tron@2186: /* $Id$ */
tron@2186: 
belugas@6352: /** @file pathfind.cpp */
belugas@6352: 
truelight@0: #include "stdafx.h"
Darkvater@1891: #include "openttd.h"
tron@3234: #include "bridge_map.h"
KUDr@3900: #include "station_map.h"
KUDr@3900: #include "depot.h"
rubidium@8119: #include "tile_cmd.h"
maedhros@6453: #include "landscape.h"
truelight@0: #include "pathfind.h"
rubidium@8103: #include "rail_type.h"
ludde@2044: #include "debug.h"
tron@3154: #include "tunnel_map.h"
rubidium@8270: #include "settings_type.h"
KUDr@3735: #include "depot.h"
smatz@8083: #include "tunnelbridge_map.h"
rubidium@8119: #include "core/random_func.hpp"
truelight@0: 
belugas@6352: /* remember which tiles we have already visited so we don't visit them again. */
tron@1977: static bool TPFSetTileBit(TrackPathFinder *tpf, TileIndex tile, int dir)
truelight@0: {
truelight@0: 	uint hash, val, offs;
truelight@0: 	TrackPathFinderLink *link, *new_link;
truelight@0: 	uint bits = 1 << dir;
truelight@0: 
truelight@0: 	if (tpf->disable_tile_hash)
truelight@0: 		return true;
truelight@0: 
truelight@0: 	hash = PATHFIND_HASH_TILE(tile);
truelight@0: 
truelight@0: 	val = tpf->hash_head[hash];
truelight@0: 
truelight@0: 	if (val == 0) {
truelight@0: 		/* unused hash entry, set the appropriate bit in it and return true
truelight@0: 		 * to indicate that a bit was set. */
truelight@0: 		tpf->hash_head[hash] = bits;
tron@1986: 		tpf->hash_tile[hash] = tile;
truelight@0: 		return true;
truelight@0: 	} else if (!(val & 0x8000)) {
truelight@0: 		/* single tile */
truelight@0: 
tron@1986: 		if (tile == tpf->hash_tile[hash]) {
truelight@0: 			/* found another bit for the same tile,
truelight@0: 			 * check if this bit is already set, if so, return false */
truelight@0: 			if (val & bits)
truelight@0: 				return false;
truelight@0: 
truelight@0: 			/* otherwise set the bit and return true to indicate that the bit
truelight@0: 			 * was set */
truelight@0: 			tpf->hash_head[hash] = val | bits;
truelight@0: 			return true;
truelight@0: 		} else {
truelight@0: 			/* two tiles with the same hash, need to make a link */
truelight@193: 
truelight@0: 			/* allocate a link. if out of links, handle this by returning
truelight@0: 			 * that a tile was already visisted. */
ludde@2044: 			if (tpf->num_links_left == 0) {
truelight@0: 				return false;
ludde@2044: 			}
truelight@0: 			tpf->num_links_left--;
truelight@0: 			link = tpf->new_link++;
truelight@0: 
truelight@0: 			/* move the data that was previously in the hash_??? variables
truelight@0: 			 * to the link struct, and let the hash variables point to the link */
truelight@0: 			link->tile = tpf->hash_tile[hash];
truelight@0: 			tpf->hash_tile[hash] = PATHFIND_GET_LINK_OFFS(tpf, link);
truelight@0: 
truelight@0: 			link->flags = tpf->hash_head[hash];
belugas@6352: 			tpf->hash_head[hash] = 0xFFFF; // multi link
truelight@0: 
truelight@0: 			link->next = 0xFFFF;
truelight@0: 		}
truelight@0: 	} else {
truelight@0: 		/* a linked list of many tiles,
truelight@0: 		 * find the one corresponding to the tile, if it exists.
truelight@0: 		 * otherwise make a new link */
truelight@193: 
truelight@0: 		offs = tpf->hash_tile[hash];
truelight@0: 		do {
truelight@0: 			link = PATHFIND_GET_LINK_PTR(tpf, offs);
tron@1986: 			if (tile == link->tile) {
truelight@0: 				/* found the tile in the link list,
truelight@0: 				 * check if the bit was alrady set, if so return false to indicate that the
truelight@0: 				 * bit was already set */
truelight@0: 				if (link->flags & bits)
truelight@0: 					return false;
truelight@0: 				link->flags |= bits;
truelight@0: 				return true;
truelight@0: 			}
truelight@0: 		} while ((offs=link->next) != 0xFFFF);
truelight@0: 	}
truelight@193: 
truelight@0: 	/* get here if we need to add a new link to link,
truelight@0: 	 * first, allocate a new link, in the same way as before */
ludde@2044: 	if (tpf->num_links_left == 0) {
truelight@0: 			return false;
ludde@2044: 	}
truelight@0: 	tpf->num_links_left--;
truelight@0: 	new_link = tpf->new_link++;
truelight@0: 
truelight@0: 	/* then fill the link with the new info, and establish a ptr from the old
truelight@0: 	 * link to the new one */
tron@1986: 	new_link->tile = tile;
truelight@0: 	new_link->flags = bits;
truelight@0: 	new_link->next = 0xFFFF;
truelight@0: 
truelight@0: 	link->next = PATHFIND_GET_LINK_OFFS(tpf, new_link);
truelight@0: 	return true;
truelight@0: }
truelight@0: 
truelight@0: static const byte _bits_mask[4] = {
truelight@0: 	0x19,
truelight@0: 	0x16,
truelight@0: 	0x25,
truelight@0: 	0x2A,
truelight@0: };
truelight@0: 
rubidium@5587: static const DiagDirection _tpf_new_direction[14] = {
rubidium@5587: 	DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW, DIAGDIR_SE,
rubidium@5587: 	INVALID_DIAGDIR, INVALID_DIAGDIR,
rubidium@5587: 	DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE,
truelight@0: };
truelight@0: 
rubidium@5587: static const DiagDirection _tpf_prev_direction[14] = {
rubidium@5587: 	DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW,
rubidium@5587: 	INVALID_DIAGDIR, INVALID_DIAGDIR,
rubidium@5587: 	DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE, DIAGDIR_NW,
truelight@0: };
truelight@0: 
truelight@0: 
truelight@0: static const byte _otherdir_mask[4] = {
truelight@0: 	0x10,
truelight@0: 	0,
truelight@0: 	0x5,
truelight@0: 	0x2A,
truelight@0: };
truelight@0: 
tron@3153: static void TPFMode2(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
truelight@0: {
truelight@0: 	uint bits;
truelight@0: 	RememberData rd;
truelight@747: 
celestar@3618: 	assert(tpf->tracktype == TRANSPORT_WATER);
truelight@0: 
belugas@6352: 	/* This addition will sometimes overflow by a single tile.
belugas@6352: 	 * The use of TILE_MASK here makes sure that we still point at a valid
belugas@6352: 	 * tile, and then this tile will be in the sentinel row/col, so GetTileTrackStatus will fail. */
Darkvater@4559: 	tile = TILE_MASK(tile + TileOffsByDiagDir(direction));
truelight@0: 
truelight@0: 	if (++tpf->rd.cur_length > 50)
truelight@0: 		return;
truelight@193: 
rubidium@6683: 	bits = GetTileTrackStatus(tile, tpf->tracktype, tpf->sub_type);
truelight@0: 	bits = (byte)((bits | (bits >> 8)) & _bits_mask[direction]);
truelight@0: 	if (bits == 0)
truelight@0: 		return;
truelight@0: 
tron@926: 	assert(TileX(tile) != MapMaxX() && TileY(tile) != MapMaxY());
truelight@0: 
skidd13@7930: 	uint i = 0;
skidd13@7930: 	/* only one direction */
skidd13@7930: 	if (KillFirstBit(bits) == 0) {
skidd13@7930: 		i = FindFirstBit(bits);
truelight@0: 		rd = tpf->rd;
truelight@0: 		goto continue_here;
truelight@0: 	}
truelight@0: 	/* several directions */
truelight@0: 	do {
skidd13@7930: 		i = FindFirstBit(bits);
truelight@0: 		rd = tpf->rd;
truelight@0: 
belugas@6352: 		/* Change direction 4 times only */
truelight@0: 		if ((byte)i != tpf->rd.pft_var6) {
tron@2952: 			if (++tpf->rd.depth > 4) {
truelight@193: 				tpf->rd = rd;
truelight@0: 				return;
truelight@0: 			}
truelight@0: 			tpf->rd.pft_var6 = (byte)i;
truelight@0: 		}
truelight@0: 
skidd13@7930: continue_here:
skidd13@7928: 		tpf->the_dir = (Trackdir)(i + (HasBit(_otherdir_mask[direction], i) ? 8 : 0));
truelight@193: 
truelight@0: 		if (!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, NULL)) {
truelight@0: 			TPFMode2(tpf, tile, _tpf_new_direction[tpf->the_dir]);
truelight@0: 		}
truelight@0: 
truelight@0: 		tpf->rd = rd;
skidd13@7930: 	} while (ClrBit(bits, i) != 0);
truelight@0: 
truelight@0: }
truelight@0: 
truelight@0: 
darkvater@22: /* Returns the end tile and the length of a tunnel. The length does not
darkvater@22:  * include the starting tile (entry), it does include the end tile (exit).
darkvater@22:  */
tron@3420: FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, DiagDirection dir)
truelight@0: {
Darkvater@4559: 	TileIndexDiff delta = TileOffsByDiagDir(dir);
tron@3420: 	uint z = GetTileZ(tile);
truelight@0: 	FindLengthOfTunnelResult flotr;
truelight@0: 
truelight@0: 	flotr.length = 0;
truelight@0: 
tron@3420: 	dir = ReverseDiagDir(dir);
tron@3420: 	do {
truelight@0: 		flotr.length++;
tron@3420: 		tile += delta;
tron@3420: 	} while(
tron@3420: 		!IsTunnelTile(tile) ||
smatz@8083: 		GetTunnelBridgeDirection(tile) != dir ||
tron@3420: 		GetTileZ(tile) != z
tron@3420: 	);
truelight@0: 
truelight@0: 	flotr.tile = tile;
truelight@0: 	return flotr;
truelight@0: }
truelight@0: 
truelight@0: static const uint16 _tpfmode1_and[4] = { 0x1009, 0x16, 0x520, 0x2A00 };
truelight@0: 
tron@3157: static uint SkipToEndOfTunnel(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
tron@1977: {
truelight@0: 	FindLengthOfTunnelResult flotr;
truelight@0: 	TPFSetTileBit(tpf, tile, 14);
truelight@159: 	flotr = FindLengthOfTunnel(tile, direction);
truelight@0: 	tpf->rd.cur_length += flotr.length;
truelight@0: 	TPFSetTileBit(tpf, flotr.tile, 14);
truelight@0: 	return flotr.tile;
truelight@0: }
truelight@0: 
peter1138@7071: static void TPFMode1(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction);
truelight@0: 
peter1138@7071: /** Most code of the "Normal" case of TPF Mode 1; for signals special tricks
peter1138@7071:  * have to be done, but those happen in TPFMode1; this is just to prevent
peter1138@7071:  * gotos ;). */
peter1138@7071: static inline void TPFMode1_NormalCase(TrackPathFinder* tpf, TileIndex tile, TileIndex tile_org, DiagDirection direction)
peter1138@7071: {
peter1138@5455: 	/* Check in case of rail if the owner is the same */
peter1138@5455: 	if (tpf->tracktype == TRANSPORT_RAIL) {
belugas@6352: 		/* don't enter train depot from the back */
peter1138@5455: 		if (IsTileDepotType(tile, TRANSPORT_RAIL) && GetRailDepotDirection(tile) == direction) return;
KUDr@5417: 
peter1138@5455: 		if (IsTileType(tile_org, MP_RAILWAY) || IsTileType(tile_org, MP_STATION) || IsTileType(tile_org, MP_TUNNELBRIDGE))
peter1138@5455: 			if (IsTileType(tile, MP_RAILWAY) || IsTileType(tile, MP_STATION) || IsTileType(tile, MP_TUNNELBRIDGE))
peter1138@5455: 				if (GetTileOwner(tile_org) != GetTileOwner(tile)) return;
truelight@752: 	}
truelight@747: 
belugas@6352: 	/* check if the new tile can be entered from that direction */
peter1138@5455: 	if (tpf->tracktype == TRANSPORT_ROAD) {
belugas@6352: 		/* road stops and depots now have a track (r4419)
belugas@6352: 		 * don't enter road stop from the back */
rubidium@6012: 		if (IsStandardRoadStopTile(tile) && ReverseDiagDir(GetRoadStopDir(tile)) != direction) return;
belugas@6352: 		/* don't enter road depot from the back */
peter1138@5455: 		if (IsTileDepotType(tile, TRANSPORT_ROAD) && ReverseDiagDir(GetRoadDepotDirection(tile)) != direction) return;
peter1138@5455: 	}
KUDr@3900: 
peter1138@5457: 	/* Check if the new tile is a tunnel or bridge head and that the direction
peter1138@5457: 	 * and transport type match */
peter1138@5457: 	if (IsTileType(tile, MP_TUNNELBRIDGE)) {
smatz@8088: 		if (GetTunnelBridgeDirection(tile) != direction ||
smatz@8088: 				GetTunnelBridgeTransportType(tile) != tpf->tracktype) {
smatz@8088: 			return;
peter1138@5457: 		}
peter1138@5457: 	}
peter1138@5457: 
truelight@0: 	tpf->rd.cur_length++;
truelight@0: 
peter1138@7071: 	uint bits = GetTileTrackStatus(tile, tpf->tracktype, tpf->sub_type);
peter1138@5455: 
truelight@0: 	if ((byte)bits != tpf->var2) {
truelight@0: 		bits &= _tpfmode1_and[direction];
skidd13@7930: 		bits |= bits >> 8;
truelight@0: 	}
truelight@0: 	bits &= 0xBF;
truelight@0: 
truelight@0: 	if (bits != 0) {
truelight@7833: 		if (!tpf->disable_tile_hash || (tpf->rd.cur_length <= 64 && (KillFirstBit(bits) == 0 || ++tpf->rd.depth <= 7))) {
truelight@0: 			do {
peter1138@7071: 				int i = FIND_FIRST_BIT(bits);
truelight@7833: 				bits = KillFirstBit(bits);
truelight@0: 
belugas@6352: 				tpf->the_dir = (Trackdir)((_otherdir_mask[direction] & (byte)(1 << i)) ? (i + 8) : i);
peter1138@7071: 				RememberData rd = tpf->rd;
truelight@193: 
truelight@0: 				if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&
truelight@0: 						!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {
truelight@0: 					TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);
truelight@0: 				}
truelight@0: 				tpf->rd = rd;
truelight@0: 			} while (bits != 0);
truelight@0: 		}
truelight@0: 	}
peter1138@7071: }
peter1138@7071: 
peter1138@7071: static void TPFMode1(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
peter1138@7071: {
peter1138@7071: 	TileIndex tile_org = tile;
peter1138@7071: 
peter1138@7071: 	if (IsTileType(tile, MP_TUNNELBRIDGE)) {
peter1138@7071: 		if (IsTunnel(tile)) {
smatz@8083: 			if (GetTunnelBridgeTransportType(tile) != tpf->tracktype) {
peter1138@7071: 				return;
peter1138@7071: 			}
matthijs@7080: 			/* Only skip through the tunnel if heading inwards. We can
matthijs@7080: 			 * be headed outwards if our starting position was in a
matthijs@7080: 			 * tunnel and we're pathfinding backwards */
smatz@8083: 			if (GetTunnelBridgeDirection(tile) == direction) {
matthijs@7080: 				tile = SkipToEndOfTunnel(tpf, tile, direction);
smatz@8083: 			} else if (GetTunnelBridgeDirection(tile) != ReverseDiagDir(direction)) {
matthijs@7080: 				/* We don't support moving through the sides of a tunnel
matthijs@7080: 				 * entrance :-) */
matthijs@7080: 				return;
matthijs@7080: 			}
peter1138@7071: 		} else {
peter1138@7071: 			TileIndex tile_end;
smatz@8083: 			if (GetTunnelBridgeDirection(tile) != direction ||
smatz@8083: 					GetTunnelBridgeTransportType(tile) != tpf->tracktype) {
peter1138@7071: 				return;
peter1138@7071: 			}
peter1138@7071: 			//fprintf(stderr, "%s: Planning over bridge\n", __func__);
peter1138@7071: 			// TODO doesn't work - WHAT doesn't work?
peter1138@7071: 			TPFSetTileBit(tpf, tile, 14);
peter1138@7071: 			tile_end = GetOtherBridgeEnd(tile);
peter1138@7071: 			tpf->rd.cur_length += DistanceManhattan(tile, tile_end);
peter1138@7071: 			tile = tile_end;
peter1138@7071: 			TPFSetTileBit(tpf, tile, 14);
peter1138@7071: 		}
peter1138@7071: 	}
peter1138@7071: 	tile += TileOffsByDiagDir(direction);
peter1138@7071: 
peter1138@7071: 	TPFMode1_NormalCase(tpf, tile, tile_org, direction);
truelight@0: 
truelight@0: 	/* the next is only used when signals are checked.
truelight@0: 	 * seems to go in 2 directions simultaneously */
truelight@193: 
truelight@0: 	/* if i can get rid of this, tail end recursion can be used to minimize
truelight@193: 	 * stack space dramatically. */
matthijs@2006: 
matthijs@2006: 	/* If we are doing signal setting, we must reverse at evere tile, so we
matthijs@2006: 	 * iterate all the tracks in a signal block, even when a normal train would
matthijs@2006: 	 * not reach it (for example, when two lines merge */
truelight@0: 	if (tpf->hasbit_13)
truelight@0: 		return;
truelight@193: 
tron@3153: 	direction = ReverseDiagDir(direction);
peter1138@5456: 	tile += TileOffsByDiagDir(direction);
truelight@0: 
peter1138@7071: 	uint bits = GetTileTrackStatus(tile, tpf->tracktype, tpf->sub_type);
truelight@0: 	bits |= (bits >> 8);
truelight@0: 
truelight@0: 	if ( (byte)bits != tpf->var2) {
truelight@0: 		bits &= _bits_mask[direction];
truelight@0: 	}
truelight@0: 
truelight@0: 	bits &= 0xBF;
truelight@0: 	if (bits == 0)
truelight@0: 		return;
truelight@0: 
truelight@0: 	do {
peter1138@7071: 		uint i = FIND_FIRST_BIT(bits);
truelight@7833: 		bits = KillFirstBit(bits);
truelight@193: 
belugas@6352: 		tpf->the_dir = (Trackdir)((_otherdir_mask[direction] & (byte)(1 << i)) ? (i + 8) : i);
peter1138@7071: 		RememberData rd = tpf->rd;
truelight@0: 		if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&
truelight@0: 				!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {
truelight@0: 			TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);
truelight@0: 		}
truelight@0: 		tpf->rd = rd;
truelight@0: 	} while (bits != 0);
truelight@0: }
truelight@0: 
rubidium@6683: void FollowTrack(TileIndex tile, uint16 flags, uint sub_type, DiagDirection direction, TPFEnumProc *enum_proc, TPFAfterProc *after_proc, void *data)
truelight@0: {
darkvater@318: 	TrackPathFinder tpf;
truelight@0: 
truelight@0: 	assert(direction < 4);
truelight@0: 
truelight@193: 	/* initialize path finder variables */
darkvater@318: 	tpf.userdata = data;
darkvater@318: 	tpf.enum_proc = enum_proc;
darkvater@318: 	tpf.new_link = tpf.links;
darkvater@318: 	tpf.num_links_left = lengthof(tpf.links);
truelight@0: 
darkvater@318: 	tpf.rd.cur_length = 0;
darkvater@318: 	tpf.rd.depth = 0;
darkvater@318: 	tpf.rd.pft_var6 = 0;
truelight@193: 
skidd13@7928: 	tpf.var2 = HasBit(flags, 15) ? 0x43 : 0xFF; // 0x8000
truelight@0: 
skidd13@7928: 	tpf.disable_tile_hash = HasBit(flags, 12);  // 0x1000
skidd13@7928: 	tpf.hasbit_13         = HasBit(flags, 13);  // 0x2000
truelight@0: 
truelight@0: 
rubidium@5587: 	tpf.tracktype = (TransportType)(flags & 0xFF);
rubidium@6683: 	tpf.sub_type = sub_type;
truelight@0: 
skidd13@7928: 	if (HasBit(flags, 11)) {
darkvater@318: 		tpf.rd.pft_var6 = 0xFF;
rubidium@5587: 		tpf.enum_proc(tile, data, INVALID_TRACKDIR, 0, 0);
darkvater@318: 		TPFMode2(&tpf, tile, direction);
truelight@0: 	} else {
truelight@0: 		/* clear the hash_heads */
darkvater@318: 		memset(tpf.hash_head, 0, sizeof(tpf.hash_head));
darkvater@318: 		TPFMode1(&tpf, tile, direction);
truelight@0: 	}
truelight@0: 
truelight@0: 	if (after_proc != NULL)
darkvater@318: 		after_proc(&tpf);
truelight@0: }
truelight@0: 
rubidium@6248: struct StackedItem {
truelight@0: 	TileIndex tile;
belugas@6352: 	uint16 cur_length; ///< This is the current length to this tile.
belugas@6352: 	uint16 priority;   ///< This is the current length + estimated length to the goal.
rubidium@5587: 	TrackdirByte track;
truelight@0: 	byte depth;
truelight@0: 	byte state;
truelight@0: 	byte first_track;
rubidium@6248: };
truelight@0: 
rubidium@5587: static const Trackdir _new_trackdir[6][4] = {
rubidium@5587: {TRACKDIR_X_NE,    INVALID_TRACKDIR, TRACKDIR_X_SW,    INVALID_TRACKDIR,},
rubidium@5587: {INVALID_TRACKDIR, TRACKDIR_Y_SE,    INVALID_TRACKDIR, TRACKDIR_Y_NW,},
rubidium@5587: {INVALID_TRACKDIR, TRACKDIR_UPPER_E, TRACKDIR_UPPER_W, INVALID_TRACKDIR,},
rubidium@5587: {TRACKDIR_LOWER_E, INVALID_TRACKDIR, INVALID_TRACKDIR, TRACKDIR_LOWER_W,},
rubidium@5587: {TRACKDIR_LEFT_N,  TRACKDIR_LEFT_S,  INVALID_TRACKDIR, INVALID_TRACKDIR,},
rubidium@5587: {INVALID_TRACKDIR, INVALID_TRACKDIR, TRACKDIR_RIGHT_S, TRACKDIR_RIGHT_N,},
truelight@0: };
truelight@0: 
rubidium@6248: struct HashLink {
truelight@0: 	TileIndex tile;
truelight@0: 	uint16 typelength;
truelight@0: 	uint16 next;
rubidium@6248: };
truelight@0: 
rubidium@6248: struct NewTrackPathFinder {
ludde@2125: 	NTPEnumProc *enum_proc;
truelight@0: 	void *userdata;
ludde@2125: 	TileIndex dest;
truelight@0: 
celestar@3355: 	TransportType tracktype;
rubidium@8236: 	RailTypes railtypes;
truelight@0: 	uint maxlength;
truelight@0: 
truelight@0: 	HashLink *new_link;
truelight@0: 	uint num_links_left;
truelight@0: 
tron@979: 	uint nstack;
belugas@6352: 	StackedItem stack[256];     ///< priority queue of stacked items
truelight@0: 
belugas@6352: 	uint16 hash_head[0x400];    ///< hash heads. 0 means unused. 0xFFFC = length, 0x3 = dir
belugas@6352: 	TileIndex hash_tile[0x400]; ///< tiles. or links.
truelight@0: 
belugas@6352: 	HashLink links[0x400];      ///< hash links
truelight@0: 
rubidium@6248: };
truelight@0: #define NTP_GET_LINK_OFFS(tpf, link) ((byte*)(link) - (byte*)tpf->links)
truelight@0: #define NTP_GET_LINK_PTR(tpf, link_offs) (HashLink*)((byte*)tpf->links + (link_offs))
truelight@0: 
truelight@0: #define ARR(i) tpf->stack[(i)-1]
truelight@0: 
belugas@6352: /** called after a new element was added in the queue at the last index.
belugas@6352:  * move it down to the proper position */
tron@536: static inline void HeapifyUp(NewTrackPathFinder *tpf)
truelight@0: {
truelight@0: 	StackedItem si;
truelight@0: 	int i = ++tpf->nstack;
truelight@193: 
ludde@2125: 	while (i != 1 && ARR(i).priority < ARR(i>>1).priority) {
belugas@6352: 		/* the child element is larger than the parent item.
belugas@6352: 		 * swap the child item and the parent item. */
belugas@6352: 		si = ARR(i); ARR(i) = ARR(i >> 1); ARR(i >> 1) = si;
belugas@6352: 		i >>= 1;
truelight@0: 	}
truelight@0: }
truelight@0: 
belugas@6352: /** called after the element 0 was eaten. fill it with a new element */
tron@536: static inline void HeapifyDown(NewTrackPathFinder *tpf)
truelight@0: {
truelight@0: 	StackedItem si;
truelight@0: 	int i = 1, j;
tron@979: 	int n;
tron@979: 
tron@979: 	assert(tpf->nstack > 0);
tron@979: 	n = --tpf->nstack;
truelight@0: 
truelight@0: 	if (n == 0) return; // heap is empty so nothing to do?
truelight@0: 
belugas@6352: 	/* copy the last item to index 0. we use it as base for heapify. */
belugas@6352: 	ARR(1) = ARR(n + 1);
truelight@0: 
belugas@6352: 	while ((j = i * 2) <= n) {
belugas@6352: 		/* figure out which is smaller of the children. */
belugas@6352: 		if (j != n && ARR(j).priority > ARR(j + 1).priority)
truelight@0: 			j++; // right item is smaller
truelight@0: 
truelight@0: 		assert(i <= n && j <= n);
ludde@2125: 		if (ARR(i).priority <= ARR(j).priority)
truelight@0: 			break; // base elem smaller than smallest, done!
truelight@193: 
belugas@6352: 		/* swap parent with the child */
truelight@0: 		si = ARR(i); ARR(i) = ARR(j); ARR(j) = si;
truelight@0: 		i = j;
truelight@0: 	}
truelight@0: }
truelight@0: 
belugas@6352: /** mark a tile as visited and store the length of the path.
belugas@6352:  * if we already had a better path to this tile, return false.
belugas@6352:  * otherwise return true. */
tron@3153: static bool NtpVisit(NewTrackPathFinder* tpf, TileIndex tile, DiagDirection dir, uint length)
truelight@0: {
truelight@0: 	uint hash,head;
truelight@0: 	HashLink *link, *new_link;
truelight@0: 
ludde@2044: 	assert(length < 16384-1);
truelight@193: 
truelight@0: 	hash = PATHFIND_HASH_TILE(tile);
truelight@0: 
belugas@6352: 	/* never visited before? */
truelight@0: 	if ((head=tpf->hash_head[hash]) == 0) {
truelight@0: 		tpf->hash_tile[hash] = tile;
truelight@0: 		tpf->hash_head[hash] = dir | (length << 2);
truelight@0: 		return true;
truelight@0: 	}
truelight@0: 
truelight@0: 	if (head != 0xffff) {
rubidium@5587: 		if (tile == tpf->hash_tile[hash] && (head & 0x3) == (uint)dir) {
truelight@193: 
belugas@6352: 			/* longer length */
truelight@0: 			if (length >= (head >> 2)) return false;
truelight@193: 
truelight@0: 			tpf->hash_head[hash] = dir | (length << 2);
truelight@0: 			return true;
truelight@0: 		}
belugas@6352: 		/* two tiles with the same hash, need to make a link
belugas@6352: 		 * allocate a link. if out of links, handle this by returning
belugas@6352: 		 * that a tile was already visisted. */
ludde@2125: 		if (tpf->num_links_left == 0) {
Darkvater@5380: 			DEBUG(ntp, 1, "No links left");
truelight@0: 			return false;
ludde@2125: 		}
ludde@2125: 
truelight@0: 		tpf->num_links_left--;
truelight@0: 		link = tpf->new_link++;
truelight@0: 
truelight@0: 		/* move the data that was previously in the hash_??? variables
truelight@0: 		 * to the link struct, and let the hash variables point to the link */
truelight@0: 		link->tile = tpf->hash_tile[hash];
truelight@0: 		tpf->hash_tile[hash] = NTP_GET_LINK_OFFS(tpf, link);
truelight@0: 
truelight@0: 		link->typelength = tpf->hash_head[hash];
belugas@6352: 		tpf->hash_head[hash] = 0xFFFF; // multi link
truelight@0: 		link->next = 0xFFFF;
truelight@0: 	} else {
belugas@6352: 		/* a linked list of many tiles,
belugas@6352: 		 * find the one corresponding to the tile, if it exists.
belugas@6352: 		 * otherwise make a new link */
truelight@193: 
truelight@0: 		uint offs = tpf->hash_tile[hash];
truelight@0: 		do {
truelight@0: 			link = NTP_GET_LINK_PTR(tpf, offs);
rubidium@5587: 			if (tile == link->tile && (link->typelength & 0x3U) == (uint)dir) {
truelight@3019: 				if (length >= (uint)(link->typelength >> 2)) return false;
truelight@0: 				link->typelength = dir | (length << 2);
truelight@0: 				return true;
truelight@0: 			}
tron@3017: 		} while ((offs = link->next) != 0xFFFF);
truelight@0: 	}
truelight@193: 
truelight@0: 	/* get here if we need to add a new link to link,
truelight@0: 	 * first, allocate a new link, in the same way as before */
ludde@2125: 	if (tpf->num_links_left == 0) {
Darkvater@5380: 		DEBUG(ntp, 1, "No links left");
ludde@2125: 		return false;
ludde@2125: 	}
truelight@0: 	tpf->num_links_left--;
truelight@0: 	new_link = tpf->new_link++;
truelight@0: 
truelight@0: 	/* then fill the link with the new info, and establish a ptr from the old
truelight@0: 	 * link to the new one */
tron@1986: 	new_link->tile = tile;
truelight@0: 	new_link->typelength = dir | (length << 2);
truelight@0: 	new_link->next = 0xFFFF;
truelight@0: 
truelight@0: 	link->next = NTP_GET_LINK_OFFS(tpf, new_link);
truelight@0: 	return true;
truelight@0: }
truelight@0: 
matthijs@2782: /**
matthijs@2782:  * Checks if the shortest path to the given tile/dir so far is still the given
matthijs@2782:  * length.
matthijs@2782:  * @return true if the length is still the same
matthijs@2782:  * @pre    The given tile/dir combination should be present in the hash, by a
matthijs@2782:  *         previous call to NtpVisit().
matthijs@2782:  */
tron@1977: static bool NtpCheck(NewTrackPathFinder *tpf, TileIndex tile, uint dir, uint length)
truelight@0: {
truelight@0: 	uint hash,head,offs;
truelight@0: 	HashLink *link;
truelight@0: 
truelight@0: 	hash = PATHFIND_HASH_TILE(tile);
truelight@0: 	head=tpf->hash_head[hash];
truelight@0: 	assert(head);
truelight@0: 
truelight@0: 	if (head != 0xffff) {
truelight@0: 		assert( tpf->hash_tile[hash] == tile && (head & 3) == dir);
truelight@0: 		assert( (head >> 2) <= length);
truelight@0: 		return length == (head >> 2);
truelight@0: 	}
truelight@0: 
belugas@6352: 	/* else it's a linked list of many tiles */
truelight@0: 	offs = tpf->hash_tile[hash];
tron@2952: 	for (;;) {
truelight@0: 		link = NTP_GET_LINK_PTR(tpf, offs);
tron@3017: 		if (tile == link->tile && (link->typelength & 0x3U) == dir) {
truelight@3019: 			assert((uint)(link->typelength >> 2) <= length);
truelight@3019: 			return length == (uint)(link->typelength >> 2);
truelight@0: 		}
truelight@0: 		offs = link->next;
truelight@0: 		assert(offs != 0xffff);
truelight@0: 	}
truelight@0: }
truelight@0: 
truelight@0: 
ludde@2044: static const uint16 _is_upwards_slope[15] = {
belugas@6352: 	0,                                           ///< no tileh
belugas@6352: 	(1 << TRACKDIR_X_SW) | (1 << TRACKDIR_Y_NW), ///< 1
belugas@6352: 	(1 << TRACKDIR_X_SW) | (1 << TRACKDIR_Y_SE), ///< 2
belugas@6352: 	(1 << TRACKDIR_X_SW),                        ///< 3
belugas@6352: 	(1 << TRACKDIR_X_NE) | (1 << TRACKDIR_Y_SE), ///< 4
belugas@6352: 	0,                                           ///< 5
belugas@6352: 	(1 << TRACKDIR_Y_SE),                        ///< 6
belugas@6352: 	0,                                           ///< 7
belugas@6352: 	(1 << TRACKDIR_X_NE) | (1 << TRACKDIR_Y_NW), ///< 8,
belugas@6352: 	(1 << TRACKDIR_Y_NW),                        ///< 9
belugas@6352: 	0,                                           ///< 10
belugas@6352: 	0,                                           ///< 11,
belugas@6352: 	(1 << TRACKDIR_X_NE),                        ///< 12
belugas@6352: 	0,                                           ///< 13
belugas@6352: 	0,                                           ///< 14
ludde@2044: };
ludde@2044: 
ludde@2125: static uint DistanceMoo(TileIndex t0, TileIndex t1)
ludde@2125: {
skidd13@7970: 	const uint dx = Delta(TileX(t0), TileX(t1));
skidd13@7970: 	const uint dy = Delta(TileY(t0), TileY(t1));
ludde@2125: 
belugas@6352: 	const uint straightTracks = 2 * min(dx, dy); // The number of straight (not full length) tracks
ludde@2125: 	/* OPTIMISATION:
ludde@2125: 	 * Original: diagTracks = max(dx, dy) - min(dx,dy);
ludde@2125: 	 * Proof:
ludde@2125: 	 * (dx-dy) - straightTracks  == (min + max) - straightTracks = min + // max - 2 * min = max - min */
belugas@6352: 	const uint diagTracks = dx + dy - straightTracks; // The number of diagonal (full tile length) tracks.
ludde@2125: 
ludde@2125: 	return diagTracks*DIAG_FACTOR + straightTracks*STR_FACTOR;
ludde@2125: }
ludde@2125: 
belugas@6352: /* These has to be small cause the max length of a track
belugas@6352:  * is currently limited to 16384 */
ludde@2125: 
ludde@2125: static const byte _length_of_track[16] = {
rubidium@4344: 	DIAG_FACTOR, DIAG_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, 0, 0,
rubidium@4344: 	DIAG_FACTOR, DIAG_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, 0, 0
ludde@2125: };
ludde@2125: 
belugas@6352: /* new more optimized pathfinder for trains...
belugas@6352:  * Tile is the tile the train is at.
belugas@6352:  * direction is the tile the train is moving towards. */
ludde@2125: 
tron@3153: static void NTPEnum(NewTrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
truelight@0: {
matthijs@2782: 	TrackBits bits, allbits;
rubidium@5587: 	Trackdir track;
matthijs@2782: 	TileIndex tile_org;
truelight@0: 	StackedItem si;
ludde@2125: 	int estimation;
truelight@0: 
ludde@2261: 
ludde@2136: 
belugas@6352: 	/* Need to have a special case for the start.
belugas@6352: 	 * We shouldn't call the callback for the current tile. */
ludde@2125: 	si.cur_length = 1; // Need to start at 1 cause 0 is a reserved value.
truelight@0: 	si.depth = 0;
truelight@0: 	si.state = 0;
ludde@2136: 	si.first_track = 0xFF;
ludde@2125: 	goto start_at;
truelight@0: 
tron@2952: 	for (;;) {
belugas@6352: 		/* Get the next item to search from from the priority queue */
ludde@2125: 		do {
ludde@2125: 			if (tpf->nstack == 0)
ludde@2125: 				return; // nothing left? then we're done!
ludde@2125: 			si = tpf->stack[0];
ludde@2125: 			tile = si.tile;
truelight@0: 
ludde@2125: 			HeapifyDown(tpf);
belugas@6352: 			/* Make sure we havn't already visited this tile. */
ludde@2125: 		} while (!NtpCheck(tpf, tile, _tpf_prev_direction[si.track], si.cur_length));
truelight@0: 
belugas@6352: 		/* Add the length of this track. */
ludde@2125: 		si.cur_length += _length_of_track[si.track];
truelight@193: 
ludde@2125: callback_and_continue:
ludde@2125: 		if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length))
ludde@2125: 			return;
truelight@0: 
ludde@2136: 		assert(si.track <= 13);
ludde@2125: 		direction = _tpf_new_direction[si.track];
ludde@2044: 
ludde@2125: start_at:
belugas@6352: 		/* If the tile is the entry tile of a tunnel, and we're not going out of the tunnel,
belugas@6352: 		 *   need to find the exit of the tunnel. */
celestar@5385: 		if (IsTileType(tile, MP_TUNNELBRIDGE)) {
celestar@5385: 			if (IsTunnel(tile)) {
smatz@8083: 				if (GetTunnelBridgeDirection(tile) != ReverseDiagDir(direction)) {
celestar@5385: 					FindLengthOfTunnelResult flotr;
celestar@5385: 
celestar@5385: 					/* We are not just driving out of the tunnel */
smatz@8083: 					if (GetTunnelBridgeDirection(tile) != direction ||
smatz@8083: 							GetTunnelBridgeTransportType(tile) != tpf->tracktype) {
belugas@6352: 						/* We are not driving into the tunnel, or it is an invalid tunnel */
celestar@5385: 						continue;
celestar@5385: 					}
skidd13@7928: 					if (!HasBit(tpf->railtypes, GetRailType(tile))) {
rubidium@5587: 						bits = TRACK_BIT_NONE;
celestar@5385: 						break;
celestar@5385: 					}
celestar@5385: 					flotr = FindLengthOfTunnel(tile, direction);
celestar@5385: 					si.cur_length += flotr.length * DIAG_FACTOR;
celestar@5385: 					tile = flotr.tile;
belugas@6352: 					/* tile now points to the exit tile of the tunnel */
celestar@5385: 				}
celestar@5385: 			} else {
celestar@5385: 				TileIndex tile_end;
smatz@8083: 				if (GetTunnelBridgeDirection(tile) != ReverseDiagDir(direction)) {
belugas@6352: 					/* We are not just leaving the bridge */
smatz@8083: 					if (GetTunnelBridgeDirection(tile) != direction ||
smatz@8083: 							GetTunnelBridgeTransportType(tile) != tpf->tracktype) {
belugas@6352: 						/* Not entering the bridge or not compatible */
celestar@5385: 						continue;
celestar@5385: 					}
celestar@5385: 				}
celestar@5385: 				tile_end = GetOtherBridgeEnd(tile);
celestar@5385: 				si.cur_length += DistanceManhattan(tile, tile_end) * DIAG_FACTOR;
celestar@5385: 				tile = tile_end;
ludde@2125: 			}
ludde@2044: 		}
ludde@2044: 
belugas@6352: 		/* This is a special loop used to go through
belugas@6352: 		 * a rail net and find the first intersection */
ludde@2125: 		tile_org = tile;
tron@2952: 		for (;;) {
ludde@2136: 			assert(direction <= 3);
Darkvater@4559: 			tile += TileOffsByDiagDir(direction);
ludde@2044: 
belugas@6352: 			/* too long search length? bail out. */
ludde@2125: 			if (si.cur_length >= tpf->maxlength) {
Darkvater@5380: 				DEBUG(ntp, 1, "Cur_length too big");
rubidium@5587: 				bits = TRACK_BIT_NONE;
ludde@2125: 				break;
ludde@2044: 			}
ludde@2044: 
belugas@6352: 			/* Not a regular rail tile?
belugas@6352: 			 * Then we can't use the code below, but revert to more general code. */
ludde@2125: 			if (!IsTileType(tile, MP_RAILWAY) || !IsPlainRailTile(tile)) {
belugas@6352: 				/* We found a tile which is not a normal railway tile.
belugas@6352: 				 * Determine which tracks that exist on this tile. */
rubidium@6683: 				uint32 ts = GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & _tpfmode1_and[direction];
rubidium@5587: 				bits = TrackdirBitsToTrackBits((TrackdirBits)(ts & TRACKDIR_BIT_MASK));
ludde@2125: 
belugas@6352: 				/* Check that the tile contains exactly one track */
truelight@7833: 				if (bits == 0 || KillFirstBit(bits) != 0) break;
ludde@2125: 
skidd13@7928: 				if (!HasBit(tpf->railtypes, GetRailType(tile))) {
rubidium@5587: 					bits = TRACK_BIT_NONE;
celestar@5385: 					break;
celestar@3804: 				}
celestar@3804: 
belugas@6352: 				/*******************
belugas@6352: 				 * If we reach here, the tile has exactly one track.
belugas@6352: 				 *   tile - index to a tile that is not rail tile, but still straight (with optional signals)
belugas@6352: 				 *   bits - bitmask of which track that exist on the tile (exactly one bit is set)
belugas@6352: 				 *   direction - which direction are we moving in?
belugas@6352: 				 *******************/
rubidium@5587: 				si.track = _new_trackdir[FIND_FIRST_BIT(bits)][direction];
ludde@2125: 				si.cur_length += _length_of_track[si.track];
ludde@2125: 				goto callback_and_continue;
ludde@2125: 			}
ludde@2125: 
matthijs@2782: 			/* Regular rail tile, determine which tracks exist. */
tron@3267: 			allbits = GetTrackBits(tile);
matthijs@2782: 			/* Which tracks are reachable? */
matthijs@2782: 			bits = allbits & DiagdirReachesTracks(direction);
ludde@2125: 
matthijs@2782: 			/* The tile has no reachable tracks => End of rail segment
matthijs@2782: 			 * or Intersection => End of rail segment. We check this agains all the
matthijs@2782: 			 * bits, not just reachable ones, to prevent infinite loops. */
rubidium@5587: 			if (bits == TRACK_BIT_NONE || TracksOverlap(allbits)) break;
ludde@2137: 
skidd13@7928: 			if (!HasBit(tpf->railtypes, GetRailType(tile))) {
rubidium@5587: 				bits = TRACK_BIT_NONE;
celestar@3355: 				break;
celestar@3355: 			}
celestar@3355: 
matthijs@2782: 			/* If we reach here, the tile has exactly one track, and this
rubidium@6491: 			 track is reachable = > Rail segment continues */
ludde@2125: 
rubidium@5587: 			track = _new_trackdir[FIND_FIRST_BIT(bits)][direction];
rubidium@5587: 			assert(track != INVALID_TRACKDIR);
ludde@2137: 
ludde@2125: 			si.cur_length += _length_of_track[track];
ludde@2125: 
belugas@6352: 			/* Check if this rail is an upwards slope. If it is, then add a penalty.
belugas@6352: 			 * Small optimization here.. if (track&7)>1 then it can't be a slope so we avoid calling GetTileSlope */
ludde@2125: 			if ((track & 7) <= 1 && (_is_upwards_slope[GetTileSlope(tile, NULL)] & (1 << track)) ) {
ludde@2125: 				// upwards slope. add some penalty.
belugas@6352: 				si.cur_length += 4 * DIAG_FACTOR;
ludde@2125: 			}
ludde@2125: 
belugas@6352: 			/* railway tile with signals..? */
ludde@2125: 			if (HasSignals(tile)) {
glx@4631: 				if (!HasSignalOnTrackdir(tile, track)) {
belugas@6352: 					/* if one way signal not pointing towards us, stop going in this direction => End of rail segment. */
glx@4631: 					if (HasSignalOnTrackdir(tile, ReverseTrackdir(track))) {
rubidium@5587: 						bits = TRACK_BIT_NONE;
ludde@2125: 						break;
ludde@2125: 					}
glx@4631: 				} else if (GetSignalStateByTrackdir(tile, track) == SIGNAL_STATE_GREEN) {
belugas@6352: 					/* green signal in our direction. either one way or two way. */
ludde@2125: 					si.state |= 3;
ludde@2125: 				} else {
belugas@6352: 					/* reached a red signal. */
glx@4631: 					if (HasSignalOnTrackdir(tile, ReverseTrackdir(track))) {
belugas@6352: 						/* two way red signal. unless we passed another green signal on the way,
belugas@6352: 						 * stop going in this direction => End of rail segment.
belugas@6352: 						 * this is to prevent us from going into a full platform. */
belugas@6352: 						if (!(si.state & 1)) {
rubidium@5587: 							bits = TRACK_BIT_NONE;
ludde@2125: 							break;
ludde@2125: 						}
ludde@2125: 					}
ludde@2125: 					if (!(si.state & 2)) {
belugas@6352: 						/* Is this the first signal we see? And it's red... add penalty */
belugas@6352: 						si.cur_length += 10 * DIAG_FACTOR;
ludde@2125: 						si.state += 2; // remember that we added penalty.
belugas@6352: 						/* Because we added a penalty, we can't just continue as usual.
belugas@6352: 						 * Need to get out and let A* do it's job with
belugas@6352: 						 * possibly finding an even shorter path. */
ludde@2125: 						break;
ludde@2125: 					}
ludde@2125: 				}
ludde@2125: 
ludde@2125: 				if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length))
belugas@6352: 					return; // Don't process this tile any further
ludde@2125: 			}
ludde@2125: 
belugas@6352: 			/* continue with the next track */
ludde@2125: 			direction = _tpf_new_direction[track];
ludde@2125: 
belugas@6352: 			/* safety check if we're running around chasing our tail... (infinite loop) */
ludde@2125: 			if (tile == tile_org) {
rubidium@5587: 				bits = TRACK_BIT_NONE;
ludde@2125: 				break;
ludde@2125: 			}
ludde@2044: 		}
ludde@2044: 
belugas@6352: 		/* There are no tracks to choose between.
belugas@6352: 		 * Stop searching in this direction */
rubidium@5587: 		if (bits == TRACK_BIT_NONE)
ludde@2125: 			continue;
truelight@0: 
belugas@6352: 		/****************
belugas@6352: 		 * We got multiple tracks to choose between (intersection).
belugas@6352: 		 * Branch the search space into several branches.
belugas@6352: 		 ****************/
truelight@193: 
belugas@6352: 		/* Check if we've already visited this intersection.
belugas@6352: 		 * If we've already visited it with a better length, then
belugas@6352: 		 * there's no point in visiting it again. */
ludde@2125: 		if (!NtpVisit(tpf, tile, direction, si.cur_length))
ludde@2125: 			continue;
truelight@0: 
belugas@6352: 		/* Push all possible alternatives that we can reach from here
belugas@6352: 		 * onto the priority heap.
belugas@6352: 		 * 'bits' contains the tracks that we can choose between. */
ludde@2125: 
belugas@6352: 		/* First compute the estimated distance to the target.
belugas@6352: 		 * This is used to implement A* */
ludde@2125: 		estimation = 0;
ludde@2125: 		if (tpf->dest != 0)
ludde@2125: 			estimation = DistanceMoo(tile, tpf->dest);
ludde@2125: 
ludde@2125: 		si.depth++;
matthijs@2774: 		if (si.depth == 0)
belugas@6352: 			continue; // We overflowed our depth. No more searching in this direction.
truelight@0: 		si.tile = tile;
rubidium@5587: 		while (bits != TRACK_BIT_NONE) {
KUDr@5598: 			Track track = RemoveFirstTrack(&bits);
rubidium@5587: 			si.track = _new_trackdir[track][direction];
matthijs@2782: 			assert(si.track != 0xFF);
ludde@2125: 			si.priority = si.cur_length + estimation;
ludde@2125: 
belugas@6352: 			/* out of stack items, bail out? */
ludde@2044: 			if (tpf->nstack >= lengthof(tpf->stack)) {
Darkvater@5380: 				DEBUG(ntp, 1, "Out of stack");
truelight@0: 				break;
ludde@2044: 			}
ludde@2125: 
truelight@0: 			tpf->stack[tpf->nstack] = si;
truelight@0: 			HeapifyUp(tpf);
rubidium@5587: 		};
truelight@0: 
belugas@6352: 		/* If this is the first intersection, we need to fill the first_track member.
belugas@6352: 		 * so the code outside knows which path is better.
belugas@6352: 		 * also randomize the order in which we search through them. */
truelight@0: 		if (si.depth == 1) {
ludde@2125: 			assert(tpf->nstack == 1 || tpf->nstack == 2 || tpf->nstack == 3);
ludde@2125: 			if (tpf->nstack != 1) {
ludde@2125: 				uint32 r = Random();
tron@5733: 				if (r & 1) Swap(tpf->stack[0].track, tpf->stack[1].track);
ludde@2125: 				if (tpf->nstack != 2) {
rubidium@5587: 					TrackdirByte t = tpf->stack[2].track;
tron@5733: 					if (r & 2) Swap(tpf->stack[0].track, t);
tron@5733: 					if (r & 4) Swap(tpf->stack[1].track, t);
ludde@2125: 					tpf->stack[2].first_track = tpf->stack[2].track = t;
ludde@2125: 				}
ludde@2125: 				tpf->stack[0].first_track = tpf->stack[0].track;
ludde@2125: 				tpf->stack[1].first_track = tpf->stack[1].track;
truelight@0: 			}
truelight@0: 		}
ludde@2044: 
belugas@6352: 		/* Continue with the next from the queue... */
ludde@2125: 	}
truelight@0: }
truelight@0: 
truelight@0: 
belugas@6352: /** new pathfinder for trains. better and faster. */
rubidium@8236: void NewTrainPathfind(TileIndex tile, TileIndex dest, RailTypes railtypes, DiagDirection direction, NTPEnumProc* enum_proc, void* data)
truelight@0: {
ludde@2044: 	NewTrackPathFinder tpf;
truelight@0: 
ludde@2125: 	tpf.dest = dest;
ludde@2044: 	tpf.userdata = data;
ludde@2044: 	tpf.enum_proc = enum_proc;
celestar@3355: 	tpf.tracktype = TRANSPORT_RAIL;
celestar@3355: 	tpf.railtypes = railtypes;
ludde@2125: 	tpf.maxlength = min(_patches.pf_maxlength * 3, 10000);
ludde@2044: 	tpf.nstack = 0;
ludde@2044: 	tpf.new_link = tpf.links;
ludde@2044: 	tpf.num_links_left = lengthof(tpf.links);
ludde@2044: 	memset(tpf.hash_head, 0, sizeof(tpf.hash_head));
ludde@2044: 
ludde@2044: 	NTPEnum(&tpf, tile, direction);
truelight@0: }