public void UndoMove(uint count)
{
while (History.Count > 0 && count > 0)
{
var move = History.Peek();
// undo 'global' information
Turn = Chess.InverseColor(move.Color);
Castling = move.Castling;
EnPassantCoord = move.EnPassantCoord;
HalfMove = move.HalfMove;
Move = move.Move;
MovePiece(move.To, move.From);
var flags = move.Flags;
if (flags.HasFlag(ChessMoveFlag.Promotion))
{
var piece = AddPiece(Turn, ChessPieceType.Pawn, move.To);
piece.Guid = move.Guid;
}
if (flags.HasFlag(ChessMoveFlag.Capture))
{
var piece = AddPiece(Turn, move.Captured, move.To);
piece.Guid = move.CapturedGuid;
}
if (flags.HasFlag(ChessMoveFlag.EnPassantCapture))
{
var enPassantFrom = new ChessPieceCoord(move.To);
enPassantFrom.MoveOffset(0, move.Color == ChessColor.Black ? 1 : -1);
var piece = AddPiece(Turn, ChessPieceType.Pawn, enPassantFrom);
piece.Guid = move.CapturedGuid;
}
if ((flags & (ChessMoveFlag.KingSideCastle | ChessMoveFlag.QueenSideCastle)) != 0)
{
var castlingTo = new ChessPieceCoord(move.To);
var castlingFrom = new ChessPieceCoord(castlingTo);
if (flags.HasFlag(ChessMoveFlag.KingSideCastle))
{
castlingTo.MoveOffset(1, 0);
castlingFrom.MoveOffset(-1, 0);
}
if (flags.HasFlag(ChessMoveFlag.QueenSideCastle))
{
castlingTo.MoveOffset(-2, 0);
castlingFrom.MoveOffset(1, 0);
}
MovePiece(castlingTo, castlingFrom);
}
History.Pop();
count--;
}
}
public void BuildMove(List <ChessMove> storage, ChessMoveFlag result, ChessColor color, ChessPieceType type, ChessPieceCoord from, ChessPieceCoord to)
{
var fromPiece = GetPiece(from);
var toPiece = GetPiece(to);
// AC's Chess implementation doesn't support underpromotion
var promotion = ChessPieceType.Empty;
if (fromPiece.Type == ChessPieceType.Pawn && (to.Rank == 1 || to.Rank == 8))
{
promotion = ChessPieceType.Queen;
result |= ChessMoveFlag.Promotion;
}
var captured = ChessPieceType.Empty;
if (toPiece != null)
{
captured = toPiece.Type;
}
else if (result.HasFlag(ChessMoveFlag.EnPassantCapture))
{
captured = ChessPieceType.Pawn;
var enPassantCoord = new ChessPieceCoord(to);
enPassantCoord.MoveOffset(0, color == ChessColor.Black ? 1 : -1);
toPiece = GetPiece(enPassantCoord);
}
storage.Add(new ChessMove(result, color, type, from, to, promotion, captured, Move, HalfMove, Castling, EnPassantCoord, fromPiece.Guid, captured != ChessPieceType.Empty ? toPiece.Guid : new ObjectGuid(0)));
}
public bool CanAttack(ChessColor attacker, ChessPieceCoord victim)
{
for (uint x = 0; x < Chess.BoardSize; x++)
{
for (uint y = 0; y < Chess.BoardSize; y++)
{
var piece = Board[x + y * Chess.BoardSize];
if (piece == null)
{
continue;
}
if (piece.Color != attacker)
{
continue;
}
if (piece.CanAttack(victim))
{
// the knight can jump over other pieces and the pawn can only attack a single space
if (piece.Type == ChessPieceType.Knight || piece.Type == ChessPieceType.Pawn)
{
return(true);
}
var range = Chess.PieceOffsets[piece.Type];
for (var i = 0; i < range.Count; i++)
{
var from = piece.Coord;
var to = new ChessPieceCoord(from);
while (true)
{
to.MoveOffset(range[i]);
if (!to.IsValid())
{
break;
}
var toPiece = GetPiece(to);
if (toPiece != null)
{
if (to.Equals(victim))
{
return(true);
}
break;
}
}
}
}
}
}
return(false);
}
public void FinalizeWeenieMove(ChessMoveResult result)
{
var move = Logic.GetLastMove();
Log.Add(move);
// need to use destination coordinate as Logic has already moved the piece
var piece = Logic.GetPiece(move.To);
if (result.HasFlag(ChessMoveResult.OKMoveToEmptySquare))
{
MoveWeeniePiece(piece);
var flags = move.Flags;
if ((flags & (ChessMoveFlag.KingSideCastle | ChessMoveFlag.QueenSideCastle)) != 0)
{
var castlingTo = new ChessPieceCoord(move.To);
if (flags.HasFlag(ChessMoveFlag.KingSideCastle))
{
castlingTo.MoveOffset(-1, 0);
}
if (flags.HasFlag(ChessMoveFlag.QueenSideCastle))
{
castlingTo.MoveOffset(1, 0);
}
var rookPiece = Logic.GetPiece(castlingTo);
Debug.Assert(rookPiece != null);
MoveWeeniePiece(rookPiece);
}
}
else if (result.HasFlag(ChessMoveResult.OKMoveToOccupiedSquare))
{
AttackWeeniePiece(piece, move.CapturedGuid);
}
}
public void InternalMove(ChessMove move)
{
var flags = move.Flags;
var to = move.To;
var from = move.From;
var color = move.Color;
var opColor = Chess.InverseColor(color);
MovePiece(from, to);
if (flags.HasFlag(ChessMoveFlag.EnPassantCapture))
{
var enPassantCoord = new ChessPieceCoord(to);
enPassantCoord.MoveOffset(0, color == ChessColor.Black ? 1 : -1);
RemovePiece(enPassantCoord);
}
if (flags.HasFlag(ChessMoveFlag.Promotion))
{
var pawnPiece = GetPiece(to);
var guid = pawnPiece.Guid;
RemovePiece(pawnPiece);
var queenPiece = AddPiece(color, ChessPieceType.Queen, (uint)to.X, (uint)to.Y);
queenPiece.Guid = guid;
}
if (move.Type == ChessPieceType.King)
{
// if we castled, move the rook next to our king
if ((flags & (ChessMoveFlag.KingSideCastle | ChessMoveFlag.QueenSideCastle)) != 0)
{
var castlingTo = new ChessPieceCoord(move.To);
var castlingFrom = new ChessPieceCoord(castlingTo);
if (flags.HasFlag(ChessMoveFlag.KingSideCastle))
{
castlingTo.MoveOffset(-1, 0);
castlingFrom.MoveOffset(1, 0);
}
if (flags.HasFlag(ChessMoveFlag.QueenSideCastle))
{
castlingTo.MoveOffset(1, 0);
castlingFrom.MoveOffset(-2, 0);
}
MovePiece(castlingFrom, castlingTo);
}
// turn off castling, our king has moved
Castling[(int)color] = ChessMoveFlag.None;
}
// turn off castling if we have moved one of our rooks
if (Castling[(int)color] != ChessMoveFlag.None)
{
DoCastleCheck(color, from);
}
// turn off castling if we capture one of the opponent's rooks
if (Castling[(int)opColor] != ChessMoveFlag.None)
{
DoCastleCheck(opColor, from);
}
if (flags.HasFlag(ChessMoveFlag.BigPawn))
{
var enPassantCoord = new ChessPieceCoord(to);
//enPassantCoord.MoveOffset(0, color == ChessColor.Black ? 2 : -2);
enPassantCoord.MoveOffset(0, color == ChessColor.Black ? 1 : -1);
EnPassantCoord = enPassantCoord;
}
else
{
EnPassantCoord = null;
}
History.Push(move);
if (color == ChessColor.Black)
{
Move++;
}
// reset 50 move rule counter if a pawn is moved or a piece is captured
if (move.Type == ChessPieceType.Pawn ||
(flags & (ChessMoveFlag.Capture | ChessMoveFlag.EnPassantCapture)) != 0)
{
HalfMove = 0;
}
else
{
HalfMove++;
}
Turn = opColor;
}
public void GenerateMoves(BasePiece piece, bool single, List <ChessMove> storage)
{
var color = piece.Color;
if (piece.Type == ChessPieceType.Pawn)
{
// single
var from = new ChessPieceCoord(piece.Coord);
var to = new ChessPieceCoord(from);
to.MoveOffset(Chess.PawnOffsets[(int)color, 0]);
if (GetPiece(to) == null)
{
BuildMove(storage, ChessMoveFlag.Normal, color, piece.Type, from, to);
// second
to = new ChessPieceCoord(from);
to.MoveOffset(Chess.PawnOffsets[(int)color, 1]);
if (GetPiece(to) == null && from.Rank == (color == ChessColor.White ? 2 : 7))
{
BuildMove(storage, ChessMoveFlag.BigPawn, color, piece.Type, from, to);
}
}
// capture
for (uint i = 2; i < 4; i++)
{
to = new ChessPieceCoord(from);
to.MoveOffset(Chess.PawnOffsets[(int)color, i]);
if (!to.IsValid())
{
continue;
}
var toPiece = GetPiece(to);
if (toPiece != null && toPiece.Color != color)
{
BuildMove(storage, ChessMoveFlag.Capture, color, piece.Type, from, to);
}
else if (to.Equals(EnPassantCoord))
{
BuildMove(storage, ChessMoveFlag.EnPassantCapture, color, piece.Type, from, EnPassantCoord);
}
}
}
else
{
var range = Chess.PieceOffsets[piece.Type];
for (var i = 0; i < range.Count; i++)
{
var from = piece.Coord;
var to = new ChessPieceCoord(from);
while (true)
{
to.MoveOffset(range[i]);
if (!to.IsValid())
{
break;
}
var toPiece = GetPiece(to);
if (toPiece != null)
{
if (toPiece.Color != color)
{
BuildMove(storage, ChessMoveFlag.Capture, color, piece.Type, from, to);
}
break;
}
BuildMove(storage, ChessMoveFlag.Normal, color, piece.Type, from, to);
// Knights and Kings can't move more than once
if (piece.Type == ChessPieceType.Knight || piece.Type == ChessPieceType.King)
{
break;
}
}
}
}
// only check for castling during full board generation or for a single king
if (!single || piece.Type == ChessPieceType.King)
{
if ((Castling[(int)color] & ChessMoveFlag.KingSideCastle | ChessMoveFlag.QueenSideCastle) != 0)
{
var king = GetPiece(color, ChessPieceType.King);
var kingCoord = king.Coord;
var opColor = Chess.InverseColor(color);
if ((Castling[(int)color] & ChessMoveFlag.KingSideCastle) != 0)
{
var castlingToK = new ChessPieceCoord(kingCoord); // destination king
castlingToK.MoveOffset(2, 0);
var castlingToR = new ChessPieceCoord(kingCoord); // destination rook
castlingToR.MoveOffset(1, 0);
if (GetPiece(castlingToR) == null &&
GetPiece(castlingToK) == null &&
!CanAttack(opColor, kingCoord) &&
!CanAttack(opColor, castlingToR) &&
!CanAttack(opColor, castlingToK))
{
BuildMove(storage, ChessMoveFlag.KingSideCastle, color, ChessPieceType.King, kingCoord, castlingToK);
}
}
if ((Castling[(int)color] & ChessMoveFlag.QueenSideCastle) != 0)
{
var castlingToK = new ChessPieceCoord(kingCoord); // destination king
castlingToK.MoveOffset(-2, 0);
var castlingToR = new ChessPieceCoord(kingCoord); // destination rook
castlingToR.MoveOffset(-1, 0);
var castlingToI = new ChessPieceCoord(kingCoord); // intermediate
castlingToI.MoveOffset(-3, 0);
if (GetPiece(castlingToR) == null &&
GetPiece(castlingToK) == null &&
GetPiece(castlingToI) == null &&
!CanAttack(opColor, kingCoord) &&
!CanAttack(opColor, castlingToR) &&
!CanAttack(opColor, castlingToK))
{
BuildMove(storage, ChessMoveFlag.QueenSideCastle, color, ChessPieceType.King, kingCoord, castlingToK);
}
}
}
}
}
