Function FloodHalftile

src/rail_cmd.cpp:759–802

* Called from water_cmd if a non-flat rail-tile gets flooded and should be converted to shore. * The function floods the lower halftile, if the tile has a halftile foundation. * * @param t The tile to flood. * @return true if something was flooded. */

 * @return true if something was flooded.
 */
bool FloodHalftile(TileIndex t)
{
	assert(IsPlainRailTile(t));

	bool flooded = false;
	if (GetRailGroundType(t) == RailGroundType::HalfTileWater) return flooded;

	Slope tileh = GetTileSlope(t);
	TrackBits rail_bits = GetTrackBits(t);

	if (IsSlopeWithOneCornerRaised(tileh)) {
		TrackBits lower_track = CornerToTrackBits(OppositeCorner(GetHighestSlopeCorner(tileh)));

		TrackBits to_remove = lower_track & rail_bits;
		if (to_remove != TRACK_BIT_NONE) {
			Backup<CompanyID> cur_company(_current_company, OWNER_WATER);
			flooded = Command<CMD_REMOVE_SINGLE_RAIL>::Do(DoCommandFlag::Execute, t, FindFirstTrack(to_remove)).Succeeded();
			cur_company.Restore();
			if (!flooded) return flooded; // not yet floodable
			rail_bits = rail_bits & ~to_remove;
			if (rail_bits == TRACK_BIT_NONE) {
				MakeShore(t);
				MarkTileDirtyByTile(t);
				return flooded;
			}
		}

		if (IsNonContinuousFoundation(GetRailFoundation(tileh, rail_bits))) {
			flooded = true;
			SetRailGroundType(t, RailGroundType::HalfTileWater);
			MarkTileDirtyByTile(t);
		}
	} else {
		/* Make shore on steep slopes and 'three-corners-raised'-slopes. */
		if (ApplyFoundationToSlope(GetRailFoundation(tileh, rail_bits), tileh) == 0) {
			if (IsSteepSlope(tileh) || IsSlopeWithThreeCornersRaised(tileh)) {
				flooded = true;
				SetRailGroundType(t, RailGroundType::HalfTileWater);
				MarkTileDirtyByTile(t);
			}
		}
	}
	return flooded;
}

static const TileIndexDiffC _trackdelta[] = {
	{ -1,  0 }, {  0,  1 }, { -1,  0 }, {  0,  1 }, {  1,  0 }, {  0,  1 },