Penalty for all enemy pawns xrayed by our bishop.

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 67e0592105516cae1d2988d4f1e328a8b1bea161..e663f21f4497129984ebf86c72f0f5e4d7d24957 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -128,6 +128,7 @@ namespace {
 
   // Assorted bonuses and penalties
   constexpr Score BishopPawns         = S(  3,  7);
+  constexpr Score BishopXRayPawns     = S(  4,  5);
   constexpr Score CorneredBishop      = S( 50, 50);
   constexpr Score FlankAttacks        = S(  8,  0);
   constexpr Score Hanging             = S( 69, 36);
@@ -318,6 +319,9 @@ namespace {
                 score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s)
                                      * (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
 
+                // Penalty for all enemy pawns x-rayed
+                score -= BishopXRayPawns * popcount(PseudoAttacks[BISHOP][s] & pos.pieces(Them, PAWN));
+
                 // Bonus for bishop on a long diagonal which can "see" both center squares
                 if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
                     score += LongDiagonalBishop;