/**
* Gets the other end of the aqueduct, if possible.
* @param tile_from The begin tile for the aqueduct.
* @param [out] tile_to The tile till where to show a selection for the aqueduct.
* @return The other end of the aqueduct, or otherwise a tile in line with the aqueduct to cause the right error message.
*/
static TileIndex GetOtherAqueductEnd(TileIndex tile_from, TileIndex *tile_to = NULL)
{
int z;
DiagDirection dir = GetInclinedSlopeDirection(GetTileSlope(tile_from, &z));
/* If the direction isn't right, just return the next tile so the command
* complains about the wrong slope instead of the ends not matching up.
* Make sure the coordinate is always a valid tile within the map, so we
* don't go "off" the map. That would cause the wrong error message. */
if (!IsValidDiagDirection(dir)) return TILE_ADDXY(tile_from, TileX(tile_from) > 2 ? -1 : 1, 0);
/* Direction the aqueduct is built to. */
TileIndexDiff offset = TileOffsByDiagDir(ReverseDiagDir(dir));
/* The maximum length of the aqueduct. */
int max_length = min(_settings_game.construction.max_bridge_length, DistanceFromEdgeDir(tile_from, ReverseDiagDir(dir)) - 1);
TileIndex endtile = tile_from;
for (int length = 0; IsValidTile(endtile) && TileX(endtile) != 0 && TileY(endtile) != 0; length++) {
endtile = TILE_ADD(endtile, offset);
if (length > max_length) break;
if (GetTileMaxZ(endtile) > z) {
if (tile_to != NULL) *tile_to = endtile;
break;
}
}
return endtile;
}
/** returns the track to choose on the next tile, or -1 when it's better to
* reverse. The tile given is the tile we are about to enter, enterdir is the
* direction in which we are entering the tile */
static Track ChooseShipTrack(const Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks)
{
assert(IsValidDiagDirection(enterdir));
switch (_settings_game.pf.pathfinder_for_ships) {
case VPF_OPF: return OPFShipChooseTrack(v, tile, enterdir, tracks);
case VPF_NPF: return NPFShipChooseTrack(v, tile, enterdir, tracks);
case VPF_YAPF: return YapfShipChooseTrack(v, tile, enterdir, tracks);
default: NOT_REACHED();
}
}
static void OPFShipFollowTrack(TileIndex tile, DiagDirection direction, TrackPathFinder *tpf)
{
assert(IsValidDiagDirection(direction));
/* initialize path finder variables */
tpf->rd.cur_length = 0;
tpf->rd.depth = 0;
tpf->rd.last_choosen_track = INVALID_TRACK;
ShipTrackFollower(tile, tpf, 0);
TPFModeShip(tpf, tile, direction);
}
/**
* Runs the pathfinder to choose a track to continue along.
*
* @param v Ship to navigate
* @param tile Tile, the ship is about to enter
* @param enterdir Direction of entering
* @param tracks Available track choices on \a tile
* @return Track to choose, or INVALID_TRACK when to reverse.
*/
static Track ChooseShipTrack(Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks)
{
assert(IsValidDiagDirection(enterdir));
bool path_found = true;
Track track;
switch (_settings_game.pf.pathfinder_for_ships) {
case VPF_OPF: track = OPFShipChooseTrack(v, tile, enterdir, tracks, path_found); break;
case VPF_NPF: track = NPFShipChooseTrack(v, tile, enterdir, tracks, path_found); break;
case VPF_YAPF: track = YapfShipChooseTrack(v, tile, enterdir, tracks, path_found); break;
default: NOT_REACHED();
}
v->HandlePathfindingResult(path_found);
return track;
}
virtual void OnPlacePresize(Point pt, TileIndex tile_from)
{
TileIndex tile_to = tile_from;
if (this->last_clicked_widget == WID_DT_BUILD_AQUEDUCT) {
GetOtherAqueductEnd(tile_from, &tile_to);
} else {
DiagDirection dir = GetInclinedSlopeDirection(GetTileSlope(tile_from));
if (IsValidDiagDirection(dir)) {
/* Locks and docks always select the tile "down" the slope. */
tile_to = TileAddByDiagDir(tile_from, ReverseDiagDir(dir));
/* Locks also select the tile "up" the slope. */
if (this->last_clicked_widget == WID_DT_LOCK) tile_from = TileAddByDiagDir(tile_from, dir);
}
}
VpSetPresizeRange(tile_from, tile_to);
}
/**
* returns the track to choose on the next tile, or -1 when it's better to
* reverse. The tile given is the tile we are about to enter, enterdir is the
* direction in which we are entering the tile
*/
Track OPFShipChooseTrack(const Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool &path_found)
{
assert(IsValidDiagDirection(enterdir));
TileIndex tile2 = TILE_ADD(tile, -TileOffsByDiagDir(enterdir));
Track track;
/* Let's find out how far it would be if we would reverse first */
TrackBits b = TrackStatusToTrackBits(GetTileTrackStatus(tile2, TRANSPORT_WATER, 0)) & DiagdirReachesTracks(ReverseDiagDir(enterdir)) & v->state;
uint distr = UINT_MAX; // distance if we reversed
if (b != 0) {
distr = FindShipTrack(v, tile2, ReverseDiagDir(enterdir), b, tile, &track);
if (distr != UINT_MAX) distr++; // penalty for reversing
}
/* And if we would not reverse? */
uint dist = FindShipTrack(v, tile, enterdir, tracks, 0, &track);
/* Due to the way this pathfinder works we cannot determine whether we're lost or not. */
path_found = true;
if (dist <= distr) return track;
return INVALID_TRACK; // We could better reverse
}