public static Bitboard KingAttacks(Bitboard king)
{
Bitboard attacks = king.EastOne() | king.WestOne();
king |= attacks;
attacks |= king.NortOne() | king.SoutOne();
return(attacks);
}
internal static void AddCastlingMoves(Position position, List <Move> allMoves)
{
Side side = position.SideToMove;
Board board = position.Board;
if (board[side, Piece.King] == 0)
{
return;
}
if (Castling.CanCastleKingside(position.CastlingRights, side))
{
var kingsideBetween = Castling.KingSideBetween(side);
bool spaceAvailable = BitUtils.IsASubsetOfB(kingsideBetween, board.EmptySquares);
var kingsideChecks = Castling.KingSideChecks(side);
Bitboard enemyAttacks = board.AttacksBy(position.OpposingSide);
bool avoidsChecks = (kingsideChecks & enemyAttacks) == 0;
if (spaceAvailable && avoidsChecks)
{
Bitboard king = board[side, Piece.King];
Bitboard castleTarget = king.EastOne().EastOne();
Square from = (Square)king.Serialize()[0];
Square to = (Square)castleTarget.Serialize()[0];
allMoves.Add(new Move(from, to, MoveFlags.KingCastle));
}
}
if (Castling.CanCastleQueenside(position.CastlingRights, side))
{
var queensideBetween = Castling.QueenSideBetween(side);
bool spaceAvailable = BitUtils.IsASubsetOfB(queensideBetween, board.EmptySquares);
var queensideChecks = Castling.QueenSideChecks(side);
Bitboard enemyAttacks = board.AttacksBy(position.OpposingSide);
bool avoidsChecks = (queensideChecks & enemyAttacks) == 0;
if (spaceAvailable && avoidsChecks)
{
Bitboard king = board[side, Piece.King];
Bitboard castleTarget = king.WestOne().WestOne();
Square from = (Square)king.Serialize()[0];
Square to = (Square)castleTarget.Serialize()[0];
allMoves.Add(new Move(from, to, MoveFlags.QueenCastle));
}
}
}
