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 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);
}
}
}
}
}
