1 : 0;
 
      switch (ti->tileh) {
        case SLOPE_SE:              edges_offset += 12; break;
        case SLOPE_NE: offset += 1; edges_offset += 24; break;
        case SLOPE_SW: offset += 2; edges_offset += 36; break;
        case SLOPE_NW: offset += 3; edges_offset += 48; break;
        default:       offset  = 0; break;
      }
 
      offset = GetCanalSpriteOffset(CF_RIVER_SLOPE, ti->tile, offset);
    }
  }
 
  DrawGroundSprite(image + offset, PAL_NONE);
 
  /* Draw river edges if available. */
  DrawWaterEdges(false, edges_offset, ti->tile);
}
 
void DrawShoreTile(Slope tileh)
{
  /* Converts the enum Slope into an offset based on SPR_SHORE_BASE.
   * This allows to calculate the proper sprite to display for this Slope */
  static const uint8_t tileh_to_shoresprite[32] = {
    0, 1, 2, 3, 4, 16, 6, 7, 8, 9, 17, 11, 12, 13, 14, 0,
    0, 0, 0, 0, 0,  0, 0, 0, 0, 0,  0,  5,  0, 10, 15, 0,
  };
 
  assert(!IsHalftileSlope(tileh)); // Halftile slopes need to get handled earlier.
  assert(tileh != SLOPE_FLAT);     // Shore is never flat
 
  assert((tileh != SLOPE_EW) && (tileh != SLOPE_NS)); // No suitable sprites for current flooding behaviour
 
  DrawGroundSprite(SPR_SHORE_BASE + tileh_to_shoresprite[tileh], PAL_NONE);
}
 
void DrawWaterClassGround(const TileInfo *ti)
{
  switch (GetWaterClass(ti->tile)) {
    case WaterClass::Sea:   DrawSeaWater(ti->tile); break;
    case WaterClass::Canal: DrawCanalWater(ti->tile); break;
    case WaterClass::River: DrawRiverWater(ti); break;
    default: NOT_REACHED();
  }
}
 
static void DrawTile_Water(TileInfo *ti)
{
  switch (GetWaterTileType(ti->tile)) {
    case WaterTileType::Clear:
      DrawWaterClassGround(ti);
      /* A plain water tile can be traversed in any direction, so setting blocked pillars here would mean all bridges
       * with edges would have no pillars above water. Instead prefer current behaviour of ships passing through. */
      DrawBridgeMiddle(ti, {});
      break;
 
    case WaterTileType::Coast: {
      DrawShoreTile(ti->tileh);
      DrawBridgeMiddle(ti, {});
      break;
    }
 
    case WaterTileType::Lock:
      DrawWaterLock(ti);
      DrawBridgeMiddle(ti, DiagDirToAxis(GetLockDirection(ti->tile)) == AXIS_X
        ? BridgePillarFlags{BridgePillarFlag::EdgeNE, BridgePillarFlag::EdgeSW}
        : BridgePillarFlags{BridgePillarFlag::EdgeNW, BridgePillarFlag::EdgeSE});
      break;
 
    case WaterTileType::Depot:
      DrawWaterDepot(ti);
      break;
  }
}
 
void DrawShipDepotSprite(int x, int y, Axis axis, DepotPart part)
{
  const DrawTileSprites &dts = _shipdepot_display_data[axis][to_underlying(part)];
 
  DrawSprite(dts.ground.sprite, dts.ground.pal, x, y);
  DrawOrigTileSeqInGUI(x, y, &dts, GetCompanyPalette(_local_company));
}
 
 
static int GetSlopePixelZ_Water(TileIndex tile, uint x, uint y, bool)
{
  auto [tileh, z] = GetTilePixelSlope(tile);
 
  return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
}
 
static Foundation GetFoundation_Water(TileIndex, Slope)
{
  return FOUNDATION_NONE;
}
 
static void GetTileDesc_Water(TileIndex tile, TileDesc &td)
{
  switch (GetWaterTileType(tile)) {
    case WaterTileType::Clear:
      switch (GetWaterClass(tile)) {
        case WaterClass::Sea:   td.str = STR_LAI_WATER_DESCRIPTION_WATER; break;
        case WaterClass::Canal: td.str = STR_LAI_WATER_DESCRIPTION_CANAL; break;
        case WaterClass::River: td.str = STR_LAI_WATER_DESCRIPTION_RIVER; break;
        default: NOT_REACHED();
      }
      break;
    case WaterTileType::Coast: td.str = STR_LAI_WATER_DESCRIPTION_COAST_OR_RIVERBANK; break;
    case WaterTileType::Lock : td.str = STR_LAI_WATER_DESCRIPTION_LOCK;               break;
    case WaterTileType::Depot:
      td.str = STR_LAI_WATER_DESCRIPTION_SHIP_DEPOT;
      td.build_date = Depot::GetByTile(tile)->build_date;
      break;
    default: NOT_REACHED();
  }
 
  td.owner[0] = GetTileOwner(tile);
}

static void FloodVehicle(Vehicle *v)
{
  uint victims = v->Crash(true);
 
  AI::NewEvent(v->owner, new ScriptEventVehicleCrashed(v->index, v->tile, ScriptEventVehicleCrashed::CRASH_FLOODED, victims, v->owner));
  Game::NewEvent(new ScriptEventVehicleCrashed(v->index, v->tile, ScriptEventVehicleCrashed::CRASH_FLOODED, victims, v->owner));
  AddTileNewsItem(GetEncodedString(STR_NEWS_DISASTER_FLOOD_VEHICLE, victims), NewsType::Accident, v->tile);
  CreateEffectVehicleRel(v, 4, 4, 8, EV_EXPLOSION_LARGE);
  if (_settings_client.sound.disaster) SndPlayVehicleFx(SND_12_EXPLOSION, v);
}

static void FloodVehicleProc(Vehicle *v, int z)
{
  if (v->vehstatus.Test(VehState::Crashed)) return;
 
  switch (v->type) {
    default: break;
 
    case VEH_AIRCRAFT: {
      if (!IsAirportTile(v->tile) || GetTileMaxZ(v->tile) != 0) break;
      if (v->subtype == AIR_SHADOW) break;
 
      /* We compare v->z_pos against delta_z + 1 because the shadow
       * is at delta_z and the actual aircraft at delta_z + 1. */
      const Station *st = Station::GetByTile(v->tile);
      const AirportFTAClass *airport = st->airport.GetFTA();
      if (v->z_pos != airport->delta_z + 1) break;
 
      FloodVehicle(v);
      break;
    }
 
    case VEH_TRAIN:
    case VEH_ROAD: {
      if (v->z_pos > z) break;
      FloodVehicle(v->First());
      break;
    }
  }
}
 
static void FloodVehiclesOnTile(TileIndex tile, int z)
{
  for (Vehicle *v : VehiclesOnTile(tile)) {
    FloodVehicleProc(v, z);
  }
}

static void FloodVehicles(TileIndex tile)
{
  if (IsAirportTile(tile)) {
    const Station *st = Station::GetByTile(tile);
    for (TileIndex airport_tile : st->airport) {
      if (st->TileBelongsToAirport(airport_tile)) FloodVehiclesOnTile(airport_tile, 0);
    }
 
    /* No vehicle could be flooded on this airport anymore */
    return;
  }
 
  if (!IsBridgeTile(tile)) {
    FloodVehiclesOnTile(tile, 0);
    return;
  }
 
  TileIndex end = GetOtherBridgeEnd(tile);
  int z = GetBridgePixelHeight(tile);
 
  FloodVehiclesOnTile(tile, z);
  FloodVehiclesOnTile(end, z);
}

FloodingBehaviour GetFloodingBehaviour(TileIndex tile)
{
  /* FLOOD_ACTIVE:  'single-corner-raised'-coast, sea, sea-shipdepots, sea-buoys, sea-docks (water part), rail with flooded halftile, sea-water-industries, sea-oilrigs
   * FLOOD_DRYUP:   coast with more than one corner raised, coast with rail-track, coast with trees
   * FLOOD_PASSIVE: (not used)
   * FLOOD_NONE:    canals, rivers, everything else
   */
  switch (GetTileType(tile)) {
    case TileType::Water:
      if (IsCoast(tile)) {
        Slope tileh = GetTileSlope(tile);
        return (IsSlopeWithOneCornerRaised(tileh) ? FLOOD_ACTIVE : FLOOD_DRYUP);
      }
      [[fallthrough]];
    case TileType::Station:
    case TileType::Industry:
    case TileType::Object:
      return (GetWaterClass(tile) == WaterClass::Sea) ? FLOOD_ACTIVE : FLOOD_NONE;
 
    case TileType::Railway:
      if (GetRailGroundType(tile) == RailGroundType::HalfTileWater) {
        return (IsSlopeWithOneCornerRaised(GetTileSlope(tile)) ? FLOOD_ACTIVE : FLOOD_DRYUP);
      }
      return FLOOD_NONE;
 
    case TileType::Trees:
      return (GetTreeGround(tile) == TreeGround::Shore ? FLOOD_DRYUP : FLOOD_NONE);
 
    case TileType::Void:
      return FLOOD_ACTIVE;
 
    default:
      return FLOOD_NONE;
  }
}

static void DoFloodTile(TileIndex target)
{
  assert(!IsTileType(target, TileType::Water));
 
  bool flooded = false; // Will be set to true if something is changed.
 
  Backup<CompanyID> cur_company(_current_company, OWNER_WATER);
 
  Slope tileh = GetTileSlope(target);
  if (tileh != SLOPE_FLAT) {
    /* make coast.. */
    switch (GetTileType(target)) {
      case TileType::Railway: {
        if (!IsPlainRail(target)) break;
        FloodVehicles(target);
        flooded = FloodHalftile(target);
        break;
      }
 
      case TileType::Trees:
        if (!IsSlopeWithOneCornerRaised(tileh)) {
          SetTreeGroundDensity(target, TreeGround::Shore, 3);
          MarkTileDirtyByTile(target);
          flooded = true;
          break;
        }
        [[fallthrough]];
 
      case TileType::Clear:
        if (Command<Commands::LandscapeClear>::Do(DoCommandFlag::Execute, target).Succeeded()) {
          MakeShore(target);
          MarkTileDirtyByTile(target);
          flooded = true;
        }
        break;
 
      default:
        break;
    }
  } else {
    /* Flood vehicles */
    FloodVehicles(target);
 
    /* flood flat tile */
    if (Command<Commands::LandscapeClear>::Do(DoCommandFlag::Execute, target).Succeeded()) {
      MakeSea(target);
      MarkTileDirtyByTile(target);
      flooded = true;
    }
  }
 
  if (flooded) {
    /* Mark surrounding canal tiles dirty too to avoid glitches */
    MarkCanalsAndRiversAroundDirty(target);
 
    /* update signals if needed */
    UpdateSignalsInBuffer();
 
    if (IsPossibleDockingTile(target)) CheckForDockingTile(target);
    InvalidateWaterRegion(target);
  }
 
  cur_company.Restore();
}

static void DoDryUp(TileIndex tile)
{
  Backup<CompanyID> cur_company(_current_company, OWNER_WATER);
 
  switch (GetTileType(tile)) {
    case TileType::Railway:
      assert(IsPlainRail(tile));
      assert(GetRailGroundType(tile) == RailGroundType::HalfTileWater);
 
      RailGroundType new_ground;
      switch (GetTrackBits(tile)) {
        case TRACK_BIT_UPPER: new_ground = RailGroundType::FenceHoriz1; break;
        case TRACK_BIT_LOWER: new_ground = RailGroundType::FenceHoriz2; break;
        case TRACK_BIT_LEFT:  new_ground = RailGroundType::FenceVert1;  break;
        case TRACK_BIT_RIGHT: new_ground = RailGroundType::FenceVert2;  break;
        default: NOT_REACHED();
      }
      SetRailGroundType(tile, new_ground);
      MarkTileDirtyByTile(tile);
      break;
 
    case TileType::Trees:
      SetTreeGroundDensity(tile, TreeGround::Grass, 3);
      MarkTileDirtyByTile(tile);
      break;
 
    case TileType::Water:
      assert(IsCoast(tile));
 
      if (Command<Commands::LandscapeClear>::Do(DoCommandFlag::Execute, tile).Succeeded()) {
        MakeClear(tile, ClearGround::Grass, 3);
        MarkTileDirtyByTile(tile);
      }
      break;
 
    default: NOT_REACHED();
  }
 
  cur_company.Restore();
}

void TileLoop_Water(TileIndex tile)
{
  if (IsTileType(tile, TileType::Water)) {
    AmbientSoundEffect(tile);
    if (IsNonFloodingWaterTile(tile)) return;
  }
 
  switch (GetFloodingBehaviour(tile)) {
    case FLOOD_ACTIVE: {
      bool continue_flooding = false;
      for (Direction dir = DIR_BEGIN; dir < DIR_END; dir++) {
        TileIndex dest = AddTileIndexDiffCWrap(tile, TileIndexDiffCByDir(dir));
        /* Contrary to drying up, flooding does not consider TileType::Void tiles. */
        if (!IsValidTile(dest)) continue;
        /* do not try to flood water tiles - increases performance a lot */
        if (IsTileType(dest, TileType::Water)) continue;
 
        /* Buoys and docks cannot be flooded, and when removed turn into flooding water. */
        if (IsTileType(dest, TileType::Station) && (IsBuoy(dest) || IsDock(dest))) continue;
 
        /* This neighbour tile might be floodable later if the tile is cleared, so allow flooding to continue. */
        continue_flooding = true;
 
        /* TreeGround::Shore is the sign of a previous flood. */
        if (IsTileType(dest, TileType::Trees) && GetTreeGround(dest) == TreeGround::Shore) continue;
 
        auto [slope_dest, z_dest] = GetFoundationSlope(dest);
        if (z_dest > 0) continue;
 
        if (!_flood_from_dirs[slope_dest & ~SLOPE_HALFTILE_MASK & ~SLOPE_STEEP].Test(ReverseDir(dir))) continue;
 
        DoFloodTile(dest);
      }
      if (!continue_flooding && IsTileType(tile, TileType::Water)) SetNonFloodingWaterTile(tile, true);
      break;
    }
 
    case FLOOD_DRYUP: {
      Slope slope_here = std::get<0>(GetFoundationSlope(tile)) & ~SLOPE_HALFTILE_MASK & ~SLOPE_STEEP;
      for (Direction dir : _flood_from_dirs[slope_here]) {
        TileIndex dest = AddTileIndexDiffCWrap(tile, TileIndexDiffCByDir(dir));
        /* Contrary to flooding, drying up does consider TileType::Void tiles. */
        if (dest == INVALID_TILE) continue;
 
        FloodingBehaviour dest_behaviour = GetFloodingBehaviour(dest);
        if ((dest_behaviour == FLOOD_ACTIVE) || (dest_behaviour == FLOOD_PASSIVE)) return;
      }
      DoDryUp(tile);
      break;
    }
 
    default: return;
  }
}
 
void ConvertGroundTilesIntoWaterTiles()
{
  for (const auto tile : Map::Iterate()) {
    auto [slope, z] = GetTileSlopeZ(tile);
    if (IsTileType(tile, TileType::Clear) && z == 0) {
      /* Make both water for tiles at level 0
       * and make shore, as that looks much better
       * during the generation. */
      switch (slope) {
        case SLOPE_FLAT:
          MakeSea(tile);
          break;
 
        case SLOPE_N:
        case SLOPE_E:
        case SLOPE_S:
        case SLOPE_W:
          MakeShore(tile);
          break;
 
        default:
          for (Direction dir : _flood_from_dirs[slope & ~SLOPE_STEEP]) {
            TileIndex dest = TileAddByDir(tile, dir);
            Slope slope_dest = GetTileSlope(dest) & ~SLOPE_STEEP;
            if (slope_dest == SLOPE_FLAT || IsSlopeWithOneCornerRaised(slope_dest) || IsTileType(dest, TileType::Void)) {
              MakeShore(tile);
              break;
            }
          }
          break;
      }
    }
  }
}
 
static TrackStatus GetTileTrackStatus_Water(TileIndex tile, TransportType mode, uint, DiagDirection)
{
  static const TrackBits coast_tracks[] = {TRACK_BIT_NONE, TRACK_BIT_RIGHT, TRACK_BIT_UPPER, TRACK_BIT_NONE, TRACK_BIT_LEFT, TRACK_BIT_NONE, TRACK_BIT_NONE,
    TRACK_BIT_NONE, TRACK_BIT_LOWER, TRACK_BIT_NONE, TRACK_BIT_NONE, TRACK_BIT_NONE, TRACK_BIT_NONE, TRACK_BIT_NONE, TRACK_BIT_NONE, TRACK_BIT_NONE};
 
  TrackBits ts;
 
  if (mode != TRANSPORT_WATER) return 0;
 
  switch (GetWaterTileType(tile)) {
    case WaterTileType::Clear: ts = IsTileFlat(tile) ? TRACK_BIT_ALL : TRACK_BIT_NONE; break;
    case WaterTileType::Coast: ts = coast_tracks[GetTileSlope(tile) & 0xF]; break;
    case WaterTileType::Lock:  ts = DiagDirToDiagTrackBits(GetLockDirection(tile)); break;
    case WaterTileType::Depot: ts = AxisToTrackBits(GetShipDepotAxis(tile)); break;
    default: return 0;
  }
  if (TileX(tile) == 0) {
    /* NE border: remove tracks that connects NE tile edge */
    ts &= ~(TRACK_BIT_X | TRACK_BIT_UPPER | TRACK_BIT_RIGHT);
  }
  if (TileY(tile) == 0) {
    /* NW border: remove tracks that connects NW tile edge */
    ts &= ~(TRACK_BIT_Y | TRACK_BIT_LEFT | TRACK_BIT_UPPER);
  }
  return CombineTrackStatus(TrackBitsToTrackdirBits(ts), TRACKDIR_BIT_NONE);
}
 
static bool ClickTile_Water(TileIndex tile)
{
  if (GetWaterTileType(tile) == WaterTileType::Depot) {
    ShowDepotWindow(GetShipDepotNorthTile(tile), VEH_SHIP);
    return true;
  }
  return false;
}
 
static void ChangeTileOwner_Water(TileIndex tile, Owner old_owner, Owner new_owner)
{
  if (!IsTileOwner(tile, old_owner)) return;
 
  bool is_lock_middle = IsLock(tile) && GetLockPart(tile) == LockPart::Middle;
 
  /* No need to dirty company windows here, we'll redraw the whole screen anyway. */
  if (is_lock_middle) Company::Get(old_owner)->infrastructure.water -= 3 * LOCK_DEPOT_TILE_FACTOR; // Lock has three parts.
  if (new_owner != INVALID_OWNER) {
    if (is_lock_middle) Company::Get(new_owner)->infrastructure.water += 3 * LOCK_DEPOT_TILE_FACTOR; // Lock has three parts.
    /* Only subtract from the old owner here if the new owner is valid,
     * otherwise we clear ship depots and canal water below. */
    if (GetWaterClass(tile) == WaterClass::Canal && !is_lock_middle) {
      Company::Get(old_owner)->infrastructure.water--;
      Company::Get(new_owner)->infrastructure.water++;
    }
    if (IsShipDepot(tile)) {
      Company::Get(old_owner)->infrastructure.water -= LOCK_DEPOT_TILE_FACTOR;
      Company::Get(new_owner)->infrastructure.water += LOCK_DEPOT_TILE_FACTOR;
    }
 
    SetTileOwner(tile, new_owner);
    return;
  }
 
  /* Remove depot */
  if (IsShipDepot(tile)) Command<Commands::LandscapeClear>::Do({DoCommandFlag::Execute, DoCommandFlag::Bankrupt}, tile);
 
  /* Set owner of canals and locks ... and also canal under dock there was before.
   * Check if the new owner after removing depot isn't OWNER_WATER. */
  if (IsTileOwner(tile, old_owner)) {
    if (GetWaterClass(tile) == WaterClass::Canal && !is_lock_middle) Company::Get(old_owner)->infrastructure.water--;
    SetTileOwner(tile, OWNER_NONE);
  }
}
 
static VehicleEnterTileStates VehicleEnter_Water(Vehicle *, TileIndex, int, int)
{
  return {};
}
 
static CommandCost TerraformTile_Water(TileIndex tile, DoCommandFlags flags, int, Slope)
{
  /* Canals can't be terraformed */
  if (IsWaterTile(tile) && IsCanal(tile)) return CommandCost(STR_ERROR_MUST_DEMOLISH_CANAL_FIRST);
 
  /* Rivers can't be terraformed */
  if (IsWaterTile(tile) && IsRiver(tile)) return CommandCost(STR_ERROR_MUST_DEMOLISH_RIVER_FIRST);
 
  return Command<Commands::LandscapeClear>::Do(flags, tile);
}
 
static CommandCost CheckBuildAbove_Water(TileIndex tile, DoCommandFlags flags, Axis, int height)
{
  if (IsWater(tile) || IsCoast(tile)) return CommandCost();
  if (IsLock(tile)) {
    if (GetTileMaxZ(tile) + GetLockPartMinimalBridgeHeight(GetLockPart(tile)) <= height) return CommandCost();
    int height_diff = (GetTileMaxZ(tile) + GetLockPartMinimalBridgeHeight(GetLockPart(tile)) - height) * TILE_HEIGHT_STEP;
    return CommandCostWithParam(STR_ERROR_BRIDGE_TOO_LOW_FOR_LOCK, height_diff);
  }
  return Command<Commands::LandscapeClear>::Do(flags, tile);
}
 
extern const TileTypeProcs _tile_type_water_procs = {
  DrawTile_Water,           // draw_tile_proc
  GetSlopePixelZ_Water,     // get_slope_z_proc
  ClearTile_Water,          // clear_tile_proc
  nullptr,                     // add_accepted_cargo_proc
  GetTileDesc_Water,        // get_tile_desc_proc
  GetTileTrackStatus_Water, // get_tile_track_status_proc
  ClickTile_Water,          // click_tile_proc
  nullptr,                     // animate_tile_proc
  TileLoop_Water,           // tile_loop_proc
  ChangeTileOwner_Water,    // change_tile_owner_proc
  nullptr,                     // add_produced_cargo_proc
  VehicleEnter_Water,       // vehicle_enter_tile_proc
  GetFoundation_Water,      // get_foundation_proc
  TerraformTile_Water,      // terraform_tile_proc
  CheckBuildAbove_Water, // check_build_above_proc
};