/** 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;
}
static Trackdir ChooseShipTrack(const Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool &path_found)
{
/* handle special case - when next tile is destination tile */
if (tile == v->dest_tile) {
/* convert tracks to trackdirs */
TrackdirBits trackdirs = (TrackdirBits)(tracks | ((int)tracks << 8));
/* limit to trackdirs reachable from enterdir */
trackdirs &= DiagdirReachesTrackdirs(enterdir);
/* use vehicle's current direction if that's possible, otherwise use first usable one. */
Trackdir veh_dir = v->GetVehicleTrackdir();
return ((trackdirs & TrackdirToTrackdirBits(veh_dir)) != 0) ? veh_dir : (Trackdir)FindFirstBit2x64(trackdirs);
}
/* move back to the old tile/trackdir (where ship is coming from) */
TileIndex src_tile = TILE_ADD(tile, TileOffsByDiagDir(ReverseDiagDir(enterdir)));
Trackdir trackdir = v->GetVehicleTrackdir();
assert(IsValidTrackdir(trackdir));
/* convert origin trackdir to TrackdirBits */
TrackdirBits trackdirs = TrackdirToTrackdirBits(trackdir);
/* get available trackdirs on the destination tile */
TrackdirBits dest_trackdirs = TrackStatusToTrackdirBits(GetTileTrackStatus(v->dest_tile, TRANSPORT_WATER, 0));
/* create pathfinder instance */
Tpf pf;
/* set origin and destination nodes */
pf.SetOrigin(src_tile, trackdirs);
pf.SetDestination(v->dest_tile, dest_trackdirs);
/* find best path */
path_found = pf.FindPath(v);
Trackdir next_trackdir = INVALID_TRACKDIR; // this would mean "path not found"
Node *pNode = pf.GetBestNode();
if (pNode != NULL) {
/* walk through the path back to the origin */
Node *pPrevNode = NULL;
while (pNode->m_parent != NULL) {
pPrevNode = pNode;
pNode = pNode->m_parent;
}
/* return trackdir from the best next node (direct child of origin) */
Node& best_next_node = *pPrevNode;
assert(best_next_node.GetTile() == tile);
next_trackdir = best_next_node.GetTrackdir();
}
return next_trackdir;
}
/**
* 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;
}
inline Trackdir ChooseRoadTrack(const RoadVehicle *v, TileIndex tile, DiagDirection enterdir, bool &path_found)
{
/* Handle special case - when next tile is destination tile.
* However, when going to a station the (initial) destination
* tile might not be a station, but a junction, in which case
* this method forces the vehicle to jump in circles. */
if (tile == v->dest_tile && !v->current_order.IsType(OT_GOTO_STATION)) {
/* choose diagonal trackdir reachable from enterdir */
return DiagDirToDiagTrackdir(enterdir);
}
/* our source tile will be the next vehicle tile (should be the given one) */
TileIndex src_tile = tile;
/* get available trackdirs on the start tile */
TrackdirBits src_trackdirs = TrackStatusToTrackdirBits(GetTileTrackStatus(tile, TRANSPORT_ROAD, v->compatible_roadtypes));
/* select reachable trackdirs only */
src_trackdirs &= DiagdirReachesTrackdirs(enterdir);
/* set origin and destination nodes */
Yapf().SetOrigin(src_tile, src_trackdirs);
Yapf().SetDestination(v);
/* find the best path */
path_found = Yapf().FindPath(v);
/* if path not found - return INVALID_TRACKDIR */
Trackdir next_trackdir = INVALID_TRACKDIR;
Node *pNode = Yapf().GetBestNode();
if (pNode != NULL) {
/* path was found or at least suggested
* walk through the path back to its origin */
while (pNode->m_parent != NULL) {
pNode = pNode->m_parent;
}
/* return trackdir from the best origin node (one of start nodes) */
Node& best_next_node = *pNode;
assert(best_next_node.GetTile() == tile);
next_trackdir = best_next_node.GetTrackdir();
}
return next_trackdir;
}
