[BitBoard] Improve kingAttacks

BitBoard.cpp

@@ -25,13 +25,6 @@ std::ostream &operator<<(std::ostream &os, const BitBoard &board) {
     return os;
 }
 
-BitBoard BitBoard::getRank(int r) {
-    return (genShift(1ULL, (r + 1) * 8) - 1) & genShift(~1ULL, r * 8 - 1);
-}
-BitBoard BitBoard::genShift(BitBoard x, const int s) {
-    return (s < 0) ? (x >> -s) : (s > 63) ? x : (x << s);
-}
-
 BitBoard BitBoard::northFill() const {
     BitBoard result(mBoard);
     result |= (result << 8);
@@ -52,11 +45,41 @@ BitBoard BitBoard::fileFill() const {
     return northFill() | southFill();
 }
 
-BitBoard BitBoard::kingAttacks(const BitBoard bb) {
-    BitBoard result = bb.east() | bb.west() | bb;
+BitBoard BitBoard::kingAttacks(const BitBoard kings) {
+    BitBoard result = kings.east() | kings.west() | kings;
     result |= (result.north() | result.south());
-    result ^= bb;
+    result ^= kings;
 
     return result;
-
+}
+
+BitBoard BitBoard::bishopAttacks(BitBoard bishops, BitBoard empty) {
+    BitBoard result = 0;
+    BitBoard diag1 = bishops;
+    BitBoard diag2 = bishops;
+    empty ^= bishops;
+
+    for (int i = 0; i < 7; i++) {
+        result |= (diag1 | diag2);
+        diag1 = (diag1.northWest() | diag1.southEast()) & empty;
+        diag2 = (diag2.northEast() | diag2.southWest()) & empty;
+    }
+
+    return (result | diag1.northWest() | diag1.southEast() | diag2.northEast() | diag2.southWest()) & ~bishops;
+}
+
+BitBoard BitBoard::pawnNorthAttacks(BitBoard pawns, BitBoard targets) {
+    return (pawns.northEast() | pawns.northWest()) & targets;
+}
+BitBoard BitBoard::pawnNorthMoves(BitBoard pawns, BitBoard empty) {
+    pawns = pawns.north() & empty;
+    return (pawns | (pawns.north() & Rank4)) & empty;
+}
+
+BitBoard BitBoard::pawnSouthAttacks(BitBoard pawns, BitBoard targets) {
+    return (pawns.southEast() | pawns.southWest()) & targets;
+}
+BitBoard BitBoard::pawnSouthMoves(BitBoard pawns, BitBoard empty) {
+    pawns = pawns.south() & empty;
+    return (pawns | (pawns.south() & Rank5)) & empty;
 }

BitBoard.hpp

@@ -14,6 +14,14 @@ enum DefinedBoards : uint64_t {
     FFile = AFile << 5,
     GFile = AFile << 6,
     HFile = AFile << 7,
+    Rank1 = 0x00000000000000FF,
+    Rank2 = Rank1 << 8,
+    Rank3 = Rank1 << 16,
+    Rank4 = Rank1 << 24,
+    Rank5 = Rank1 << 32,
+    Rank6 = Rank1 << 40,
+    Rank7 = Rank1 << 48,
+    Rank8 = Rank1 << 56,
     WhiteCastlingRank = (1ULL << A2) - 1,
     BlackCastlingRank = (~1ULL << H7),
     CastlingRanks = WhiteCastlingRank | BlackCastlingRank,
@@ -98,20 +106,24 @@ public:
     BitBoard southFill() const;
     BitBoard fileFill() const;
 
-    static BitBoard kingAttacks(BitBoard bb);
+    static BitBoard bishopAttacks(BitBoard pos, BitBoard empty);
+    static BitBoard kingAttacks(BitBoard kings);
+
+    static BitBoard pawnNorthAttacks(BitBoard pawns, BitBoard targets);
+    static BitBoard pawnSouthAttacks(BitBoard pawns, BitBoard targets);
+
+    static BitBoard pawnNorthMoves(BitBoard pawns, BitBoard empty);
+    static BitBoard pawnSouthMoves(BitBoard pawns, BitBoard empty);
 
     static BitBoard fromIndex(unsigned i);
 
-    static BitBoard getRank(int r);
-
     // Returns the number of trailing 0-bits in b.
     // WARN: Check for 0!
-    int lsb() const;
+    unsigned lsb() const;
+    unsigned pop();
 
 private:
     U64 mBoard = {};
-
-    static BitBoard genShift(BitBoard x, int s);
 };
 
 // Relational operators
@@ -255,8 +267,15 @@ inline BitBoard BitBoard::southEast() const {
 inline BitBoard BitBoard::southWest() const {
     return (mBoard >> 9) & ~HFile;
 }
-inline int BitBoard::lsb() const {
+
+inline unsigned BitBoard::lsb() const {
     return __builtin_ctzll(mBoard);
 }
+inline unsigned BitBoard::pop() {
+    unsigned i = lsb();
+    mBoard &= mBoard - 1;
+
+    return i;
+}
 
 #endif //CHESS_ENGINE_BITBOARD_HPP

CMakeLists.txt

@@ -36,6 +36,7 @@ add_library(cplchess_lib OBJECT
     EngineFactory.cpp
     Uci.cpp
     BitBoard.cpp
+    MoveGenerator.cpp
 )
 
 target_include_directories(cplchess_lib PUBLIC .)

MoveGenerator.cpp

@@ -0,0 +1,62 @@
+#include <iostream>
+#include "MoveGenerator.hpp"
+#include "Board.hpp"
+
+MoveGenerator::MoveGenerator(const std::shared_ptr<BitBoard[]> &pieceBB,
+                             const std::shared_ptr<BitBoard> &occupiedBB)
+        : mPieceBBs(pieceBB), mOccupiedBB(occupiedBB) {
+
+}
+
+void MoveGenerator::generatePawnMoves(const Square &from, const std::optional<Square> &eps,
+                                      PieceColor color, MoveVec &moves) const {
+
+    BitBoard targets = 0;
+    if (eps.has_value()) {
+        targets |= BitBoard::fromIndex(eps.value().index());
+    }
+
+    generatePawnMoves(from, targets, color, moves);
+}
+void MoveGenerator::generatePawnMoves(const Square &from, PieceColor color, MoveVec &moves) {
+    generatePawnMoves(from, BitBoard(0), color, moves);
+}
+
+void MoveGenerator::generatePawnMoves(const Square &from, BitBoard targets, PieceColor color, MoveVec &moves) const {
+
+    auto fromBB = BitBoard::fromIndex(from.index());
+    targets |= mPieceBBs[Board::toIndex(!color)];
+
+    BitBoard movesBB;
+    if (color == PieceColor::White) {
+        movesBB = BitBoard::pawnNorthAttacks(fromBB, targets) & ~mPieceBBs[Board::toIndex(color)];
+        movesBB |= BitBoard::pawnNorthMoves(fromBB, ~*mOccupiedBB);
+    } else {
+        movesBB = BitBoard::pawnSouthAttacks(fromBB, targets) & ~mPieceBBs[Board::toIndex(color)];
+        movesBB |= BitBoard::pawnSouthMoves(fromBB, ~*mOccupiedBB);
+    }
+
+    bool isPromotion = movesBB & (Rank1 | Rank8);
+    if (isPromotion) {
+        generateMovesWithPromotion(from, movesBB, moves);
+    } else {
+        generateMoves(from, movesBB, moves);
+    }
+}
+
+void MoveGenerator::generateMoves(const Square &from, BitBoard movesBB, MoveGenerator::MoveVec &moves) {
+    while (movesBB) {
+        auto to = Square(movesBB.pop());
+        moves.emplace_back(from, to, std::nullopt);
+    }
+}
+
+void MoveGenerator::generateMovesWithPromotion(const Square &from, BitBoard movesBB, MoveGenerator::MoveVec &moves) {
+    while (movesBB) {
+        auto to = Square(movesBB.pop());
+        for (const auto &kItem : Piece::PromotionTypes) {
+            moves.emplace_back(from, to, static_cast<PieceType>(kItem));
+        }
+    }
+}
+

MoveGenerator.hpp

@@ -0,0 +1,36 @@
+#ifndef CHESS_ENGINE_MOVEGENERATOR_HPP
+#define CHESS_ENGINE_MOVEGENERATOR_HPP
+
+#include "Piece.hpp"
+#include "Square.hpp"
+#include "Move.hpp"
+#include "CastlingRights.hpp"
+#include "BitBoard.hpp"
+
+#include <optional>
+#include <iosfwd>
+#include <vector>
+#include <memory>
+
+class MoveGenerator {
+public:
+    using MoveVec = std::vector<Move>;
+
+    MoveGenerator(const std::shared_ptr<BitBoard[]>& pieceBB, const std::shared_ptr<BitBoard>& occupiedBB);
+    MoveGenerator(MoveGenerator &) = delete;
+    MoveGenerator &operator=(MoveGenerator const &) = delete;
+
+    void generatePawnMoves(const Square &from, const std::optional<Square> &eps, PieceColor color, MoveVec &moves) const;
+    void generatePawnMoves(const Square &from, PieceColor color, MoveVec &moves);
+
+private:
+    const std::shared_ptr<const BitBoard[]> mPieceBBs;
+    const std::shared_ptr<const BitBoard> mOccupiedBB;
+
+    void generatePawnMoves(const Square &from, BitBoard targets, PieceColor color, MoveVec &moves) const;
+
+    static void generateMoves(const Square &from, BitBoard movesBB, MoveVec &moves);
+    static void generateMovesWithPromotion(const Square &from, BitBoard movesBB, MoveVec &moves);
+};
+
+#endif //CHESS_ENGINE_MOVEGENERATOR_HPP

Piece.hpp

@@ -24,6 +24,8 @@ class Piece {
 
 public:
 
+    constexpr static const PieceType PromotionTypes[4] = {PieceType::Knight, PieceType::Bishop, PieceType::Rook, PieceType::Queen};
+
     using Optional = std::optional<Piece>;
 
     Piece(PieceColor color, PieceType type);

Square.hpp

@@ -26,6 +26,9 @@ public:
     static Optional fromIndex(Index index);
     static Optional fromName(const std::string &name);
 
+    Square(Index index);
+
+
     Coordinate file() const;
     Coordinate rank() const;
     Index index() const;
@@ -40,9 +43,6 @@ public:
     static const Square A8, B8, C8, D8, E8, F8, G8, H8;
 
 private:
-
-    Square(Index index);
-
     Index mIndex;
 };