// Note that this doesn't check if a pawn can be taken en passant
public bool IsAttacked(int defenderIx, Color defenderColor)
{
// check in roughly descending order of power
// rook and queen
var potentialRookCaptures = RookMoveTable.GetMoves(defenderIx, GetOccupied());
if ((potentialRookCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.Rook)) > 0)
{
return(true);
}
if ((potentialRookCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.Queen)) > 0)
{
return(true);
}
// bishop and queen
var potentialBishopCaptures = BishopMoveTable.GetMoves(defenderIx, GetOccupied());
if ((potentialBishopCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.Bishop)) > 0)
{
return(true);
}
if ((potentialBishopCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.Queen)) > 0)
{
return(true);
}
var potentialKnightCaptures = KnightMoveTable.GetMoves(defenderIx);
if ((potentialKnightCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.Knight)) > 0)
{
return(true);
}
var potentialKingCaptures = KingMoveTable.GetMoves(defenderIx);
if ((potentialKingCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.King)) > 0)
{
return(true);
}
var potentialPawnCaptures = PawnCaptureMoveTable.GetMoves(defenderIx, defenderColor);
if ((potentialPawnCaptures & GetPieceBitboard(defenderColor.Other(), PieceType.Pawn)) > 0)
{
return(true);
}
// we checked all possible attacks by all possible piece types
return(false);
}
private void GenerateKingNormalMoves(List <Move> moves, Position position, ulong sourceSquares)
{
while (Bits.TryPopLsb(ref sourceSquares, out var sourceIx))
{
var dstSquares = KingMoveTable.GetMoves(sourceIx);
// don't allow king to move on piece of same color
dstSquares &= ~position.GetOccupied(position.SideToMove);
GenerateMoves(moves, MoveType.Normal, PieceType.King, sourceIx, dstSquares, position.GetOccupied());
}
}
