diff --git a/src/landscape.cpp b/src/landscape.cpp
new file mode 100644
--- /dev/null
+++ b/src/landscape.cpp
@@ -0,0 +1,731 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "bridge_map.h"
+#include "heightmap.h"
+#include "clear_map.h"
+#include "functions.h"
+#include "map.h"
+#include "player.h"
+#include "spritecache.h"
+#include "table/sprites.h"
+#include "tile.h"
+#include <stdarg.h>
+#include "viewport.h"
+#include "command.h"
+#include "vehicle.h"
+#include "variables.h"
+#include "void_map.h"
+#include "water_map.h"
+#include "tgp.h"
+#include "genworld.h"
+#include "heightmap.h"
+
+extern const TileTypeProcs
+	_tile_type_clear_procs,
+	_tile_type_rail_procs,
+	_tile_type_road_procs,
+	_tile_type_town_procs,
+	_tile_type_trees_procs,
+	_tile_type_station_procs,
+	_tile_type_water_procs,
+	_tile_type_dummy_procs,
+	_tile_type_industry_procs,
+	_tile_type_tunnelbridge_procs,
+	_tile_type_unmovable_procs;
+
+const TileTypeProcs * const _tile_type_procs[16] = {
+	&_tile_type_clear_procs,
+	&_tile_type_rail_procs,
+	&_tile_type_road_procs,
+	&_tile_type_town_procs,
+	&_tile_type_trees_procs,
+	&_tile_type_station_procs,
+	&_tile_type_water_procs,
+	&_tile_type_dummy_procs,
+	&_tile_type_industry_procs,
+	&_tile_type_tunnelbridge_procs,
+	&_tile_type_unmovable_procs,
+};
+
+/* landscape slope => sprite */
+const byte _tileh_to_sprite[32] = {
+	0, 1, 2, 3, 4, 5, 6,  7, 8, 9, 10, 11, 12, 13, 14, 0,
+	0, 0, 0, 0, 0, 0, 0, 16, 0, 0,  0, 17,  0, 15, 18, 0,
+};
+
+const byte _inclined_tileh[] = {
+	SLOPE_SW,  SLOPE_NW,  SLOPE_SW,  SLOPE_SE, SLOPE_NE, SLOPE_SE, SLOPE_NE, SLOPE_NW,
+	SLOPE_E,   SLOPE_N,   SLOPE_W,   SLOPE_S,
+	SLOPE_NWS, SLOPE_WSE, SLOPE_SEN, SLOPE_ENW
+};
+
+
+uint GetPartialZ(int x, int y, Slope corners)
+{
+	int z = 0;
+
+	switch (corners) {
+	case SLOPE_W:
+		if (x - y >= 0)
+			z = (x - y) >> 1;
+		break;
+
+	case SLOPE_S:
+		y^=0xF;
+		if ( (x - y) >= 0)
+			z = (x - y) >> 1;
+		break;
+
+	case SLOPE_SW:
+		z = (x>>1) + 1;
+		break;
+
+	case SLOPE_E:
+		if (y - x >= 0)
+			z = (y - x) >> 1;
+		break;
+
+	case SLOPE_EW:
+	case SLOPE_NS:
+	case SLOPE_ELEVATED:
+		z = 4;
+		break;
+
+	case SLOPE_SE:
+		z = (y>>1) + 1;
+		break;
+
+	case SLOPE_WSE:
+		z = 8;
+		y^=0xF;
+		if (x - y < 0)
+			z += (x - y) >> 1;
+		break;
+
+	case SLOPE_N:
+		y ^= 0xF;
+		if (y - x >= 0)
+			z = (y - x) >> 1;
+		break;
+
+	case SLOPE_NW:
+		z = (y^0xF)>>1;
+		break;
+
+	case SLOPE_NWS:
+		z = 8;
+		if (x - y < 0)
+			z += (x - y) >> 1;
+		break;
+
+	case SLOPE_NE:
+		z = (x^0xF)>>1;
+		break;
+
+	case SLOPE_ENW:
+		z = 8;
+		y ^= 0xF;
+		if (y - x < 0)
+			z += (y - x) >> 1;
+		break;
+
+	case SLOPE_SEN:
+		z = 8;
+		if (y - x < 0)
+			z += (y - x) >> 1;
+		break;
+
+	case SLOPE_STEEP_S:
+		z = 1 + ((x+y)>>1);
+		break;
+
+	case SLOPE_STEEP_W:
+		z = 1 + ((x+(y^0xF))>>1);
+		break;
+
+	case SLOPE_STEEP_N:
+		z = 1 + (((x^0xF)+(y^0xF))>>1);
+		break;
+
+	case SLOPE_STEEP_E:
+		z = 1 + (((x^0xF)+(y^0xF))>>1);
+		break;
+
+		default: break;
+	}
+
+	return z;
+}
+
+uint GetSlopeZ(int x, int y)
+{
+	TileIndex tile = TileVirtXY(x, y);
+
+	return _tile_type_procs[GetTileType(tile)]->get_slope_z_proc(tile, x, y);
+}
+
+
+static Slope GetFoundationSlope(TileIndex tile, uint* z)
+{
+	Slope tileh = GetTileSlope(tile, z);
+	Slope slope = _tile_type_procs[GetTileType(tile)]->get_slope_tileh_proc(tile, tileh);
+
+	// Flatter slope -> higher base height
+	if (slope < tileh) *z += TILE_HEIGHT;
+	return slope;
+}
+
+
+static bool HasFoundationNW(TileIndex tile, Slope slope_here, uint z_here)
+{
+	uint z;
+	Slope slope = GetFoundationSlope(TILE_ADDXY(tile, 0, -1), &z);
+
+	return
+		(
+			z_here + (slope_here & SLOPE_N ? TILE_HEIGHT : 0) + (slope_here == SLOPE_STEEP_N ? TILE_HEIGHT : 0) >
+			z      + (slope      & SLOPE_E ? TILE_HEIGHT : 0) + (slope      == SLOPE_STEEP_E ? TILE_HEIGHT : 0)
+		) || (
+			z_here + (slope_here & SLOPE_W ? TILE_HEIGHT : 0) + (slope_here == SLOPE_STEEP_W ? TILE_HEIGHT : 0) >
+			z      + (slope      & SLOPE_S ? TILE_HEIGHT : 0) + (slope      == SLOPE_STEEP_S ? TILE_HEIGHT : 0)
+		);
+}
+
+
+static bool HasFoundationNE(TileIndex tile, Slope slope_here, uint z_here)
+{
+	uint z;
+	Slope slope = GetFoundationSlope(TILE_ADDXY(tile, -1, 0), &z);
+
+	return
+		(
+			z_here + (slope_here & SLOPE_N ? TILE_HEIGHT : 0) + (slope_here == SLOPE_STEEP_N ? TILE_HEIGHT : 0) >
+			z      + (slope      & SLOPE_W ? TILE_HEIGHT : 0) + (slope      == SLOPE_STEEP_W ? TILE_HEIGHT : 0)
+		) || (
+			z_here + (slope_here & SLOPE_E ? TILE_HEIGHT : 0) + (slope_here == SLOPE_STEEP_E ? TILE_HEIGHT : 0) >
+			z      + (slope      & SLOPE_S ? TILE_HEIGHT : 0) + (slope      == SLOPE_STEEP_S ? TILE_HEIGHT : 0)
+		);
+}
+
+
+void DrawFoundation(TileInfo *ti, uint f)
+{
+	uint32 sprite_base = SPR_SLOPES_BASE - 15;
+	Slope slope;
+	uint z;
+
+	slope = GetFoundationSlope(ti->tile, &z);
+	if (!HasFoundationNW(ti->tile, slope, z)) sprite_base += 22;
+	if (!HasFoundationNE(ti->tile, slope, z)) sprite_base += 44;
+
+	if (IsSteepSlope(ti->tileh)) {
+		uint32 lower_base;
+
+		// Lower part of foundation
+		lower_base = sprite_base;
+		if (lower_base == SPR_SLOPES_BASE - 15) lower_base = SPR_FOUNDATION_BASE;
+		AddSortableSpriteToDraw(
+			lower_base + (ti->tileh & ~SLOPE_STEEP), ti->x, ti->y, 16, 16, 7, ti->z
+		);
+		ti->z += TILE_HEIGHT;
+		ti->tileh = _inclined_tileh[f - 15];
+		if (f < 15 + 8) {
+			// inclined
+			AddSortableSpriteToDraw(sprite_base + f, ti->x, ti->y, 16, 16, 1, ti->z);
+			OffsetGroundSprite(31, 9);
+		} else if (f >= 15 + 8 + 4) {
+			// three corners raised
+			uint32 upper = sprite_base + 15 + (f - 15 - 8 - 4) * 2;
+
+			AddSortableSpriteToDraw(upper, ti->x, ti->y, 16, 16, 1, ti->z);
+			AddChildSpriteScreen(upper + 1, 31, 9);
+			OffsetGroundSprite(31, 9);
+		} else {
+			// one corner raised
+			OffsetGroundSprite(31, 1);
+		}
+	} else {
+		if (f < 15) {
+			// leveled foundation
+			// Use the original slope sprites if NW and NE borders should be visible
+			if (sprite_base  == SPR_SLOPES_BASE - 15) sprite_base = SPR_FOUNDATION_BASE;
+
+			AddSortableSpriteToDraw(sprite_base + f, ti->x, ti->y, 16, 16, 7, ti->z);
+			ti->z += TILE_HEIGHT;
+			ti->tileh = SLOPE_FLAT;
+			OffsetGroundSprite(31, 1);
+		} else {
+			// inclined foundation
+			AddSortableSpriteToDraw(sprite_base + f, ti->x, ti->y, 16, 16, 1, ti->z);
+			ti->tileh = _inclined_tileh[f - 15];
+			OffsetGroundSprite(31, 9);
+		}
+	}
+}
+
+void DoClearSquare(TileIndex tile)
+{
+	MakeClear(tile, CLEAR_GRASS, _generating_world ? 3 : 0);
+	MarkTileDirtyByTile(tile);
+}
+
+uint32 GetTileTrackStatus(TileIndex tile, TransportType mode)
+{
+	return _tile_type_procs[GetTileType(tile)]->get_tile_track_status_proc(tile, mode);
+}
+
+void ChangeTileOwner(TileIndex tile, byte old_player, byte new_player)
+{
+	_tile_type_procs[GetTileType(tile)]->change_tile_owner_proc(tile, old_player, new_player);
+}
+
+void GetAcceptedCargo(TileIndex tile, AcceptedCargo ac)
+{
+	memset(ac, 0, sizeof(AcceptedCargo));
+	_tile_type_procs[GetTileType(tile)]->get_accepted_cargo_proc(tile, ac);
+}
+
+void AnimateTile(TileIndex tile)
+{
+	_tile_type_procs[GetTileType(tile)]->animate_tile_proc(tile);
+}
+
+void ClickTile(TileIndex tile)
+{
+	_tile_type_procs[GetTileType(tile)]->click_tile_proc(tile);
+}
+
+void GetTileDesc(TileIndex tile, TileDesc *td)
+{
+	_tile_type_procs[GetTileType(tile)]->get_tile_desc_proc(tile, td);
+}
+
+/** Clear a piece of landscape
+ * @param tile tile to clear
+ * @param p1 unused
+ * @param p2 unused
+ */
+int32 CmdLandscapeClear(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	return _tile_type_procs[GetTileType(tile)]->clear_tile_proc(tile, flags);
+}
+
+/** Clear a big piece of landscape
+ * @param tile end tile of area dragging
+ * @param p1 start tile of area dragging
+ * @param p2 unused
+ */
+int32 CmdClearArea(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	int32 cost, ret, money;
+	int ex;
+	int ey;
+	int sx,sy;
+	int x,y;
+	bool success = false;
+
+	if (p1 >= MapSize()) return CMD_ERROR;
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	// make sure sx,sy are smaller than ex,ey
+	ex = TileX(tile);
+	ey = TileY(tile);
+	sx = TileX(p1);
+	sy = TileY(p1);
+	if (ex < sx) intswap(ex, sx);
+	if (ey < sy) intswap(ey, sy);
+
+	money = GetAvailableMoneyForCommand();
+	cost = 0;
+
+	for (x = sx; x <= ex; ++x) {
+		for (y = sy; y <= ey; ++y) {
+			ret = DoCommand(TileXY(x, y), 0, 0, flags & ~DC_EXEC, CMD_LANDSCAPE_CLEAR);
+			if (CmdFailed(ret)) continue;
+			cost += ret;
+			success = true;
+
+			if (flags & DC_EXEC) {
+				if (ret > 0 && (money -= ret) < 0) {
+					_additional_cash_required = ret;
+					return cost - ret;
+				}
+				DoCommand(TileXY(x, y), 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+
+				// draw explosion animation...
+				if ((x == sx || x == ex) && (y == sy || y == ey)) {
+					// big explosion in each corner, or small explosion for single tiles
+					CreateEffectVehicleAbove(x * TILE_SIZE + TILE_SIZE / 2, y * TILE_SIZE + TILE_SIZE / 2, 2,
+						sy == ey && sx == ex ? EV_EXPLOSION_SMALL : EV_EXPLOSION_LARGE
+					);
+				}
+			}
+		}
+	}
+
+	return (success) ? cost : CMD_ERROR;
+}
+
+
+#define TILELOOP_BITS 4
+#define TILELOOP_SIZE (1 << TILELOOP_BITS)
+#define TILELOOP_ASSERTMASK ((TILELOOP_SIZE-1) + ((TILELOOP_SIZE-1) << MapLogX()))
+#define TILELOOP_CHKMASK (((1 << (MapLogX() - TILELOOP_BITS))-1) << TILELOOP_BITS)
+
+void RunTileLoop(void)
+{
+	TileIndex tile;
+	uint count;
+
+	tile = _cur_tileloop_tile;
+
+	assert( (tile & ~TILELOOP_ASSERTMASK) == 0);
+	count = (MapSizeX() / TILELOOP_SIZE) * (MapSizeY() / TILELOOP_SIZE);
+	do {
+		_tile_type_procs[GetTileType(tile)]->tile_loop_proc(tile);
+
+		if (TileX(tile) < MapSizeX() - TILELOOP_SIZE) {
+			tile += TILELOOP_SIZE; /* no overflow */
+		} else {
+			tile = TILE_MASK(tile - TILELOOP_SIZE * (MapSizeX() / TILELOOP_SIZE - 1) + TileDiffXY(0, TILELOOP_SIZE)); /* x would overflow, also increase y */
+		}
+	} while (--count);
+	assert( (tile & ~TILELOOP_ASSERTMASK) == 0);
+
+	tile += 9;
+	if (tile & TILELOOP_CHKMASK)
+		tile = (tile + MapSizeX()) & TILELOOP_ASSERTMASK;
+	_cur_tileloop_tile = tile;
+}
+
+void InitializeLandscape(void)
+{
+	uint maxx = MapMaxX();
+	uint maxy = MapMaxY();
+	uint sizex = MapSizeX();
+	uint x;
+	uint y;
+
+	for (y = 0; y < maxy; y++) {
+		for (x = 0; x < maxx; x++) {
+			MakeClear(sizex * y + x, CLEAR_GRASS, 3);
+			SetTileHeight(sizex * y + x, 0);
+			_m[sizex * y + x].extra = 0;
+			ClearBridgeMiddle(sizex * y + x);
+		}
+		MakeVoid(sizex * y + x);
+	}
+	for (x = 0; x < sizex; x++) MakeVoid(sizex * y + x);
+}
+
+void ConvertGroundTilesIntoWaterTiles(void)
+{
+	TileIndex tile;
+	uint z;
+	Slope slope;
+
+	for (tile = 0; tile < MapSize(); ++tile) {
+		slope = GetTileSlope(tile, &z);
+		if (IsTileType(tile, MP_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:
+					MakeWater(tile);
+					break;
+
+				case SLOPE_N:
+				case SLOPE_E:
+				case SLOPE_S:
+				case SLOPE_W:
+				case SLOPE_NW:
+				case SLOPE_SW:
+				case SLOPE_SE:
+				case SLOPE_NE:
+					MakeShore(tile);
+					break;
+
+				default:
+					break;
+			}
+		}
+	}
+}
+
+static const byte _genterrain_tbl_1[5] = { 10, 22, 33, 37, 4  };
+static const byte _genterrain_tbl_2[5] = {  0,  0,  0,  0, 33 };
+
+static void GenerateTerrain(int type, int flag)
+{
+	uint32 r;
+	uint x;
+	uint y;
+	uint w;
+	uint h;
+	const Sprite* template;
+	const byte *p;
+	Tile* tile;
+	byte direction;
+
+	r = Random();
+	template = GetSprite((((r >> 24) * _genterrain_tbl_1[type]) >> 8) + _genterrain_tbl_2[type] + 4845);
+
+	x = r & MapMaxX();
+	y = (r >> MapLogX()) & MapMaxY();
+
+
+	if (x < 2 || y < 2) return;
+
+	direction = GB(r, 22, 2);
+	if (direction & 1) {
+		w = template->height;
+		h = template->width;
+	} else {
+		w = template->width;
+		h = template->height;
+	}
+	p = template->data;
+
+	if (flag & 4) {
+		uint xw = x * MapSizeY();
+		uint yw = y * MapSizeX();
+		uint bias = (MapSizeX() + MapSizeY()) * 16;
+
+		switch (flag & 3) {
+			case 0:
+				if (xw + yw > MapSize() - bias) return;
+				break;
+
+			case 1:
+				if (yw < xw + bias) return;
+				break;
+
+			case 2:
+				if (xw + yw < MapSize() + bias) return;
+				break;
+
+			case 3:
+				if (xw < yw + bias) return;
+				break;
+		}
+	}
+
+	if (x + w >= MapMaxX() - 1) return;
+	if (y + h >= MapMaxY() - 1) return;
+
+	tile = &_m[TileXY(x, y)];
+
+	switch (direction) {
+		case 0:
+			do {
+				Tile* tile_cur = tile;
+				uint w_cur;
+
+				for (w_cur = w; w_cur != 0; --w_cur) {
+					if (*p >= tile_cur->type_height) tile_cur->type_height = *p;
+					p++;
+					tile_cur++;
+				}
+				tile += TileDiffXY(0, 1);
+			} while (--h != 0);
+			break;
+
+		case 1:
+			do {
+				Tile* tile_cur = tile;
+				uint h_cur;
+
+				for (h_cur = h; h_cur != 0; --h_cur) {
+					if (*p >= tile_cur->type_height) tile_cur->type_height = *p;
+					p++;
+					tile_cur += TileDiffXY(0, 1);
+				}
+				tile++;
+			} while (--w != 0);
+			break;
+
+		case 2:
+			tile += TileDiffXY(w - 1, 0);
+			do {
+				Tile* tile_cur = tile;
+				uint w_cur;
+
+				for (w_cur = w; w_cur != 0; --w_cur) {
+					if (*p >= tile_cur->type_height) tile_cur->type_height = *p;
+					p++;
+					tile_cur--;
+				}
+				tile += TileDiffXY(0, 1);
+			} while (--h != 0);
+			break;
+
+		case 3:
+			tile += TileDiffXY(0, h - 1);
+			do {
+				Tile* tile_cur = tile;
+				uint h_cur;
+
+				for (h_cur = h; h_cur != 0; --h_cur) {
+					if (*p >= tile_cur->type_height) tile_cur->type_height = *p;
+					p++;
+					tile_cur -= TileDiffXY(0, 1);
+				}
+				tile++;
+			} while (--w != 0);
+			break;
+	}
+}
+
+
+#include "table/genland.h"
+
+static void CreateDesertOrRainForest(void)
+{
+	TileIndex tile;
+	TileIndex update_freq = MapSize() / 4;
+	const TileIndexDiffC *data;
+	uint i;
+
+	for (tile = 0; tile != MapSize(); ++tile) {
+		if ((tile % update_freq) == 0) IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+
+		for (data = _make_desert_or_rainforest_data;
+				data != endof(_make_desert_or_rainforest_data); ++data) {
+			TileIndex t = TILE_MASK(tile + ToTileIndexDiff(*data));
+			if (TileHeight(t) >= 4 || IsTileType(t, MP_WATER)) break;
+		}
+		if (data == endof(_make_desert_or_rainforest_data))
+			SetTropicZone(tile, TROPICZONE_DESERT);
+	}
+
+	for (i = 0; i != 256; i++) {
+		if ((i % 64) == 0) IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+
+		RunTileLoop();
+	}
+
+	for (tile = 0; tile != MapSize(); ++tile) {
+		if ((tile % update_freq) == 0) IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+
+		for (data = _make_desert_or_rainforest_data;
+				data != endof(_make_desert_or_rainforest_data); ++data) {
+			TileIndex t = TILE_MASK(tile + ToTileIndexDiff(*data));
+			if (IsTileType(t, MP_CLEAR) && IsClearGround(t, CLEAR_DESERT)) break;
+		}
+		if (data == endof(_make_desert_or_rainforest_data))
+			SetTropicZone(tile, TROPICZONE_RAINFOREST);
+	}
+}
+
+void GenerateLandscape(byte mode)
+{
+	const int gwp_desert_amount = 4 + 8;
+	uint i;
+	uint flag;
+	uint32 r;
+
+	if (mode == GW_HEIGHTMAP) {
+		SetGeneratingWorldProgress(GWP_LANDSCAPE, (_opt.landscape == LT_DESERT) ? 1 + gwp_desert_amount : 1);
+		LoadHeightmap(_file_to_saveload.name);
+		IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+	} else if (_patches.land_generator == LG_TERRAGENESIS) {
+		SetGeneratingWorldProgress(GWP_LANDSCAPE, (_opt.landscape == LT_DESERT) ? 3 + gwp_desert_amount : 3);
+		GenerateTerrainPerlin();
+	} else {
+		switch (_opt.landscape) {
+			case LT_HILLY:
+				SetGeneratingWorldProgress(GWP_LANDSCAPE, 2);
+
+				for (i = ScaleByMapSize((Random() & 0x7F) + 950); i != 0; --i) {
+					GenerateTerrain(2, 0);
+				}
+				IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+
+				r = Random();
+				flag = GB(r, 0, 2) | 4;
+				for (i = ScaleByMapSize(GB(r, 16, 7) + 450); i != 0; --i) {
+					GenerateTerrain(4, flag);
+				}
+				IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+				break;
+
+			case LT_DESERT:
+				SetGeneratingWorldProgress(GWP_LANDSCAPE, 3 + gwp_desert_amount);
+
+				for (i = ScaleByMapSize((Random() & 0x7F) + 170); i != 0; --i) {
+					GenerateTerrain(0, 0);
+				}
+				IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+
+				r = Random();
+				flag = GB(r, 0, 2) | 4;
+				for (i = ScaleByMapSize(GB(r, 16, 8) + 1700); i != 0; --i) {
+					GenerateTerrain(0, flag);
+				}
+				IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+
+				flag ^= 2;
+
+				for (i = ScaleByMapSize((Random() & 0x7F) + 410); i != 0; --i) {
+					GenerateTerrain(3, flag);
+				}
+				IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+				break;
+
+			default:
+				SetGeneratingWorldProgress(GWP_LANDSCAPE, 1);
+
+				i = ScaleByMapSize((Random() & 0x7F) + (3 - _opt.diff.quantity_sea_lakes) * 256 + 100);
+				for (; i != 0; --i) {
+					GenerateTerrain(_opt.diff.terrain_type, 0);
+				}
+				IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
+				break;
+		}
+	}
+
+	ConvertGroundTilesIntoWaterTiles();
+
+	if (_opt.landscape == LT_DESERT) CreateDesertOrRainForest();
+}
+
+void OnTick_Town(void);
+void OnTick_Trees(void);
+void OnTick_Station(void);
+void OnTick_Industry(void);
+
+void OnTick_Players(void);
+void OnTick_Train(void);
+
+void CallLandscapeTick(void)
+{
+	OnTick_Town();
+	OnTick_Trees();
+	OnTick_Station();
+	OnTick_Industry();
+
+	OnTick_Players();
+	OnTick_Train();
+}
+
+TileIndex AdjustTileCoordRandomly(TileIndex a, byte rng)
+{
+	int rn = rng;
+	uint32 r = Random();
+
+	return TILE_MASK(TileXY(
+		TileX(a) + (GB(r, 0, 8) * rn * 2 >> 8) - rn,
+		TileY(a) + (GB(r, 8, 8) * rn * 2 >> 8) - rn
+	));
+}
+
+bool IsValidTile(TileIndex tile)
+{
+	return (tile < MapSizeX() * MapMaxY() && TileX(tile) != MapMaxX());
+}