Knights legal moves implementation (#76)

Hardcode3 · web-flow · commit 7a75aaf115f3 · 2025-12-28T18:01:13.000+01:00
* added missing include guards

* implemented legal knights moves generation
diff --git a/include/bitbishop/attacks/generate_attacks.hpp b/include/bitbishop/attacks/generate_attacks.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <bitbishop/attacks/bishop_attacks.hpp>
 #include <bitbishop/attacks/queen_attacks.hpp>
 #include <bitbishop/attacks/rook_attacks.hpp>
diff --git a/include/bitbishop/bitboard.hpp b/include/bitbishop/bitboard.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <bit>
 #include <bitbishop/constants.hpp>
 #include <bitbishop/square.hpp>
diff --git a/include/bitbishop/bitmasks.hpp b/include/bitbishop/bitmasks.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <cstdint>
 
 /**
diff --git a/include/bitbishop/board.hpp b/include/bitbishop/board.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/color.hpp>
 #include <bitbishop/piece.hpp>
diff --git a/include/bitbishop/color.hpp b/include/bitbishop/color.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <array>
 #include <format>
 
diff --git a/include/bitbishop/lookups/attackers.hpp b/include/bitbishop/lookups/attackers.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/board.hpp>
 #include <bitbishop/color.hpp>
diff --git a/include/bitbishop/lookups/between_squares.hpp b/include/bitbishop/lookups/between_squares.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <array>
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/constants.hpp>
diff --git a/include/bitbishop/lookups/king_attacks.hpp b/include/bitbishop/lookups/king_attacks.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <array>
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/bitmasks.hpp>
diff --git a/include/bitbishop/lookups/knight_attacks.hpp b/include/bitbishop/lookups/knight_attacks.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <array>
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/bitmasks.hpp>
diff --git a/include/bitbishop/lookups/pawn_attacks.hpp b/include/bitbishop/lookups/pawn_attacks.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <array>
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/bitmasks.hpp>
diff --git a/include/bitbishop/lookups/queen_rays.hpp b/include/bitbishop/lookups/queen_rays.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <array>
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/bitmasks.hpp>
diff --git a/include/bitbishop/lookups/rook_rays.hpp b/include/bitbishop/lookups/rook_rays.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <array>
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/bitmasks.hpp>
diff --git a/include/bitbishop/move.hpp b/include/bitbishop/move.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <bitbishop/piece.hpp>
 #include <bitbishop/square.hpp>
 #include <optional>
diff --git a/include/bitbishop/movegen/check_mask.hpp b/include/bitbishop/movegen/check_mask.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/board.hpp>
 #include <bitbishop/square.hpp>
diff --git a/include/bitbishop/movegen/king_moves.hpp b/include/bitbishop/movegen/king_moves.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <bitbishop/board.hpp>
 #include <bitbishop/color.hpp>
 #include <bitbishop/lookups/king_attacks.hpp>
diff --git a/include/bitbishop/movegen/knight_moves.hpp b/include/bitbishop/movegen/knight_moves.hpp
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <bitbishop/board.hpp>
+#include <bitbishop/color.hpp>
+#include <bitbishop/lookups/knight_attacks.hpp>
+#include <bitbishop/move.hpp>
+#include <bitbishop/movegen/pins.hpp>
+#include <utility>
+#include <vector>
+
+void generate_knight_legal_moves(std::vector<Move>& moves, const Board& board, Color us, const Bitboard& check_mask,
+                                 const PinResult& pins) {
+  const Bitboard own = board.friendly(us);
+  const Bitboard enemy = board.enemy(us);
+  Bitboard knights = board.knights(us);
+  knights &= ~pins.pinned;
+
+  // warning: this loop is destructive on Bitboard knights
+  while (auto from_opt = knights.pop_lsb()) {
+    Square from = from_opt.value();
+
+    Bitboard candidates = Lookups::KNIGHT_ATTACKS[from.value()];
+    candidates &= ~own;
+    candidates &= check_mask;
+
+    for (Square to : candidates) {
+      const bool is_capture = enemy.test(to);
+      moves.emplace_back(from, to, std::nullopt, is_capture, false, false);
+    }
+  }
+}
diff --git a/include/bitbishop/movegen/pins.hpp b/include/bitbishop/movegen/pins.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <bitbishop/bitboard.hpp>
 #include <bitbishop/board.hpp>
 #include <bitbishop/lookups/between_squares.hpp>
diff --git a/include/bitbishop/piece.hpp b/include/bitbishop/piece.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <bitbishop/color.hpp>
 #include <cctype>
 #include <format>
diff --git a/include/bitbishop/square.hpp b/include/bitbishop/square.hpp
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <bitbishop/constants.hpp>
 #include <bitbishop/square.hpp>
 #include <format>
diff --git a/tests/bitbishop/movegen/test_knight_moves.cpp b/tests/bitbishop/movegen/test_knight_moves.cpp

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+#pragma once`
	`2`	`+`
`1`	`3`	`#include <bitbishop/attacks/bishop_attacks.hpp>`
`2`	`4`	`#include <bitbishop/attacks/queen_attacks.hpp>`
`3`	`5`	`#include <bitbishop/attacks/rook_attacks.hpp>`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`#pragma once`
	`2`	`+`
`2`	`3`	`#include <bit>`
`3`	`4`	`#include <bitbishop/constants.hpp>`
`4`	`5`	`#include <bitbishop/square.hpp>`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`#pragma once`
	`2`	`+`
`2`	`3`	`#include <cstdint>`
`3`	`4`
`4`	`5`	`/**`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`#pragma once`
	`2`	`+`
`2`	`3`	`#include <bitbishop/bitboard.hpp>`
`3`	`4`	`#include <bitbishop/color.hpp>`
`4`	`5`	`#include <bitbishop/piece.hpp>`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`#pragma once`
	`2`	`+`
`2`	`3`	`#include <array>`
`3`	`4`	`#include <format>`
`4`	`5`