Function AdvanceSignalAutoFill

src/rail_cmd.cpp:1196–1238

}

static bool AdvanceSignalAutoFill(TileIndex &tile, Trackdir &trackdir, bool remove)
{
	/* We only process starting tiles of tunnels or bridges so jump to the other end before moving further. */
	if (IsTileType(tile, MP_TUNNELBRIDGE)) tile = GetOtherTunnelBridgeEnd(tile);

	tile = AddTileIndexDiffCWrap(tile, _trackdelta[trackdir]);
	if (tile == INVALID_TILE) return false;

	/* Check for track bits on the new tile */
	TrackdirBits trackdirbits = TrackStatusToTrackdirBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0));

	if (TracksOverlap(TrackdirBitsToTrackBits(trackdirbits))) return false;
	trackdirbits &= TrackdirReachesTrackdirs(trackdir);

	/* No track bits, must stop */
	if (trackdirbits == TRACKDIR_BIT_NONE) return false;

	/* Get the first track dir */
	trackdir = RemoveFirstTrackdir(&trackdirbits);

	/* Any left? It's a junction so we stop */
	if (trackdirbits != TRACKDIR_BIT_NONE) return false;

	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if (IsRailDepot(tile)) return false;
			if (!remove && HasSignalOnTrack(tile, TrackdirToTrack(trackdir))) return false;
			break;

		case MP_ROAD:
			if (!IsLevelCrossing(tile)) return false;
			break;

		case MP_TUNNELBRIDGE: {
			if (GetTunnelBridgeTransportType(tile) != TRANSPORT_RAIL) return false;
			if (GetTunnelBridgeDirection(tile) != TrackdirToExitdir(trackdir)) return false;
			break;
		}

		default: return false;
	}
	return true;
}

/**
 * Build many signals by dragging; AutoSignals