public static HashSet <HexCoord> NeighborHexagons(HexCoord coord, int range = 1)
{
var ret = new HashSet <HexCoord>();
if (range < 1)
{
return(ret);
}
for (int i = 0; i < DeltaCoords.Length; i++)
{
HexCoord c = coord.Add(DeltaCoords[i]);
ret.Add(c);
if (range > 1)
{
ret.UnionWith(NeighborHexagons(c, range - 1));
}
}
return(ret);
}