Function CheckTownBuild2x2House

src/town_cmd.cpp:2749–2763

* Checks if a 1x2 or 2x1 building is allowed here, accounting for road layout and tile heights. * Also, tests all four building positions that occupy this tile. * @param tile The tile where the building should be built. * @param t The town. * @param maxz The maximum Z level, since all tiles must have the same height. * @param noslope Are foundations disallowed for this house? */

 * @param noslope Are foundations disallowed for this house?
 */
static bool CheckTownBuild2x2House(TileIndex *tile, Town *t, int maxz, bool noslope, TownExpandModes modes)
{
	TileIndex tile2 = *tile;

	for (DiagDirection d = DIAGDIR_SE;; d++) { // 'd' goes through DIAGDIR_SE, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_END
		if (TownLayoutAllows2x2HouseHere(t, tile2, modes) && CheckFree2x2Area(tile2, maxz, noslope)) {
			*tile = tile2;
			return true;
		}
		if (d == DIAGDIR_END) break;
		tile2 += TileOffsByDiagDir(ReverseDiagDir(d)); // go clockwise
	}

	return false;
}

/**
 * Build a house at this tile.