perf(board): using magic bitboards for is square attacked helper

1 files changed, 24 insertions, 49 deletions

diff --git a/src/moves.cpp b/src/moves.cpp
index 531d8a9..8990621 100644
--- a/src/moves.cpp
+++ b/src/moves.cpp
@@ -345,12 +345,12 @@ computeBishopAttacks() {
   return BISHOP_ATTACKS;
 }
 
-std::array<std::array<uint64_t, MAGIC_INDEX_COUNT>, 64> rookAttacks;
-std::array<std::array<uint64_t, MAGIC_INDEX_COUNT>, 64> bishopAttacks;
+std::array<std::array<uint64_t, MAGIC_INDEX_COUNT>, 64> ROOK_ATTACKS;
+std::array<std::array<uint64_t, MAGIC_INDEX_COUNT>, 64> BISHOP_ATTACKS;
 
 void initMagicBitboards() {
-  rookAttacks = computeRookAttacks();
-  bishopAttacks = computeBishopAttacks();
+  ROOK_ATTACKS = computeRookAttacks();
+  BISHOP_ATTACKS = computeBishopAttacks();
 };
 
 constexpr std::array<std::uint64_t, 64> KNIGHT_ATTACKS = computeKnightAttacks();
@@ -389,7 +389,7 @@ static void GenerateRookMoves(const uint8_t &from, const Game &g,
                               const move_generate_options &options) {
   uint64_t mask = ROOK_MASKS[from] & g.PieceBitboard;
   uint64_t index = turnMaskAndSquareToSmallerUsingMagic(mask, rookMagics[from]);
-  uint64_t rook_attacks = rookAttacks[from][index];
+  uint64_t rook_attacks = ROOK_ATTACKS[from][index];
 
   rook_attacks &= ~(g.turn ? g.WhitePieceBitboard : g.BlackPieceBitboard);
   while (rook_attacks != 0) {
@@ -412,7 +412,7 @@ static void GenerateBishopMoves(const uint8_t &from, const Game &g,
   uint64_t mask = BISHOP_MASKS[from] & g.PieceBitboard;
   uint64_t index =
       turnMaskAndSquareToSmallerUsingMagic(mask, bishopMagics[from]);
-  uint64_t rook_attacks = bishopAttacks[from][index];
+  uint64_t rook_attacks = BISHOP_ATTACKS[from][index];
 
   rook_attacks &= ~(g.turn ? g.WhitePieceBitboard : g.BlackPieceBitboard);
   while (rook_attacks != 0) {
@@ -573,51 +573,26 @@ bool IsSquareAttacked(const Game &g, Position square, bool byColor) {
   if (king_attacks > 0) {
     return true;
   }
-  // Rooks + queens (orthogonal rays)
-  constexpr std::array<int, 4> rookDirs{-8, 8, -1, 1};
-  for (int dir : rookDirs) {
-    int pos = target;
-    while (true) {
-      int next = pos + dir;
-      if (next < 0 || next >= 64) {
-        break;
-      }
-      if ((dir == 1 || dir == -1) && next / 8 != pos / 8) {
-        break; // horizontal wrap
-      }
-
-      Piece p = g.pieces[next];
-      if (p.type != NONEPIECE) {
-        if (p.color == byColor && (p.type == ROOK || p.type == QUEEN))
-          return true;
-        break;
-      }
-      pos = next;
-    }
-  }
-
-  // Bishops + queens (diagonal rays)
-  constexpr std::array<int, 4> bishopDirs{-9, 9, -7, 7};
-  for (int dir : bishopDirs) {
-    int pos = target;
-    while (true) {
-      int next = pos + dir;
-      if (next < 0 || next >= 64)
-        break;
-      if (std::abs((next % 8) - (pos % 8)) != 1)
-        break; // diagonal wrap
-
-      Piece p = g.pieces[next];
-      if (p.type != NONEPIECE) {
-        if (p.color == byColor && (p.type == BISHOP || p.type == QUEEN))
-          return true;
-        break;
-      }
-      pos = next;
-    }
+  // Rooks + queens
+  auto t = static_cast<size_t>(target);
+  uint64_t rookMask = ROOK_MASKS[t] & g.PieceBitboard;
+  uint64_t rookIndex =
+      turnMaskAndSquareToSmallerUsingMagic(rookMask, rookMagics[t]);
+  uint64_t rookAttacks = ROOK_ATTACKS[t][rookIndex];
+  rookAttacks &= g.PieceBitboards[static_cast<size_t>(byColor)][ROOK] |
+                 g.PieceBitboards[static_cast<size_t>(byColor)][QUEEN];
+  if (rookAttacks > 0) {
+    return true;
   }
 
-  return false;
+  // Bishops + queens
+  uint64_t bishopMask = BISHOP_MASKS[t] & g.PieceBitboard;
+  uint64_t bishopIndex =
+      turnMaskAndSquareToSmallerUsingMagic(bishopMask, bishopMagics[t]);
+  uint64_t bishop_attacks = BISHOP_ATTACKS[t][bishopIndex];
+  bishop_attacks &= g.PieceBitboards[static_cast<size_t>(byColor)][BISHOP] |
+                    g.PieceBitboards[static_cast<size_t>(byColor)][QUEEN];
+  return bishop_attacks > 0;
 }
 GameState GetNewGameState(Game *g) {
   // make sure we dont override game ending states