/**
* Returns the driveable Trackdirs on a tile.
*
* One-way-roads are taken into account. Signals are not tested.
*
* @param dst_tile The tile of interest.
* @param src_trackdir The direction the vehicle is currently moving.
* @param type The transporttype of the vehicle.
* @param subtype For TRANSPORT_ROAD the compatible RoadTypes of the vehicle.
* @return The Trackdirs the vehicle can continue moving on.
*/
static TrackdirBits GetDriveableTrackdirBits(TileIndex dst_tile, Trackdir src_trackdir, TransportType type, uint subtype)
{
TrackdirBits trackdirbits = TrackStatusToTrackdirBits(GetTileTrackStatus(dst_tile, type, subtype));
if (trackdirbits == 0 && type == TRANSPORT_ROAD && HasBit(subtype, ROADTYPE_TRAM)) {
/* GetTileTrackStatus() returns 0 for single tram bits.
* As we cannot change it there (easily) without breaking something, change it here */
switch (GetSingleTramBit(dst_tile)) {
case DIAGDIR_NE:
case DIAGDIR_SW:
trackdirbits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
break;
case DIAGDIR_NW:
case DIAGDIR_SE:
trackdirbits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
break;
default: break;
}
}
DEBUG(npf, 4, "Next node: (%d, %d) [%d], possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), dst_tile, trackdirbits);
/* Select only trackdirs we can reach from our current trackdir */
trackdirbits &= TrackdirReachesTrackdirs(src_trackdir);
/* Filter out trackdirs that would make 90 deg turns for trains */
if (_settings_game.pf.forbid_90_deg && (type == TRANSPORT_RAIL || type == TRANSPORT_WATER)) trackdirbits &= ~TrackdirCrossesTrackdirs(src_trackdir);
DEBUG(npf, 6, "After filtering: (%d, %d), possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), trackdirbits);
return trackdirbits;
}
/** main follower routine. Fills all members and return true on success.
* Otherwise returns false if track can't be followed. */
inline bool Follow(TileIndex old_tile, Trackdir old_td)
{
m_old_tile = old_tile;
m_old_td = old_td;
m_err = EC_NONE;
assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
(IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
m_exitdir = TrackdirToExitdir(m_old_td);
if (ForcedReverse()) return true;
if (!CanExitOldTile()) return false;
FollowTileExit();
if (!QueryNewTileTrackStatus()) return TryReverse();
if (!CanEnterNewTile()) return false;
m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
if (m_new_td_bits == TRACKDIR_BIT_NONE) {
m_err = EC_NO_WAY;
return false;
}
if (!Allow90degTurns()) {
m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
if (m_new_td_bits == TRACKDIR_BIT_NONE) {
m_err = EC_90DEG;
return false;
}
}
return true;
}
/**
* Tests if a tile can be entered or left only from one side.
*
* Depots, non-drive-through roadstops, and tiles with single trambits are tested.
*
* @param tile The tile of interest.
* @param type The transporttype of the vehicle.
* @param subtype For TRANSPORT_ROAD the compatible RoadTypes of the vehicle.
* @return The single entry/exit-direction of the tile, or INVALID_DIAGDIR if there are more or less directions
*/
static DiagDirection GetTileSingleEntry(TileIndex tile, TransportType type, uint subtype)
{
if (type != TRANSPORT_WATER && IsDepotTypeTile(tile, type)) return GetDepotDirection(tile, type);
if (type == TRANSPORT_ROAD) {
if (IsStandardRoadStopTile(tile)) return GetRoadStopDir(tile);
if (HasBit(subtype, ROADTYPE_TRAM)) return GetSingleTramBit(tile);
}
return INVALID_DIAGDIR;
}
/**
* main follower routine. Fills all members and return true on success.
* Otherwise returns false if track can't be followed.
*/
inline bool Follow(TileIndex old_tile, Trackdir old_td)
{
m_old_tile = old_tile;
m_old_td = old_td;
m_err = EC_NONE;
assert(
((TrackStatusToTrackdirBits(
GetTileTrackStatus(m_old_tile, TT(), (IsRoadTT() && m_veh != NULL) ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)
) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
(IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR) // Disable the assertion for single tram bits
);
m_exitdir = TrackdirToExitdir(m_old_td);
if (ForcedReverse()) return true;
if (!CanExitOldTile()) return false;
FollowTileExit();
if (!QueryNewTileTrackStatus()) return TryReverse();
m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
if (m_new_td_bits == TRACKDIR_BIT_NONE || !CanEnterNewTile()) {
/* In case we can't enter the next tile, but are
* a normal road vehicle, then we can actually
* try to reverse as this is the end of the road.
* Trams can only turn on the appropriate bits in
* which case reaching this would mean a dead end
* near a building and in that case there would
* a "false" QueryNewTileTrackStatus result and
* as such reversing is already tried. The fact
* that function failed can have to do with a
* missing road bit, or inability to connect the
* different bits due to slopes. */
if (IsRoadTT() && !IsTram() && TryReverse()) return true;
/* CanEnterNewTile already set a reason.
* Do NOT overwrite it (important for example for EC_RAIL_TYPE).
* Only set a reason if CanEnterNewTile was not called */
if (m_new_td_bits == TRACKDIR_BIT_NONE) m_err = EC_NO_WAY;
return false;
}
if (!Allow90degTurns()) {
m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
if (m_new_td_bits == TRACKDIR_BIT_NONE) {
m_err = EC_90DEG;
return false;
}
}
return true;
}
