// https://github.com/ledpup/Othello/blob/cf3f21ebe2550393cf9300d01f02182184364b91/Othello.Model/Play.cs#L61
public static ulong GetWouldFlips(this BitBoard board, byte player, ulong bitMove)
{
// TODO improve this function, make it faster
var playerPiece = board.Pieces[player];
var opponentPiece = board.Pieces[Constant.Opponent(player)];
var wouldFlips = 0UL;
foreach (var direction in DirectionValues)
{
var potentialEndPoint = bitMove.Shift(direction);
var potentialWouldFlips = 0UL;
do
{
if ((potentialEndPoint & playerPiece) != 0)
{
wouldFlips |= potentialWouldFlips;
break;
}
potentialEndPoint &= opponentPiece;
potentialWouldFlips |= potentialEndPoint;
potentialEndPoint = potentialEndPoint.Shift(direction);
} while (potentialEndPoint != 0);
}
return(wouldFlips);
}
public static void MakeMove(this BitBoard board, byte player, ulong bitMove)
{
var wouldFlips = board.GetWouldFlips(player, bitMove);
board.Pieces[player] |= wouldFlips | bitMove;
board.Pieces[Constant.Opponent(player)] ^= wouldFlips;
}
public static BitBoard Rotate90AntiClockwise(this BitBoard board)
{
var clone = board.Clone();
clone.Pieces[Black] = clone.Pieces[Black].Rotate90AntiClockwise();
clone.Pieces[White] = clone.Pieces[White].Rotate90AntiClockwise();
return(clone);
}
public static BitBoard FlipDiagA1H8(this BitBoard board)
{
var clone = board.Clone();
clone.Pieces[Black] = clone.Pieces[Black].FlipDiagA1H8();
clone.Pieces[White] = clone.Pieces[White].FlipDiagA1H8();
return(clone);
}
public static BitBoard MirrorHorizontal(this BitBoard board)
{
var clone = board.Clone();
clone.Pieces[Black] = clone.Pieces[Black].MirrorHorizontal();
clone.Pieces[White] = clone.Pieces[White].MirrorHorizontal();
return(clone);
}
public static bool IsLegalMove(this BitBoard board, byte player, ulong bitMove)
{
if (board.GetPieceAt(bitMove) != Constant.EmptyCell)
{
return(false);
}
var legalMoves = board.GetLegalMoves(player);
return((bitMove & legalMoves) != 0);
}
public static byte GetPieceAt(this BitBoard board, ulong position)
{
if ((board.Pieces[Black] & position) != 0)
{
return(Constant.BlackCell);
}
if ((board.Pieces[White] & position) != 0)
{
return(Constant.WhiteCell);
}
return(Constant.EmptyCell);
}
public static void DisplayWithLastMoveAndLegalMoves(this BitBoard board, ulong lastBitMove, byte player)
{
Console.WriteLine(" a b c d e f g h");
var legalMoves = board.GetLegalMoves(player);
var moveIndex = lastBitMove.BitScanReverse();
var row = 0;
for (var i = 0; i < 64; i++)
{
if (i % 8 == 0)
{
row++;
if (i != 0)
{
Console.WriteLine();
}
Console.Write(row + " ");
}
var pos = 1UL << i;
var isBlack = (board.Pieces[Black] & pos) != 0;
var isWhite = (board.Pieces[White] & pos) != 0;
if (isBlack && isWhite)
{
Console.Write(Constant.WrongCellStr);
}
else if (isBlack)
{
Console.Write(moveIndex == i ? Constant.LastBlackMoveStr : Constant.BlackPieceStr);
}
else if (isWhite)
{
Console.Write(moveIndex == i ? Constant.LastWhiteMoveStr : Constant.WhitePieceStr);
}
else if ((legalMoves & pos) != 0)
{
Console.Write(Constant.LegalMoveStr);
}
else
{
Console.Write(Constant.EmptyCellStr);
}
}
Console.WriteLine();
}
public static void Display(this BitBoard board)
{
Console.WriteLine(" a b c d e f g h");
var row = 0;
for (var i = 0; i < 64; i++)
{
if (i % 8 == 0)
{
row++;
if (i != 0)
{
Console.WriteLine();
}
Console.Write(row + " ");
}
var pos = 1UL << i;
var isBlack = (board.Pieces[Black] & pos) != 0;
var isWhite = (board.Pieces[White] & pos) != 0;
if (isBlack && isWhite)
{
Console.Write(Constant.WrongCellStr);
}
else if (isBlack)
{
Console.Write(Constant.BlackPieceStr);
}
else if (isWhite)
{
Console.Write(Constant.WhitePieceStr);
}
else
{
Console.Write(Constant.EmptyCellStr);
}
}
Console.WriteLine();
}
public static ulong GetLegalMoves(this BitBoard board, byte player)
{
// https://intellitect.com/when-to-use-and-not-use-var-in-c/
// https://stackoverflow.com/a/41505/11898496
var moves = 0UL;
var playerPiece = board.Pieces[player];
var opponentPiece = board.Pieces[Constant.Opponent(player)];
var empties = board.GetEmpties();
// https://stackoverflow.com/a/105402/11898496
foreach (var direction in DirectionValues)
{
var candidates = opponentPiece & playerPiece.Shift(direction);
while (candidates != 0)
{
var candidatesShifted = candidates.Shift(direction);
moves |= empties & candidatesShifted;
candidates = opponentPiece & candidatesShifted;
}
}
return(moves);
}
public static void Clear(this BitBoard board)
{
board.Pieces[Black] = 0;
board.Pieces[White] = 0;
}
public static void SetPieceAt(this BitBoard board, ulong position, byte color)
{
board.Pieces[color] |= position;
}
public static bool HasAnyPlayerHasAnyLegalMove(this BitBoard board)
{
return(board.HasLegalMoves(Black) || board.HasLegalMoves(White));
}
public static byte CountPieces(this BitBoard board, byte player)
{
return(board.Pieces[player].PopCount());
}
public static ulong GetFilled(this BitBoard board)
{
return(board.Pieces[Black] | board.Pieces[White]);
}
public static ulong GetEmpties(this BitBoard board)
{
return(~board.Pieces[Black] & ~board.Pieces[White]);
}
public static bool IsEquals(this BitBoard board, BitBoard other)
{
return(board.Pieces[Black] == other.Pieces[Black] &&
board.Pieces[White] == other.Pieces[White]);
}
public static BitBoard Clone(this BitBoard board)
{
return(new(board));
}
public static bool HasLegalMoves(this BitBoard board, byte player)
{
return(board.GetLegalMoves(player) != 0);
}
public State(BitBoard board, byte player)
{
Player = player;
Board = board;
BitLegalMoves = board.GetLegalMoves(player);
}
public BitBoard(BitBoard board)
{
Pieces = new[] { board.Pieces[0], board.Pieces[1] };
}
public State(BitBoard board, byte player, ulong bitLegalMoves)
{
Player = player;
Board = board;
BitLegalMoves = bitLegalMoves;
}
public static bool IsGameComplete(this BitBoard board)
{
return(board.GetEmpties() == 0 || !board.HasAnyPlayerHasAnyLegalMove());
}
