1 files changed, 510 insertions, 0 deletions

diff --git a/src/ai/trolly/pathfinder.cpp b/src/ai/trolly/pathfinder.cpp
new file mode 100644
index 000000000..6ffdf1fec
--- /dev/null
+++ b/src/ai/trolly/pathfinder.cpp
@@ -0,0 +1,510 @@
+/* $Id$ */
+
+#include "../../stdafx.h"
+#include "../../openttd.h"
+#include "../../bridge_map.h"
+#include "../../debug.h"
+#include "../../functions.h"
+#include "../../map.h"
+#include "../../tile.h"
+#include "../../command.h"
+#include "trolly.h"
+#include "../../depot.h"
+#include "../../tunnel_map.h"
+#include "../../bridge.h"
+#include "../ai.h"
+
+#define TEST_STATION_NO_DIR 0xFF
+
+// Tests if a station can be build on the given spot
+// TODO: make it train compatible
+static bool TestCanBuildStationHere(TileIndex tile, byte dir)
+{
+	Player *p = GetPlayer(_current_player);
+
+	if (dir == TEST_STATION_NO_DIR) {
+		int32 ret;
+		// TODO: currently we only allow spots that can be access from al 4 directions...
+		//  should be fixed!!!
+		for (dir = 0; dir < 4; dir++) {
+			ret = AiNew_Build_Station(p, p->ainew.tbt, tile, 1, 1, dir, DC_QUERY_COST);
+			if (!CmdFailed(ret)) return true;
+		}
+		return false;
+	}
+
+	// return true if command succeeded, so the inverse of CmdFailed()
+	return !CmdFailed(AiNew_Build_Station(p, p->ainew.tbt, tile, 1, 1, dir, DC_QUERY_COST));
+}
+
+
+static bool IsRoad(TileIndex tile)
+{
+	return
+		// MP_STREET, but not a road depot?
+		(IsTileType(tile, MP_STREET) && !IsTileDepotType(tile, TRANSPORT_ROAD)) ||
+		(IsTileType(tile, MP_TUNNELBRIDGE) && (
+			(IsTunnel(tile) && GetTunnelTransportType(tile) == TRANSPORT_ROAD) ||
+			(IsBridge(tile) && GetBridgeTransportType(tile) == TRANSPORT_ROAD)
+		));
+}
+
+
+// Checks if a tile 'a' is between the tiles 'b' and 'c'
+#define TILES_BETWEEN(a, b, c) (TileX(a) >= TileX(b) && TileX(a) <= TileX(c) && TileY(a) >= TileY(b) && TileY(a) <= TileY(c))
+
+
+// Check if the current tile is in our end-area
+static int32 AyStar_AiPathFinder_EndNodeCheck(AyStar *aystar, OpenListNode *current)
+{
+	const Ai_PathFinderInfo* PathFinderInfo = aystar->user_target;
+
+	// It is not allowed to have a station on the end of a bridge or tunnel ;)
+	if (current->path.node.user_data[0] != 0) return AYSTAR_DONE;
+	if (TILES_BETWEEN(current->path.node.tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br))
+		if (IsTileType(current->path.node.tile, MP_CLEAR) || IsTileType(current->path.node.tile, MP_TREES))
+			if (current->path.parent == NULL || TestCanBuildStationHere(current->path.node.tile, AiNew_GetDirection(current->path.parent->node.tile, current->path.node.tile)))
+				return AYSTAR_FOUND_END_NODE;
+
+	return AYSTAR_DONE;
+}
+
+
+// Calculates the hash
+//   Currently it is a 10 bit hash, so the hash array has a max depth of 6 bits (so 64)
+static uint AiPathFinder_Hash(uint key1, uint key2)
+{
+	return (TileX(key1) & 0x1F) + ((TileY(key1) & 0x1F) << 5);
+}
+
+
+// Clear the memory of all the things
+static void AyStar_AiPathFinder_Free(AyStar *aystar)
+{
+	AyStarMain_Free(aystar);
+	free(aystar);
+}
+
+
+static int32 AyStar_AiPathFinder_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent);
+static int32 AyStar_AiPathFinder_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent);
+static void AyStar_AiPathFinder_FoundEndNode(AyStar *aystar, OpenListNode *current);
+static void AyStar_AiPathFinder_GetNeighbours(AyStar *aystar, OpenListNode *current);
+
+
+// This creates the AiPathFinder
+AyStar *new_AyStar_AiPathFinder(int max_tiles_around, Ai_PathFinderInfo *PathFinderInfo)
+{
+	PathNode start_node;
+	uint x;
+	uint y;
+	// Create AyStar
+	AyStar *result = malloc(sizeof(AyStar));
+	init_AyStar(result, AiPathFinder_Hash, 1 << 10);
+	// Set the function pointers
+	result->CalculateG = AyStar_AiPathFinder_CalculateG;
+	result->CalculateH = AyStar_AiPathFinder_CalculateH;
+	result->EndNodeCheck = AyStar_AiPathFinder_EndNodeCheck;
+	result->FoundEndNode = AyStar_AiPathFinder_FoundEndNode;
+	result->GetNeighbours = AyStar_AiPathFinder_GetNeighbours;
+
+	result->free = AyStar_AiPathFinder_Free;
+
+	// Set some information
+	result->loops_per_tick = AI_PATHFINDER_LOOPS_PER_TICK;
+	result->max_path_cost = 0;
+	result->max_search_nodes = AI_PATHFINDER_MAX_SEARCH_NODES;
+
+	// Set the user_data to the PathFinderInfo
+	result->user_target = PathFinderInfo;
+
+	// Set the start node
+	start_node.parent = NULL;
+	start_node.node.direction = 0;
+	start_node.node.user_data[0] = 0;
+
+	// Now we add all the starting tiles
+	for (x = TileX(PathFinderInfo->start_tile_tl); x <= TileX(PathFinderInfo->start_tile_br); x++) {
+		for (y = TileY(PathFinderInfo->start_tile_tl); y <= TileY(PathFinderInfo->start_tile_br); y++) {
+			start_node.node.tile = TileXY(x, y);
+			result->addstart(result, &start_node.node, 0);
+		}
+	}
+
+	return result;
+}
+
+
+// To reuse AyStar we sometimes have to clean all the memory
+void clean_AyStar_AiPathFinder(AyStar *aystar, Ai_PathFinderInfo *PathFinderInfo)
+{
+	PathNode start_node;
+	uint x;
+	uint y;
+
+	aystar->clear(aystar);
+
+	// Set the user_data to the PathFinderInfo
+	aystar->user_target = PathFinderInfo;
+
+	// Set the start node
+	start_node.parent = NULL;
+	start_node.node.direction = 0;
+	start_node.node.user_data[0] = 0;
+	start_node.node.tile = PathFinderInfo->start_tile_tl;
+
+	// Now we add all the starting tiles
+	for (x = TileX(PathFinderInfo->start_tile_tl); x <= TileX(PathFinderInfo->start_tile_br); x++) {
+		for (y = TileY(PathFinderInfo->start_tile_tl); y <= TileY(PathFinderInfo->start_tile_br); y++) {
+			TileIndex tile = TileXY(x, y);
+
+			if (!IsTileType(tile, MP_CLEAR) && !IsTileType(tile, MP_TREES)) continue;
+			if (!TestCanBuildStationHere(tile, TEST_STATION_NO_DIR)) continue;
+			start_node.node.tile = tile;
+			aystar->addstart(aystar, &start_node.node, 0);
+		}
+	}
+}
+
+
+// The h-value, simple calculation
+static int32 AyStar_AiPathFinder_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent)
+{
+	const Ai_PathFinderInfo* PathFinderInfo = aystar->user_target;
+	int r, r2;
+
+	if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION) {
+		// The station is pointing to a direction, add a tile towards that direction, so the H-value is more accurate
+		r = DistanceManhattan(current->tile, PathFinderInfo->end_tile_tl + TileOffsByDiagDir(PathFinderInfo->end_direction));
+		r2 = DistanceManhattan(current->tile, PathFinderInfo->end_tile_br + TileOffsByDiagDir(PathFinderInfo->end_direction));
+	} else {
+		// No direction, so just get the fastest route to the station
+		r = DistanceManhattan(current->tile, PathFinderInfo->end_tile_tl);
+		r2 = DistanceManhattan(current->tile, PathFinderInfo->end_tile_br);
+	}
+	// See if the bottomright is faster than the topleft..
+	if (r2 < r) r = r2;
+	return r * AI_PATHFINDER_H_MULTIPLER;
+}
+
+
+// We found the end.. let's get the route back and put it in an array
+static void AyStar_AiPathFinder_FoundEndNode(AyStar *aystar, OpenListNode *current)
+{
+	Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+	uint i = 0;
+	PathNode *parent = &current->path;
+
+	do {
+		PathFinderInfo->route_extra[i] = parent->node.user_data[0];
+		PathFinderInfo->route[i++] = parent->node.tile;
+		if (i > lengthof(PathFinderInfo->route)) {
+			// We ran out of space for the PathFinder
+			DEBUG(ai, 0, "No more space in pathfinder route[] array");
+			PathFinderInfo->route_length = -1; // -1 indicates out of space
+			return;
+		}
+		parent = parent->parent;
+	} while (parent != NULL);
+	PathFinderInfo->route_length = i;
+	DEBUG(ai, 1, "Found route of %d nodes long in %d nodes of searching", i, Hash_Size(&aystar->ClosedListHash));
+}
+
+
+// What tiles are around us.
+static void AyStar_AiPathFinder_GetNeighbours(AyStar *aystar, OpenListNode *current)
+{
+	uint i;
+	int ret;
+	int dir;
+
+	Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+
+	aystar->num_neighbours = 0;
+
+	// Go through all surrounding tiles and check if they are within the limits
+	for (i = 0; i < 4; i++) {
+		TileIndex ctile = current->path.node.tile; // Current tile
+		TileIndex atile = ctile + TileOffsByDiagDir(i); // Adjacent tile
+
+		if (TileX(atile) > 1 && TileX(atile) < MapMaxX() - 1 &&
+				TileY(atile) > 1 && TileY(atile) < MapMaxY() - 1) {
+			// We also directly test if the current tile can connect to this tile..
+			//  We do this simply by just building the tile!
+
+			// If the next step is a bridge, we have to enter it the right way
+			if (!PathFinderInfo->rail_or_road && IsRoad(atile)) {
+				if (IsTileType(atile, MP_TUNNELBRIDGE)) {
+					if (IsTunnel(atile)) {
+						if (GetTunnelDirection(atile) != i) continue;
+					} else {
+						if ((_m[atile].m5 & 1U) != DiagDirToAxis(i)) continue;
+					}
+				}
+			}
+			// But also if we are on a bridge, we can only move a certain direction
+			if (!PathFinderInfo->rail_or_road && IsRoad(ctile)) {
+				if (IsTileType(ctile, MP_TUNNELBRIDGE)) {
+					// An existing bridge/tunnel... let's test the direction ;)
+					if ((_m[ctile].m5 & 1U) != (i & 1)) continue;
+				}
+			}
+
+			if ((AI_PATHFINDER_FLAG_BRIDGE & current->path.node.user_data[0]) != 0 ||
+					(AI_PATHFINDER_FLAG_TUNNEL & current->path.node.user_data[0]) != 0) {
+				// We are a bridge/tunnel, how cool!!
+				//  This means we can only point forward.. get the direction from the user_data
+				if (i != (current->path.node.user_data[0] >> 8)) continue;
+			}
+			dir = 0;
+
+			// First, check if we have a parent
+			if (current->path.parent == NULL && current->path.node.user_data[0] == 0) {
+				// If not, this means we are at the starting station
+				if (PathFinderInfo->start_direction != AI_PATHFINDER_NO_DIRECTION) {
+					// We do need a direction?
+					if (AiNew_GetDirection(ctile, atile) != PathFinderInfo->start_direction) {
+						// We are not pointing the right way, invalid tile
+						continue;
+					}
+				}
+			} else if (current->path.node.user_data[0] == 0) {
+				if (PathFinderInfo->rail_or_road) {
+					// Rail check
+					dir = AiNew_GetRailDirection(current->path.parent->node.tile, ctile, atile);
+					ret = AI_DoCommand(ctile, 0, dir, DC_AUTO | DC_NO_WATER, CMD_BUILD_SINGLE_RAIL);
+					if (CmdFailed(ret)) continue;
+#ifdef AI_PATHFINDER_NO_90DEGREES_TURN
+					if (current->path.parent->parent != NULL) {
+						// Check if we don't make a 90degree curve
+						int dir1 = AiNew_GetRailDirection(current->path.parent->parent->node.tile, current->path.parent->node.tile, ctile);
+						if (_illegal_curves[dir1] == dir || _illegal_curves[dir] == dir1) {
+							continue;
+						}
+					}
+#endif
+				} else {
+					// Road check
+					dir = AiNew_GetRoadDirection(current->path.parent->node.tile, ctile, atile);
+					if (IsRoad(ctile)) {
+						if (IsTileType(ctile, MP_TUNNELBRIDGE)) {
+							// We have a bridge, how nicely! We should mark it...
+							dir = 0;
+						} else {
+							// It already has road.. check if we miss any bits!
+							if ((_m[ctile].m5 & dir) != dir) {
+								// We do miss some pieces :(
+								dir &= ~_m[ctile].m5;
+							} else {
+								dir = 0;
+							}
+						}
+					}
+					// Only destruct things if it is MP_CLEAR of MP_TREES
+					if (dir != 0) {
+						ret = AI_DoCommand(ctile, dir, 0, DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD);
+						if (CmdFailed(ret)) continue;
+					}
+				}
+			}
+
+			// The tile can be connected
+			aystar->neighbours[aystar->num_neighbours].tile = atile;
+			aystar->neighbours[aystar->num_neighbours].user_data[0] = 0;
+			aystar->neighbours[aystar->num_neighbours++].direction = 0;
+		}
+	}
+
+	// Next step, check for bridges and tunnels
+	if (current->path.parent != NULL && current->path.node.user_data[0] == 0) {
+		// First we get the dir from this tile and his parent
+		DiagDirection dir = AiNew_GetDirection(current->path.parent->node.tile, current->path.node.tile);
+		// It means we can only walk with the track, so the bridge has to be in the same direction
+		TileIndex tile = current->path.node.tile;
+		TileIndex new_tile = tile;
+		Slope tileh = GetTileSlope(tile, NULL);
+
+		// Bridges can only be build on land that is not flat
+		//  And if there is a road or rail blocking
+		if (tileh != SLOPE_FLAT ||
+				(PathFinderInfo->rail_or_road && IsTileType(tile + TileOffsByDiagDir(dir), MP_STREET)) ||
+				(!PathFinderInfo->rail_or_road && IsTileType(tile + TileOffsByDiagDir(dir), MP_RAILWAY))) {
+			for (;;) {
+				new_tile += TileOffsByDiagDir(dir);
+
+				// Precheck, is the length allowed?
+				if (!CheckBridge_Stuff(0, GetBridgeLength(tile, new_tile))) break;
+
+				// Check if we hit the station-tile.. we don't like that!
+				if (TILES_BETWEEN(new_tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br)) break;
+
+				// Try building the bridge..
+				ret = AI_DoCommand(tile, new_tile, (0 << 8) + (MAX_BRIDGES / 2), DC_AUTO, CMD_BUILD_BRIDGE);
+				if (CmdFailed(ret)) continue;
+				// We can build a bridge here.. add him to the neighbours
+				aystar->neighbours[aystar->num_neighbours].tile = new_tile;
+				aystar->neighbours[aystar->num_neighbours].user_data[0] = AI_PATHFINDER_FLAG_BRIDGE + (dir << 8);
+				aystar->neighbours[aystar->num_neighbours++].direction = 0;
+				// We can only have 12 neighbours, and we need 1 left for tunnels
+				if (aystar->num_neighbours == 11) break;
+			}
+		}
+
+		// Next, check for tunnels!
+		// Tunnels can only be built on slopes corresponding to the direction
+		//  For now, we check both sides for this tile.. terraforming gives fuzzy result
+		if ((dir == DIAGDIR_NE && tileh == SLOPE_NE) ||
+				(dir == DIAGDIR_SE && tileh == SLOPE_SE) ||
+				(dir == DIAGDIR_SW && tileh == SLOPE_SW) ||
+				(dir == DIAGDIR_NW && tileh == SLOPE_NW)) {
+			// Now simply check if a tunnel can be build
+			ret = AI_DoCommand(tile, (PathFinderInfo->rail_or_road?0:0x200), 0, DC_AUTO, CMD_BUILD_TUNNEL);
+			tileh = GetTileSlope(_build_tunnel_endtile, NULL);
+			if (!CmdFailed(ret) && (tileh == SLOPE_SW || tileh == SLOPE_SE || tileh == SLOPE_NW || tileh == SLOPE_NE)) {
+				aystar->neighbours[aystar->num_neighbours].tile = _build_tunnel_endtile;
+				aystar->neighbours[aystar->num_neighbours].user_data[0] = AI_PATHFINDER_FLAG_TUNNEL + (dir << 8);
+				aystar->neighbours[aystar->num_neighbours++].direction = 0;
+			}
+		}
+	}
+}
+
+
+extern uint GetRailFoundation(Slope tileh, TrackBits bits); // XXX function declaration in .c
+extern uint GetRoadFoundation(Slope tileh, uint bits); // XXX function declaration in .c
+extern uint GetBridgeFoundation(Slope tileh, Axis); // XXX function declaration in .c
+enum {
+	BRIDGE_NO_FOUNDATION = 1 << 0 | 1 << 3 | 1 << 6 | 1 << 9 | 1 << 12,
+};
+
+// The most important function: it calculates the g-value
+static int32 AyStar_AiPathFinder_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent)
+{
+	Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+	int r, res = 0;
+	Slope tileh = GetTileSlope(current->tile, NULL);
+	Slope parent_tileh = GetTileSlope(parent->path.node.tile, NULL);
+
+	// Check if we hit the end-tile
+	if (TILES_BETWEEN(current->tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br)) {
+		// We are at the end-tile, check if we had a direction or something...
+		if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION && AiNew_GetDirection(current->tile, parent->path.node.tile) != PathFinderInfo->end_direction) {
+			// We are not pointing the right way, invalid tile
+			return AYSTAR_INVALID_NODE;
+		}
+		// If it was valid, drop out.. we don't build on the endtile
+		return 0;
+	}
+
+	// Give everything a small penalty
+	res += AI_PATHFINDER_PENALTY;
+
+	if (!PathFinderInfo->rail_or_road) {
+		// Road has the lovely advantage it can use other road... check if
+		//  the current tile is road, and if so, give a good bonus
+		if (IsRoad(current->tile)) {
+			res -= AI_PATHFINDER_ROAD_ALREADY_EXISTS_BONUS;
+		}
+	}
+
+	// We should give a penalty when the tile is going up or down.. this is one way to do so!
+	//  Too bad we have to count it from the parent.. but that is not so bad.
+	// We also dislike long routes on slopes, since they do not look too realistic
+	//  when there is a flat land all around, they are more expensive to build, and
+	//  especially they essentially block the ability to connect or cross the road
+	//  from one side.
+	if (parent_tileh != SLOPE_FLAT && parent->path.parent != NULL) {
+		// Skip if the tile was from a bridge or tunnel
+		if (parent->path.node.user_data[0] == 0 && current->user_data[0] == 0) {
+			if (PathFinderInfo->rail_or_road) {
+				r = GetRailFoundation(parent_tileh, 1 << AiNew_GetRailDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile));
+				// Maybe is BRIDGE_NO_FOUNDATION a bit strange here, but it contains just the right information..
+				if (r >= 15 || (r == 0 && HASBIT(BRIDGE_NO_FOUNDATION, tileh))) {
+					res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;
+				} else {
+					res += AI_PATHFINDER_FOUNDATION_PENALTY;
+				}
+			} else {
+				if (!IsRoad(parent->path.node.tile) || !IsTileType(parent->path.node.tile, MP_TUNNELBRIDGE)) {
+					r = GetRoadFoundation(parent_tileh, AiNew_GetRoadDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile));
+					if (r >= 15 || r == 0) {
+						res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;
+					} else {
+						res += AI_PATHFINDER_FOUNDATION_PENALTY;
+					}
+				}
+			}
+		}
+	}
+
+	// Are we part of a tunnel?
+	if ((AI_PATHFINDER_FLAG_TUNNEL & current->user_data[0]) != 0) {
+		// Tunnels are very expensive when build on long routes..
+		// Ironicly, we are using BridgeCode here ;)
+		r = AI_PATHFINDER_TUNNEL_PENALTY * GetBridgeLength(current->tile, parent->path.node.tile);
+		res += r + (r >> 8);
+	}
+
+	// Are we part of a bridge?
+	if ((AI_PATHFINDER_FLAG_BRIDGE & current->user_data[0]) != 0) {
+		// That means for every length a penalty
+		res += AI_PATHFINDER_BRIDGE_PENALTY * GetBridgeLength(current->tile, parent->path.node.tile);
+		// Check if we are going up or down, first for the starting point
+		// In user_data[0] is at the 8th bit the direction
+		if (!HASBIT(BRIDGE_NO_FOUNDATION, parent_tileh)) {
+			if (GetBridgeFoundation(parent_tileh, (current->user_data[0] >> 8) & 1) < 15) {
+				res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+			}
+		}
+		// Second for the end point
+		if (!HASBIT(BRIDGE_NO_FOUNDATION, tileh)) {
+			if (GetBridgeFoundation(tileh, (current->user_data[0] >> 8) & 1) < 15) {
+				res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+			}
+		}
+		if (parent_tileh == SLOPE_FLAT) res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+		if (tileh == SLOPE_FLAT) res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+	}
+
+	//  To prevent the AI from taking the fastest way in tiles, but not the fastest way
+	//    in speed, we have to give a good penalty to direction changing
+	//  This way, we get almost the fastest way in tiles, and a very good speed on the track
+	if (!PathFinderInfo->rail_or_road) {
+		if (parent->path.parent != NULL &&
+				AiNew_GetDirection(current->tile, parent->path.node.tile) != AiNew_GetDirection(parent->path.node.tile, parent->path.parent->node.tile)) {
+			// When road exists, we don't like turning, but its free, so don't be to piggy about it
+			if (IsRoad(parent->path.node.tile)) {
+				res += AI_PATHFINDER_DIRECTION_CHANGE_ON_EXISTING_ROAD_PENALTY;
+			} else {
+				res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;
+			}
+		}
+	} else {
+		// For rail we have 1 exeption: diagonal rail..
+		// So we fetch 2 raildirection. That of the current one, and of the one before that
+		if (parent->path.parent != NULL && parent->path.parent->parent != NULL) {
+			int dir1 = AiNew_GetRailDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile);
+			int dir2 = AiNew_GetRailDirection(parent->path.parent->parent->node.tile, parent->path.parent->node.tile, parent->path.node.tile);
+			// First, see if we are on diagonal path, that is better than straight path
+			if (dir1 > 1) res -= AI_PATHFINDER_DIAGONAL_BONUS;
+
+			// First see if they are different
+			if (dir1 != dir2) {
+				// dir 2 and 3 are 1 diagonal track, and 4 and 5.
+				if (!(((dir1 == 2 || dir1 == 3) && (dir2 == 2 || dir2 == 3)) || ((dir1 == 4 || dir1 == 5) && (dir2 == 4 || dir2 == 5)))) {
+					// It is not, so we changed of direction
+					res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;
+				}
+				if (parent->path.parent->parent->parent != NULL) {
+					int dir3 = AiNew_GetRailDirection(parent->path.parent->parent->parent->node.tile, parent->path.parent->parent->node.tile, parent->path.parent->node.tile);
+					// Check if we changed 3 tiles of direction in 3 tiles.. bad!!!
+					if ((dir1 == 0 || dir1 == 1) && dir2 > 1 && (dir3 == 0 || dir3 == 1)) {
+						res += AI_PATHFINDER_CURVE_PENALTY;
+					}
+				}
+			}
+		}
+	}
+
+	return (res < 0) ? 0 : res;
+}