OpenTTD-patches/src/clear_cmd.cpp

/* $Id$ */

/** @file clear_cmd.cpp */

#include "stdafx.h"
#include "openttd.h"
#include "clear_map.h"
#include "rail_map.h"
#include "table/strings.h"
#include "functions.h"
#include "map.h"
#include "player.h"
#include "tile.h"
#include "viewport.h"
#include "command.h"
#include "tunnel_map.h"
#include "bridge_map.h"
#include "bridge.h"
#include "landscape.h"
#include "variables.h"
#include "table/sprites.h"
#include "unmovable_map.h"
#include "genworld.h"
#include "industry.h"

struct TerraformerHeightMod {
	TileIndex tile;
	byte height;
};

struct TerraformerState {
	int height[4];
	uint32 flags;

	int direction;
	int modheight_count;
	int tile_table_count;

	CommandCost cost;

	TileIndex *tile_table;
	TerraformerHeightMod *modheight;

};

static int TerraformAllowTileProcess(TerraformerState *ts, TileIndex tile)
{
	TileIndex *t;
	int count;

	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return -1;

	t = ts->tile_table;
	for (count = ts->tile_table_count; count != 0; count--, t++) {
		if (*t == tile) return 0;
	}

	return 1;
}

static int TerraformGetHeightOfTile(TerraformerState *ts, TileIndex tile)
{
	TerraformerHeightMod *mod = ts->modheight;
	int count;

	for (count = ts->modheight_count; count != 0; count--, mod++) {
		if (mod->tile == tile) return mod->height;
	}

	return TileHeight(tile);
}

static void TerraformAddDirtyTile(TerraformerState *ts, TileIndex tile)
{
	int count;
	TileIndex *t;

	count = ts->tile_table_count;

	if (count >= 625) return;

	for (t = ts->tile_table; count != 0; count--, t++) {
		if (*t == tile) return;
	}

	ts->tile_table[ts->tile_table_count++] = tile;
}

static void TerraformAddDirtyTileAround(TerraformerState *ts, TileIndex tile)
{
	TerraformAddDirtyTile(ts, tile + TileDiffXY( 0, -1));
	TerraformAddDirtyTile(ts, tile + TileDiffXY(-1, -1));
	TerraformAddDirtyTile(ts, tile + TileDiffXY(-1,  0));
	TerraformAddDirtyTile(ts, tile);
}

static int TerraformProc(TerraformerState *ts, TileIndex tile, int mode)
{
	int r;
	CommandCost ret;

	assert(tile < MapSize());

	r = TerraformAllowTileProcess(ts, tile);
	if (r <= 0) return r;

	if (IsTileType(tile, MP_RAILWAY)) {
		static const TrackBits safe_track[] = { TRACK_BIT_LOWER, TRACK_BIT_LEFT, TRACK_BIT_UPPER, TRACK_BIT_RIGHT };
		static const Slope unsafe_slope[] = { SLOPE_S, SLOPE_W, SLOPE_N, SLOPE_E };

		Slope tileh;
		uint z;

		/* Nothing could be built at the steep slope - this avoids a bug
		 * when you have a single diagonal track in one corner on a
		 * basement and then you raise/lower the other corner. */
		tileh = GetTileSlope(tile, &z);
		if (tileh == unsafe_slope[mode] ||
				tileh == ComplementSlope(unsafe_slope[mode])) {
			_terraform_err_tile = tile;
			_error_message = STR_1008_MUST_REMOVE_RAILROAD_TRACK;
			return -1;
		}

		/* If we have a single diagonal track there, the other side of
		 * tile can be terraformed. */
		if (IsPlainRailTile(tile) && GetTrackBits(tile) == safe_track[mode]) {
			/* If terraforming downwards prevent damaging a potential tunnel below.
			 * This check is only necessary for flat tiles, because if the tile is
			 * non-flat, then the corner opposing the rail is raised. Only this corner
			 * can be lowered and this is a safe action
			 */
			if (tileh == SLOPE_FLAT &&
					ts->direction == -1 &&
					IsTunnelInWay(tile, z - TILE_HEIGHT)) {
				_terraform_err_tile = tile;
				_error_message = STR_1002_EXCAVATION_WOULD_DAMAGE;
				return -1;
			}
			return 0;
		}
	}

	ret = DoCommand(tile, 0, 0, ts->flags & ~DC_EXEC, CMD_LANDSCAPE_CLEAR);

	if (CmdFailed(ret)) {
		_terraform_err_tile = tile;
		return -1;
	}

	ts->cost.AddCost(ret.GetCost());

	if (ts->tile_table_count >= 625) return -1;
	ts->tile_table[ts->tile_table_count++] = tile;

	return 0;
}

static bool TerraformTileHeight(TerraformerState *ts, TileIndex tile, int height)
{
	int nh;
	TerraformerHeightMod *mod;
	int count;

	assert(tile < MapSize());

	if (height < 0) {
		_error_message = STR_1003_ALREADY_AT_SEA_LEVEL;
		return false;
	}

	_error_message = STR_1004_TOO_HIGH;

	if (height > 15) return false;

	nh = TerraformGetHeightOfTile(ts, tile);
	if (nh < 0 || height == nh) return false;

	if (TerraformProc(ts, tile, 0) < 0) return false;
	if (TerraformProc(ts, tile + TileDiffXY( 0, -1), 1) < 0) return false;
	if (TerraformProc(ts, tile + TileDiffXY(-1, -1), 2) < 0) return false;
	if (TerraformProc(ts, tile + TileDiffXY(-1,  0), 3) < 0) return false;

	mod = ts->modheight;
	count = ts->modheight_count;

	for (;;) {
		if (count == 0) {
			if (ts->modheight_count >= 576) return false;
			ts->modheight_count++;
			break;
		}
		if (mod->tile == tile) break;
		mod++;
		count--;
	}

	mod->tile = tile;
	mod->height = (byte)height;

	ts->cost.AddCost(_price.terraform);

	{
		int direction = ts->direction, r;
		const TileIndexDiffC *ttm;

		static const TileIndexDiffC _terraform_tilepos[] = {
			{ 1,  0},
			{-2,  0},
			{ 1,  1},
			{ 0, -2}
		};

		for (ttm = _terraform_tilepos; ttm != endof(_terraform_tilepos); ttm++) {
			tile += ToTileIndexDiff(*ttm);

			r = TerraformGetHeightOfTile(ts, tile);
			if (r != height && r - direction != height && r + direction != height) {
				if (!TerraformTileHeight(ts, tile, r + direction))
					return false;
			}
		}
	}

	return true;
}

/** Terraform land
 * @param tile tile to terraform
 * @param flags for this command type
 * @param p1 corners to terraform.
 * @param p2 direction; eg up or down
 * @return error or cost of terraforming
 */
CommandCost CmdTerraformLand(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	TerraformerState ts;
	TileIndex t;
	int direction;

	TerraformerHeightMod modheight_data[576];
	TileIndex tile_table_data[625];

	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);

	_terraform_err_tile = 0;

	ts.direction = direction = p2 ? 1 : -1;
	ts.flags = flags;
	ts.modheight_count = ts.tile_table_count = 0;
	ts.cost = CommandCost();
	ts.modheight = modheight_data;
	ts.tile_table = tile_table_data;

	/* Make an extra check for map-bounds cause we add tiles to the originating tile */
	if (tile + TileDiffXY(1, 1) >= MapSize()) return CMD_ERROR;

	if (p1 & 1) {
		t = tile + TileDiffXY(1, 0);
		if (!TerraformTileHeight(&ts, t, TileHeight(t) + direction)) {
			return CMD_ERROR;
		}
	}

	if (p1 & 2) {
		t = tile + TileDiffXY(1, 1);
		if (!TerraformTileHeight(&ts, t, TileHeight(t) + direction)) {
			return CMD_ERROR;
		}
	}

	if (p1 & 4) {
		t = tile + TileDiffXY(0, 1);
		if (!TerraformTileHeight(&ts, t, TileHeight(t) + direction)) {
			return CMD_ERROR;
		}
	}

	if (p1 & 8) {
		t = tile + TileDiffXY(0, 0);
		if (!TerraformTileHeight(&ts, t, TileHeight(t) + direction)) {
			return CMD_ERROR;
		}
	}

	{
		/* Check if tunnel would take damage */
		int count;
		TileIndex *ti = ts.tile_table;

		for (count = ts.tile_table_count; count != 0; count--, ti++) {
			TileIndex tile = *ti;

			uint z_min = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 0));
			uint z_max = z_min;
			uint t = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 0));
			z_min = min(z_min, t);
			z_max = max(z_max, t);
			t = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 1));
			z_min = min(z_min, t);
			z_max = max(z_max, t);
			t = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 1));
			z_min = min(z_min, t);
			z_max = max(z_max, t);

			if (direction == 1 && MayHaveBridgeAbove(tile) && IsBridgeAbove(tile) &&
					GetBridgeHeight(GetSouthernBridgeEnd(tile)) <= z_max * TILE_HEIGHT) {
				return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
			}
			if (direction == -1 && IsTunnelInWay(tile, z_min * TILE_HEIGHT)) {
				return_cmd_error(STR_1002_EXCAVATION_WOULD_DAMAGE);
			}
		}
	}

	if (flags & DC_EXEC) {
		/* Clear the landscape at the tiles */
		{
			int count;
			TileIndex *ti = ts.tile_table;
			for (count = ts.tile_table_count; count != 0; count--, ti++) {
				DoCommand(*ti, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
			}
		}

		/* change the height */
		{
			int count;
			TerraformerHeightMod *mod;

			mod = ts.modheight;
			for (count = ts.modheight_count; count != 0; count--, mod++) {
				TileIndex til = mod->tile;

				SetTileHeight(til, mod->height);
				TerraformAddDirtyTileAround(&ts, til);
			}
		}

		/* finally mark the dirty tiles dirty */
		{
			int count;
			TileIndex *ti = ts.tile_table;
			for (count = ts.tile_table_count; count != 0; count--, ti++) {
				MarkTileDirtyByTile(*ti);
			}
		}
	}
	return ts.cost;
}


/** Levels a selected (rectangle) area of land
 * @param tile end tile of area-drag
 * @param flags for this command type
 * @param p1 start tile of area drag
 * @param p2 unused
 * @return  error or cost of terraforming
 */
CommandCost CmdLevelLand(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	int size_x, size_y;
	int ex;
	int ey;
	int sx, sy;
	uint h, curh;
	CommandCost money;
	CommandCost ret;
	CommandCost cost;

	if (p1 >= MapSize()) return CMD_ERROR;

	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);

	/* remember level height */
	h = TileHeight(p1);

	/* make sure sx,sy are smaller than ex,ey */
	ex = TileX(tile);
	ey = TileY(tile);
	sx = TileX(p1);
	sy = TileY(p1);
	if (ex < sx) Swap(ex, sx);
	if (ey < sy) Swap(ey, sy);
	tile = TileXY(sx, sy);

	size_x = ex - sx + 1;
	size_y = ey - sy + 1;

	money.AddCost(GetAvailableMoneyForCommand());

	BEGIN_TILE_LOOP(tile2, size_x, size_y, tile) {
		curh = TileHeight(tile2);
		while (curh != h) {
			ret = DoCommand(tile2, 8, (curh > h) ? 0 : 1, flags & ~DC_EXEC, CMD_TERRAFORM_LAND);
			if (CmdFailed(ret)) break;

			if (flags & DC_EXEC) {
				money.AddCost(-ret.GetCost());
				if (money.GetCost() < 0) {
					_additional_cash_required = ret.GetCost();
					return cost;
				}
				DoCommand(tile2, 8, (curh > h) ? 0 : 1, flags, CMD_TERRAFORM_LAND);
			}

			cost.AddCost(ret);
			curh += (curh > h) ? -1 : 1;
		}
	} END_TILE_LOOP(tile2, size_x, size_y, tile)

	return (cost.GetCost() == 0) ? CMD_ERROR : cost;
}

/** Purchase a land area. Actually you only purchase one tile, so
 * the name is a bit confusing ;p
 * @param tile the tile the player is purchasing
 * @param flags for this command type
 * @param p1 unused
 * @param p2 unused
 * @return error of cost of operation
 */
CommandCost CmdPurchaseLandArea(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	CommandCost cost;

	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);

	if (!EnsureNoVehicle(tile)) return CMD_ERROR;

	if (IsOwnedLandTile(tile) && IsTileOwner(tile, _current_player)) {
		return_cmd_error(STR_5807_YOU_ALREADY_OWN_IT);
	}

	cost = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
	if (CmdFailed(cost)) return CMD_ERROR;

	if (flags & DC_EXEC) {
		MakeOwnedLand(tile, _current_player);
		MarkTileDirtyByTile(tile);
	}

	return cost.AddCost(_price.purchase_land * 10);
}


static CommandCost ClearTile_Clear(TileIndex tile, byte flags)
{
	static const Money* clear_price_table[] = {
		&_price.clear_1,
		&_price.purchase_land,
		&_price.clear_2,
		&_price.clear_3,
		&_price.purchase_land,
		&_price.purchase_land,
		&_price.clear_2, // XXX unused?
	};
	CommandCost price;

	if (!IsClearGround(tile, CLEAR_GRASS) || GetClearDensity(tile) != 0) {
		price.AddCost(*clear_price_table[GetClearGround(tile)]);
	}

	if (flags & DC_EXEC) DoClearSquare(tile);

	return price;
}

/** Sell a land area. Actually you only sell one tile, so
 * the name is a bit confusing ;p
 * @param tile the tile the player is selling
 * @param flags for this command type
 * @param p1 unused
 * @param p2 unused
 * @return error or cost of operation
 */
CommandCost CmdSellLandArea(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);

	if (!IsOwnedLandTile(tile)) return CMD_ERROR;
	if (!CheckTileOwnership(tile) && _current_player != OWNER_WATER) return CMD_ERROR;


	if (!EnsureNoVehicle(tile)) return CMD_ERROR;

	if (flags & DC_EXEC) DoClearSquare(tile);

	return CommandCost(- _price.purchase_land * 2);
}


#include "table/clear_land.h"


void DrawClearLandTile(const TileInfo *ti, byte set)
{
	DrawGroundSprite(SPR_FLAT_BARE_LAND + _tileh_to_sprite[ti->tileh] + set * 19, PAL_NONE);
}

void DrawHillyLandTile(const TileInfo *ti)
{
	if (ti->tileh != SLOPE_FLAT) {
		DrawGroundSprite(SPR_FLAT_ROUGH_LAND + _tileh_to_sprite[ti->tileh], PAL_NONE);
	} else {
		DrawGroundSprite(_landscape_clear_sprites[GB(ti->x ^ ti->y, 4, 3)], PAL_NONE);
	}
}

void DrawClearLandFence(const TileInfo *ti)
{
	byte z = ti->z;

	if (ti->tileh & SLOPE_S) {
		z += TILE_HEIGHT;
		if (ti->tileh == SLOPE_STEEP_S) z += TILE_HEIGHT;
	}

	if (GetFenceSW(ti->tile) != 0) {
		DrawGroundSpriteAt(_clear_land_fence_sprites_1[GetFenceSW(ti->tile) - 1] + _fence_mod_by_tileh[ti->tileh], PAL_NONE, ti->x, ti->y, z);
	}

	if (GetFenceSE(ti->tile) != 0) {
		DrawGroundSpriteAt(_clear_land_fence_sprites_1[GetFenceSE(ti->tile) - 1] + _fence_mod_by_tileh_2[ti->tileh], PAL_NONE, ti->x, ti->y, z);
	}
}

static void DrawTile_Clear(TileInfo *ti)
{
	switch (GetClearGround(ti->tile)) {
		case CLEAR_GRASS:
			DrawClearLandTile(ti, GetClearDensity(ti->tile));
			break;

		case CLEAR_ROUGH:
			DrawHillyLandTile(ti);
			break;

		case CLEAR_ROCKS:
			DrawGroundSprite(SPR_FLAT_ROCKY_LAND_1 + _tileh_to_sprite[ti->tileh], PAL_NONE);
			break;

		case CLEAR_FIELDS:
			DrawGroundSprite(_clear_land_sprites_1[GetFieldType(ti->tile)] + _tileh_to_sprite[ti->tileh], PAL_NONE);
			break;

		case CLEAR_SNOW:
			DrawGroundSprite(_clear_land_sprites_2[GetClearDensity(ti->tile)] + _tileh_to_sprite[ti->tileh], PAL_NONE);
			break;

		case CLEAR_DESERT:
			DrawGroundSprite(_clear_land_sprites_3[GetClearDensity(ti->tile)] + _tileh_to_sprite[ti->tileh], PAL_NONE);
			break;
	}

	DrawClearLandFence(ti);
	DrawBridgeMiddle(ti);
}

static uint GetSlopeZ_Clear(TileIndex tile, uint x, uint y)
{
	uint z;
	Slope tileh = GetTileSlope(tile, &z);

	return z + GetPartialZ(x & 0xF, y & 0xF, tileh);
}

static Slope GetSlopeTileh_Clear(TileIndex tile, Slope tileh)
{
	return tileh;
}

static void GetAcceptedCargo_Clear(TileIndex tile, AcceptedCargo ac)
{
	/* unused */
}

static void AnimateTile_Clear(TileIndex tile)
{
	/* unused */
}

void TileLoopClearHelper(TileIndex tile)
{
	byte self;
	byte neighbour;
	TileIndex dirty = INVALID_TILE;

	self = (IsTileType(tile, MP_CLEAR) && IsClearGround(tile, CLEAR_FIELDS));

	neighbour = (IsTileType(TILE_ADDXY(tile, 1, 0), MP_CLEAR) && IsClearGround(TILE_ADDXY(tile, 1, 0), CLEAR_FIELDS));
	if (GetFenceSW(tile) == 0) {
		if (self != neighbour) {
			SetFenceSW(tile, 3);
			dirty = tile;
		}
	} else {
		if (self == 0 && neighbour == 0) {
			SetFenceSW(tile, 0);
			dirty = tile;
		}
	}

	neighbour = (IsTileType(TILE_ADDXY(tile, 0, 1), MP_CLEAR) && IsClearGround(TILE_ADDXY(tile, 0, 1), CLEAR_FIELDS));
	if (GetFenceSE(tile) == 0) {
		if (self != neighbour) {
			SetFenceSE(tile, 3);
			dirty = tile;
		}
	} else {
		if (self == 0 && neighbour == 0) {
			SetFenceSE(tile, 0);
			dirty = tile;
		}
	}

	if (dirty != INVALID_TILE) MarkTileDirtyByTile(dirty);
}


/* convert into snowy tiles */
static void TileLoopClearAlps(TileIndex tile)
{
	int k = GetTileZ(tile) - GetSnowLine() + TILE_HEIGHT;

	if (k < 0) { // well below the snow line
		if (!IsClearGround(tile, CLEAR_SNOW)) return;
		if (GetClearDensity(tile) == 0) SetClearGroundDensity(tile, CLEAR_GRASS, 3);
	} else {
		if (!IsClearGround(tile, CLEAR_SNOW)) {
			SetClearGroundDensity(tile, CLEAR_SNOW, 0);
		} else {
			uint density = min((uint)k / TILE_HEIGHT, 3);

			if (GetClearDensity(tile) < density) {
				AddClearDensity(tile, 1);
			} else if (GetClearDensity(tile) > density) {
				AddClearDensity(tile, -1);
			} else {
				return;
			}
		}
	}

	MarkTileDirtyByTile(tile);
}

static void TileLoopClearDesert(TileIndex tile)
{
	if (IsClearGround(tile, CLEAR_DESERT)) return;

	if (GetTropicZone(tile) == TROPICZONE_DESERT) {
		SetClearGroundDensity(tile, CLEAR_DESERT, 3);
	} else {
		if (GetTropicZone(tile + TileDiffXY( 1,  0)) != TROPICZONE_DESERT &&
				GetTropicZone(tile + TileDiffXY(-1,  0)) != TROPICZONE_DESERT &&
				GetTropicZone(tile + TileDiffXY( 0,  1)) != TROPICZONE_DESERT &&
				GetTropicZone(tile + TileDiffXY( 0, -1)) != TROPICZONE_DESERT)
			return;
		SetClearGroundDensity(tile, CLEAR_DESERT, 1);
	}

	MarkTileDirtyByTile(tile);
}

static void TileLoop_Clear(TileIndex tile)
{
	TileLoopClearHelper(tile);

	switch (_opt.landscape) {
		case LT_TROPIC: TileLoopClearDesert(tile); break;
		case LT_ARCTIC: TileLoopClearAlps(tile);   break;
	}

	switch (GetClearGround(tile)) {
		case CLEAR_GRASS:
			if (GetClearDensity(tile) == 3) return;

			if (_game_mode != GM_EDITOR) {
				if (GetClearCounter(tile) < 7) {
					AddClearCounter(tile, 1);
					return;
				} else {
					SetClearCounter(tile, 0);
					AddClearDensity(tile, 1);
				}
			} else {
				SetClearGroundDensity(tile, GB(Random(), 0, 8) > 21 ? CLEAR_GRASS : CLEAR_ROUGH, 3);
			}
			break;

		case CLEAR_FIELDS: {
			uint field_type;

			if (_game_mode == GM_EDITOR) return;

			if (GetClearCounter(tile) < 7) {
				AddClearCounter(tile, 1);
				return;
			} else {
				SetClearCounter(tile, 0);
			}

			if (GetIndustryIndexOfField(tile) == INVALID_INDUSTRY && GetFieldType(tile) >= 7) {
				/* This farmfield is no longer farmfield, so make it grass again */
				MakeClear(tile, CLEAR_GRASS, 2);
			} else {
				field_type = GetFieldType(tile);
				field_type = (field_type < 8) ? field_type + 1 : 0;
				SetFieldType(tile, field_type);
			}
			break;
		}

		default:
			return;
	}

	MarkTileDirtyByTile(tile);
}

void GenerateClearTile()
{
	uint i, gi;
	TileIndex tile;

	/* add rough tiles */
	i = ScaleByMapSize(GB(Random(), 0, 10) + 0x400);
	gi = ScaleByMapSize(GB(Random(), 0, 7) + 0x80);

	SetGeneratingWorldProgress(GWP_ROUGH_ROCKY, gi + i);
	do {
		IncreaseGeneratingWorldProgress(GWP_ROUGH_ROCKY);
		tile = RandomTile();
		if (IsTileType(tile, MP_CLEAR) && !IsClearGround(tile, CLEAR_DESERT)) SetClearGroundDensity(tile, CLEAR_ROUGH, 3);
	} while (--i);

	/* add rocky tiles */
	i = gi;
	do {
		uint32 r = Random();
		tile = RandomTileSeed(r);

		IncreaseGeneratingWorldProgress(GWP_ROUGH_ROCKY);
		if (IsTileType(tile, MP_CLEAR) && !IsClearGround(tile, CLEAR_DESERT)) {
			uint j = GB(r, 16, 4) + 5;
			for (;;) {
				TileIndex tile_new;

				SetClearGroundDensity(tile, CLEAR_ROCKS, 3);
				do {
					if (--j == 0) goto get_out;
					tile_new = tile + TileOffsByDiagDir(GB(Random(), 0, 2));
				} while (!IsTileType(tile_new, MP_CLEAR) || IsClearGround(tile_new, CLEAR_DESERT));
				tile = tile_new;
			}
get_out:;
		}
	} while (--i);
}

static void ClickTile_Clear(TileIndex tile)
{
	/* not used */
}

static uint32 GetTileTrackStatus_Clear(TileIndex tile, TransportType mode, uint sub_mode)
{
	return 0;
}

static const StringID _clear_land_str[] = {
	STR_080D_GRASS,
	STR_080B_ROUGH_LAND,
	STR_080A_ROCKS,
	STR_080E_FIELDS,
	STR_080F_SNOW_COVERED_LAND,
	STR_0810_DESERT
};

static void GetTileDesc_Clear(TileIndex tile, TileDesc *td)
{
	if (IsClearGround(tile, CLEAR_GRASS) && GetClearDensity(tile) == 0) {
		td->str = STR_080C_BARE_LAND;
	} else {
		td->str = _clear_land_str[GetClearGround(tile)];
	}
	td->owner = GetTileOwner(tile);
}

static void ChangeTileOwner_Clear(TileIndex tile, PlayerID old_player, PlayerID new_player)
{
	return;
}

void InitializeClearLand()
{
	_opt.snow_line = _patches.snow_line_height * TILE_HEIGHT;
}

extern const TileTypeProcs _tile_type_clear_procs = {
	DrawTile_Clear,           ///< draw_tile_proc
	GetSlopeZ_Clear,          ///< get_slope_z_proc
	ClearTile_Clear,          ///< clear_tile_proc
	GetAcceptedCargo_Clear,   ///< get_accepted_cargo_proc
	GetTileDesc_Clear,        ///< get_tile_desc_proc
	GetTileTrackStatus_Clear, ///< get_tile_track_status_proc
	ClickTile_Clear,          ///< click_tile_proc
	AnimateTile_Clear,        ///< animate_tile_proc
	TileLoop_Clear,           ///< tile_loop_clear
	ChangeTileOwner_Clear,    ///< change_tile_owner_clear
	NULL,                     ///< get_produced_cargo_proc
	NULL,                     ///< vehicle_enter_tile_proc
	GetSlopeTileh_Clear,      ///< get_slope_tileh_proc
};