/// <summary>
/// Removes en passant piece from the specified bitboard.
/// </summary>
/// <param name="bitboard">The bitboard.</param>
/// <param name="enemyColor">The enemy color.</param>
/// <param name="fieldLSB">The bitboard with set field.</param>
private void RemoveEnPassantPiece(Bitboard bitboard, Color enemyColor, ulong fieldLSB)
{
var enPassantPiece = Color == Color.White ? fieldLSB >> 8 : fieldLSB << 8;
bitboard.Pieces[FastArray.GetPieceIndex(enemyColor, PieceType.Pawn)] &= ~enPassantPiece;
bitboard.Occupancy[(int)enemyColor] ^= enPassantPiece;
IncrementalMaterial.RemovePiece(bitboard, enemyColor, PieceType.Pawn);
IncrementalPosition.RemovePiece(bitboard, enemyColor, PieceType.Pawn, enPassantPiece);
IncrementalZobrist.AddOrRemovePiece(enemyColor, PieceType.Pawn, enPassantPiece, bitboard);
}
/// <summary>
/// Helper method for derived classes, calculates move with the specified parameters.
/// </summary>
/// <param name="bitboard">The bitboard.</param>
/// <param name="pieceFrom">The source piece type.</param>
/// <param name="from">The piece source position.</param>
/// <param name="pieceTo">The destination piece type.</param>
/// <param name="to">The piece destination position.</param>
protected void CalculatePieceMove(Bitboard bitboard, PieceType pieceFrom, ulong from, PieceType pieceTo, ulong to)
{
bitboard.Pieces[FastArray.GetPieceIndex(Color, pieceFrom)] &= ~from;
bitboard.Pieces[FastArray.GetPieceIndex(Color, pieceTo)] |= to;
bitboard.Occupancy[(int)Color] ^= from | to;
IncrementalPosition.RemovePiece(bitboard, Color, pieceFrom, from);
IncrementalPosition.AddPiece(bitboard, Color, pieceTo, to);
IncrementalZobrist.AddOrRemovePiece(Color, pieceFrom, from, bitboard);
IncrementalZobrist.AddOrRemovePiece(Color, pieceTo, to, bitboard);
if (pieceFrom == PieceType.Pawn)
{
bitboard.ReversibleMoves = 0;
}
}
/// <summary>
/// Removes killed piece from the specified bitboard.
/// </summary>
/// <param name="bitboard">The bitboard.</param>
/// <param name="enemyColor">The enemy color.</param>
/// <param name="fieldLSB">The bitboard with set field.</param>
protected void CalculateKill(Bitboard bitboard, Color enemyColor, ulong fieldLSB)
{
for (var piece = 0; piece < 6; piece++)
{
var index = FastArray.GetPieceIndex(enemyColor, (PieceType)piece);
if ((bitboard.Pieces[index] & fieldLSB) != 0)
{
bitboard.Pieces[index] &= ~fieldLSB;
bitboard.Occupancy[(int)enemyColor] &= ~fieldLSB;
IncrementalMaterial.RemovePiece(bitboard, enemyColor, (PieceType)piece);
IncrementalPosition.RemovePiece(bitboard, enemyColor, (PieceType)piece, fieldLSB);
IncrementalZobrist.AddOrRemovePiece(enemyColor, (PieceType)piece, fieldLSB, bitboard);
bitboard.ReversibleMoves = 0;
break;
}
}
}
