/** 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;
}
/**
* 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;
}