private static List <Move> ComputeUnRayedMoves(Board _board, Piece piece)
{
List <Move> moves = new List <Move>();
// Fetch the bitboard containing positions of these pieces
ulong pieces;
ulong friendBoard, oppBoard;
Side side = (Side)((int)piece % 2);
Position[, ][] pieceMoves;
if (piece == Piece.BlackKnight || piece == Piece.WhiteKnight)
{
pieceMoves = KnightMoves;
}
else
if (piece == Piece.BlackKing || piece == Piece.WhiteKing)
{
pieceMoves = KingMoves;
}
else
{
throw new Exception("illegal piece");
}
pieces = _board.BitBoards[(int)piece];
// Check for pieces of type
if (pieces == 0)
{
return(moves);
}
friendBoard = _board.BitBoards[(int)Piece.AllBlacks + ((int)piece % 2)];
oppBoard = _board.BitBoards[(int)Piece.AllBlacks + (((int)piece + 1) % 2)];
//lets roll over all pieces and examine possible moves (already stored)
foreach (Position sourceSquare in Position.FindPositions(pieces))
{
for (int k = 0; k < pieceMoves[sourceSquare.Row, sourceSquare.Col].Length; k++)
{
Position dest = pieceMoves[sourceSquare.Row, sourceSquare.Col][k];
//if dest is friendly, continue
if ((friendBoard & dest.ToBitBoard()) != 0)
{
continue;
}
//add the move
Move move = new Move()
{
SourceSquare = sourceSquare, DestinationSquare = dest, MovingPiece = piece
};
//check for capture
if ((oppBoard & dest.ToBitBoard()) != 0)
{
move.CapturedPiece = _board.FindPiece(dest);
if (move.CapturedPiece == Piece.BlackKing)
{
//move is a checkmate, change board and return null ( so move generation will stop).
move.MoveType = MoveType.Checkmate;
_board.IsTerminal = (TerminalType)(TerminalType.BlackWon + (int)piece % 2);
return(null);
}
else
{
move.MoveType = MoveType.Capture;
}
}
else
{
move.MoveType = MoveType.Normal;
}
moves.Add(move);
}
}
return(moves);
}
private static List <Move> ComputePawnMoves(Board _board, Side _side)
{
List <Move> moves = new List <Move>();
Piece movingPiece = Piece.BlackPawn + (int)_side;
ulong pawns = _board.BitBoards[(int)movingPiece];
ulong oppBoard = _board.BitBoards[(int)Piece.AllBlacks + ((int)_side + 1) % 2];
ulong emptyBoard = _board.BitBoards[(int)Piece.EmptySquare];
int directionSign = _side == Side.White ? -1 : +1;
int startingPos = _side == Side.White ? 7 : 0;
//check which pawns can move one step by moving all pawns one row forward and AND-ing with the empty squares
ulong canOneStep, canTwoSteps, canCaptureLeft, canCaptureRight;
if (_side == Side.White)
{
canOneStep = ((pawns >> 8) & emptyBoard) << 8;
//to check two-steps moves ( 7th row) we first clear all other pawn pieces by shifting 6 rows then we shift back to the position
//of two steps forward. If empty then that pawn can move there.
canTwoSteps = (((canOneStep >> (8 * 6)) << 8 * 4) & emptyBoard) << 8 * 2;
//look for capture moves
canCaptureLeft = ((pawns >> 9) & oppBoard) << 9;
canCaptureRight = ((pawns >> 7) & oppBoard) << 7;
}
else
{
canOneStep = ((pawns << 8) & emptyBoard) >> 8;
canTwoSteps = (((canOneStep << (8 * 6)) >> 8 * 4) & emptyBoard) >> 8 * 2;
canCaptureLeft = ((pawns << 9) & oppBoard) >> 9;
canCaptureRight = ((pawns << 7) & oppBoard) >> 7;
}
//add normal one-step moves, (including promotion)
foreach (Position sourceSquare in Position.FindPositions(canOneStep))
{
if (sourceSquare.Row == 7 - startingPos + directionSign)
{
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.PromotionQueen, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign, sourceSquare.Col)
});
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.PromotionBishop, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign, sourceSquare.Col)
});
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.PromotionKnight, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign, sourceSquare.Col)
});
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.PromotionRook, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign, sourceSquare.Col)
});
}
else
{
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.Normal, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign, sourceSquare.Col)
});
}
}
//add two-step moves
foreach (Position sourceSquare in Position.FindPositions(canTwoSteps))
{
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.Normal, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign * 2, sourceSquare.Col)
});
}
//add capture moves
//to the left
foreach (Position sourceSquare in Position.FindPositions(canCaptureLeft))
{
Position capturedPosition = new Position(sourceSquare.Row + directionSign, sourceSquare.Col + directionSign);
//might happen when bitwise shifting
if (capturedPosition.Col == -1 || capturedPosition.Col == 8)
{
continue;
}
Piece captured = _board.FindPiece(capturedPosition);
if (captured == Piece.BlackKing)
{
//move is a checkmate, change board and return null ( so move generation will stop).
_board.IsTerminal = (TerminalType)(TerminalType.BlackWon + (int)_side);
return(null);
}
if (sourceSquare.Row == 7 - startingPos + directionSign)
{
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionQueen, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionBishop, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionKnight, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionRook, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
}
else
{
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
}
}
//to the right
foreach (Position sourceSquare in Position.FindPositions(canCaptureRight))
{
Position capturedPosition = new Position(sourceSquare.Row + directionSign, sourceSquare.Col - directionSign);
//might happen when bitwise shifting
if (capturedPosition.Col == 8 || capturedPosition.Col == -1)
{
continue;
}
Piece captured = _board.FindPiece(capturedPosition);
if (sourceSquare.Col == 7 - startingPos + directionSign)
{
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionQueen, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionBishop, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionKnight, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture & MoveType.PromotionRook, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
}
else
{
moves.Add(new Move {
MovingPiece = movingPiece, CapturedPiece = captured, MoveType = MoveType.Capture, SourceSquare = sourceSquare, DestinationSquare = capturedPosition
});
}
}
//find EnPassant
foreach (Position sourceSquare in Position.FindPositions(pawns))
{
//check en-passant
if (_board.EnPassantOptionColumn == sourceSquare.Col - 1 || _board.EnPassantOptionColumn == sourceSquare.Col + 1)
{
moves.Add(new Move {
MovingPiece = movingPiece, MoveType = MoveType.EnPassant, CapturedPiece = movingPiece == Piece.BlackPawn ? Piece.WhitePawn : Piece.BlackPawn, SourceSquare = sourceSquare, DestinationSquare = new Position(sourceSquare.Row + directionSign, _board.EnPassantOptionColumn)
});
}
}
return(moves);
}
private static List <Move> ComputeRayedMoves_Internal(Board _board, Piece piece, Position[, ][][] pieceMoves)
{
List <Move> moves = new List <Move>();
// Fetch the bitboard containing positions of these pieces
ulong pieces;
ulong friendBoard, oppBoard;
pieces = _board.BitBoards[(int)piece];
// Check for pieces of type
if (pieces == 0)
{
return(moves);
}
friendBoard = _board.BitBoards[(int)Piece.AllBlacks + ((int)piece % 2)];
oppBoard = _board.BitBoards[(int)Piece.AllBlacks + (((int)piece + 1) % 2)];
foreach (Position sourceSquare in Position.FindPositions(pieces))
{
//loop over all rays (initalized at engine start)
for (int ray = 0; ray < pieceMoves[sourceSquare.Row, sourceSquare.Col].Length; ray++)
{
for (int k = 0; k < pieceMoves[sourceSquare.Row, sourceSquare.Col][ray].Length; k++)
{
// Get the destination square
Position dest = pieceMoves[sourceSquare.Row, sourceSquare.Col][ray][k];
//if dest is friendly, continue
if ((friendBoard & dest.ToBitBoard()) != 0)
{
break;
}
// Otherwise, the move is legal, so we must prepare to add it
Move move = new Move()
{
SourceSquare = sourceSquare, DestinationSquare = dest, MovingPiece = piece
};
// Is the destination occupied by an enemy? If so, we have a capture
if ((oppBoard & dest.ToBitBoard()) != 0)
{
move.CapturedPiece = _board.FindPiece(dest);
if (move.CapturedPiece == Piece.BlackKing)
{
//move is a checkmate, change board and return null ( so move generation will stop).
move.MoveType = MoveType.Checkmate;
_board.IsTerminal = (TerminalType)(TerminalType.BlackWon + (int)piece % 2);
return(null);
}
else
{
move.MoveType = MoveType.Capture;
}
}
// otherwise, it is a simple move
else
{
move.MoveType = MoveType.Normal;
}
moves.Add(move);
}
}
}
return(moves);
}