Function GetRailContinuationInfo

src/newgrf_station.cpp:197–235

static uint32_t GetRailContinuationInfo(TileIndex tile)
{
	/* Tile offsets and exit dirs for X axis */
	static const Direction x_dir[8] = { DIR_SW, DIR_NE, DIR_SE, DIR_NW, DIR_S, DIR_E, DIR_W, DIR_N };
	static const DiagDirection x_exits[8] = { DIAGDIR_SW, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NE, DIAGDIR_SW, DIAGDIR_NE };

	/* Tile offsets and exit dirs for Y axis */
	static const Direction y_dir[8] = { DIR_SE, DIR_NW, DIR_SW, DIR_NE, DIR_S, DIR_W, DIR_E, DIR_N };
	static const DiagDirection y_exits[8] = { DIAGDIR_SE, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NW, DIAGDIR_SE, DIAGDIR_NW };

	Axis axis = GetRailStationAxis(tile);

	/* Choose appropriate lookup table to use */
	const Direction *dir = axis == AXIS_X ? x_dir : y_dir;
	const DiagDirection *diagdir = axis == AXIS_X ? x_exits : y_exits;

	uint32_t res = 0;
	uint i;

	for (i = 0; i < lengthof(x_dir); i++, dir++, diagdir++) {
		TileIndex neighbour_tile = tile + TileOffsByDir(*dir);
		TrackBits trackbits = TrackStatusToTrackBits(GetTileTrackStatus(neighbour_tile, TRANSPORT_RAIL, 0));
		if (trackbits != TRACK_BIT_NONE) {
			/* If there is any track on the tile, set the bit in the second byte */
			SetBit(res, i + 8);

			/* With tunnels and bridges the tile has tracks, but they are not necessarily connected
			 * with the next tile because the ramp is not going in the right direction. */
			if (IsTileType(neighbour_tile, MP_TUNNELBRIDGE) && GetTunnelBridgeDirection(neighbour_tile) != *diagdir) {
				continue;
			}

			/* If any track reaches our exit direction, set the bit in the lower byte */
			if (trackbits & DiagdirReachesTracks(*diagdir)) SetBit(res, i);
		}
	}

	return res;
}


/* Station Resolver Functions */