public Boolean InCheck(int sideToMove)
{
int kingsq = King[sideToMove].BitScanForward();
int xside = sideToMove ^ 1;
if ((MoveGenerator.BishopAttacks(this, kingsq) & (Bishops[xside] | Queens[xside])) > 0)
return true;
else if ((MoveGenerator.RookAttacks(this, kingsq) & (Rooks[xside] | Queens[xside])) > 0)
return true;
else if ((MoveGenerator.PawnAttacks[sideToMove, kingsq] & Pawns[xside]) > 0)
return true;
else if ((MoveGenerator.KnightMoves[kingsq] & Knights[xside]) > 0)
return true;
else if ((MoveGenerator.KingMoves[kingsq] & King[xside]) > 0)
return true;
return false;
}
public string ToAlegbraicNotation(Board b)
{
//find Piece
String output = String.Empty;
MoveBits bits = 0;
if ((b.Knights[b.SideToMove] & BitMask.Mask[From]) > 0)
{
bits = MoveBits.Knight;
}
else if ((b.Bishops[b.SideToMove] & BitMask.Mask[From]) > 0)
{
bits = MoveBits.Bishop;
}
else if ((b.Rooks[b.SideToMove] & BitMask.Mask[From]) > 0)
{
bits = MoveBits.Rook;
}
else if ((b.Queens[b.SideToMove] & BitMask.Mask[From]) > 0)
{
bits = MoveBits.Queen;
}
else if ((b.Pawns[b.SideToMove] & BitMask.Mask[From]) > 0)
{
bits = MoveBits.Pawn;
}
else if ((b.King[b.SideToMove] & BitMask.Mask[From]) > 0)
{
bits = MoveBits.King;
}
if (bits == MoveBits.Pawn)
{
if ((Bits & (byte)MoveBits.Capture) > 0)
{
output += outputFiles[From.File()];
}
}
else if (bits == MoveBits.Knight)
{
output += 'N';
var sqs = MoveGenerator.KnightMoves[To] & b.Knights[b.SideToMove];
if ((sqs).Count() > 1)
{
output += FileOrRank(b, bits);
}
}
else if (bits == MoveBits.Bishop)
{
output += 'B';
var sqs = MoveGenerator.BishopAttacks(b, To) & b.Bishops[b.SideToMove];
if (sqs.Count() > 1)
{
output += FileOrRank(b, bits);
}
}
else if (bits == MoveBits.Rook)
{
output += 'R';
var sqs = MoveGenerator.RookAttacks(b, To) & b.Rooks[b.SideToMove];
if (sqs.Count() > 1)
{
output += FileOrRank(b, bits);
}
}
else if (bits == MoveBits.Queen)
{
var sqs = MoveGenerator.QueenAttacks(b, To) & b.Queens[b.SideToMove];
output += 'Q';
if (sqs.Count() > 1)
{
output += FileOrRank(b, bits);
}
}
else if (bits == MoveBits.King)
{
//if we are castling
if (Math.Abs(To.File() - From.File()) > 1)
{
if (To == 6 || To == 62)
{
return("O-O");
}
else
{
return("O-O-O");
}
}
output += 'K';
}
else
{
output = Board.SquareNames[From];
}
if ((Bits & (byte)MoveBits.Capture) > 0)
{
output += 'x';
}
output += Board.SquareNames[To];
if (Promotion > 0)
{
output += "=";
switch ((Piece)Promotion)
{
case Piece.Knight:
output += "N";
break;
case Piece.Bishop:
output += "B";
break;
case Piece.Rook:
output += "R";
break;
case Piece.Queen:
output += "Q";
break;
}
}
b.MakeMove(this);
if (b.InCheck(b.SideToMove))
{
output += "+";
}
b.UnMakeMove();
return(output);
}
//evaluates exchanges on a square initiated by stm
public static int Eval(Board b, Move m, int stm)
{
ulong[] attackers = new ulong[2];
int score = 0;
var sq = m.To;
var pieceVal = Evaluator.PieceValueOnSquare(b, sq);
var attacks = MoveGenerator.Attacks(b, sq);
var mystm = stm ^ 1;
attackers[mystm] = attacks & b.Pieces[mystm];
attackers[stm] = attacks & b.Pieces[stm];
//change the pieceVal to be the new piece
//if there is a promotion, then stm is already up material
if (m.Promotion > 0)
{
pieceVal = Evaluator.PieceValues[m.Promotion];
score = pieceVal - 100; //lose the initial pawn
}
else
{
pieceVal = Evaluator.PieceValues[(int)Move.GetPiece((MoveBits)m.Bits)];
}
//add in any material taken on the first capture
if ((m.Bits & (byte)MoveBits.Capture) > 0)
{
score += Evaluator.PieceValueOnSquare(b, m.To);
}
//remove the first Move, unless this was a straight pawn push
if (!((m.Bits & (byte)MoveBits.Pawn) > 0 && Math.Abs(m.From - m.To) == 8))
{
attackers[stm] ^= BitMask.Mask[m.From];
}
while (attackers[mystm] > 0)
{
var tempAttackers = attackers[mystm];
var leastValuable = int.MaxValue;
int leastValSq = -1;
bool promote, promoting = false;
//make a pass over the attackers to find the lowest valued piece
while (tempAttackers > 0)
{
promote = false;
var attack_sq = tempAttackers.BitScanForward();
tempAttackers ^= BitMask.Mask[attack_sq];
var attackerVal = Evaluator.PieceValueOnSquare(b, attack_sq);
//if we found a pawn capturing onto the 8th rank, we need to consider promotion
if (attackerVal == 100 && (sq.Rank() == 0 || sq.Rank() == 7))
{
//we will treat this attacker as if it were a queen
attackerVal = Evaluator.PieceValues[(int)Piece.Queen];
promote = true;
}
if (attackerVal < leastValuable)
{
promoting = promote;
leastValSq = attack_sq;
leastValuable = attackerVal;
}
}
//now we have the least valuable attacker
//remove whatever value is on the square
if (mystm == stm)
{
score += pieceVal;
if (promoting)
{
score += leastValuable - 100;//lose the promoting pawn, add in queen
}
}
else
{
score -= pieceVal;
if (promoting)
{
score -= leastValuable + 100;//lose the promoting pawn, add in queen
}
}
//update the attacked piece
pieceVal = leastValuable;
//remove the attacker
attackers[mystm] ^= BitMask.Mask[leastValSq];
//now we check for x-ray attacks
//the idea here is that if any rooks, queens, or bishops attack the temporary
//square from the same direction that the temporary square is attacking the target
//then we have an xray attacker
var direction = MoveGenerator.Directions[leastValSq, sq];
ulong xrayAttacks = 0;
switch (Math.Abs(direction))
{
case 1:
case 8:
if (((b.Rooks[mystm] | b.Queens[mystm]) & Board.FileMask[sq.File()]) > 0)
{
xrayAttacks = MoveGenerator.RookAttacks(b, leastValSq) & (b.Rooks[mystm] | b.Queens[mystm]) & attackers[mystm];
}
break;
case 7:
case 9:
xrayAttacks = MoveGenerator.BishopAttacks(b, leastValSq) & (b.Bishops[mystm] | b.Queens[mystm]) & attackers[mystm];
break;
}
while (xrayAttacks > 0)
{
var xraySq = xrayAttacks.BitScanForward();
xrayAttacks ^= BitMask.Mask[xraySq];
if (MoveGenerator.Directions[xraySq, sq] == direction)
{
//put this piece in main attackers bitboard
attackers[mystm] |= BitMask.Mask[xraySq];
}
}
//switch stm
mystm ^= 1;
}
return(score);
}
static int EvaluatePieces(Evaluation e)
{
//evaluate things like material imbalance,
//bishop pair, knights supported by pawns, etc.
int[] eval = new int[2];
for (int side = 0; side < 2; side++)
{
int xside = side ^ 1;
//evaluate material imbalances
// a rook+pawn for two pieces is not good
//if side has only one rook and opponent has two
if (e.Board.Rooks[side] > 0 &&
e.Board.Rooks[xside] > 0 &&
e.Board.Rooks[side].Count() == 1 &&
e.Board.Rooks[xside].Count() == 2)
{
//if opposite side has two less minors then we get a bonus
if (e.Board.Minors(side).Count() - e.Board.Minors(xside).Count() == 2)
{
eval[side] += MinorMaterialInbalanceBonus;
}
}
//bishop pair bonus
eval[side] += (e.Board.Bishops[side].Count() == 2) ? BishopPairBonus : 0;
//increase the value of rooks as pawns come off the board
int totalPawns = e.Board.Pawns[0].Count() + e.Board.Pawns[1].Count();
eval[side] += RookBonusPawnCount[totalPawns];
//rooks
var rooks = e.Board.Rooks[side];
while (rooks > 0)
{
int sq = rooks.BitScanForward();
rooks ^= BitMask.Mask[sq];
//open file bonus
if (e.PawnScore.Files[side, sq.File()] == 0)
{
eval[side] += RookOnOpenFileBonus / 2;
if (e.PawnScore.Files[xside, sq.File()] == 0)
{
eval[side] = RookOnOpenFileBonus;
}
}
//rooks on the seventh (or eigth)
if (side == 0 && sq.Rank() <= 1)
{
eval[0] += RookOnSeventhBonus;
}
else if (side == 1 && sq.Rank() >= 6)
{
eval[1] += RookOnSeventhBonus;
}
}
//knights
var knights = e.Board.Knights[side];
while (knights > 0)
{
int sq = knights.BitScanForward();
knights ^= BitMask.Mask[sq];
//only looking for forward knights
if (side == 0 && sq.Rank() > 3)
{
continue;
}
else if (side == 1 && sq.Rank() < 3)
{
continue;
}
//look for knights on outposts
if ((MoveGenerator.PawnAttacks[xside, sq] & e.Board.Pawns[side]) > 0)
{
//knight is defended by a pawn
//use the passed pawn lookup - minus the file to see if
//we have an ouput
if ((PassedPawnMask[side, sq] & ~Board.FileMask[sq.File()] & e.Board.Pawns[xside]) == 0)
{
eval[side] += KnightOnOutpostBonus;
}
}
EvalTrappedKnights(e, eval, side, sq);
}
var bishops = e.Board.Bishops[side];
while (bishops > 0)
{
int sq = bishops.BitScanForward();
bishops ^= BitMask.Mask[sq];
//evaluate trapped bishops
if (side == 0)
{
if (sq == 23 && //white bishop on h6
(e.Board.Pawns[1] & BitMask.Mask[30]) > 0 &&
(e.Board.Pawns[1] & BitMask.Mask[21]) > 0)
{
eval[side] -= PieceValues[(int)Piece.Bishop] / 3;
}
else if (sq == 16 && //white bishop on a6
(e.Board.Pawns[1] & BitMask.Mask[25]) > 0 &&
(e.Board.Pawns[1] & BitMask.Mask[18]) > 0)
{
eval[side] -= PieceValues[(int)Piece.Bishop] / 3;
}
}
else
{
if (sq == 47 && //blackbishop on h3
(e.Board.Pawns[0] & BitMask.Mask[38]) > 0 &&
(e.Board.Pawns[0] & BitMask.Mask[47]) > 0)
{
eval[side] -= PieceValues[(int)Piece.Bishop] / 3;
}
else if (sq == 40 && //black bishop on a3
(e.Board.Pawns[0] & BitMask.Mask[33]) > 0 &&
(e.Board.Pawns[0] & BitMask.Mask[42]) > 0)
{
eval[side] -= PieceValues[(int)Piece.Bishop] / 3;
}
}
//mobility score
var mobilitySquares = MoveGenerator.BishopAttacks(e.Board, sq);
eval[side] += mobilitySquares.Count();
}
}
return(eval[e.Board.SideToMove] - eval[e.Board.SideToMove ^ 1]);
}