/**
* Transform a given Point.
*
* The center point of the transformation is (0, 0).
* For example, point (1, 2) rotated 90 degree left is (-2, 1).
*
* @param point The Point to transform.
* @param transformation Transformation to perform.
* @return The transformed Point.
*/
Point TransformPoint(Point point, DirTransformation transformation)
{
TileIndexDiffC diff_from_x = TileIndexDiffCByDiagDir(TransformDiagDir(DIAGDIR_SW, transformation));
TileIndexDiffC diff_from_y = TileIndexDiffCByDiagDir(TransformDiagDir(DIAGDIR_SE, transformation));
Point ret = {
point.x * diff_from_x.x + point.y * diff_from_y.x,
point.x * diff_from_x.y + point.y * diff_from_y.y
};
return ret;
}
/* Will just follow the results of GetTileTrackStatus concerning where we can
* go and where not. Uses AyStar.user_data[NPF_TYPE] as the transport type and
* an argument to GetTileTrackStatus. Will skip tunnels, meaning that the
* entry and exit are neighbours. Will fill
* AyStarNode.user_data[NPF_TRACKDIR_CHOICE] with an appropriate value, and
* copy AyStarNode.user_data[NPF_NODE_FLAGS] from the parent */
static void NPFFollowTrack(AyStar *aystar, OpenListNode *current)
{
/* We leave src_tile on track src_trackdir in direction src_exitdir */
Trackdir src_trackdir = current->path.node.direction;
TileIndex src_tile = current->path.node.tile;
DiagDirection src_exitdir = TrackdirToExitdir(src_trackdir);
/* Is src_tile valid, and can be used?
* When choosing track on a junction src_tile is the tile neighboured to the junction wrt. exitdir.
* But we must not check the validity of this move, as src_tile is totally unrelated to the move, if a roadvehicle reversed on a junction. */
bool ignore_src_tile = (current->path.parent == NULL && NPFGetFlag(¤t->path.node, NPF_FLAG_IGNORE_START_TILE));
/* Information about the vehicle: TransportType (road/rail/water) and SubType (compatible rail/road types) */
TransportType type = (TransportType)aystar->user_data[NPF_TYPE];
uint subtype = aystar->user_data[NPF_SUB_TYPE];
/* Initialize to 0, so we can jump out (return) somewhere an have no neighbours */
aystar->num_neighbours = 0;
DEBUG(npf, 4, "Expanding: (%d, %d, %d) [%d]", TileX(src_tile), TileY(src_tile), src_trackdir, src_tile);
/* We want to determine the tile we arrive, and which choices we have there */
TileIndex dst_tile;
TrackdirBits trackdirbits;
/* Find dest tile */
if (ignore_src_tile) {
/* Do not perform any checks that involve src_tile */
dst_tile = src_tile + TileOffsByDiagDir(src_exitdir);
trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
} else if (IsTileType(src_tile, MP_TUNNELBRIDGE) && GetTunnelBridgeDirection(src_tile) == src_exitdir) {
/* We drive through the wormhole and arrive on the other side */
dst_tile = GetOtherTunnelBridgeEnd(src_tile);
trackdirbits = TrackdirToTrackdirBits(src_trackdir);
} else if (ForceReverse(src_tile, src_exitdir, type, subtype)) {
/* We can only reverse on this tile */
dst_tile = src_tile;
src_trackdir = ReverseTrackdir(src_trackdir);
trackdirbits = TrackdirToTrackdirBits(src_trackdir);
} else {
/* We leave src_tile in src_exitdir and reach dst_tile */
dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDiagDir(src_exitdir));
if (dst_tile != INVALID_TILE && !CanEnterTile(dst_tile, src_exitdir, type, subtype, (RailTypes)aystar->user_data[NPF_RAILTYPES], (Owner)aystar->user_data[NPF_OWNER])) dst_tile = INVALID_TILE;
if (dst_tile == INVALID_TILE) {
/* We cannot enter the next tile. Road vehicles can reverse, others reach dead end */
if (type != TRANSPORT_ROAD || HasBit(subtype, ROADTYPE_TRAM)) return;
dst_tile = src_tile;
src_trackdir = ReverseTrackdir(src_trackdir);
}
trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
if (trackdirbits == 0) {
/* We cannot enter the next tile. Road vehicles can reverse, others reach dead end */
if (type != TRANSPORT_ROAD || HasBit(subtype, ROADTYPE_TRAM)) return;
dst_tile = src_tile;
src_trackdir = ReverseTrackdir(src_trackdir);
trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
}
}
if (NPFGetFlag(¤t->path.node, NPF_FLAG_IGNORE_RESERVED)) {
/* Mask out any reserved tracks. */
TrackBits reserved = GetReservedTrackbits(dst_tile);
trackdirbits &= ~TrackBitsToTrackdirBits(reserved);
uint bits = TrackdirBitsToTrackBits(trackdirbits);
int i;
FOR_EACH_SET_BIT(i, bits) {
if (TracksOverlap(reserved | TrackToTrackBits((Track)i))) trackdirbits &= ~TrackToTrackdirBits((Track)i);
}
}