(svn r26864) -Codechange: bring a bit more OO into the disaster vehicles

1 files changed, 982 insertions, 0 deletions

diff --git a/src/disaster_vehicle.cpp b/src/disaster_vehicle.cpp
new file mode 100644
index 000000000..703893d63
--- /dev/null
+++ b/src/disaster_vehicle.cpp
@@ -0,0 +1,982 @@
+/* $Id$ */
+
+/*
+ * 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_vehicle.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 "aircraft.h"
+#include "disaster_vehicle.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 "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 "table/strings.h"
+
+#include "safeguards.h"
+
+/** Delay counter for considering the next disaster. */
+uint16 _disaster_delay;
+
+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;
+
+	switch (GetTileType(tile)) {
+		case MP_RAILWAY:
+			if (Company::IsHumanID(GetTileOwner(tile)) && !IsRailDepot(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 MP_HOUSE: {
+			Backup<CompanyByte> cur_company(_current_company, OWNER_NONE, FILE_LINE);
+			DoCommand(tile, 0, 0, DC_EXEC, CMD_LANDSCAPE_CLEAR);
+			cur_company.Restore();
+			break;
+		}
+
+		case MP_TREES:
+		case MP_CLEAR:
+			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
+};
+
+void DisasterVehicle::UpdateImage()
+{
+	SpriteID img = this->image_override;
+	if (img == 0) img = _disaster_images[this->subtype][this->direction];
+	this->cur_image = img;
+}
+
+/**
+ * Construct the disaster vehicle.
+ * @param x         The X coordinate.
+ * @param y         The Y coordinate.
+ * @param direction The direction the vehicle is facing.
+ * @param subtype   The sub type of vehicle.
+ * @param big_ufo_destroyer_target The target for the UFO destroyer.
+ */
+DisasterVehicle::DisasterVehicle(int x, int y, Direction direction, DisasterSubType subtype, VehicleID big_ufo_destroyer_target) :
+		SpecializedVehicleBase(), big_ufo_destroyer_target(big_ufo_destroyer_target)
+{
+	this->x_pos = x;
+	this->y_pos = y;
+	switch (subtype) {
+		case ST_ZEPPELINER:
+		case ST_SMALL_UFO:
+		case ST_AIRPLANE:
+		case ST_HELICOPTER:
+		case ST_BIG_UFO:
+		case ST_BIG_UFO_DESTROYER:
+			this->z_pos = INITIAL_DISASTER_VEHICLE_ZPOS;
+			break;
+
+		case ST_HELICOPTER_ROTORS:
+			this->z_pos = INITIAL_DISASTER_VEHICLE_ZPOS + ROTOR_Z_OFFSET;
+			break;
+
+		case ST_SMALL_SUBMARINE:
+		case ST_BIG_SUBMARINE:
+			this->z_pos = 0;
+			break;
+
+		case ST_ZEPPELINER_SHADOW:
+		case ST_SMALL_UFO_SHADOW:
+		case ST_AIRPLANE_SHADOW:
+		case ST_HELICOPTER_SHADOW:
+		case ST_BIG_UFO_SHADOW:
+		case ST_BIG_UFO_DESTROYER_SHADOW:
+			this->z_pos = 0;
+			this->vehstatus |= VS_SHADOW;
+			break;
+	}
+
+	this->direction = direction;
+	this->tile = TileVirtXY(x, y);
+	this->subtype = subtype;
+	this->UpdateDeltaXY(INVALID_DIR);
+	this->owner = OWNER_NONE;
+	this->vehstatus = VS_UNCLICKABLE;
+	this->image_override = 0;
+	this->current_order.Free();
+
+	this->UpdateImage();
+	this->UpdatePositionAndViewport();
+}
+
+/**
+ * Update the position of the vehicle.
+ * @param x The new X-coordinate.
+ * @param y The new Y-coordinate.
+ * @param z The new Z-coordinate.
+ */
+void DisasterVehicle::UpdatePosition(int x, int y, int z)
+{
+	this->x_pos = x;
+	this->y_pos = y;
+	this->z_pos = z;
+	this->tile = TileVirtXY(x, y);
+
+	this->UpdateImage();
+	this->UpdatePositionAndViewport();
+
+	DisasterVehicle *u = this->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 = this->direction;
+
+		u->UpdateImage();
+		u->UpdatePositionAndViewport();
+
+		if ((u = u->Next()) != NULL) {
+			u->x_pos = x;
+			u->y_pos = y;
+			u->z_pos = z + ROTOR_Z_OFFSET;
+			u->UpdatePositionAndViewport();
+		}
+	}
+}
+
+/**
+ * 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;
+
+		GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+
+		v->UpdatePosition(gp.x, gp.y, v->z_pos);
+
+		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));
+		}
+
+		v->UpdatePosition(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;
+	v->UpdatePosition(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);
+			GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+			v->UpdatePosition(gp.x, gp.y, v->z_pos);
+			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);
+		GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+
+		int z = v->z_pos;
+		if (dist <= TILE_SIZE && z > u->z_pos) z--;
+		v->UpdatePosition(gp.x, gp.y, 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;
+
+	GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+	v->UpdatePosition(gp.x, gp.y, v->z_pos);
+
+	if ((leave_at_top && gp.x < (-10 * (int)TILE_SIZE)) || (!leave_at_top && gp.x > (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 (!IsTileType(tile, MP_INDUSTRY)) 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;
+
+	v->UpdatePositionAndViewport();
+
+	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);
+
+			GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+			v->UpdatePosition(gp.x, gp.y, v->z_pos);
+			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) {
+			v->UpdatePosition(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(-6 * (int)TILE_SIZE, v->y_pos, DIR_SW, ST_BIG_UFO_DESTROYER, v->index);
+		DisasterVehicle *w = new DisasterVehicle(-6 * (int)TILE_SIZE, v->y_pos, DIR_SW, ST_BIG_UFO_DESTROYER_SHADOW);
+		u->SetNext(w);
+	} 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);
+			GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+			v->UpdatePosition(gp.x, gp.y, v->z_pos);
+			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 (IsPlainRailTile(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++;
+
+	GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+	v->UpdatePosition(gp.x, gp.y, v->z_pos);
+
+	if (gp.x > (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 = TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_WATER, 0));
+		if (trackbits == TRACK_BIT_ALL && !Chance16(1, 90)) {
+			GetNewVehiclePosResult gp = GetNewVehiclePos(v);
+			v->UpdatePosition(gp.x, gp.y, v->z_pos);
+			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(x, 0, DIR_SE, ST_ZEPPELINER);
+	/* Allocate shadow */
+	DisasterVehicle *u = new DisasterVehicle(x, 0, DIR_SE, ST_ZEPPELINER_SHADOW);
+	v->SetNext(u);
+}
+
+
+/**
+ * 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;
+
+	int x = TileX(Random()) * TILE_SIZE + TILE_SIZE / 2;
+	DisasterVehicle *v = new DisasterVehicle(x, 0, DIR_SE, ST_SMALL_UFO);
+	v->dest_tile = TileXY(MapSizeX() / 2, MapSizeY() / 2);
+
+	/* Allocate shadow */
+	DisasterVehicle *u = new DisasterVehicle(x, 0, DIR_SE, ST_SMALL_UFO_SHADOW);
+	v->SetNext(u);
+}
+
+
+/* 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;
+
+	/* 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;
+
+	DisasterVehicle *v = new DisasterVehicle(x, y, DIR_NE, ST_AIRPLANE);
+	DisasterVehicle *u = new DisasterVehicle(x, y, DIR_NE, ST_AIRPLANE_SHADOW);
+	v->SetNext(u);
+}
+
+
+/** 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;
+
+	int x = -16 * (int)TILE_SIZE;
+	int y = TileY(found->location.tile) * TILE_SIZE + 37;
+
+	DisasterVehicle *v = new DisasterVehicle(x, y, DIR_SW, ST_HELICOPTER);
+	DisasterVehicle *u = new DisasterVehicle(x, y, DIR_SW, ST_HELICOPTER_SHADOW);
+	v->SetNext(u);
+
+	DisasterVehicle *w = new DisasterVehicle(x, y, DIR_SW, ST_HELICOPTER_ROTORS);
+	u->SetNext(w);
+}
+
+
+/* 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;
+
+	int x = TileX(Random()) * TILE_SIZE + TILE_SIZE / 2;
+	int y = MapMaxX() * TILE_SIZE - 1;
+
+	DisasterVehicle *v = new DisasterVehicle(x, y, DIR_NW, ST_BIG_UFO);
+	v->dest_tile = TileXY(MapSizeX() / 2, MapSizeY() / 2);
+
+	/* Allocate shadow */
+	DisasterVehicle *u = new DisasterVehicle(x, y, DIR_NW, ST_BIG_UFO_SHADOW);
+	v->SetNext(u);
+}
+
+
+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 (!IsWaterTile(TileVirtXY(x, y))) return;
+
+	new DisasterVehicle(x, y, dir, subtype);
+}
+
+/* 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;
+}