public ChessPosition()
{
initChessEval();
Board = new SquareInfo[64];
emptyBoard = new SquareInfo[64];
Princ = new ChessMove[maxDepth, maxDepth];
killers = new ChessMove[2, 1000];
mvvLva = new int[8, 8];
searchHistory = new int[16, 64];
// Init the mvvLva array
for (int v = 0; v <= 6; v++)
for (int a = 0; a <= 6; a++)
mvvLva[v, a] = v * 100 +6 - a;
// Init the killers array
for (int i = 0; i < 1000; i++)
{
killers[0, i] = new ChessMove(new Square(99, 99), new Square(99, 99));
killers[1, i] = new ChessMove(new Square(99, 99), new Square(99, 99));
}
// Init the emptyBoard and Board arrays
for (int i = 0; i <= 63; i++)
{
emptyBoard[i] = new SquareInfo(Pieces.None, new Square(i));
Board[i] = emptyBoard[i];
}
// Init the hashKeys
Random rng = new Random();
pieceKeys = new UInt64[16, 64];
for (int p = 0; p <= 15; p++)
for (int sq = 0; sq <= 63; sq++)
pieceKeys[p, sq] = (UInt64)rng.Next() + ((UInt64)rng.Next() << 15) + ((UInt64)rng.Next() << 30) + ((UInt64)rng.Next() << 45) + ((UInt64)rng.Next() << 60);
castleKeys = new UInt64[16];
for (int i = 0; i <= 15; i++)
castleKeys[i] = (UInt64)rng.Next() + ((UInt64)rng.Next() << 15) + ((UInt64)rng.Next() << 30) + ((UInt64)rng.Next() << 45) + ((UInt64)rng.Next() << 60);
sideKey = (UInt64)rng.Next() + ((UInt64)rng.Next() << 15) + ((UInt64)rng.Next() << 30) + ((UInt64)rng.Next() << 45) + ((UInt64)rng.Next() << 60);
// Init the pvTable
pvTable = new Dictionary<ulong, int>();
EpSquare = new Square(0, 0);
white = new ToMoveData(PieceColour.White, new Piece(PieceType.Pawn, PieceColour.White), new Piece(PieceType.Knight, PieceColour.White),
new Piece(PieceType.Bishop, PieceColour.White), new Piece(PieceType.Rook, PieceColour.White), new Piece(PieceType.Queen, PieceColour.White),
new Piece(PieceType.King, PieceColour.White), 1, 7, 1, CastleFlags.Wks, CastleFlags.Wqs, new Square("e1"), new Square("h1"), new Square("a1"));
black = new ToMoveData(PieceColour.Black, new Piece(PieceType.Pawn, PieceColour.Black), new Piece(PieceType.Knight, PieceColour.Black),
new Piece(PieceType.Bishop, PieceColour.Black), new Piece(PieceType.Rook, PieceColour.Black), new Piece(PieceType.Queen, PieceColour.Black),
new Piece(PieceType.King, PieceColour.Black), 6, 0, -1, CastleFlags.Bks, CastleFlags.Bqs, new Square("e8"), new Square("h8"), new Square("a8"));
PossibleMoves = new Collection<ChessMove>();
MoveHistory = new Collection<ChessMove>();
undoStack = new Stack<ChessMove>();
NewGame();
}
void updatePrinc(ChessMove move, int ply)
{
Princ[ply, ply] = move;
for (int i = ply + 1; i < maxDepth; i++)
Princ[ply, i] = Princ[ply + 1, i];
pvTable[HashKey] = (int)move.FromSq + ((int)move.ToSq << 8);
}
void makeMove(ChessMove move)
{
Square from = move.FromSq;
Square to = move.ToSq;
SquareInfo CapturedSqInfo = Board[to];
Board[to] = Board[from]; // Move the piece
Board[from] = emptyBoard[from]; // Replace from SquareInfo with the empty SquareInfo from emptyBoard
Board[to].Location = to; // Update SqInfo location
move.OldHashKey = HashKey;
move.OldEpSq = EpSquare;
EpSquare = new Square(0, 0);
move.OldCastleFlags = CastleFlags;
HashKey ^= pieceKeys[move.Piece.ToInt(), from] ^ pieceKeys[move.Piece.ToInt(), to];
bool pawnMoveOrCapture = false;
switch (move.Special)
{
case SpecialMoveType.PawnMove:
pawnMoveOrCapture = true;
break;
case SpecialMoveType.DoublePawnMove:
EpSquare = new Square(from.File, from.Rank + thisSide.PawnYDir);
pawnMoveOrCapture = true;
break;
case SpecialMoveType.Promotion:
Board[to].Piece = move.PromotedTo;
pawnMoveOrCapture = true;
HashKey ^= pieceKeys[move.Piece.ToInt(), to] ^ pieceKeys[move.PromotedTo.ToInt(), to];
break;
case SpecialMoveType.EnPassant:
// After the piece has been moved make to = the square of the captured ep pawn
to.Rank -= thisSide.PawnYDir;
CapturedSqInfo = Board[to]; // CapturedSqInfo is the enemy pawn not the square moved into
Board[to] = emptyBoard[to];
break;
case SpecialMoveType.CastleKS:
// Move the rook
to = thisSide.RookKCastleSq;
from = thisSide.KingRookSq;
Board[to] = Board[from]; // Move the piece
Board[from] = emptyBoard[from]; // Replace from SquareInfo with the empty SquareInfo from emptyBoard
Board[to].Location = to; // Update SqInfo location
HashKey ^= pieceKeys[Board[to].Piece.ToInt(), from] ^ pieceKeys[Board[to].Piece.ToInt(), to];
break;
case SpecialMoveType.CastleQS:
to = thisSide.RookQCastleSq;
from = thisSide.QueenRookSq;
Board[to] = Board[from]; // Move the piece
Board[from] = emptyBoard[from]; // Replace from SquareInfo with the empty SquareInfo from emptyBoard
Board[to].Location = to; // Update SqInfo location
HashKey ^= pieceKeys[Board[to].Piece.ToInt(), from] ^ pieceKeys[Board[to].Piece.ToInt(), to];
break;
}
if (CapturedSqInfo.Piece.PieceColour != PieceColour.None)
{
CapturedSqInfo.Prev.Next = CapturedSqInfo.Next; // Delink the captured piece
CapturedSqInfo.Next.Prev = CapturedSqInfo.Prev;
pawnMoveOrCapture = true;
// Clear enemy castling rights when capturing one of their rooks on its starting square
if (to == otherSide.KingRookSq)
CastleFlags = CastleFlags & ~(otherSide.CanCastleKS);
if (to == otherSide.QueenRookSq)
CastleFlags = CastleFlags & ~(otherSide.CanCastleQS);
HashKey ^= pieceKeys[CapturedSqInfo.Piece.ToInt(), to];
}
// Clear castle flag if king or rooks have moved
if (Board[thisSide.KingStartSq].Piece == thisSide.King)
{
if (Board[thisSide.KingRookSq].Piece != thisSide.Rook)
CastleFlags = CastleFlags & ~thisSide.CanCastleKS;
if (Board[thisSide.QueenRookSq].Piece != thisSide.Rook)
CastleFlags = CastleFlags & ~thisSide.CanCastleQS;
}
else
CastleFlags = CastleFlags & ~(thisSide.CanCastleKS | thisSide.CanCastleQS);
ToMove = toMove == PieceColour.White ? PieceColour.Black : PieceColour.White;
HashKey ^= castleKeys[(int)move.OldCastleFlags] ^ castleKeys[(int)CastleFlags] ^ sideKey;
move.CapturedSqInfo = CapturedSqInfo;
move.HalfMovesSinceLastPawnMoveOrCapture = HalfMovesSinceLastPawnMoveOrCapture;
undoStack.Push(move);
if (pawnMoveOrCapture)
HalfMovesSinceLastPawnMoveOrCapture = 0;
else
HalfMovesSinceLastPawnMoveOrCapture++;
return;
}
public bool MakeMove(ChessMove move)
{
// Make a move at Ply in the MoveHistory deleting all moves following
// Look for the move with matching from and to squares in PossibleMoves and make that move since it has SpecialMoveType set up
ChessMove foundMove = PossibleMoves.FirstOrDefault(o => o.FromSq == move.FromSq && o.ToSq == move.ToSq);
if (foundMove == null) return false; // No matching move
if (foundMove.Special == SpecialMoveType.Promotion)
// If the match is a promotion, filter to the promoted piece if specified else a queen
foundMove = PossibleMoves.FirstOrDefault(o => o.FromSq == move.FromSq && o.ToSq == move.ToSq &&
o.PromotedTo.PieceType == (move.PromotedTo.PieceType != PieceType.None ? move.PromotedTo.PieceType : PieceType.Queen));
while (MoveHistory.Count > undoStack.Count)
MoveHistory.RemoveAt(MoveHistory.Count - 1);
foundMove.GamePlyNr = CurrentGamePly;
fillMoveText(foundMove);
makeMove(foundMove);
MoveHistory.Add(foundMove);
generatePossibleMoves(PossibleMoves);
removeIllegalMoves(PossibleMoves);
if (isInCheck(thisSide, otherSide))
if (PossibleMoves.Count > 0)
foundMove.Text += "+";
else
foundMove.Text += "#";
return true;
}
void fillMoveText(ChessMove move)
{
move.Text = "";
if (move.Special == SpecialMoveType.CastleKS)
{
move.Text = "O-O";
return;
}
if (move.Special == SpecialMoveType.CastleQS)
{
move.Text = "O-O-O";
return;
}
PieceType piece = Board[move.FromSq].Piece.PieceType;
bool capture = (Board[move.ToSq].Piece.PieceType != PieceType.None || move.Special == SpecialMoveType.EnPassant);
if (piece == PieceType.Pawn)
{
if (capture)
move.Text += ((char)(move.FromSq.File + 'a')).ToString();
}
else
{
// Can more than one of the move's PieceType move to the same square?
int sameTo = 0, sameFile = 0, sameRank = 0;
foreach (ChessMove m in PossibleMoves)
{
if (Board[m.FromSq].Piece.PieceType == piece)
if (m.FromSq != move.FromSq && m.ToSq == move.ToSq)
{
sameTo++;
if (m.FromSq.File == move.FromSq.File)
sameFile++; // Another possible move with the same PieceType and From file moving to the same square
if (m.FromSq.Rank == move.FromSq.Rank)
sameRank++; // Likewise with rank
}
}
move.Text = pieceStr[(int)piece].ToString();
if (sameTo > 0)
{
if (sameFile == 0 && sameRank == 0 || sameRank > 0)
move.Text += ((char)(move.FromSq.File + 'a')).ToString(); // Needs rank specification to disambiguify
if (sameFile > 0)
move.Text += ((char)(move.FromSq.Rank + '1')).ToString(); // Needs file specificatino to disambiguify
}
}
if (capture)
move.Text += "x"; // Capture
move.Text += move.ToSq.ToString();
if (move.Special == SpecialMoveType.Promotion)
move.Text += "=" + pieceStr[(int)move.PromotedTo.PieceType].ToString(); // Promotion
}
void addCaptureMove(ChessMove move)
{
move.Piece = Board[move.FromSq].Piece;
// Adjust score according to most valuable victim least valuable attacker
move.Score = captureScore + mvvLva[(int)Board[move.ToSq].Piece.PieceType, (int)move.Piece.PieceType];
tmpMoveList.Add(move);
}
void addQuietMove(ChessMove move)
{
move.Piece = Board[move.FromSq].Piece;
if (killers[0, CurrentGamePly].Piece == move.Piece && killers[0, CurrentGamePly].FromSq == move.FromSq && killers[0, CurrentGamePly].ToSq == move.ToSq)
move.Score = killer0Score;
else
if (killers[1, CurrentGamePly].Piece == move.Piece && killers[1, CurrentGamePly].FromSq == move.FromSq && killers[1, CurrentGamePly].ToSq == move.ToSq)
move.Score = killer1Score;
else
move.Score += searchHistory[move.Piece.ToInt(), move.ToSq];
tmpMoveList.Add(move);
}
void movePiece(object o)
{
object[] args = (object[])o;
ChessPiece piece = (ChessPiece)args[0];
int toFile = (int)args[1];
int toRank = (int)args[2];
if (toFile < 0 || toFile > 7 || toRank < 0 || toRank > 7 || (toFile == piece.File && toRank == piece.Rank)) return;
ChessMove move = new ChessMove(new Square(piece.File, piece.Rank), new Square(toFile, toRank));
makeMove(move);
}