src/tree_cmd.cpp
author truebrain
Thu, 12 Jun 2008 19:47:02 +0000
branchnoai
changeset 10942 cd3f2d07199f
parent 10776 07203fc29812
permissions -rw-r--r--
(svn r13496) [NoAI] -Fix: if a library depends on an other library, the import became globally known, which defeats the idea of imports. They are now restricted to their scope, and 'import' returns the class of import (if any)
/* $Id$ */

/** @file tree_cmd.cpp Handling of tree tiles. */

#include "stdafx.h"
#include "openttd.h"
#include "bridge_map.h"
#include "clear_map.h"
#include "tile_cmd.h"
#include "landscape.h"
#include "tree_map.h"
#include "viewport_func.h"
#include "command_func.h"
#include "economy_func.h"
#include "town.h"
#include "variables.h"
#include "genworld.h"
#include "transparency.h"
#include "functions.h"
#include "player_func.h"
#include "sound_func.h"
#include "settings_type.h"
#include "water_map.h"
#include "water.h"
#include "landscape_type.h"

#include "table/strings.h"
#include "table/sprites.h"
#include "table/tree_land.h"

/**
 * List of tree placer algorithm.
 *
 * This enumeration defines all possible tree placer algorithm in the game.
 */
enum TreePlacer {
	TP_NONE,     ///< No tree placer algorithm
	TP_ORIGINAL, ///< The original algorithm
	TP_IMPROVED, ///< A 'improved' algorithm
};

/**
 * Tests if a tile can be converted to MP_TREES
 * This is true for clear ground without farms or rocks.
 *
 * @param tile the tile of interest
 * @param allow_desert Allow planting trees on CLEAR_DESERT?
 * @return true if trees can be built.
 */
static bool CanPlantTreesOnTile(TileIndex tile, bool allow_desert)
{
	switch (GetTileType(tile)) {
		case MP_WATER:
			return !IsBridgeAbove(tile) && IsCoast(tile) && !IsSlopeWithOneCornerRaised(GetTileSlope(tile, NULL));

		case MP_CLEAR:
			return !IsBridgeAbove(tile) && !IsClearGround(tile, CLEAR_FIELDS) && !IsClearGround(tile, CLEAR_ROCKS) &&
			       (allow_desert || !IsClearGround(tile, CLEAR_DESERT));

		default: return false;
	}
}

/**
 * Creates a tree tile
 * Ground type and density is preserved.
 *
 * @pre the tile must be suitable for trees.
 *
 * @param tile where to plant the trees.
 * @param type The type of the tree
 * @param count the number of trees (minus 1)
 * @param growth the growth status
 */
static void PlantTreesOnTile(TileIndex tile, TreeType treetype, uint count, uint growth)
{
	assert(treetype != TREE_INVALID);
	assert(CanPlantTreesOnTile(tile, true));

	TreeGround ground;
	uint density = 3;

	switch (GetTileType(tile)) {
		case MP_WATER:
			ground = TREE_GROUND_SHORE;
			break;

		case MP_CLEAR:
			switch (GetClearGround(tile)) {
				case CLEAR_GRASS:  ground = TREE_GROUND_GRASS;       density = GetClearDensity(tile); break;
				case CLEAR_ROUGH:  ground = TREE_GROUND_ROUGH;                                        break;
				default:           ground = TREE_GROUND_SNOW_DESERT; density = GetClearDensity(tile); break;
			}
			break;

		default: NOT_REACHED();
	}

	MakeTree(tile, treetype, count, growth, ground, density);
}

/**
 * Get a random TreeType for the given tile based on a given seed
 *
 * This function returns a random TreeType which can be placed on the given tile.
 * The seed for randomness must be less or equal 256, use #GB on the value of Random()
 * to get such a value.
 *
 * @param tile The tile to get a random TreeType from
 * @param seed The seed for randomness, must be less or equal 256
 * @return The random tree type
 */
static TreeType GetRandomTreeType(TileIndex tile, uint seed)
{
	switch (_settings_game.game_creation.landscape) {
		case LT_TEMPERATE:
			return (TreeType)(seed * TREE_COUNT_TEMPERATE / 256 + TREE_TEMPERATE);

		case LT_ARCTIC:
			return (TreeType)(seed * TREE_COUNT_SUB_ARCTIC / 256 + TREE_SUB_ARCTIC);

		case LT_TROPIC:
			switch (GetTropicZone(tile)) {
				case TROPICZONE_NORMAL:  return (TreeType)(seed * TREE_COUNT_SUB_TROPICAL / 256 + TREE_SUB_TROPICAL);
				case TROPICZONE_DESERT:  return (TreeType)((seed > 12) ? TREE_INVALID : TREE_CACTUS);
				default:                 return (TreeType)(seed * TREE_COUNT_RAINFOREST / 256 + TREE_RAINFOREST);
			}

		default:
			return (TreeType)(seed * TREE_COUNT_TOYLAND / 256 + TREE_TOYLAND);
	}
}

/**
 * Make a random tree tile of the given tile
 *
 * Create a new tree-tile for the given tile. The second parameter is used for
 * randomness like type and number of trees.
 *
 * @param tile The tile to make a tree-tile from
 * @param r The randomness value from a Random() value
 */
static void PlaceTree(TileIndex tile, uint32 r)
{
	TreeType tree = GetRandomTreeType(tile, GB(r, 24, 8));

	if (tree != TREE_INVALID) {
		PlantTreesOnTile(tile, tree, GB(r, 22, 2), min(GB(r, 16, 3), 6));

		/* Rerandomize ground, if neither snow nor shore */
		TreeGround ground = GetTreeGround(tile);
		if (ground != TREE_GROUND_SNOW_DESERT && ground != TREE_GROUND_SHORE) {
			SetTreeGroundDensity(tile, (TreeGround)GB(r, 28, 1), 3);
		}

		/* Set the counter to a random start value */
		SetTreeCounter(tile, (TreeGround)GB(r, 24, 4));
	}
}

/**
 * Place some amount of trees around a given tile.
 *
 * This function adds some trees around a given tile. As this function use
 * the Random() call it depends on the random how many trees are actually placed
 * around the given tile.
 *
 * @param tile The center of the trees to add
 */
static void DoPlaceMoreTrees(TileIndex tile)
{
	uint i;

	for (i = 0; i < 1000; i++) {
		uint32 r = Random();
		int x = GB(r, 0, 5) - 16;
		int y = GB(r, 8, 5) - 16;
		uint dist = abs(x) + abs(y);
		TileIndex cur_tile = TILE_MASK(tile + TileDiffXY(x, y));

		if (dist <= 13 && CanPlantTreesOnTile(cur_tile, true)) {
			PlaceTree(cur_tile, r);
		}
	}
}

/**
 * Place more trees on the map.
 *
 * This function add more trees to the map.
 */
static void PlaceMoreTrees()
{
	uint i = ScaleByMapSize(GB(Random(), 0, 5) + 25);
	do {
		DoPlaceMoreTrees(RandomTile());
	} while (--i);
}

/**
 * Place a tree at the same height as an existing tree.
 *
 * Add a new tree around the given tile which is at the same
 * height or at some offset (2 units) of it.
 *
 * @param tile The base tile to add a new tree somewhere around
 * @param height The height (like the one from the tile)
 */
static void PlaceTreeAtSameHeight(TileIndex tile, uint height)
{
	uint i;

	for (i = 0; i < 1000; i++) {
		uint32 r = Random();
		int x = GB(r, 0, 5) - 16;
		int y = GB(r, 8, 5) - 16;
		TileIndex cur_tile = TILE_MASK(tile + TileDiffXY(x, y));

		/* Keep in range of the existing tree */
		if (abs(x) + abs(y) > 16) continue;

		/* Clear tile, no farm-tiles or rocks */
		if (!CanPlantTreesOnTile(cur_tile, true)) continue;

		/* Not too much height difference */
		if (Delta(GetTileZ(cur_tile), height) > 2) continue;

		/* Place one tree and quit */
		PlaceTree(cur_tile, r);
		break;
	}
}

/**
 * Place some trees randomly
 *
 * This function just place some trees randomly on the map.
 */
void PlaceTreesRandomly()
{
	uint i, j, ht;

	i = ScaleByMapSize(1000);
	do {
		uint32 r = Random();
		TileIndex tile = RandomTileSeed(r);

		IncreaseGeneratingWorldProgress(GWP_TREE);

		if (CanPlantTreesOnTile(tile, true)) {
			PlaceTree(tile, r);
			if (_settings_game.game_creation.tree_placer != TP_IMPROVED) continue;

			/* Place a number of trees based on the tile height.
			 *  This gives a cool effect of multiple trees close together.
			 *  It is almost real life ;) */
			ht = GetTileZ(tile);
			/* The higher we get, the more trees we plant */
			j = GetTileZ(tile) / TILE_HEIGHT * 2;
			while (j--) {
				/* Above snowline more trees! */
				if (_settings_game.game_creation.landscape == LT_ARCTIC && ht > GetSnowLine()) {
					PlaceTreeAtSameHeight(tile, ht);
					PlaceTreeAtSameHeight(tile, ht);
				};

				PlaceTreeAtSameHeight(tile, ht);
			}
		}
	} while (--i);

	/* place extra trees at rainforest area */
	if (_settings_game.game_creation.landscape == LT_TROPIC) {
		i = ScaleByMapSize(15000);

		do {
			uint32 r = Random();
			TileIndex tile = RandomTileSeed(r);

			IncreaseGeneratingWorldProgress(GWP_TREE);

			if (GetTropicZone(tile) == TROPICZONE_RAINFOREST && CanPlantTreesOnTile(tile, false)) {
				PlaceTree(tile, r);
			}
		} while (--i);
	}
}

/**
 * Place new trees.
 *
 * This function takes care of the selected tree placer algorithm and
 * place randomly the trees for a new game.
 */
void GenerateTrees()
{
	uint i, total;

	if (_settings_game.game_creation.tree_placer == TP_NONE) return;

	if (_settings_game.game_creation.landscape != LT_TOYLAND) PlaceMoreTrees();

	switch (_settings_game.game_creation.tree_placer) {
		case TP_ORIGINAL: i = _settings_game.game_creation.landscape == LT_ARCTIC ? 15 : 6; break;
		case TP_IMPROVED: i = _settings_game.game_creation.landscape == LT_ARCTIC ?  4 : 2; break;
		default: NOT_REACHED(); return;
	}

	total = ScaleByMapSize(1000);
	if (_settings_game.game_creation.landscape == LT_TROPIC) total += ScaleByMapSize(15000);
	total *= i;
	SetGeneratingWorldProgress(GWP_TREE, total);

	for (; i != 0; i--) {
		PlaceTreesRandomly();
	}
}

/** Plant a tree.
 * @param tile start tile of area-drag of tree plantation
 * @param flags type of operation
 * @param p1 tree type, -1 means random.
 * @param p2 end tile of area-drag
 */
CommandCost CmdPlantTree(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	StringID msg = INVALID_STRING_ID;
	CommandCost cost(EXPENSES_OTHER);
	int ex;
	int ey;
	int sx, sy, x, y;

	if (p2 >= MapSize()) return CMD_ERROR;
	/* Check the tree type. It can be random or some valid value within the current climate */
	if (p1 != (uint)-1 && p1 - _tree_base_by_landscape[_settings_game.game_creation.landscape] >= _tree_count_by_landscape[_settings_game.game_creation.landscape]) return CMD_ERROR;

	// make sure sx,sy are smaller than ex,ey
	ex = TileX(tile);
	ey = TileY(tile);
	sx = TileX(p2);
	sy = TileY(p2);
	if (ex < sx) Swap(ex, sx);
	if (ey < sy) Swap(ey, sy);

	for (x = sx; x <= ex; x++) {
		for (y = sy; y <= ey; y++) {
			TileIndex tile = TileXY(x, y);

			switch (GetTileType(tile)) {
				case MP_TREES:
					/* no more space for trees? */
					if (_game_mode != GM_EDITOR && GetTreeCount(tile) == 3) {
						msg = STR_2803_TREE_ALREADY_HERE;
						continue;
					}

					if (flags & DC_EXEC) {
						AddTreeCount(tile, 1);
						MarkTileDirtyByTile(tile);
					}
					/* 2x as expensive to add more trees to an existing tile */
					cost.AddCost(_price.build_trees * 2);
					break;

				case MP_WATER:
					if (!IsCoast(tile) || IsSlopeWithOneCornerRaised(GetTileSlope(tile, NULL))) {
						msg = STR_3807_CAN_T_BUILD_ON_WATER;
						continue;
					}
				/* FALL THROUGH */
				case MP_CLEAR:
					if (IsBridgeAbove(tile)) {
						msg = STR_2804_SITE_UNSUITABLE;
						continue;
					}

					if (IsTileType(tile, MP_CLEAR)) {
						/* Remove fields or rocks. Note that the ground will get barrened */
						switch (GetClearGround(tile)) {
							case CLEAR_FIELDS:
							case CLEAR_ROCKS: {
								CommandCost ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
								if (CmdFailed(ret)) return ret;
								cost.AddCost(ret);
								break;
							}

							default: break;
						}
					}

					if (_game_mode != GM_EDITOR && IsValidPlayer(_current_player)) {
						Town *t = ClosestTownFromTile(tile, _settings_game.economy.dist_local_authority);
						if (t != NULL) ChangeTownRating(t, RATING_TREE_UP_STEP, RATING_TREE_MAXIMUM);
					}

					if (flags & DC_EXEC) {
						TreeType treetype;

						treetype = (TreeType)p1;
						if (treetype == TREE_INVALID) {
							treetype = GetRandomTreeType(tile, GB(Random(), 24, 8));
							if (treetype == TREE_INVALID) treetype = TREE_CACTUS;
						}

						/* Plant full grown trees in scenario editor */
						PlantTreesOnTile(tile, treetype, 0, _game_mode == GM_EDITOR ? 3 : 0);
						MarkTileDirtyByTile(tile);

						/* When planting rainforest-trees, set tropiczone to rainforest in editor. */
						if (_game_mode == GM_EDITOR && IsInsideMM(treetype, TREE_RAINFOREST, TREE_CACTUS))
							SetTropicZone(tile, TROPICZONE_RAINFOREST);
					}
					cost.AddCost(_price.build_trees);
					break;

				default:
					msg = STR_2804_SITE_UNSUITABLE;
					break;
			}
		}
	}

	if (cost.GetCost() == 0) {
		return_cmd_error(msg);
	} else {
		return cost;
	}
}

struct TreeListEnt {
	SpriteID image;
	SpriteID pal;
	byte x, y;
};

static void DrawTile_Trees(TileInfo *ti)
{
	switch (GetTreeGround(ti->tile)) {
		case TREE_GROUND_SHORE: DrawShoreTile(ti->tileh); break;
		case TREE_GROUND_GRASS: DrawClearLandTile(ti, GetTreeDensity(ti->tile)); break;
		case TREE_GROUND_ROUGH: DrawHillyLandTile(ti); break;
		default: DrawGroundSprite(_tree_sprites_1[GetTreeDensity(ti->tile)] + _tileh_to_sprite[ti->tileh], PAL_NONE); break;
	}

	DrawClearLandFence(ti);

	/* Do not draw trees when the invisible trees patch and transparency tree are set */
	if (IsInvisibilitySet(TO_TREES)) return;

	uint16 tmp = ti->x;

	tmp = ROR(tmp, 2);
	tmp -= ti->y;
	tmp = ROR(tmp, 3);
	tmp -= ti->x;
	tmp = ROR(tmp, 1);
	tmp += ti->y;

	uint index = GB(tmp, 6, 2) + (GetTreeType(ti->tile) << 2);

	/* different tree styles above one of the grounds */
	if (GetTreeGround(ti->tile) == TREE_GROUND_SNOW_DESERT &&
			GetTreeDensity(ti->tile) >= 2 &&
			IsInsideMM(index, TREE_SUB_ARCTIC << 2, TREE_RAINFOREST << 2)) {
		index += 164 - (TREE_SUB_ARCTIC << 2);
	}

	assert(index < lengthof(_tree_layout_sprite));

	const PalSpriteID *s = _tree_layout_sprite[index];
	const TreePos *d = _tree_layout_xy[GB(tmp, 4, 2)];

	/* combine trees into one sprite object */
	StartSpriteCombine();

	TreeListEnt te[4];

	/* put the trees to draw in a list */
	uint trees = GetTreeCount(ti->tile) + 1;

	for (uint i = 0; i < trees; i++) {
		SpriteID image = s[0].sprite + (i == trees - 1 ? GetTreeGrowth(ti->tile) : 3);
		SpriteID pal = s[0].pal;

		te[i].image = image;
		te[i].pal   = pal;
		te[i].x = d->x;
		te[i].y = d->y;
		s++;
		d++;
	}

	/* draw them in a sorted way */
	byte z = ti->z + GetSlopeMaxZ(ti->tileh) / 2;

	for (; trees > 0; trees--) {
		uint min = te[0].x + te[0].y;
		uint mi = 0;

		for (uint i = 1; i < trees; i++) {
			if ((uint)(te[i].x + te[i].y) < min) {
				min = te[i].x + te[i].y;
				mi = i;
			}
		}

		AddSortableSpriteToDraw(te[mi].image, te[mi].pal, ti->x + te[mi].x, ti->y + te[mi].y, 16 - te[mi].x, 16 - te[mi].y, 0x30, z, IsTransparencySet(TO_TREES), -te[mi].x, -te[mi].y);

		/* replace the removed one with the last one */
		te[mi] = te[trees - 1];
	}

	EndSpriteCombine();
}


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

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

static Foundation GetFoundation_Trees(TileIndex tile, Slope tileh)
{
	return FOUNDATION_NONE;
}

static CommandCost ClearTile_Trees(TileIndex tile, byte flags)
{
	uint num;

	if (IsValidPlayer(_current_player)) {
		Town *t = ClosestTownFromTile(tile, _settings_game.economy.dist_local_authority);
		if (t != NULL) ChangeTownRating(t, RATING_TREE_DOWN_STEP, RATING_TREE_MINIMUM);
	}

	num = GetTreeCount(tile) + 1;
	if (IsInsideMM(GetTreeType(tile), TREE_RAINFOREST, TREE_CACTUS)) num *= 4;

	if (flags & DC_EXEC) DoClearSquare(tile);

	return CommandCost(EXPENSES_CONSTRUCTION, num * _price.remove_trees);
}

static void GetAcceptedCargo_Trees(TileIndex tile, AcceptedCargo ac)
{
	/* not used */
}

static void GetTileDesc_Trees(TileIndex tile, TileDesc *td)
{
	TreeType tt = GetTreeType(tile);

	if (IsInsideMM(tt, TREE_RAINFOREST, TREE_CACTUS)) {
		td->str = STR_280F_RAINFOREST;
	} else {
		td->str = tt == TREE_CACTUS ? STR_2810_CACTUS_PLANTS : STR_280E_TREES;
	}

	td->owner[0] = GetTileOwner(tile);
}

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

static void TileLoopTreesDesert(TileIndex tile)
{
	switch (GetTropicZone(tile)) {
		case TROPICZONE_DESERT:
			if (GetTreeGround(tile) != TREE_GROUND_SNOW_DESERT) {
				SetTreeGroundDensity(tile, TREE_GROUND_SNOW_DESERT, 3);
				MarkTileDirtyByTile(tile);
			}
			break;

		case TROPICZONE_RAINFOREST: {
			static const SoundFx forest_sounds[] = {
				SND_42_LOON_BIRD,
				SND_43_LION,
				SND_44_MONKEYS,
				SND_48_DISTANT_BIRD
			};
			uint32 r = Random();

			if (Chance16I(1, 200, r)) SndPlayTileFx(forest_sounds[GB(r, 16, 2)], tile);
			break;
		}

		default: break;
	}
}

static void TileLoopTreesAlps(TileIndex tile)
{
	int k = GetTileZ(tile) - GetSnowLine() + TILE_HEIGHT;

	if (k < 0) {
		if (GetTreeGround(tile) != TREE_GROUND_SNOW_DESERT) return;
		SetTreeGroundDensity(tile, TREE_GROUND_GRASS, 3);
	} else {
		uint density = min((uint)k / TILE_HEIGHT, 3);

		if (GetTreeGround(tile) != TREE_GROUND_SNOW_DESERT ||
				GetTreeDensity(tile) != density) {
			SetTreeGroundDensity(tile, TREE_GROUND_SNOW_DESERT, density);
		} else {
			if (GetTreeDensity(tile) == 3) {
				uint32 r = Random();
				if (Chance16I(1, 200, r)) {
					SndPlayTileFx((r & 0x80000000) ? SND_39_HEAVY_WIND : SND_34_WIND, tile);
				}
			}
			return;
		}
	}
	MarkTileDirtyByTile(tile);
}

static void TileLoop_Trees(TileIndex tile)
{
	if (GetTreeGround(tile) == TREE_GROUND_SHORE) {
		TileLoop_Water(tile);
	} else {
		switch (_settings_game.game_creation.landscape) {
			case LT_TROPIC: TileLoopTreesDesert(tile); break;
			case LT_ARCTIC: TileLoopTreesAlps(tile);   break;
		}
	}

	TileLoopClearHelper(tile);

	uint treeCounter = GetTreeCounter(tile);

	/* Handle growth of grass at every 8th processings, like it's done for grass */
	if ((treeCounter & 7) == 7 && GetTreeGround(tile) == TREE_GROUND_GRASS) {
		uint density = GetTreeDensity(tile);
		if (density < 3) {
			SetTreeGroundDensity(tile, TREE_GROUND_GRASS, density + 1);
			MarkTileDirtyByTile(tile);
		}
	}
	if (GetTreeCounter(tile) < 15) {
		AddTreeCounter(tile, 1);
		return;
	}
	SetTreeCounter(tile, 0);

	switch (GetTreeGrowth(tile)) {
		case 3: /* regular sized tree */
			if (_settings_game.game_creation.landscape == LT_TROPIC &&
					GetTreeType(tile) != TREE_CACTUS &&
					GetTropicZone(tile) == TROPICZONE_DESERT) {
				AddTreeGrowth(tile, 1);
			} else {
				switch (GB(Random(), 0, 3)) {
					case 0: /* start destructing */
						AddTreeGrowth(tile, 1);
						break;

					case 1: /* add a tree */
						if (GetTreeCount(tile) < 3) {
							AddTreeCount(tile, 1);
							SetTreeGrowth(tile, 0);
							break;
						}
						/* FALL THROUGH */

					case 2: { /* add a neighbouring tree */
						TreeType treetype = GetTreeType(tile);

						tile += TileOffsByDir((Direction)(Random() & 7));

						/* Cacti don't spread */
						if (!CanPlantTreesOnTile(tile, false)) return;

						/* Don't plant trees, if ground was freshly cleared */
						if (IsTileType(tile, MP_CLEAR) && GetClearGround(tile) == CLEAR_GRASS && GetClearDensity(tile) != 3) return;

						PlantTreesOnTile(tile, treetype, 0, 0);

						break;
					}

					default:
						return;
				}
			}
			break;

		case 6: /* final stage of tree destruction */
			if (GetTreeCount(tile) > 0) {
				/* more than one tree, delete it */
				AddTreeCount(tile, -1);
				SetTreeGrowth(tile, 3);
			} else {
				/* just one tree, change type into MP_CLEAR */
				switch (GetTreeGround(tile)) {
					case TREE_GROUND_SHORE: MakeShore(tile); break;
					case TREE_GROUND_GRASS: MakeClear(tile, CLEAR_GRASS, GetTreeDensity(tile)); break;
					case TREE_GROUND_ROUGH: MakeClear(tile, CLEAR_ROUGH, 3); break;
					default: // snow or desert
						MakeClear(tile, _settings_game.game_creation.landscape == LT_TROPIC ? CLEAR_DESERT : CLEAR_SNOW, GetTreeDensity(tile));
						break;
				}
			}
			break;

		default:
			AddTreeGrowth(tile, 1);
			break;
	}

	MarkTileDirtyByTile(tile);
}

void OnTick_Trees()
{
	uint32 r;
	TileIndex tile;
	TreeType tree;

	/* place a tree at a random rainforest spot */
	if (_settings_game.game_creation.landscape == LT_TROPIC &&
			(r = Random(), tile = RandomTileSeed(r), GetTropicZone(tile) == TROPICZONE_RAINFOREST) &&
			CanPlantTreesOnTile(tile, false) &&
			(tree = GetRandomTreeType(tile, GB(r, 24, 8))) != TREE_INVALID) {
		PlantTreesOnTile(tile, tree, 0, 0);
	}

	/* byte underflow */
	if (--_trees_tick_ctr != 0) return;

	/* place a tree at a random spot */
	r = Random();
	tile = TILE_MASK(r);
	if (CanPlantTreesOnTile(tile, false) && (tree = GetRandomTreeType(tile, GB(r, 24, 8))) != TREE_INVALID) {
		PlantTreesOnTile(tile, tree, 0, 0);
	}
}

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

static TrackStatus GetTileTrackStatus_Trees(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
{
	return 0;
}

static void ChangeTileOwner_Trees(TileIndex tile, PlayerID old_player, PlayerID new_player)
{
	/* not used */
}

void InitializeTrees()
{
	_trees_tick_ctr = 0;
}

static CommandCost TerraformTile_Trees(TileIndex tile, uint32 flags, uint z_new, Slope tileh_new)
{
	return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
}


extern const TileTypeProcs _tile_type_trees_procs = {
	DrawTile_Trees,           /* draw_tile_proc */
	GetSlopeZ_Trees,          /* get_slope_z_proc */
	ClearTile_Trees,          /* clear_tile_proc */
	GetAcceptedCargo_Trees,   /* get_accepted_cargo_proc */
	GetTileDesc_Trees,        /* get_tile_desc_proc */
	GetTileTrackStatus_Trees, /* get_tile_track_status_proc */
	ClickTile_Trees,          /* click_tile_proc */
	AnimateTile_Trees,        /* animate_tile_proc */
	TileLoop_Trees,           /* tile_loop_clear */
	ChangeTileOwner_Trees,    /* change_tile_owner_clear */
	NULL,                     /* get_produced_cargo_proc */
	NULL,                     /* vehicle_enter_tile_proc */
	GetFoundation_Trees,      /* get_foundation_proc */
	TerraformTile_Trees,      /* terraform_tile_proc */
};