public int EvaluateSlidingPiece(Position position, int color, int pieceType, int materialValue, int mobilityMultiplier, ref Bitboard destinationBitboard)
{
Bitboard pieces = position.GetPieceBitboard(color, pieceType);
int score = 0;
while (pieces != 0)
{
score += materialValue;
int square = pieces.BitScanForward();
Bitboards.PopLsb(ref pieces);
Bitboard attacks = 0;
if (pieceType == Position.ROOK || pieceType == Position.QUEEN)
{
attacks = Bitboards.GetRookMoveBitboard(square, position.AllPiecesBitboard);
}
if (pieceType == Position.BISHOP || pieceType == Position.QUEEN)
{
attacks |= Bitboards.GetBishopMoveBitboard(square, position.AllPiecesBitboard);
}
attacks &= destinationBitboard;
score += Bitboards.CountBits(attacks) * mobilityMultiplier;
}
return(score);
}
static int[] GenerateShifts(Bitboard[] occupancyBBs)
{
int[] result = new int[64];
for (int i = 0; i < 64; i++)
{
result[i] = 64 - Bitboards.CountBits(occupancyBBs[i]);
}
return(result);
}
public int EvaluateKnights(Position position, int color, int mobilityMultiplier, ref Bitboard destinationBitboard)
{
Bitboard pieces = position.GetPieceBitboard(color, Position.KNIGHT);
int score = 0;
while (pieces != 0)
{
score += 300; // Material value
int square = pieces.BitScanForward();
Bitboards.PopLsb(ref pieces);
score += mobilityMultiplier * (Bitboards.CountBits(destinationBitboard & Bitboards.KnightBitboards[square]));
}
return(score);
}
public int EvaluatePosition(Position position)
{
int score = 0;
Bitboard notWhite = ~position.GetPieceBitboard(Position.WHITE, Position.ALL_PIECES);
Bitboard notBlack = ~position.GetPieceBitboard(Position.BLACK, Position.ALL_PIECES);
// King mobility
int whiteKingSquare = Bitboards.BitScanForward(position.GetPieceBitboard(Position.WHITE, Position.KING));
int blackKingSquare = Bitboards.BitScanForward(position.GetPieceBitboard(Position.BLACK, Position.KING));
int whiteKing = Bitboards.CountBits(notWhite & Bitboards.KingBitboards[whiteKingSquare]);
int blackKing = Bitboards.CountBits(notBlack & Bitboards.KingBitboards[blackKingSquare]);
// Queen evalution
int whiteQueen = EvaluateSlidingPiece(position, Position.WHITE, Position.QUEEN, 900, 1, ref notWhite);
int blackQueen = EvaluateSlidingPiece(position, Position.BLACK, Position.QUEEN, 900, 1, ref notBlack);
// Rook Evaluation
int whiteRook = EvaluateSlidingPiece(position, Position.WHITE, Position.ROOK, 500, 3, ref notWhite);
int blackRook = EvaluateSlidingPiece(position, Position.BLACK, Position.ROOK, 500, 3, ref notBlack);
// Bishop Evaluation
int whiteBishop = EvaluateSlidingPiece(position, Position.WHITE, Position.BISHOP, 325, 8, ref notWhite);
int blackBishop = EvaluateSlidingPiece(position, Position.BLACK, Position.BISHOP, 325, 8, ref notBlack);
// Knight Evaluation
int whiteKnight = EvaluateKnights(position, Position.WHITE, 8, ref notWhite);
int blackKnight = EvaluateKnights(position, Position.BLACK, 8, ref notBlack);
// For now, do not include pawn mobility
int whitePawn = 100 * Bitboards.CountBits(position.GetPieceBitboard(Position.WHITE, Position.PAWN));
int blackPawn = 100 * Bitboards.CountBits(position.GetPieceBitboard(Position.BLACK, Position.PAWN));
score = whitePawn + whiteKnight + whiteBishop + whiteRook + whiteQueen + whiteKing;
score -= (blackPawn + blackKnight + blackBishop + blackRook + blackQueen + blackKing);
if (position.PlayerToMove == Position.BLACK)
{
score *= -1;
}
return(score);
}
public int EvaluatePosition(Position position)
{
int score = 0;
Bitboard notWhite = ~position.GetPieceBitboard(Position.WHITE, Position.ALL_PIECES);
Bitboard notBlack = ~position.GetPieceBitboard(Position.BLACK, Position.ALL_PIECES);
// King mobility
int whiteKingSquare = Bitboards.BitScanForward(position.GetPieceBitboard(Position.WHITE, Position.KING));
int blackKingSquare = Bitboards.BitScanForward(position.GetPieceBitboard(Position.BLACK, Position.KING));
int whiteKing = Bitboards.CountBits(notWhite & Bitboards.KingBitboards[whiteKingSquare]);
int blackKing = Bitboards.CountBits(notBlack & Bitboards.KingBitboards[blackKingSquare]);
// Queen evalution
int whiteQueen = EvaluateSliders(ref position, Position.WHITE, Position.QUEEN);
int blackQueen = EvaluateSliders(ref position, Position.BLACK, Position.QUEEN);
// Rook Evaluation
int whiteRook = EvaluateSliders(ref position, Position.WHITE, Position.ROOK);
int blackRook = EvaluateSliders(ref position, Position.BLACK, Position.ROOK);
// Bishop Evaluation
int whiteBishop = EvaluateSliders(ref position, Position.WHITE, Position.BISHOP);
int blackBishop = EvaluateSliders(ref position, Position.BLACK, Position.BISHOP);
// Knight Evaluation
int whiteKnight = EvaluateKnights(ref position, Position.WHITE);
int blackKnight = EvaluateKnights(ref position, Position.BLACK);
int whitePawn = EvaluatePawns(ref position, Position.WHITE);
int blackPawn = EvaluatePawns(ref position, Position.BLACK);
score = whitePawn + whiteKnight + whiteBishop + whiteRook + whiteQueen + whiteKing;
score -= (blackPawn + blackKnight + blackBishop + blackRook + blackQueen + blackKing);
if (position.PlayerToMove == Position.BLACK)
{
score *= -1;
}
return(score);
}
public void CalculatesCorrectly()
{
Assert.AreEqual(10, Bitboards.CountBits(0x3578900000000UL));
Assert.AreEqual(0, Bitboards.CountBits(0));
Assert.AreEqual(64, Bitboards.CountBits(0xFFFFFFFFFFFFFFFFUL));
}