Simplify previous patch

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 854ab42a1c3c132899e54dddd315653f2e60d11f..409024f1112685bcc97e0008d0bb23ee28c38dc9 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -899,16 +899,19 @@ Value do_evaluate(const Position& pos, Value& margin) {
                 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));
+                // If there aren't enemy attacks huge bonus, a bit smaller if at
+                // least block square is not attacked, otherwise smallest bonus.
+                int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
+
+                // Big bonus if the path to queen is fully defended, a bit less
+                // if at least block square is defended.
+                if (defendedSquares == squaresToQueen)
+                    k += 6;
+
+                else if (defendedSquares & blockSq)
+                    k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
+
+                mbonus += Value(k * rr), ebonus += Value(k * rr);
             }
         } // rr != 0