(svn r8033) [cpp] - Prepare for merge from branches/cpp (all .c files renamed to .cpp)

1 files changed, 968 insertions, 0 deletions

diff --git a/src/pathfind.cpp b/src/pathfind.cpp
new file mode 100644
index 000000000..81ccc699c
--- /dev/null
+++ b/src/pathfind.cpp
@@ -0,0 +1,968 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "bridge_map.h"
+#include "station_map.h"
+#include "depot.h"
+#include "functions.h"
+#include "map.h"
+#include "tile.h"
+#include "pathfind.h"
+#include "rail.h"
+#include "debug.h"
+#include "tunnel_map.h"
+#include "variables.h"
+#include "depot.h"
+
+// remember which tiles we have already visited so we don't visit them again.
+static bool TPFSetTileBit(TrackPathFinder *tpf, TileIndex tile, int dir)
+{
+	uint hash, val, offs;
+	TrackPathFinderLink *link, *new_link;
+	uint bits = 1 << dir;
+
+	if (tpf->disable_tile_hash)
+		return true;
+
+	hash = PATHFIND_HASH_TILE(tile);
+
+	val = tpf->hash_head[hash];
+
+	if (val == 0) {
+		/* unused hash entry, set the appropriate bit in it and return true
+		 * to indicate that a bit was set. */
+		tpf->hash_head[hash] = bits;
+		tpf->hash_tile[hash] = tile;
+		return true;
+	} else if (!(val & 0x8000)) {
+		/* single tile */
+
+		if (tile == tpf->hash_tile[hash]) {
+			/* found another bit for the same tile,
+			 * check if this bit is already set, if so, return false */
+			if (val & bits)
+				return false;
+
+			/* otherwise set the bit and return true to indicate that the bit
+			 * was set */
+			tpf->hash_head[hash] = val | bits;
+			return true;
+		} else {
+			/* two tiles with the same hash, need to make a link */
+
+			/* allocate a link. if out of links, handle this by returning
+			 * that a tile was already visisted. */
+			if (tpf->num_links_left == 0) {
+				return false;
+			}
+			tpf->num_links_left--;
+			link = tpf->new_link++;
+
+			/* move the data that was previously in the hash_??? variables
+			 * to the link struct, and let the hash variables point to the link */
+			link->tile = tpf->hash_tile[hash];
+			tpf->hash_tile[hash] = PATHFIND_GET_LINK_OFFS(tpf, link);
+
+			link->flags = tpf->hash_head[hash];
+			tpf->hash_head[hash] = 0xFFFF; /* multi link */
+
+			link->next = 0xFFFF;
+		}
+	} else {
+		/* a linked list of many tiles,
+		 * find the one corresponding to the tile, if it exists.
+		 * otherwise make a new link */
+
+		offs = tpf->hash_tile[hash];
+		do {
+			link = PATHFIND_GET_LINK_PTR(tpf, offs);
+			if (tile == link->tile) {
+				/* found the tile in the link list,
+				 * check if the bit was alrady set, if so return false to indicate that the
+				 * bit was already set */
+				if (link->flags & bits)
+					return false;
+				link->flags |= bits;
+				return true;
+			}
+		} while ((offs=link->next) != 0xFFFF);
+	}
+
+	/* get here if we need to add a new link to link,
+	 * first, allocate a new link, in the same way as before */
+	if (tpf->num_links_left == 0) {
+			return false;
+	}
+	tpf->num_links_left--;
+	new_link = tpf->new_link++;
+
+	/* then fill the link with the new info, and establish a ptr from the old
+	 * link to the new one */
+	new_link->tile = tile;
+	new_link->flags = bits;
+	new_link->next = 0xFFFF;
+
+	link->next = PATHFIND_GET_LINK_OFFS(tpf, new_link);
+	return true;
+}
+
+static const byte _bits_mask[4] = {
+	0x19,
+	0x16,
+	0x25,
+	0x2A,
+};
+
+static const byte _tpf_new_direction[14] = {
+	0, 1, 0, 1, 2, 1,
+	0, 0,
+	2, 3, 3, 2, 3, 0,
+};
+
+static const byte _tpf_prev_direction[14] = {
+	0, 1, 1, 0, 1, 2,
+	0, 0,
+	2, 3, 2, 3, 0, 3,
+};
+
+
+static const byte _otherdir_mask[4] = {
+	0x10,
+	0,
+	0x5,
+	0x2A,
+};
+
+static void TPFMode2(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
+{
+	uint bits;
+	int i;
+	RememberData rd;
+
+	assert(tpf->tracktype == TRANSPORT_WATER);
+
+	// This addition will sometimes overflow by a single tile.
+	// The use of TILE_MASK here makes sure that we still point at a valid
+	// tile, and then this tile will be in the sentinel row/col, so GetTileTrackStatus will fail.
+	tile = TILE_MASK(tile + TileOffsByDiagDir(direction));
+
+	if (++tpf->rd.cur_length > 50)
+		return;
+
+	bits = GetTileTrackStatus(tile, tpf->tracktype);
+	bits = (byte)((bits | (bits >> 8)) & _bits_mask[direction]);
+	if (bits == 0)
+		return;
+
+	assert(TileX(tile) != MapMaxX() && TileY(tile) != MapMaxY());
+
+	if ( (bits & (bits - 1)) == 0 ) {
+		/* only one direction */
+		i = 0;
+		while (!(bits&1))
+			i++, bits>>=1;
+
+		rd = tpf->rd;
+		goto continue_here;
+	}
+	/* several directions */
+	i=0;
+	do {
+		if (!(bits & 1)) continue;
+		rd = tpf->rd;
+
+		// Change direction 4 times only
+		if ((byte)i != tpf->rd.pft_var6) {
+			if (++tpf->rd.depth > 4) {
+				tpf->rd = rd;
+				return;
+			}
+			tpf->rd.pft_var6 = (byte)i;
+		}
+
+continue_here:;
+		tpf->the_dir = i + (HASBIT(_otherdir_mask[direction], i) ? 8 : 0);
+
+		if (!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, NULL)) {
+			TPFMode2(tpf, tile, _tpf_new_direction[tpf->the_dir]);
+		}
+
+		tpf->rd = rd;
+	} while (++i, bits>>=1);
+
+}
+
+
+/* Returns the end tile and the length of a tunnel. The length does not
+ * include the starting tile (entry), it does include the end tile (exit).
+ */
+FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, DiagDirection dir)
+{
+	TileIndexDiff delta = TileOffsByDiagDir(dir);
+	uint z = GetTileZ(tile);
+	FindLengthOfTunnelResult flotr;
+
+	flotr.length = 0;
+
+	dir = ReverseDiagDir(dir);
+	do {
+		flotr.length++;
+		tile += delta;
+	} while(
+		!IsTunnelTile(tile) ||
+		GetTunnelDirection(tile) != dir ||
+		GetTileZ(tile) != z
+	);
+
+	flotr.tile = tile;
+	return flotr;
+}
+
+static const uint16 _tpfmode1_and[4] = { 0x1009, 0x16, 0x520, 0x2A00 };
+
+static uint SkipToEndOfTunnel(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
+{
+	FindLengthOfTunnelResult flotr;
+	TPFSetTileBit(tpf, tile, 14);
+	flotr = FindLengthOfTunnel(tile, direction);
+	tpf->rd.cur_length += flotr.length;
+	TPFSetTileBit(tpf, flotr.tile, 14);
+	return flotr.tile;
+}
+
+const byte _ffb_64[128] = {
+ 0,  0,  1,  0,  2,  0,  1,  0,
+ 3,  0,  1,  0,  2,  0,  1,  0,
+ 4,  0,  1,  0,  2,  0,  1,  0,
+ 3,  0,  1,  0,  2,  0,  1,  0,
+ 5,  0,  1,  0,  2,  0,  1,  0,
+ 3,  0,  1,  0,  2,  0,  1,  0,
+ 4,  0,  1,  0,  2,  0,  1,  0,
+ 3,  0,  1,  0,  2,  0,  1,  0,
+
+ 0,  0,  0,  2,  0,  4,  4,  6,
+ 0,  8,  8, 10,  8, 12, 12, 14,
+ 0, 16, 16, 18, 16, 20, 20, 22,
+16, 24, 24, 26, 24, 28, 28, 30,
+ 0, 32, 32, 34, 32, 36, 36, 38,
+32, 40, 40, 42, 40, 44, 44, 46,
+32, 48, 48, 50, 48, 52, 52, 54,
+48, 56, 56, 58, 56, 60, 60, 62,
+};
+
+static void TPFMode1(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
+{
+	uint bits;
+	int i;
+	RememberData rd;
+	TileIndex tile_org = tile;
+
+	if (IsTileType(tile, MP_TUNNELBRIDGE)) {
+		if (IsTunnel(tile)) {
+			if (GetTunnelDirection(tile) != direction ||
+					GetTunnelTransportType(tile) != tpf->tracktype) {
+				return;
+			}
+			tile = SkipToEndOfTunnel(tpf, tile, direction);
+		} else {
+			TileIndex tile_end;
+			if (GetBridgeRampDirection(tile) != direction ||
+					GetBridgeTransportType(tile) != tpf->tracktype) {
+				return;
+			}
+			//fprintf(stderr, "%s: Planning over bridge\n", __func__);
+			// TODO doesn't work - WHAT doesn't work?
+			TPFSetTileBit(tpf, tile, 14);
+			tile_end = GetOtherBridgeEnd(tile);
+			tpf->rd.cur_length += DistanceManhattan(tile, tile_end);
+			tile = tile_end;
+			TPFSetTileBit(tpf, tile, 14);
+		}
+	}
+	tile += TileOffsByDiagDir(direction);
+
+	/* Check in case of rail if the owner is the same */
+	if (tpf->tracktype == TRANSPORT_RAIL) {
+		// don't enter train depot from the back
+		if (IsTileDepotType(tile, TRANSPORT_RAIL) && GetRailDepotDirection(tile) == direction) return;
+
+		if (IsTileType(tile_org, MP_RAILWAY) || IsTileType(tile_org, MP_STATION) || IsTileType(tile_org, MP_TUNNELBRIDGE))
+			if (IsTileType(tile, MP_RAILWAY) || IsTileType(tile, MP_STATION) || IsTileType(tile, MP_TUNNELBRIDGE))
+				if (GetTileOwner(tile_org) != GetTileOwner(tile)) return;
+	}
+
+	// check if the new tile can be entered from that direction
+	if (tpf->tracktype == TRANSPORT_ROAD) {
+		// road stops and depots now have a track (r4419)
+		// don't enter road stop from the back
+		if (IsRoadStopTile(tile) && ReverseDiagDir(GetRoadStopDir(tile)) != direction) return;
+		// don't enter road depot from the back
+		if (IsTileDepotType(tile, TRANSPORT_ROAD) && ReverseDiagDir(GetRoadDepotDirection(tile)) != direction) return;
+	}
+
+	/* Check if the new tile is a tunnel or bridge head and that the direction
+	 * and transport type match */
+	if (IsTileType(tile, MP_TUNNELBRIDGE)) {
+		if (IsTunnel(tile)) {
+			if (GetTunnelDirection(tile) != direction ||
+					GetTunnelTransportType(tile) != tpf->tracktype) {
+				return;
+			}
+		} else if (IsBridge(tile)) {
+			if (GetBridgeRampDirection(tile) != direction ||
+					GetBridgeTransportType(tile) != tpf->tracktype) {
+				return;
+			}
+		}
+	}
+
+	tpf->rd.cur_length++;
+
+	bits = GetTileTrackStatus(tile, tpf->tracktype);
+
+	if ((byte)bits != tpf->var2) {
+		bits &= _tpfmode1_and[direction];
+		bits = bits | (bits>>8);
+	}
+	bits &= 0xBF;
+
+	if (bits != 0) {
+		if (!tpf->disable_tile_hash || (tpf->rd.cur_length <= 64 && (KILL_FIRST_BIT(bits) == 0 || ++tpf->rd.depth <= 7))) {
+			do {
+				i = FIND_FIRST_BIT(bits);
+				bits = KILL_FIRST_BIT(bits);
+
+				tpf->the_dir = (_otherdir_mask[direction] & (byte)(1 << i)) ? (i+8) : i;
+				rd = tpf->rd;
+
+				if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&
+						!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {
+					TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);
+				}
+				tpf->rd = rd;
+			} while (bits != 0);
+		}
+	}
+
+	/* the next is only used when signals are checked.
+	 * seems to go in 2 directions simultaneously */
+
+	/* if i can get rid of this, tail end recursion can be used to minimize
+	 * stack space dramatically. */
+
+	/* If we are doing signal setting, we must reverse at evere tile, so we
+	 * iterate all the tracks in a signal block, even when a normal train would
+	 * not reach it (for example, when two lines merge */
+	if (tpf->hasbit_13)
+		return;
+
+	direction = ReverseDiagDir(direction);
+	tile += TileOffsByDiagDir(direction);
+
+	bits = GetTileTrackStatus(tile, tpf->tracktype);
+	bits |= (bits >> 8);
+
+	if ( (byte)bits != tpf->var2) {
+		bits &= _bits_mask[direction];
+	}
+
+	bits &= 0xBF;
+	if (bits == 0)
+		return;
+
+	do {
+		i = FIND_FIRST_BIT(bits);
+		bits = KILL_FIRST_BIT(bits);
+
+		tpf->the_dir = (_otherdir_mask[direction] & (byte)(1 << i)) ? (i+8) : i;
+		rd = tpf->rd;
+		if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&
+				!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {
+			TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);
+		}
+		tpf->rd = rd;
+	} while (bits != 0);
+}
+
+void FollowTrack(TileIndex tile, uint16 flags, DiagDirection direction, TPFEnumProc *enum_proc, TPFAfterProc *after_proc, void *data)
+{
+	TrackPathFinder tpf;
+
+	assert(direction < 4);
+
+	/* initialize path finder variables */
+	tpf.userdata = data;
+	tpf.enum_proc = enum_proc;
+	tpf.new_link = tpf.links;
+	tpf.num_links_left = lengthof(tpf.links);
+
+	tpf.rd.cur_length = 0;
+	tpf.rd.depth = 0;
+	tpf.rd.pft_var6 = 0;
+
+	tpf.var2 = HASBIT(flags, 15) ? 0x43 : 0xFF; /* 0x8000 */
+
+	tpf.disable_tile_hash = HASBIT(flags, 12);  /* 0x1000 */
+	tpf.hasbit_13         = HASBIT(flags, 13);  /* 0x2000 */
+
+
+	tpf.tracktype = (byte)flags;
+
+	if (HASBIT(flags, 11)) {
+		tpf.rd.pft_var6 = 0xFF;
+		tpf.enum_proc(tile, data, 0, 0, 0);
+		TPFMode2(&tpf, tile, direction);
+	} else {
+		/* clear the hash_heads */
+		memset(tpf.hash_head, 0, sizeof(tpf.hash_head));
+		TPFMode1(&tpf, tile, direction);
+	}
+
+	if (after_proc != NULL)
+		after_proc(&tpf);
+}
+
+typedef struct {
+	TileIndex tile;
+	uint16 cur_length; // This is the current length to this tile.
+	uint16 priority; // This is the current length + estimated length to the goal.
+	byte track;
+	byte depth;
+	byte state;
+	byte first_track;
+} StackedItem;
+
+static const byte _new_track[6][4] = {
+{0,    0xff, 8,    0xff,},
+{0xff, 1,    0xff, 9,},
+{0xff, 2,    10,   0xff,},
+{3,    0xff, 0xff, 11,},
+{12,   4,    0xff, 0xff,},
+{0xff, 0xff, 5,    13,},
+};
+
+typedef struct HashLink {
+	TileIndex tile;
+	uint16 typelength;
+	uint16 next;
+} HashLink;
+
+typedef struct {
+	NTPEnumProc *enum_proc;
+	void *userdata;
+	TileIndex dest;
+
+	TransportType tracktype;
+	RailTypeMask railtypes;
+	uint maxlength;
+
+	HashLink *new_link;
+	uint num_links_left;
+
+	uint nstack;
+	StackedItem stack[256]; // priority queue of stacked items
+
+	uint16 hash_head[0x400]; // hash heads. 0 means unused. 0xFFFC = length, 0x3 = dir
+	TileIndex hash_tile[0x400]; // tiles. or links.
+
+	HashLink links[0x400]; // hash links
+
+} NewTrackPathFinder;
+#define NTP_GET_LINK_OFFS(tpf, link) ((byte*)(link) - (byte*)tpf->links)
+#define NTP_GET_LINK_PTR(tpf, link_offs) (HashLink*)((byte*)tpf->links + (link_offs))
+
+#define ARR(i) tpf->stack[(i)-1]
+
+// called after a new element was added in the queue at the last index.
+// move it down to the proper position
+static inline void HeapifyUp(NewTrackPathFinder *tpf)
+{
+	StackedItem si;
+	int i = ++tpf->nstack;
+
+	while (i != 1 && ARR(i).priority < ARR(i>>1).priority) {
+		// the child element is larger than the parent item.
+		// swap the child item and the parent item.
+		si = ARR(i); ARR(i) = ARR(i>>1); ARR(i>>1) = si;
+		i>>=1;
+	}
+}
+
+// called after the element 0 was eaten. fill it with a new element
+static inline void HeapifyDown(NewTrackPathFinder *tpf)
+{
+	StackedItem si;
+	int i = 1, j;
+	int n;
+
+	assert(tpf->nstack > 0);
+	n = --tpf->nstack;
+
+	if (n == 0) return; // heap is empty so nothing to do?
+
+	// copy the last item to index 0. we use it as base for heapify.
+	ARR(1) = ARR(n+1);
+
+	while ((j=i*2) <= n) {
+		// figure out which is smaller of the children.
+		if (j != n && ARR(j).priority > ARR(j+1).priority)
+			j++; // right item is smaller
+
+		assert(i <= n && j <= n);
+		if (ARR(i).priority <= ARR(j).priority)
+			break; // base elem smaller than smallest, done!
+
+		// swap parent with the child
+		si = ARR(i); ARR(i) = ARR(j); ARR(j) = si;
+		i = j;
+	}
+}
+
+// mark a tile as visited and store the length of the path.
+// if we already had a better path to this tile, return false.
+// otherwise return true.
+static bool NtpVisit(NewTrackPathFinder* tpf, TileIndex tile, DiagDirection dir, uint length)
+{
+	uint hash,head;
+	HashLink *link, *new_link;
+
+	assert(length < 16384-1);
+
+	hash = PATHFIND_HASH_TILE(tile);
+
+	// never visited before?
+	if ((head=tpf->hash_head[hash]) == 0) {
+		tpf->hash_tile[hash] = tile;
+		tpf->hash_head[hash] = dir | (length << 2);
+		return true;
+	}
+
+	if (head != 0xffff) {
+		if (tile == tpf->hash_tile[hash] && (head & 0x3) == dir) {
+
+			// longer length
+			if (length >= (head >> 2)) return false;
+
+			tpf->hash_head[hash] = dir | (length << 2);
+			return true;
+		}
+		// two tiles with the same hash, need to make a link
+		// allocate a link. if out of links, handle this by returning
+		// that a tile was already visisted.
+		if (tpf->num_links_left == 0) {
+			DEBUG(ntp, 1, "No links left");
+			return false;
+		}
+
+		tpf->num_links_left--;
+		link = tpf->new_link++;
+
+		/* move the data that was previously in the hash_??? variables
+		 * to the link struct, and let the hash variables point to the link */
+		link->tile = tpf->hash_tile[hash];
+		tpf->hash_tile[hash] = NTP_GET_LINK_OFFS(tpf, link);
+
+		link->typelength = tpf->hash_head[hash];
+		tpf->hash_head[hash] = 0xFFFF; /* multi link */
+		link->next = 0xFFFF;
+	} else {
+		// a linked list of many tiles,
+		// find the one corresponding to the tile, if it exists.
+		// otherwise make a new link
+
+		uint offs = tpf->hash_tile[hash];
+		do {
+			link = NTP_GET_LINK_PTR(tpf, offs);
+			if (tile == link->tile && (link->typelength & 0x3U) == dir) {
+				if (length >= (uint)(link->typelength >> 2)) return false;
+				link->typelength = dir | (length << 2);
+				return true;
+			}
+		} while ((offs = link->next) != 0xFFFF);
+	}
+
+	/* get here if we need to add a new link to link,
+	 * first, allocate a new link, in the same way as before */
+	if (tpf->num_links_left == 0) {
+		DEBUG(ntp, 1, "No links left");
+		return false;
+	}
+	tpf->num_links_left--;
+	new_link = tpf->new_link++;
+
+	/* then fill the link with the new info, and establish a ptr from the old
+	 * link to the new one */
+	new_link->tile = tile;
+	new_link->typelength = dir | (length << 2);
+	new_link->next = 0xFFFF;
+
+	link->next = NTP_GET_LINK_OFFS(tpf, new_link);
+	return true;
+}
+
+/**
+ * Checks if the shortest path to the given tile/dir so far is still the given
+ * length.
+ * @return true if the length is still the same
+ * @pre    The given tile/dir combination should be present in the hash, by a
+ *         previous call to NtpVisit().
+ */
+static bool NtpCheck(NewTrackPathFinder *tpf, TileIndex tile, uint dir, uint length)
+{
+	uint hash,head,offs;
+	HashLink *link;
+
+	hash = PATHFIND_HASH_TILE(tile);
+	head=tpf->hash_head[hash];
+	assert(head);
+
+	if (head != 0xffff) {
+		assert( tpf->hash_tile[hash] == tile && (head & 3) == dir);
+		assert( (head >> 2) <= length);
+		return length == (head >> 2);
+	}
+
+	// else it's a linked list of many tiles
+	offs = tpf->hash_tile[hash];
+	for (;;) {
+		link = NTP_GET_LINK_PTR(tpf, offs);
+		if (tile == link->tile && (link->typelength & 0x3U) == dir) {
+			assert((uint)(link->typelength >> 2) <= length);
+			return length == (uint)(link->typelength >> 2);
+		}
+		offs = link->next;
+		assert(offs != 0xffff);
+	}
+}
+
+
+static const uint16 _is_upwards_slope[15] = {
+	0, // no tileh
+	(1 << TRACKDIR_X_SW) | (1 << TRACKDIR_Y_NW), // 1
+	(1 << TRACKDIR_X_SW) | (1 << TRACKDIR_Y_SE), // 2
+	(1 << TRACKDIR_X_SW), // 3
+	(1 << TRACKDIR_X_NE) | (1 << TRACKDIR_Y_SE), // 4
+	0, // 5
+	(1 << TRACKDIR_Y_SE), // 6
+	0, // 7
+	(1 << TRACKDIR_X_NE) | (1 << TRACKDIR_Y_NW), // 8,
+	(1 << TRACKDIR_Y_NW), // 9
+	0, //10
+	0, //11,
+	(1 << TRACKDIR_X_NE), //12
+	0, //13
+	0, //14
+};
+
+static uint DistanceMoo(TileIndex t0, TileIndex t1)
+{
+	const uint dx = abs(TileX(t0) - TileX(t1));
+	const uint dy = abs(TileY(t0) - TileY(t1));
+
+	const uint straightTracks = 2 * min(dx, dy); /* The number of straight (not full length) tracks */
+	/* OPTIMISATION:
+	 * Original: diagTracks = max(dx, dy) - min(dx,dy);
+	 * Proof:
+	 * (dx-dy) - straightTracks  == (min + max) - straightTracks = min + // max - 2 * min = max - min */
+	const uint diagTracks = dx + dy - straightTracks; /* The number of diagonal (full tile length) tracks. */
+
+	return diagTracks*DIAG_FACTOR + straightTracks*STR_FACTOR;
+}
+
+// These has to be small cause the max length of a track
+// is currently limited to 16384
+
+static const byte _length_of_track[16] = {
+	DIAG_FACTOR, DIAG_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, 0, 0,
+	DIAG_FACTOR, DIAG_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, STR_FACTOR, 0, 0
+};
+
+// new more optimized pathfinder for trains...
+// Tile is the tile the train is at.
+// direction is the tile the train is moving towards.
+
+static void NTPEnum(NewTrackPathFinder* tpf, TileIndex tile, DiagDirection direction)
+{
+	TrackBits bits, allbits;
+	uint track;
+	TileIndex tile_org;
+	StackedItem si;
+	int estimation;
+
+
+
+	// Need to have a special case for the start.
+	// We shouldn't call the callback for the current tile.
+	si.cur_length = 1; // Need to start at 1 cause 0 is a reserved value.
+	si.depth = 0;
+	si.state = 0;
+	si.first_track = 0xFF;
+	goto start_at;
+
+	for (;;) {
+		// Get the next item to search from from the priority queue
+		do {
+			if (tpf->nstack == 0)
+				return; // nothing left? then we're done!
+			si = tpf->stack[0];
+			tile = si.tile;
+
+			HeapifyDown(tpf);
+			// Make sure we havn't already visited this tile.
+		} while (!NtpCheck(tpf, tile, _tpf_prev_direction[si.track], si.cur_length));
+
+		// Add the length of this track.
+		si.cur_length += _length_of_track[si.track];
+
+callback_and_continue:
+		if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length))
+			return;
+
+		assert(si.track <= 13);
+		direction = _tpf_new_direction[si.track];
+
+start_at:
+		// If the tile is the entry tile of a tunnel, and we're not going out of the tunnel,
+		//   need to find the exit of the tunnel.
+		if (IsTileType(tile, MP_TUNNELBRIDGE)) {
+			if (IsTunnel(tile)) {
+				if (GetTunnelDirection(tile) != ReverseDiagDir(direction)) {
+					FindLengthOfTunnelResult flotr;
+
+					/* We are not just driving out of the tunnel */
+					if (GetTunnelDirection(tile) != direction ||
+							GetTunnelTransportType(tile) != tpf->tracktype) {
+						// We are not driving into the tunnel, or it is an invalid tunnel
+						continue;
+					}
+					if (!HASBIT(tpf->railtypes, GetRailType(tile))) {
+						bits = 0;
+						break;
+					}
+					flotr = FindLengthOfTunnel(tile, direction);
+					si.cur_length += flotr.length * DIAG_FACTOR;
+					tile = flotr.tile;
+					// tile now points to the exit tile of the tunnel
+				}
+			} else {
+				TileIndex tile_end;
+				if (GetBridgeRampDirection(tile) != ReverseDiagDir(direction)) {
+					// We are not just leaving the bridge
+					if (GetBridgeRampDirection(tile) != direction ||
+							GetBridgeTransportType(tile) != tpf->tracktype) {
+						// Not entering the bridge or not compatible
+						continue;
+					}
+				}
+				tile_end = GetOtherBridgeEnd(tile);
+				si.cur_length += DistanceManhattan(tile, tile_end) * DIAG_FACTOR;
+				tile = tile_end;
+			}
+		}
+
+		// This is a special loop used to go through
+		// a rail net and find the first intersection
+		tile_org = tile;
+		for (;;) {
+			assert(direction <= 3);
+			tile += TileOffsByDiagDir(direction);
+
+			// too long search length? bail out.
+			if (si.cur_length >= tpf->maxlength) {
+				DEBUG(ntp, 1, "Cur_length too big");
+				bits = 0;
+				break;
+			}
+
+			// Not a regular rail tile?
+			// Then we can't use the code below, but revert to more general code.
+			if (!IsTileType(tile, MP_RAILWAY) || !IsPlainRailTile(tile)) {
+				// We found a tile which is not a normal railway tile.
+				// Determine which tracks that exist on this tile.
+				bits = GetTileTrackStatus(tile, TRANSPORT_RAIL) & _tpfmode1_and[direction];
+				bits = (bits | (bits >> 8)) & 0x3F;
+
+				// Check that the tile contains exactly one track
+				if (bits == 0 || KILL_FIRST_BIT(bits) != 0) break;
+
+				if (!HASBIT(tpf->railtypes, IsTileType(tile, MP_STREET) ? GetRailTypeCrossing(tile) : GetRailType(tile))) {
+					bits = 0;
+					break;
+				}
+
+				///////////////////
+				// If we reach here, the tile has exactly one track.
+				//   tile - index to a tile that is not rail tile, but still straight (with optional signals)
+				//   bits - bitmask of which track that exist on the tile (exactly one bit is set)
+				//   direction - which direction are we moving in?
+				///////////////////
+				si.track = _new_track[FIND_FIRST_BIT(bits)][direction];
+				si.cur_length += _length_of_track[si.track];
+				goto callback_and_continue;
+			}
+
+			/* Regular rail tile, determine which tracks exist. */
+			allbits = GetTrackBits(tile);
+			/* Which tracks are reachable? */
+			bits = allbits & DiagdirReachesTracks(direction);
+
+			/* The tile has no reachable tracks => End of rail segment
+			 * or Intersection => End of rail segment. We check this agains all the
+			 * bits, not just reachable ones, to prevent infinite loops. */
+			if (bits == 0 || TracksOverlap(allbits)) break;
+
+			if (!HASBIT(tpf->railtypes, GetRailType(tile))) {
+				bits = 0;
+				break;
+			}
+
+			/* If we reach here, the tile has exactly one track, and this
+			 track is reachable => Rail segment continues */
+
+			track = _new_track[FIND_FIRST_BIT(bits)][direction];
+			assert(track != 0xff);
+
+			si.cur_length += _length_of_track[track];
+
+			// Check if this rail is an upwards slope. If it is, then add a penalty.
+			// Small optimization here.. if (track&7)>1 then it can't be a slope so we avoid calling GetTileSlope
+			if ((track & 7) <= 1 && (_is_upwards_slope[GetTileSlope(tile, NULL)] & (1 << track)) ) {
+				// upwards slope. add some penalty.
+				si.cur_length += 4*DIAG_FACTOR;
+			}
+
+			// railway tile with signals..?
+			if (HasSignals(tile)) {
+				if (!HasSignalOnTrackdir(tile, track)) {
+					// if one way signal not pointing towards us, stop going in this direction => End of rail segment.
+					if (HasSignalOnTrackdir(tile, ReverseTrackdir(track))) {
+						bits = 0;
+						break;
+					}
+				} else if (GetSignalStateByTrackdir(tile, track) == SIGNAL_STATE_GREEN) {
+					// green signal in our direction. either one way or two way.
+					si.state |= 3;
+				} else {
+					// reached a red signal.
+					if (HasSignalOnTrackdir(tile, ReverseTrackdir(track))) {
+						// two way red signal. unless we passed another green signal on the way,
+						// stop going in this direction => End of rail segment.
+						// this is to prevent us from going into a full platform.
+						if (!(si.state&1)) {
+							bits = 0;
+							break;
+						}
+					}
+					if (!(si.state & 2)) {
+						// Is this the first signal we see? And it's red... add penalty
+						si.cur_length += 10*DIAG_FACTOR;
+						si.state += 2; // remember that we added penalty.
+						// Because we added a penalty, we can't just continue as usual.
+						// Need to get out and let A* do it's job with
+						// possibly finding an even shorter path.
+						break;
+					}
+				}
+
+				if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length))
+					return; /* Don't process this tile any further */
+			}
+
+			// continue with the next track
+			direction = _tpf_new_direction[track];
+
+			// safety check if we're running around chasing our tail... (infinite loop)
+			if (tile == tile_org) {
+				bits = 0;
+				break;
+			}
+		}
+
+		// There are no tracks to choose between.
+		// Stop searching in this direction
+		if (bits == 0)
+			continue;
+
+		////////////////
+		// We got multiple tracks to choose between (intersection).
+		// Branch the search space into several branches.
+		////////////////
+
+		// Check if we've already visited this intersection.
+		// If we've already visited it with a better length, then
+		// there's no point in visiting it again.
+		if (!NtpVisit(tpf, tile, direction, si.cur_length))
+			continue;
+
+		// Push all possible alternatives that we can reach from here
+		// onto the priority heap.
+		// 'bits' contains the tracks that we can choose between.
+
+		// First compute the estimated distance to the target.
+		// This is used to implement A*
+		estimation = 0;
+		if (tpf->dest != 0)
+			estimation = DistanceMoo(tile, tpf->dest);
+
+		si.depth++;
+		if (si.depth == 0)
+			continue; /* We overflowed our depth. No more searching in this direction. */
+		si.tile = tile;
+		do {
+			si.track = _new_track[FIND_FIRST_BIT(bits)][direction];
+			assert(si.track != 0xFF);
+			si.priority = si.cur_length + estimation;
+
+			// out of stack items, bail out?
+			if (tpf->nstack >= lengthof(tpf->stack)) {
+				DEBUG(ntp, 1, "Out of stack");
+				break;
+			}
+
+			tpf->stack[tpf->nstack] = si;
+			HeapifyUp(tpf);
+		} while ((bits = KILL_FIRST_BIT(bits)) != 0);
+
+		// If this is the first intersection, we need to fill the first_track member.
+		// so the code outside knows which path is better.
+		// also randomize the order in which we search through them.
+		if (si.depth == 1) {
+			assert(tpf->nstack == 1 || tpf->nstack == 2 || tpf->nstack == 3);
+			if (tpf->nstack != 1) {
+				uint32 r = Random();
+				if (r&1) swap_byte(&tpf->stack[0].track, &tpf->stack[1].track);
+				if (tpf->nstack != 2) {
+					byte t = tpf->stack[2].track;
+					if (r&2) swap_byte(&tpf->stack[0].track, &t);
+					if (r&4) swap_byte(&tpf->stack[1].track, &t);
+					tpf->stack[2].first_track = tpf->stack[2].track = t;
+				}
+				tpf->stack[0].first_track = tpf->stack[0].track;
+				tpf->stack[1].first_track = tpf->stack[1].track;
+			}
+		}
+
+		// Continue with the next from the queue...
+	}
+}
+
+
+// new pathfinder for trains. better and faster.
+void NewTrainPathfind(TileIndex tile, TileIndex dest, RailTypeMask railtypes, DiagDirection direction, NTPEnumProc* enum_proc, void* data)
+{
+	NewTrackPathFinder tpf;
+
+	tpf.dest = dest;
+	tpf.userdata = data;
+	tpf.enum_proc = enum_proc;
+	tpf.tracktype = TRANSPORT_RAIL;
+	tpf.railtypes = railtypes;
+	tpf.maxlength = min(_patches.pf_maxlength * 3, 10000);
+	tpf.nstack = 0;
+	tpf.new_link = tpf.links;
+	tpf.num_links_left = lengthof(tpf.links);
+	memset(tpf.hash_head, 0, sizeof(tpf.hash_head));
+
+	NTPEnum(&tpf, tile, direction);
+}