else
unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
- // If there aren't enemy attacks or pieces along the path to queen give
- // huge bonus. Even bigger if we protect the pawn's path.
- if (!unsafeSquares)
- ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
- else
- // OK, there are enemy attacks or pieces (but not pawns). Are those
- // squares which are attacked by the enemy also attacked by us ?
- // If yes, big bonus (but smaller than when there are no enemy attacks),
- // if no, somewhat smaller bonus.
- ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
+ // Default bonus for the empty square in front
+ int bonusMultiplier = 3;
+
+ if ((defendedSquares & SquareBB[blockSq]) != 0)
+ {
+ // Defending the square in front
+ bonusMultiplier += 2;
+ if ((unsafeSquares & defendedSquares) == unsafeSquares)
+ // Defending all the attacked squares
+ // bigger bonus if we are defending everything
+ bonusMultiplier += (squaresToQueen == defendedSquares) ? 4 : 2;
+ }
+
+ if ((unsafeSquares & SquareBB[blockSq]) == 0)
+ {
+ // The square infront isn't attacked
+ bonusMultiplier += 6;
+ if (!unsafeSquares)
+ bonusMultiplier += 6;
+ }
+
+ Value bonus = Value(rr * bonusMultiplier);
+ ebonus += bonus;
+ mbonus += bonus;
}
} // rr != 0