Silence uninitialised variable warnings in SSE blitters

[openttd/fttd.git] / src / disaster_cmd.cpp

/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * @file disaster_cmd.cpp
 * All disaster/easter egg vehicles are handled here.
 * The general flow of control for the disaster vehicles is as follows:
 * <ol>
 * <li>Initialize the disaster in a disaster specific way (eg start position,
 *     possible target, etc.) Disaster_XXX_Init() function
 * <li>Add a subtype to a disaster, which is an index into the function array
 *     that handles the vehicle's ticks.
 * <li>Run the disaster vehicles each tick until their target has been reached,
 *     this happens in the DisasterTick_XXX() functions. In here, a vehicle's
 *     state is kept by v->current_order.dest variable. Each achieved sub-target
 *     will increase this value, and the last one will remove the disaster itself
 * </ol>
 */


#include "stdafx.h"

#include "industry.h"
#include "station_base.h"
#include "command_func.h"
#include "news_func.h"
#include "town.h"
#include "company_func.h"
#include "strings_func.h"
#include "date_func.h"
#include "viewport_func.h"
#include "vehicle_func.h"
#include "signal_func.h"
#include "sound_func.h"
#include "effectvehicle_func.h"
#include "roadveh.h"
#include "ai/ai.hpp"
#include "game/game.hpp"
#include "company_base.h"
#include "core/random_func.hpp"
#include "core/backup_type.hpp"
#include "map/water.h"

#include "table/strings.h"

/** Delay counter for considering the next disaster. */
uint16 _disaster_delay;

enum DisasterSubType {
        ST_ZEPPELINER,
        ST_ZEPPELINER_SHADOW,
        ST_SMALL_UFO,
        ST_SMALL_UFO_SHADOW,
        ST_AIRPLANE,
        ST_AIRPLANE_SHADOW,
        ST_HELICOPTER,
        ST_HELICOPTER_SHADOW,
        ST_HELICOPTER_ROTORS,
        ST_BIG_UFO,
        ST_BIG_UFO_SHADOW,
        ST_BIG_UFO_DESTROYER,
        ST_BIG_UFO_DESTROYER_SHADOW,
        ST_SMALL_SUBMARINE,
        ST_BIG_SUBMARINE,
};

static const uint INITIAL_DISASTER_VEHICLE_ZPOS = 135; ///< Initial Z position of flying disaster vehicles.

static void DisasterClearSquare(TileIndex tile)
{
        if (EnsureNoVehicleOnGround(tile).Failed()) return;

        if (IsHouseTile(tile)) {
                Backup<CompanyByte> cur_company(_current_company, OWNER_NONE, FILE_LINE);
                DoCommand(tile, 0, 0, DC_EXEC, CMD_LANDSCAPE_CLEAR);
                cur_company.Restore();
        } else switch (GetTileType(tile)) {
                case TT_RAILWAY:
                        if (Company::IsHumanID(GetTileOwner(tile))) {
                                Backup<CompanyByte> cur_company(_current_company, OWNER_WATER, FILE_LINE);
                                DoCommand(tile, 0, 0, DC_EXEC, CMD_LANDSCAPE_CLEAR);
                                cur_company.Restore();

                                /* update signals in buffer */
                                UpdateSignalsInBuffer();
                        }
                        break;

                case TT_GROUND:
                        DoClearSquare(tile);
                        break;

                default:
                        break;
        }
}

static const SpriteID _disaster_images_1[] = {SPR_BLIMP, SPR_BLIMP, SPR_BLIMP, SPR_BLIMP, SPR_BLIMP, SPR_BLIMP, SPR_BLIMP, SPR_BLIMP};
static const SpriteID _disaster_images_2[] = {SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT, SPR_UFO_SMALL_SCOUT};
static const SpriteID _disaster_images_3[] = {SPR_F_15, SPR_F_15, SPR_F_15, SPR_F_15, SPR_F_15, SPR_F_15, SPR_F_15, SPR_F_15};
static const SpriteID _disaster_images_4[] = {SPR_SUB_SMALL_NE, SPR_SUB_SMALL_NE, SPR_SUB_SMALL_SE, SPR_SUB_SMALL_SE, SPR_SUB_SMALL_SW, SPR_SUB_SMALL_SW, SPR_SUB_SMALL_NW, SPR_SUB_SMALL_NW};
static const SpriteID _disaster_images_5[] = {SPR_SUB_LARGE_NE, SPR_SUB_LARGE_NE, SPR_SUB_LARGE_SE, SPR_SUB_LARGE_SE, SPR_SUB_LARGE_SW, SPR_SUB_LARGE_SW, SPR_SUB_LARGE_NW, SPR_SUB_LARGE_NW};
static const SpriteID _disaster_images_6[] = {SPR_UFO_HARVESTER, SPR_UFO_HARVESTER, SPR_UFO_HARVESTER, SPR_UFO_HARVESTER, SPR_UFO_HARVESTER, SPR_UFO_HARVESTER, SPR_UFO_HARVESTER, SPR_UFO_HARVESTER};
static const SpriteID _disaster_images_7[] = {SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER, SPR_XCOM_SKYRANGER};
static const SpriteID _disaster_images_8[] = {SPR_AH_64A, SPR_AH_64A, SPR_AH_64A, SPR_AH_64A, SPR_AH_64A, SPR_AH_64A, SPR_AH_64A, SPR_AH_64A};
static const SpriteID _disaster_images_9[] = {SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1, SPR_ROTOR_MOVING_1};

static const SpriteID * const _disaster_images[] = {
        _disaster_images_1, _disaster_images_1,                     ///< zeppeliner and zeppeliner shadow
        _disaster_images_2, _disaster_images_2,                     ///< small ufo and small ufo shadow
        _disaster_images_3, _disaster_images_3,                     ///< combat aircraft and shadow
        _disaster_images_8, _disaster_images_8, _disaster_images_9, ///< combat helicopter, shadow and rotor
        _disaster_images_6, _disaster_images_6,                     ///< big ufo and shadow
        _disaster_images_7, _disaster_images_7,                     ///< skyranger and shadow
        _disaster_images_4, _disaster_images_5,                     ///< small and big submarine sprites
};

static void DisasterVehicleUpdateImage(DisasterVehicle *v)
{
        SpriteID img = v->image_override;
        if (img == 0) img = _disaster_images[v->subtype][v->direction];
        v->cur_image = img;
}

/**
 * Initialize a disaster vehicle. These vehicles are of type VEH_DISASTER, are unclickable
 * and owned by nobody
 */
static void InitializeDisasterVehicle(DisasterVehicle *v, int x, int y, int z, Direction direction, byte subtype)
{
        v->x_pos = x;
        v->y_pos = y;
        v->z_pos = z;
        v->tile = TileVirtXY(x, y);
        v->direction = direction;
        v->subtype = subtype;
        v->UpdateDeltaXY(INVALID_DIR);
        v->owner = OWNER_NONE;
        v->vehstatus = VS_UNCLICKABLE;
        v->image_override = 0;
        v->current_order.Free();

        DisasterVehicleUpdateImage(v);
        VehicleUpdatePositionAndViewport(v);
}

static void SetDisasterVehiclePos(DisasterVehicle *v, int x, int y, int z)
{
        v->x_pos = x;
        v->y_pos = y;
        v->z_pos = z;
        v->tile = TileVirtXY(x, y);

        DisasterVehicleUpdateImage(v);
        VehicleUpdatePositionAndViewport(v);

        DisasterVehicle *u = v->Next();
        if (u != NULL) {
                int safe_x = Clamp(x, 0, MapMaxX() * TILE_SIZE);
                int safe_y = Clamp(y - 1, 0, MapMaxY() * TILE_SIZE);

                u->x_pos = x;
                u->y_pos = y - 1 - (max(z - GetSlopePixelZ(safe_x, safe_y), 0) >> 3);
                safe_y = Clamp(u->y_pos, 0, MapMaxY() * TILE_SIZE);
                u->z_pos = GetSlopePixelZ(safe_x, safe_y);
                u->direction = v->direction;

                DisasterVehicleUpdateImage(u);
                VehicleUpdatePositionAndViewport(u);

                if ((u = u->Next()) != NULL) {
                        u->x_pos = x;
                        u->y_pos = y;
                        u->z_pos = z + 5;
                        VehicleUpdatePositionAndViewport(u);
                }
        }
}

static void SetDisasterVehiclePosAutoZ(DisasterVehicle *v, int z)
{
        VehiclePos gp = GetNewVehiclePos(v);

        SetDisasterVehiclePos(v, gp.x, gp.y, z);
}

static void SetDisasterVehiclePosAuto(DisasterVehicle *v)
{
        SetDisasterVehiclePosAutoZ(v, v->z_pos);
}

/**
 * Zeppeliner handling, v->current_order.dest states:
 * 0: Zeppeliner initialization has found a small airport, go there and crash
 * 1: Create crash and animate falling down for extra dramatic effect
 * 2: Create more smoke and leave debris on ground
 * 2: Clear the runway after some time and remove crashed zeppeliner
 * If not airport was found, only state 0 is reached until zeppeliner leaves map
 */
static bool DisasterTick_Zeppeliner(DisasterVehicle *v)
{
        v->tick_counter++;

        if (v->current_order.GetDestination() < 2) {
                if (HasBit(v->tick_counter, 0)) return true;

                SetDisasterVehiclePosAuto(v);

                if (v->current_order.GetDestination() == 1) {
                        if (++v->age == 38) {
                                v->current_order.SetDestination(2);
                                v->age = 0;
                        }

                        if (GB(v->tick_counter, 0, 3) == 0) CreateEffectVehicleRel(v, 0, -17, 2, EV_CRASH_SMOKE);

                } else if (v->current_order.GetDestination() == 0) {
                        if (IsValidTile(v->tile) && IsAirportTile(v->tile)) {
                                v->current_order.SetDestination(1);
                                v->age = 0;

                                SetDParam(0, GetStationIndex(v->tile));
                                AddVehicleNewsItem(STR_NEWS_DISASTER_ZEPPELIN, NT_ACCIDENT, v->index); // Delete the news, when the zeppelin is gone
                                AI::NewEvent(GetTileOwner(v->tile), new ScriptEventDisasterZeppelinerCrashed(GetStationIndex(v->tile)));
                        }
                }

                if (v->y_pos >= (int)((MapSizeY() + 9) * TILE_SIZE - 1)) {
                        delete v;
                        return false;
                }

                return true;
        }

        if (v->current_order.GetDestination() > 2) {
                if (++v->age <= 13320) return true;

                if (IsValidTile(v->tile) && IsAirportTile(v->tile)) {
                        Station *st = Station::GetByTile(v->tile);
                        CLRBITS(st->airport.flags, RUNWAY_IN_block);
                        AI::NewEvent(GetTileOwner(v->tile), new ScriptEventDisasterZeppelinerCleared(st->index));
                }

                SetDisasterVehiclePos(v, v->x_pos, v->y_pos, v->z_pos);
                delete v;
                return false;
        }

        int x = v->x_pos;
        int y = v->y_pos;
        int z = GetSlopePixelZ(x, y);
        if (z < v->z_pos) z = v->z_pos - 1;
        SetDisasterVehiclePos(v, x, y, z);

        if (++v->age == 1) {
                CreateEffectVehicleRel(v, 0, 7, 8, EV_EXPLOSION_LARGE);
                if (_settings_client.sound.disaster) SndPlayVehicleFx(SND_12_EXPLOSION, v);
                v->image_override = SPR_BLIMP_CRASHING;
        } else if (v->age == 70) {
                v->image_override = SPR_BLIMP_CRASHED;
        } else if (v->age <= 300) {
                if (GB(v->tick_counter, 0, 3) == 0) {
                        uint32 r = Random();

                        CreateEffectVehicleRel(v,
                                GB(r, 0, 4) - 7,
                                GB(r, 4, 4) - 7,
                                GB(r, 8, 3) + 5,
                                EV_EXPLOSION_SMALL);
                }
        } else if (v->age == 350) {
                v->current_order.SetDestination(3);
                v->age = 0;
        }

        if (IsValidTile(v->tile) && IsAirportTile(v->tile)) {
                SETBITS(Station::GetByTile(v->tile)->airport.flags, RUNWAY_IN_block);
        }

        return true;
}

/**
 * (Small) Ufo handling, v->current_order.dest states:
 * 0: Fly around to the middle of the map, then randomly, after a while target a road vehicle
 * 1: Home in on a road vehicle and crash it >:)
 * If not road vehicle was found, only state 0 is used and Ufo disappears after a while
 */
static bool DisasterTick_Ufo(DisasterVehicle *v)
{
        v->image_override = (HasBit(++v->tick_counter, 3)) ? SPR_UFO_SMALL_SCOUT_DARKER : SPR_UFO_SMALL_SCOUT;

        if (v->current_order.GetDestination() == 0) {
                /* Fly around randomly */
                int x = TileX(v->dest_tile) * TILE_SIZE;
                int y = TileY(v->dest_tile) * TILE_SIZE;
                if (Delta(x, v->x_pos) + Delta(y, v->y_pos) >= (int)TILE_SIZE) {
                        v->direction = GetDirectionTowards(v, x, y);
                        SetDisasterVehiclePosAuto(v);
                        return true;
                }
                if (++v->age < 6) {
                        v->dest_tile = RandomTile();
                        return true;
                }
                v->current_order.SetDestination(1);

                uint n = 0; // Total number of targetable road vehicles.
                RoadVehicle *u;
                FOR_ALL_ROADVEHICLES(u) {
                        if (u->IsFrontEngine()) n++;
                }

                if (n == 0) {
                        /* If there are no targetable road vehicles, destroy the UFO. */
                        delete v;
                        return false;
                }

                n = RandomRange(n); // Choose one of them.
                FOR_ALL_ROADVEHICLES(u) {
                        /* Find (n+1)-th road vehicle. */
                        if (u->IsFrontEngine() && (n-- == 0)) break;
                }

                /* Target it. */
                v->dest_tile = u->index;
                v->age = 0;
                return true;
        } else {
                /* Target a vehicle */
                RoadVehicle *u = RoadVehicle::Get(v->dest_tile);
                assert(u != NULL && u->type == VEH_ROAD && u->IsFrontEngine());

                uint dist = Delta(v->x_pos, u->x_pos) + Delta(v->y_pos, u->y_pos);

                if (dist < TILE_SIZE && !(u->vehstatus & VS_HIDDEN) && u->breakdown_ctr == 0) {
                        u->breakdown_ctr = 3;
                        u->breakdown_delay = 140;
                }

                v->direction = GetDirectionTowards(v, u->x_pos, u->y_pos);

                int z = v->z_pos;
                if (dist <= TILE_SIZE && z > u->z_pos) z--;
                SetDisasterVehiclePosAutoZ(v, z);

                if (z <= u->z_pos && (u->vehstatus & VS_HIDDEN) == 0) {
                        v->age++;
                        if (u->crashed_ctr == 0) {
                                u->Crash();

                                AddVehicleNewsItem(STR_NEWS_DISASTER_SMALL_UFO, NT_ACCIDENT, u->index); // delete the news, when the roadvehicle is gone

                                AI::NewEvent(u->owner, new ScriptEventVehicleCrashed(u->index, u->tile, ScriptEventVehicleCrashed::CRASH_RV_UFO));
                                Game::NewEvent(new ScriptEventVehicleCrashed(u->index, u->tile, ScriptEventVehicleCrashed::CRASH_RV_UFO));
                        }
                }

                /* Destroy? */
                if (v->age > 50) {
                        CreateEffectVehicleRel(v, 0, 7, 8, EV_EXPLOSION_LARGE);
                        if (_settings_client.sound.disaster) SndPlayVehicleFx(SND_12_EXPLOSION, v);
                        delete v;
                        return false;
                }
        }

        return true;
}

static void DestructIndustry(Industry *i)
{
        for (TileIndex tile = 0; tile != MapSize(); tile++) {
                if (i->TileBelongsToIndustry(tile)) {
                        ResetIndustryConstructionStage(tile);
                        MarkTileDirtyByTile(tile);
                }
        }
}

/**
 * Aircraft handling, v->current_order.dest states:
 * 0: Fly towards the targeted industry
 * 1: If within 15 tiles, fire away rockets and destroy industry
 * 2: Industry explosions
 * 3: Fly out of the map
 * If the industry was removed in the meantime just fly to the end of the map.
 * @param v The disaster vehicle.
 * @param image_override The image at the time the aircraft is firing.
 * @param leave_at_top True iff the vehicle leaves the map at the north side.
 * @param news_message The string that's used as news message.
 * @param industry_flag Only attack industries that have this flag set.
 */
static bool DisasterTick_Aircraft(DisasterVehicle *v, uint16 image_override, bool leave_at_top, StringID news_message, IndustryBehaviour industry_flag)
{
        v->tick_counter++;
        v->image_override = (v->current_order.GetDestination() == 1 && HasBit(v->tick_counter, 2)) ? image_override : 0;

        SetDisasterVehiclePosAuto(v);

        if (leave_at_top ? (v->x_pos < (-10 * (int)TILE_SIZE)) : (v->x_pos > (int)(MapSizeX() * TILE_SIZE + 9 * TILE_SIZE) - 1)) {
                delete v;
                return false;
        }

        if (v->current_order.GetDestination() == 2) {
                if (GB(v->tick_counter, 0, 2) == 0) {
                        Industry *i = Industry::Get(v->dest_tile); // Industry destructor calls ReleaseDisastersTargetingIndustry, so this is valid
                        int x = TileX(i->location.tile) * TILE_SIZE;
                        int y = TileY(i->location.tile) * TILE_SIZE;
                        uint32 r = Random();

                        CreateEffectVehicleAbove(
                                GB(r,  0, 6) + x,
                                GB(r,  6, 6) + y,
                                GB(r, 12, 4),
                                EV_EXPLOSION_SMALL);

                        if (++v->age >= 55) v->current_order.SetDestination(3);
                }
        } else if (v->current_order.GetDestination() == 1) {
                if (++v->age == 112) {
                        v->current_order.SetDestination(2);
                        v->age = 0;

                        Industry *i = Industry::Get(v->dest_tile); // Industry destructor calls ReleaseDisastersTargetingIndustry, so this is valid
                        DestructIndustry(i);

                        SetDParam(0, i->town->index);
                        AddIndustryNewsItem(news_message, NT_ACCIDENT, i->index); // delete the news, when the industry closes
                        if (_settings_client.sound.disaster) SndPlayTileFx(SND_12_EXPLOSION, i->location.tile);
                }
        } else if (v->current_order.GetDestination() == 0) {
                int x = v->x_pos + ((leave_at_top ? -15 : 15) * TILE_SIZE);
                int y = v->y_pos;

                if ((uint)x > MapMaxX() * TILE_SIZE - 1) return true;

                TileIndex tile = TileVirtXY(x, y);
                if (!IsIndustryTile(tile)) return true;

                IndustryID ind = GetIndustryIndex(tile);
                v->dest_tile = ind;

                if (GetIndustrySpec(Industry::Get(ind)->type)->behaviour & industry_flag) {
                        v->current_order.SetDestination(1);
                        v->age = 0;
                }
        }

        return true;
}

/** Airplane handling. */
static bool DisasterTick_Airplane(DisasterVehicle *v)
{
        return DisasterTick_Aircraft(v, SPR_F_15_FIRING, true, STR_NEWS_DISASTER_AIRPLANE_OIL_REFINERY, INDUSTRYBEH_AIRPLANE_ATTACKS);
}

/** Helicopter handling. */
static bool DisasterTick_Helicopter(DisasterVehicle *v)
{
        return DisasterTick_Aircraft(v, SPR_AH_64A_FIRING, false, STR_NEWS_DISASTER_HELICOPTER_FACTORY, INDUSTRYBEH_CHOPPER_ATTACKS);
}

/** Helicopter rotor blades; keep these spinning */
static bool DisasterTick_Helicopter_Rotors(DisasterVehicle *v)
{
        v->tick_counter++;
        if (HasBit(v->tick_counter, 0)) return true;

        if (++v->cur_image > SPR_ROTOR_MOVING_3) v->cur_image = SPR_ROTOR_MOVING_1;

        VehicleUpdatePositionAndViewport(v);

        return true;
}

/**
 * (Big) Ufo handling, v->current_order.dest states:
 * 0: Fly around to the middle of the map, then randomly for a while and home in on a piece of rail
 * 1: Land there and breakdown all trains in a radius of 12 tiles; and now we wait...
 *    because as soon as the Ufo lands, a fighter jet, a Skyranger, is called to clear up the mess
 */
static bool DisasterTick_Big_Ufo(DisasterVehicle *v)
{
        v->tick_counter++;

        if (v->current_order.GetDestination() == 1) {
                int x = TileX(v->dest_tile) * TILE_SIZE + TILE_SIZE / 2;
                int y = TileY(v->dest_tile) * TILE_SIZE + TILE_SIZE / 2;
                if (Delta(v->x_pos, x) + Delta(v->y_pos, y) >= 8) {
                        v->direction = GetDirectionTowards(v, x, y);

                        SetDisasterVehiclePosAuto(v);
                        return true;
                }

                if (!IsValidTile(v->dest_tile)) {
                        /* Make sure we don't land outside the map. */
                        delete v;
                        return false;
                }

                int z = GetSlopePixelZ(v->x_pos, v->y_pos);
                if (z < v->z_pos) {
                        SetDisasterVehiclePos(v, v->x_pos, v->y_pos, v->z_pos - 1);
                        return true;
                }

                v->current_order.SetDestination(2);

                Vehicle *target;
                FOR_ALL_VEHICLES(target) {
                        if (target->IsGroundVehicle()) {
                                if (Delta(target->x_pos, v->x_pos) + Delta(target->y_pos, v->y_pos) <= 12 * (int)TILE_SIZE) {
                                        target->breakdown_ctr = 5;
                                        target->breakdown_delay = 0xF0;
                                }
                        }
                }

                Town *t = ClosestTownFromTile(v->dest_tile, UINT_MAX);
                SetDParam(0, t->index);
                AddTileNewsItem(STR_NEWS_DISASTER_BIG_UFO, NT_ACCIDENT, v->tile);

                if (!Vehicle::CanAllocateItem(2)) {
                        delete v;
                        return false;
                }
                DisasterVehicle *u = new DisasterVehicle();

                InitializeDisasterVehicle(u, -6 * (int)TILE_SIZE, v->y_pos, INITIAL_DISASTER_VEHICLE_ZPOS, DIR_SW, ST_BIG_UFO_DESTROYER);
                u->big_ufo_destroyer_target = v->index;

                DisasterVehicle *w = new DisasterVehicle();

                u->SetNext(w);
                InitializeDisasterVehicle(w, -6 * (int)TILE_SIZE, v->y_pos, 0, DIR_SW, ST_BIG_UFO_DESTROYER_SHADOW);
                w->vehstatus |= VS_SHADOW;
        } else if (v->current_order.GetDestination() == 0) {
                int x = TileX(v->dest_tile) * TILE_SIZE;
                int y = TileY(v->dest_tile) * TILE_SIZE;
                if (Delta(x, v->x_pos) + Delta(y, v->y_pos) >= (int)TILE_SIZE) {
                        v->direction = GetDirectionTowards(v, x, y);
                        SetDisasterVehiclePosAuto(v);
                        return true;
                }

                if (++v->age < 6) {
                        v->dest_tile = RandomTile();
                        return true;
                }
                v->current_order.SetDestination(1);

                TileIndex tile_org = RandomTile();
                TileIndex tile = tile_org;
                do {
                        if (IsNormalRailTile(tile) &&
                                        Company::IsHumanID(GetTileOwner(tile))) {
                                break;
                        }
                        tile = TILE_MASK(tile + 1);
                } while (tile != tile_org);
                v->dest_tile = tile;
                v->age = 0;
        }

        return true;
}

/**
 * Skyranger destroying (Big) Ufo handling, v->current_order.dest states:
 * 0: Home in on landed Ufo and shoot it down
 */
static bool DisasterTick_Big_Ufo_Destroyer(DisasterVehicle *v)
{
        v->tick_counter++;

        SetDisasterVehiclePosAuto(v);

        if (v->x_pos > (int)(MapSizeX() * TILE_SIZE + 9 * TILE_SIZE) - 1) {
                delete v;
                return false;
        }

        if (v->current_order.GetDestination() == 0) {
                Vehicle *u = Vehicle::Get(v->big_ufo_destroyer_target);
                if (Delta(v->x_pos, u->x_pos) > (int)TILE_SIZE) return true;
                v->current_order.SetDestination(1);

                CreateEffectVehicleRel(u, 0, 7, 8, EV_EXPLOSION_LARGE);
                if (_settings_client.sound.disaster) SndPlayVehicleFx(SND_12_EXPLOSION, u);

                delete u;

                for (int i = 0; i != 80; i++) {
                        uint32 r = Random();
                        CreateEffectVehicleAbove(
                                GB(r, 0, 6) + v->x_pos - 32,
                                GB(r, 5, 6) + v->y_pos - 32,
                                0,
                                EV_EXPLOSION_SMALL);
                }

                for (int dy = -3; dy < 3; dy++) {
                        for (int dx = -3; dx < 3; dx++) {
                                TileIndex tile = TileAddWrap(v->tile, dx, dy);
                                if (tile != INVALID_TILE) DisasterClearSquare(tile);
                        }
                }
        }

        return true;
}

/**
 * Submarine, v->current_order.dest states:
 * Unused, just float around aimlessly and pop up at different places, turning around
 */
static bool DisasterTick_Submarine(DisasterVehicle *v)
{
        v->tick_counter++;

        if (++v->age > 8880) {
                delete v;
                return false;
        }

        if (!HasBit(v->tick_counter, 0)) return true;

        TileIndex tile = v->tile + TileOffsByDiagDir(DirToDiagDir(v->direction));
        if (IsValidTile(tile)) {
                TrackBits trackbits = TrackdirBitsToTrackBits(GetTileWaterwayStatus(tile));
                if (trackbits == TRACK_BIT_ALL && !Chance16(1, 90)) {
                        SetDisasterVehiclePosAuto(v);
                        return true;
                }
        }

        v->direction = ChangeDir(v->direction, GB(Random(), 0, 1) ? DIRDIFF_90RIGHT : DIRDIFF_90LEFT);

        return true;
}


static bool DisasterTick_NULL(DisasterVehicle *v)
{
        return true;
}

typedef bool DisasterVehicleTickProc(DisasterVehicle *v);

static DisasterVehicleTickProc * const _disastervehicle_tick_procs[] = {
        DisasterTick_Zeppeliner, DisasterTick_NULL,
        DisasterTick_Ufo,        DisasterTick_NULL,
        DisasterTick_Airplane,   DisasterTick_NULL,
        DisasterTick_Helicopter, DisasterTick_NULL, DisasterTick_Helicopter_Rotors,
        DisasterTick_Big_Ufo,    DisasterTick_NULL, DisasterTick_Big_Ufo_Destroyer,
        DisasterTick_NULL,
        DisasterTick_Submarine,
        DisasterTick_Submarine,
};


bool DisasterVehicle::Tick()
{
        return _disastervehicle_tick_procs[this->subtype](this);
}

typedef void DisasterInitProc();


/**
 * Zeppeliner which crashes on a small airport if one found,
 * otherwise crashes on a random tile
 */
static void Disaster_Zeppeliner_Init()
{
        if (!Vehicle::CanAllocateItem(2)) return;

        /* Pick a random place, unless we find a small airport */
        int x = TileX(Random()) * TILE_SIZE + TILE_SIZE / 2;

        Station *st;
        FOR_ALL_STATIONS(st) {
                if (st->airport.tile != INVALID_TILE && (st->airport.type == AT_SMALL || st->airport.type == AT_LARGE)) {
                        x = (TileX(st->airport.tile) + 2) * TILE_SIZE;
                        break;
                }
        }

        DisasterVehicle *v = new DisasterVehicle();
        InitializeDisasterVehicle(v, x, 0, INITIAL_DISASTER_VEHICLE_ZPOS, DIR_SE, ST_ZEPPELINER);

        /* Allocate shadow */
        DisasterVehicle *u = new DisasterVehicle();
        v->SetNext(u);
        InitializeDisasterVehicle(u, x, 0, 0, DIR_SE, ST_ZEPPELINER_SHADOW);
        u->vehstatus |= VS_SHADOW;
}


/**
 * Ufo which flies around aimlessly from the middle of the map a bit
 * until it locates a road vehicle which it targets and then destroys
 */
static void Disaster_Small_Ufo_Init()
{
        if (!Vehicle::CanAllocateItem(2)) return;

        DisasterVehicle *v = new DisasterVehicle();
        int x = TileX(Random()) * TILE_SIZE + TILE_SIZE / 2;

        InitializeDisasterVehicle(v, x, 0, INITIAL_DISASTER_VEHICLE_ZPOS, DIR_SE, ST_SMALL_UFO);
        v->dest_tile = TileXY(MapSizeX() / 2, MapSizeY() / 2);
        v->age = 0;

        /* Allocate shadow */
        DisasterVehicle *u = new DisasterVehicle();
        v->SetNext(u);
        InitializeDisasterVehicle(u, x, 0, 0, DIR_SE, ST_SMALL_UFO_SHADOW);
        u->vehstatus |= VS_SHADOW;
}


/* Combat airplane which destroys an oil refinery */
static void Disaster_Airplane_Init()
{
        if (!Vehicle::CanAllocateItem(2)) return;

        Industry *i, *found = NULL;

        FOR_ALL_INDUSTRIES(i) {
                if ((GetIndustrySpec(i->type)->behaviour & INDUSTRYBEH_AIRPLANE_ATTACKS) &&
                                (found == NULL || Chance16(1, 2))) {
                        found = i;
                }
        }

        if (found == NULL) return;

        DisasterVehicle *v = new DisasterVehicle();

        /* Start from the bottom (south side) of the map */
        int x = (MapSizeX() + 9) * TILE_SIZE - 1;
        int y = TileY(found->location.tile) * TILE_SIZE + 37;

        InitializeDisasterVehicle(v, x, y, INITIAL_DISASTER_VEHICLE_ZPOS, DIR_NE, ST_AIRPLANE);

        DisasterVehicle *u = new DisasterVehicle();
        v->SetNext(u);
        InitializeDisasterVehicle(u, x, y, 0, DIR_SE, ST_AIRPLANE_SHADOW);
        u->vehstatus |= VS_SHADOW;
}


/** Combat helicopter that destroys a factory */
static void Disaster_Helicopter_Init()
{
        if (!Vehicle::CanAllocateItem(3)) return;

        Industry *i, *found = NULL;

        FOR_ALL_INDUSTRIES(i) {
                if ((GetIndustrySpec(i->type)->behaviour & INDUSTRYBEH_CHOPPER_ATTACKS) &&
                                (found == NULL || Chance16(1, 2))) {
                        found = i;
                }
        }

        if (found == NULL) return;

        DisasterVehicle *v = new DisasterVehicle();

        int x = -16 * (int)TILE_SIZE;
        int y = TileY(found->location.tile) * TILE_SIZE + 37;

        InitializeDisasterVehicle(v, x, y, INITIAL_DISASTER_VEHICLE_ZPOS, DIR_SW, ST_HELICOPTER);

        DisasterVehicle *u = new DisasterVehicle();
        v->SetNext(u);
        InitializeDisasterVehicle(u, x, y, 0, DIR_SW, ST_HELICOPTER_SHADOW);
        u->vehstatus |= VS_SHADOW;

        DisasterVehicle *w = new DisasterVehicle();
        u->SetNext(w);
        InitializeDisasterVehicle(w, x, y, 140, DIR_SW, ST_HELICOPTER_ROTORS);
}


/* Big Ufo which lands on a piece of rail and will consequently be shot
 * down by a combat airplane, destroying the surroundings */
static void Disaster_Big_Ufo_Init()
{
        if (!Vehicle::CanAllocateItem(2)) return;

        DisasterVehicle *v = new DisasterVehicle();
        int x = TileX(Random()) * TILE_SIZE + TILE_SIZE / 2;
        int y = MapMaxX() * TILE_SIZE - 1;

        InitializeDisasterVehicle(v, x, y, INITIAL_DISASTER_VEHICLE_ZPOS, DIR_NW, ST_BIG_UFO);
        v->dest_tile = TileXY(MapSizeX() / 2, MapSizeY() / 2);
        v->age = 0;

        /* Allocate shadow */
        DisasterVehicle *u = new DisasterVehicle();
        v->SetNext(u);
        InitializeDisasterVehicle(u, x, y, 0, DIR_NW, ST_BIG_UFO_SHADOW);
        u->vehstatus |= VS_SHADOW;
}


static void Disaster_Submarine_Init(DisasterSubType subtype)
{
        if (!Vehicle::CanAllocateItem()) return;

        int y;
        Direction dir;
        uint32 r = Random();
        int x = TileX(r) * TILE_SIZE + TILE_SIZE / 2;

        if (HasBit(r, 31)) {
                y = MapMaxY() * TILE_SIZE - TILE_SIZE / 2 - 1;
                dir = DIR_NW;
        } else {
                y = TILE_SIZE / 2;
                if (_settings_game.construction.freeform_edges) y += TILE_SIZE;
                dir = DIR_SE;
        }
        if (!IsPlainWaterTile(TileVirtXY(x, y))) return;

        DisasterVehicle *v = new DisasterVehicle();
        InitializeDisasterVehicle(v, x, y, 0, dir, subtype);
        v->age = 0;
}

/* Curious submarine #1, just floats around */
static void Disaster_Small_Submarine_Init()
{
        Disaster_Submarine_Init(ST_SMALL_SUBMARINE);
}


/* Curious submarine #2, just floats around */
static void Disaster_Big_Submarine_Init()
{
        Disaster_Submarine_Init(ST_BIG_SUBMARINE);
}


/**
 * Coal mine catastrophe, destroys a stretch of 30 tiles of
 * land in a certain direction
 */
static void Disaster_CoalMine_Init()
{
        int index = GB(Random(), 0, 4);
        uint m;

        for (m = 0; m < 15; m++) {
                const Industry *i;

                FOR_ALL_INDUSTRIES(i) {
                        if ((GetIndustrySpec(i->type)->behaviour & INDUSTRYBEH_CAN_SUBSIDENCE) && --index < 0) {
                                SetDParam(0, i->town->index);
                                AddTileNewsItem(STR_NEWS_DISASTER_COAL_MINE_SUBSIDENCE, NT_ACCIDENT, i->location.tile + TileDiffXY(1, 1)); // keep the news, even when the mine closes

                                {
                                        TileIndex tile = i->location.tile;
                                        TileIndexDiff step = TileOffsByDiagDir((DiagDirection)GB(Random(), 0, 2));

                                        for (uint n = 0; n < 30; n++) {
                                                DisasterClearSquare(tile);
                                                tile += step;
                                                if (!IsValidTile(tile)) break;
                                        }
                                }
                                return;
                        }
                }
        }
}

struct Disaster {
        DisasterInitProc *init_proc; ///< The init function for this disaster.
        Year min_year;               ///< The first year this disaster will occur.
        Year max_year;               ///< The last year this disaster will occur.
};

static const Disaster _disasters[] = {
        {Disaster_Zeppeliner_Init,      1930, 1955}, // zeppeliner
        {Disaster_Small_Ufo_Init,       1940, 1970}, // ufo (small)
        {Disaster_Airplane_Init,        1960, 1990}, // airplane
        {Disaster_Helicopter_Init,      1970, 2000}, // helicopter
        {Disaster_Big_Ufo_Init,         2000, 2100}, // ufo (big)
        {Disaster_Small_Submarine_Init, 1940, 1965}, // submarine (small)
        {Disaster_Big_Submarine_Init,   1975, 2010}, // submarine (big)
        {Disaster_CoalMine_Init,        1950, 1985}, // coalmine
};

static void DoDisaster()
{
        byte buf[lengthof(_disasters)];

        byte j = 0;
        for (size_t i = 0; i != lengthof(_disasters); i++) {
                if (_cur_year >= _disasters[i].min_year && _cur_year < _disasters[i].max_year) buf[j++] = (byte)i;
        }

        if (j == 0) return;

        _disasters[buf[RandomRange(j)]].init_proc();
}


static void ResetDisasterDelay()
{
        _disaster_delay = GB(Random(), 0, 9) + 730;
}

void DisasterDailyLoop()
{
        if (--_disaster_delay != 0) return;

        ResetDisasterDelay();

        if (_settings_game.difficulty.disasters != 0) DoDisaster();
}

void StartupDisasters()
{
        ResetDisasterDelay();
}

/**
 * Marks all disasters targeting this industry in such a way
 * they won't call Industry::Get(v->dest_tile) on invalid industry anymore.
 * @param i deleted industry
 */
void ReleaseDisastersTargetingIndustry(IndustryID i)
{
        DisasterVehicle *v;
        FOR_ALL_DISASTERVEHICLES(v) {
                /* primary disaster vehicles that have chosen target */
                if (v->subtype == ST_AIRPLANE || v->subtype == ST_HELICOPTER) {
                        /* if it has chosen target, and it is this industry (yes, dest_tile is IndustryID here), set order to "leaving map peacefully" */
                        if (v->current_order.GetDestination() > 0 && v->dest_tile == i) v->current_order.SetDestination(3);
                }
        }
}

/**
 * Notify disasters that we are about to delete a vehicle. So make them head elsewhere.
 * @param vehicle deleted vehicle
 */
void ReleaseDisastersTargetingVehicle(VehicleID vehicle)
{
        DisasterVehicle *v;
        FOR_ALL_DISASTERVEHICLES(v) {
                /* primary disaster vehicles that have chosen target */
                if (v->subtype == ST_SMALL_UFO) {
                        if (v->current_order.GetDestination() != 0 && v->dest_tile == vehicle) {
                                /* Revert to target-searching */
                                v->current_order.SetDestination(0);
                                v->dest_tile = RandomTile();
                                v->z_pos = INITIAL_DISASTER_VEHICLE_ZPOS;
                                v->age = 0;
                        }
                }
        }
}

void DisasterVehicle::UpdateDeltaXY(Direction direction)
{
        this->x_offs        = -1;
        this->y_offs        = -1;
        this->x_extent      =  2;
        this->y_extent      =  2;
        this->z_extent      =  5;
}