CastlingBits CanCastleSwitch(int fromPosition)
{
CastlingBits castling = CastlingBits.CAN_ALL;
switch (fromPosition)
{
case BoardStateOffset.A1:
castling = castling & CastlingBits.CAN_NOT_BQ;
break;
case BoardStateOffset.E1:
castling = castling & CastlingBits.CAN_NOT_B;
break;
case BoardStateOffset.H1:
castling = castling & CastlingBits.CAN_NOT_BK;
break;
case BoardStateOffset.A8:
castling = castling & CastlingBits.CAN_NOT_WQ;
break;
case BoardStateOffset.E8:
castling = castling & CastlingBits.CAN_NOT_W;
break;
case BoardStateOffset.H8:
castling = castling & CastlingBits.CAN_NOT_WK;
break;
}
return(castling);
}
CastlingBits CanCastleIf(int fromPosition)
{
CastlingBits castling = CastlingBits.CAN_ALL;
if (fromPosition == BoardStateOffset.A1)
{
castling = castling & CastlingBits.CAN_NOT_BQ;
}
else if (fromPosition == BoardStateOffset.E1)
{
castling = castling & CastlingBits.CAN_NOT_B;
}
else if (fromPosition == BoardStateOffset.H1)
{
castling = castling & CastlingBits.CAN_NOT_BK;
}
else if (fromPosition == BoardStateOffset.A8)
{
castling = castling & CastlingBits.CAN_NOT_WQ;
}
else if (fromPosition == BoardStateOffset.E8)
{
castling = castling & CastlingBits.CAN_NOT_W;
}
else if (fromPosition == BoardStateOffset.H8)
{
castling = castling & CastlingBits.CAN_NOT_WK;
}
return(castling);
}
CastlingBits CanCastleLookup(int fromPosition)
{
CastlingBits castleBits = CastlingBits.CAN_ALL;
castleBits = (CastlingBits)((int)castleBits & (int)CastlingHelper.castleLookup[fromPosition]);
return(castleBits);
}
public bool CanCastleKingSide()
{
CastlingBits castlingBits = CastlingBits;
// TODO bitshift optimize?
if (IsWhiteTurnBool)
{
return((castlingBits & CastlingBits.WHITE_KING_SIDE_CASTLE) == CastlingBits.WHITE_KING_SIDE_CASTLE);
}
else
{
return((castlingBits & CastlingBits.BLACK_KING_SIDE_CASTLE) == CastlingBits.BLACK_KING_SIDE_CASTLE);
}
}
public bool CanICastleQueenSide()
{
CastlingBits castlingBits = CastlingBits;
// TODO bitshift optimize?
if (IsWhiteTurnBool)
{
return((castlingBits & CastlingBits.WHITE_QUEEN_SIDE_CASTLE) == CastlingBits.WHITE_QUEEN_SIDE_CASTLE);
}
else
{
return((castlingBits & CastlingBits.BLACK_QUEEN_SIDE_CASTLE) == CastlingBits.BLACK_QUEEN_SIDE_CASTLE);
}
}
public void BlackCannotCastleQueenSideAfterH8Moves()
{
CastlingBits castling = CastlingBits.CAN_ALL;
castling = castling & CastlingHelper.castleLookup[BoardStateOffset.H8];
Assert.IsTrue((castling & CastlingBits.BLACK_QUEEN_SIDE_CASTLE) == CastlingBits.BLACK_QUEEN_SIDE_CASTLE,
"Black can still castle queen side after h8 moves");
Assert.IsFalse((castling & CastlingBits.BLACK_KING_SIDE_CASTLE) == CastlingBits.BLACK_KING_SIDE_CASTLE,
"Black cannot castle king side after h8 moves");
Assert.IsTrue((castling & CastlingBits.WHITE_KING_SIDE_CASTLE) == CastlingBits.WHITE_KING_SIDE_CASTLE,
"White can still castle");
Assert.IsTrue((castling & CastlingBits.WHITE_QUEEN_SIDE_CASTLE) == CastlingBits.WHITE_QUEEN_SIDE_CASTLE,
"White can still castle");
}
public static String BoardToFen(Board board, int move = 0)
{
StringBuilder fen = new StringBuilder();
for (int row = 7; row >= 0; row--)
{
int count = 0;
for (int column = 0; column < 8; column++)
{
var position = row * BoardStateOffset.ROW_OFFSET + column;
var piece = board.GetPiece(position);
//var piece = Board.GetPiece(board, position);
char c = PieceParser.ToChar(piece);
if (c == '_')
{
count++;
}
else
{
if (count != 0)
{
fen.Append(count);
count = 0;
}
fen.Append(c);
}
}
if (count != 0)
{
fen.Append(count);
}
if (row != 0)
{
fen.Append("/");
}
}
fen.Append(" ");
fen.Append(board.IsWhiteTurnBool ? "w" : "b");
fen.Append(" ");
CastlingBits castlingBits = board.CastlingBits;
if (castlingBits == CastlingBits.EMPTY)
{
fen.Append("-");
}
else
{
if ((castlingBits & CastlingBits.WHITE_KING_SIDE_CASTLE) != CastlingBits.EMPTY)
{
fen.Append("K");
}
if ((castlingBits & CastlingBits.WHITE_QUEEN_SIDE_CASTLE) != CastlingBits.EMPTY)
{
fen.Append("Q");
}
if ((castlingBits & CastlingBits.BLACK_KING_SIDE_CASTLE) != CastlingBits.EMPTY)
{
fen.Append("k");
}
if ((castlingBits & CastlingBits.BLACK_QUEEN_SIDE_CASTLE) != CastlingBits.EMPTY)
{
fen.Append("q");
}
}
fen.Append(" ");
fen.Append(board.EnPassantTarget != EnPassant.NO_ENPASSANT ? BoardPosition.ReadablePosition(board.EnPassantTarget) : "-");
fen.Append(" ");
fen.Append(board.HalfTurnCounter);
fen.Append(" ");
fen.Append(move);
return(fen.ToString());
}
public void UndoMove(Move move)
{
int targetPosition = move.targetPosition;
int fromPosition = move.fromPosition;
int theirColor = IsWhiteTurn;
int ourColor = IsWhiteTurn ^ 1;
bytes[fromPosition] = bytes[targetPosition];
bytes[targetPosition] = move.capturedPiece;
Piece movedPiece = GetPiece(fromPosition);
CastlingBits previous = (CastlingBits)move.previousCastlingBits;
bytes[BoardStateOffset.HALF_TURN_COUNTER] = move.previousHalfMove;
bytes[BoardStateOffset.CASTLING] = move.previousCastlingBits;
bytes[BoardStateOffset.EN_PASSANT_FIELD] = move.previousEnpassant;
MoveFlags moveFlags = (MoveFlags)move.moveFlags;
if ((moveFlags & MoveFlags.ENPASSANT) == MoveFlags.ENPASSANT)
{
// when undoing a enpassant move spawn their pawn back
// we abuse that isWhite is a integer which is 1 on whites turn and 0 and blacks turn
// if it was black move then we have to spawn it one row above
// if it was whites move we spawn it one move below
// keep in mind the IsWhiteTurn is currently opposite of who made the move
int enpassantSpawnPosition = targetPosition - BoardStateOffset.ROW_OFFSET + 2 * BoardStateOffset.ROW_OFFSET * IsWhiteTurn;
SetPiece(enpassantSpawnPosition, Piece.PAWN | (Piece)theirColor);
// when capturing with enpassant don't place the captured piece back since it was taken from another square
bytes[targetPosition] = (byte)Piece.EMPTY;
}
if (move.promotion != 0)
{
bytes[fromPosition] = (byte)(Piece.PAWN | (Piece)ourColor);
}
// if black made a move decrement the turn counter
// we abuse that isWhite is a integer which is 1 on whites turn and 0 and blacks turn
//TurnCounter -= IsWhiteTurn;
if ((movedPiece & Piece.PIECE_MASK) == Piece.KING)
{
if ((moveFlags & MoveFlags.CASTLING) == MoveFlags.CASTLING)
{
// if the target move is less than the kingsposition it is queenside castling,
// otherwise it is kingside castle
if (targetPosition < fromPosition)
{
// copy the rook back to its starting position
bytes[fromPosition - 4] = bytes[fromPosition - 1];
bytes[fromPosition - 1] = 0;
}
else
{
bytes[fromPosition + 3] = bytes[fromPosition + 1];
bytes[fromPosition + 1] = 0;
}
}
SetKingPosition(ourColor, (byte)fromPosition);
}
// switch turn back to whites turn
IsWhiteTurn = (byte)ourColor;
}
