/// <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>
/// Calculates a promotion move.
/// </summary>
/// <param name="bitboard">The bitboard.</param>
public override void CalculateMove(Bitboard bitboard)
{
var from = BitPositionConverter.ToULong(From);
var to = BitPositionConverter.ToULong(To);
if (KillMove)
{
CalculateKill(bitboard, ColorOperations.Invert(Color), to);
}
CalculatePieceMove(bitboard, Piece, from, PromotionPiece, to);
IncrementalMaterial.RemovePiece(bitboard, Color, Piece);
IncrementalMaterial.AddPiece(bitboard, Color, PromotionPiece);
}
/// <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;
}
}
}