public void AISelect()
{
// wait for previous ai thread to stop
while (AI.RUNNING)
{
Thread.Sleep(100);
}
// ai is dump
this.m_UI.SetStatus(true, "Thinking...");
// calculate move
move_t move = AI.MiniMaxAB(this.Board, this.Turn);
// if valid move, make the move
if (move.to.letter >= 0 && move.to.number >= 0)
{
MakeMove(move);
}
else // if invalid move
{
if (!AI.STOP) // and not caused by AI interupt
{
// fuuuuuu
this.m_UI.LogMove("Null Move\n");
}
}
bool checkmate = false;
// if the AI wasn't interupted finish our turn
if (!AI.STOP)
{
switchPlayer();
checkmate = detectCheckmate();
}
// we're done now
AI.RUNNING = false;
// if the AI wan't interupted
// and we're in AI vs AI mode
// and not in checkmate/stalemate
// start the next AI's turn
if (!AI.STOP && this.m_nPlayers == 0 && !checkmate)
{
new Thread(AISelect).Start();
}
}
public static bool isEnPassant(ChessBoard b, move_t m)
{
// step = where opposite pawn is
int step = ((b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? -1 : 1);
// true if
// move is pawn
// space is blank
// move is diagonal
// opposite pawn exists at step
// the last move for opposite player was the pawn
// the last move for opposite pawn was the double jump
return(
b.Grid[m.from.number][m.from.letter].piece == Piece.PAWN &&
b.Grid[m.to.number][m.to.letter].piece == Piece.NONE &&
m.to.letter != m.from.letter &&
b.Grid[m.to.number + step][m.to.letter].piece == Piece.PAWN &&
b.LastMove[(b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? Player.BLACK : Player.WHITE].Equals(new position_t(m.to.letter, m.to.number + step)) &&
Math.Abs(b.Grid[m.to.number + step][m.to.letter].lastPosition.number - (m.to.number + step)) == 2 //jumped from last position
);
}
private void MakeMove(move_t m)
{
// start move log output
string move = (this.Turn == Player.WHITE) ? "W" : "B";
move += ":\t";
// piece
switch (this.Board.Grid[m.from.number][m.from.letter].piece)
{
case Piece.PAWN:
move += "P";
break;
case Piece.ROOK:
move += "R";
break;
case Piece.KNIGHT:
move += "k";
break;
case Piece.BISHOP:
move += "B";
break;
case Piece.QUEEN:
move += "Q";
break;
case Piece.KING:
move += "K";
break;
}
// kill
if (this.Board.Grid[m.to.number][m.to.letter].piece != Piece.NONE || LegalMoveSet.isEnPassant(this.Board, m))
{
move += "x";
}
// letter
switch (m.to.letter)
{
case 0: move += "a"; break;
case 1: move += "b"; break;
case 2: move += "c"; break;
case 3: move += "d"; break;
case 4: move += "e"; break;
case 5: move += "f"; break;
case 6: move += "g"; break;
case 7: move += "h"; break;
}
// number
move += (m.to.number + 1).ToString();
// update board / make actual move
this.Board = LegalMoveSet.move(this.Board, m);
// if that move put someone in check
if (LegalMoveSet.isCheck(this.Board, (Turn == Player.WHITE) ? Player.BLACK : Player.WHITE))
{
move += "+";
}
// show log
this.m_UI.LogMove(move + "\n");
}
public static move_t MiniMaxAB(ChessBoard board, Player turn)
{
RUNNING = true; // we've started running
STOP = false; // no interupt command sent
MAX = turn; // who is maximizing
// gather all possible moves
Dictionary <position_t, List <position_t> > moves = LegalMoveSet.getPlayerMoves(board, turn);
// because we're threading safely store best result from each thread
int[] bestresults = new int[moves.Count];
move_t[] bestmoves = new move_t[moves.Count];
// thread the generation of each move
Parallel.ForEach(moves, (movelist, state, index) =>
{
if (STOP) // interupt
{
state.Stop();
return;
}
// initialize thread best
bestresults[index] = int.MinValue;
bestmoves[index] = new move_t(new position_t(-1, -1), new position_t(-1, -1));
// for each move for the current piece(thread)
foreach (position_t move in movelist.Value)
{
if (STOP) // interupt
{
state.Stop();
return;
}
// make initial move and start recursion
ChessBoard b2 = LegalMoveSet.move(board, new move_t(movelist.Key, move));
int result = mimaab(b2, (turn == Player.WHITE) ? Player.BLACK : Player.WHITE, 1, Int32.MinValue, Int32.MaxValue);
// if result is better or best hasn't been set yet
if (bestresults[index] < result || (bestmoves[index].to.Equals(new position_t(-1, -1)) && bestresults[index] == int.MinValue))
{
bestresults[index] = result;
bestmoves[index].from = movelist.Key;
bestmoves[index].to = move;
}
}
});
// interupted
if (STOP)
{
return(new move_t(new position_t(-1, -1), new position_t(-1, -1)));
}
// find the best of the thread results
int best = int.MinValue;
move_t m = new move_t(new position_t(-1, -1), new position_t(-1, -1));
for (int i = 0; i < bestmoves.Length; i++)
{
if (best < bestresults[i] || (m.to.Equals(new position_t(-1, -1)) && !bestmoves[i].to.Equals(new position_t(-1, -1))))
{
best = bestresults[i];
m = bestmoves[i];
}
}
return(m);
}
private void MakeMove(move_t m)
{
// start move log output
string move = (this.Turn == Player.WHITE) ? "W" : "B";
move += ":\t";
// piece
switch (this.Board.Grid[m.from.number][m.from.letter].piece)
{
case Piece.PAWN:
move += "P";
break;
case Piece.ROOK:
move += "R";
break;
case Piece.KNIGHT:
move += "k";
break;
case Piece.BISHOP:
move += "B";
break;
case Piece.QUEEN:
move += "Q";
break;
case Piece.KING:
move += "K";
break;
}
// kill
if (this.Board.Grid[m.to.number][m.to.letter].piece != Piece.NONE || LegalMoveSet.isEnPassant(this.Board, m))
{
move += "x";
}
// letter
switch (m.to.letter)
{
case 0: move += "a"; break;
case 1: move += "b"; break;
case 2: move += "c"; break;
case 3: move += "d"; break;
case 4: move += "e"; break;
case 5: move += "f"; break;
case 6: move += "g"; break;
case 7: move += "h"; break;
}
// number
move += (m.to.number + 1).ToString();
// update board / make actual move
this.Board = LegalMoveSet.move(this.Board, m);
// if that move put someone in check
if (LegalMoveSet.isCheck(this.Board, (Turn == Player.WHITE) ? Player.BLACK : Player.WHITE))
{
move += "+";
}
// show log
this.m_UI.LogMove(move + "\n");
}
/// <summary>
/// Performs all necessary steps to update the game state and move the pieces.
/// </summary>
/// <param name="b">The state of the game.</param>
/// <param name="m">The desired move.</param>
/// <returns>The new state of the game.</returns>
public static ChessBoard move(ChessBoard b, move_t m)
{
// create a copy of the board
ChessBoard b2 = new ChessBoard(b);
// determine if move is enpassant or castling
bool enpassant = (b2.Grid[m.from.number][m.from.letter].piece == Piece.PAWN && isEnPassant(b2, m));
bool castle = (b2.Grid[m.from.number][m.from.letter].piece == Piece.KING && Math.Abs(m.to.letter - m.from.letter) == 2);
// update piece list, remove old position from piece list for moving player
b2.Pieces[b2.Grid[m.from.number][m.from.letter].player].Remove(m.from);
// if move kills a piece directly, remove killed piece from killed player piece list
if (b2.Grid[m.to.number][m.to.letter].piece != Piece.NONE && b2.Grid[m.from.number][m.from.letter].player != b2.Grid[m.to.number][m.to.letter].player)
{
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(m.to);
}
else if (enpassant)
{
// if kill was through enpassant determine which direction and remove the killed pawn
int step = (b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? -1 : 1;
b2.Pieces[b2.Grid[m.to.number + step][m.to.letter].player].Remove(new position_t(m.to.letter, m.to.number + step));
}
else if (castle)
{
// if no kill but enpassant, update the rook position
if (m.to.letter == 6)
{
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(new position_t(7, m.to.number));
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Add(new position_t(5, m.to.number));
}
else
{
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(new position_t(0, m.to.number));
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(new position_t(3, m.to.number));
}
}
// add the new piece location to piece list
b2.Pieces[b2.Grid[m.from.number][m.from.letter].player].Add(m.to);
// update board grid
b2.Grid[m.to.number][m.to.letter] = new piece_t(b2.Grid[m.from.number][m.from.letter]);
b2.Grid[m.to.number][m.to.letter].lastPosition = m.from;
b2.Grid[m.from.number][m.from.letter].piece = Piece.NONE;
if (enpassant)
{
// if kill was through enpassant determine which direction and remove the killed pawn
int step = (b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? -1 : 1;
b2.Grid[m.to.number + step][m.to.letter].piece = Piece.NONE;
}
else if (castle)
{
// if no kill but enpassant, update the rook position
if (m.to.letter == 6)
{
b2.Grid[m.to.number][5] = new piece_t(b2.Grid[m.to.number][7]);
b2.Grid[m.to.number][7].piece = Piece.NONE;
}
else
{
b2.Grid[m.to.number][3] = new piece_t(b2.Grid[m.to.number][0]);
b2.Grid[m.to.number][0].piece = Piece.NONE;
}
}
//promotion
if (b2.Grid[m.to.number][m.to.letter].piece == Piece.PAWN)
{
for (int i = 0; i < 8; i++)
{
if (b2.Grid[0][i].piece == Piece.PAWN)
{
b2.Grid[0][i].piece = Piece.QUEEN;
}
if (b2.Grid[7][i].piece == Piece.PAWN)
{
b2.Grid[7][i].piece = Piece.QUEEN;
}
}
}
// update king position
if (b2.Grid[m.to.number][m.to.letter].piece == Piece.KING)
{
b2.Kings[b2.Grid[m.to.number][m.to.letter].player] = m.to;
}
// update last move
b2.LastMove[b2.Grid[m.to.number][m.to.letter].player] = m.to;
return(b2);
}
public static move_t MiniMaxAB(ChessBoard board, Player turn)
{
RUNNING = true; // we've started running
STOP = false; // no interupt command sent
MAX = turn; // who is maximizing
// gather all possible moves
Dictionary<position_t, List<position_t>> moves = LegalMoveSet.getPlayerMoves(board, turn);
// because we're threading safely store best result from each thread
int[] bestresults = new int[moves.Count];
move_t[] bestmoves = new move_t[moves.Count];
// thread the generation of each move
Parallel.ForEach(moves, (movelist,state,index) =>
{
if (STOP) // interupt
{
state.Stop();
return;
}
// initialize thread best
bestresults[index] = int.MinValue;
bestmoves[index] = new move_t(new position_t(-1, -1), new position_t(-1, -1));
// for each move for the current piece(thread)
foreach (position_t move in movelist.Value)
{
if (STOP) // interupt
{
state.Stop();
return;
}
// make initial move and start recursion
ChessBoard b2 = LegalMoveSet.move(board, new move_t(movelist.Key, move));
int result = mimaab(b2, (turn == Player.WHITE) ? Player.BLACK : Player.WHITE, 1, Int32.MinValue, Int32.MaxValue);
// if result is better or best hasn't been set yet
if (bestresults[index] < result || (bestmoves[index].to.Equals(new position_t(-1, -1)) && bestresults[index] == int.MinValue))
{
bestresults[index] = result;
bestmoves[index].from = movelist.Key;
bestmoves[index].to = move;
}
}
});
// interupted
if (STOP)
return new move_t(new position_t(-1, -1), new position_t(-1, -1));
// find the best of the thread results
int best = int.MinValue;
move_t m = new move_t(new position_t(-1, -1), new position_t(-1, -1));
for(int i = 0; i < bestmoves.Length; i++)
{
if (best < bestresults[i] || (m.to.Equals(new position_t(-1,-1)) && !bestmoves[i].to.Equals(new position_t(-1,-1))))
{
best = bestresults[i];
m = bestmoves[i];
}
}
return m;
}
public static bool isEnPassant(ChessBoard b, move_t m)
{
// step = where opposite pawn is
int step = ((b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? -1 : 1);
// true if
// move is pawn
// space is blank
// move is diagonal
// opposite pawn exists at step
// the last move for opposite player was the pawn
// the last move for opposite pawn was the double jump
return (
b.Grid[m.from.number][m.from.letter].piece == Piece.PAWN &&
b.Grid[m.to.number][m.to.letter].piece == Piece.NONE &&
m.to.letter != m.from.letter &&
b.Grid[m.to.number + step][m.to.letter].piece == Piece.PAWN &&
b.LastMove[(b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? Player.BLACK : Player.WHITE].Equals(new position_t(m.to.letter, m.to.number + step)) &&
Math.Abs(b.Grid[m.to.number + step][m.to.letter].lastPosition.number - (m.to.number + step)) == 2 //jumped from last position
);
}
/// <summary>
/// Performs all necessary steps to update the game state and move the pieces.
/// </summary>
/// <param name="b">The state of the game.</param>
/// <param name="m">The desired move.</param>
/// <returns>The new state of the game.</returns>
public static ChessBoard move(ChessBoard b, move_t m)
{
// create a copy of the board
ChessBoard b2 = new ChessBoard(b);
// determine if move is enpassant or castling
bool enpassant = (b2.Grid[m.from.number][m.from.letter].piece == Piece.PAWN && isEnPassant(b2, m));
bool castle = (b2.Grid[m.from.number][m.from.letter].piece == Piece.KING && Math.Abs(m.to.letter - m.from.letter) == 2);
// update piece list, remove old position from piece list for moving player
b2.Pieces[b2.Grid[m.from.number][m.from.letter].player].Remove(m.from);
// if move kills a piece directly, remove killed piece from killed player piece list
if (b2.Grid[m.to.number][m.to.letter].piece != Piece.NONE && b2.Grid[m.from.number][m.from.letter].player != b2.Grid[m.to.number][m.to.letter].player)
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(m.to);
else if(enpassant)
{
// if kill was through enpassant determine which direction and remove the killed pawn
int step = (b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? -1 : 1;
b2.Pieces[b2.Grid[m.to.number + step][m.to.letter].player].Remove(new position_t(m.to.letter, m.to.number + step));
}
else if (castle)
{
// if no kill but enpassant, update the rook position
if (m.to.letter == 6)
{
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(new position_t(7, m.to.number));
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Add(new position_t(5, m.to.number));
}
else
{
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(new position_t(0, m.to.number));
b2.Pieces[b2.Grid[m.to.number][m.to.letter].player].Remove(new position_t(3, m.to.number));
}
}
// add the new piece location to piece list
b2.Pieces[b2.Grid[m.from.number][m.from.letter].player].Add(m.to);
// update board grid
b2.Grid[m.to.number][m.to.letter] = new piece_t(b2.Grid[m.from.number][m.from.letter]);
b2.Grid[m.to.number][m.to.letter].lastPosition = m.from;
b2.Grid[m.from.number][m.from.letter].piece = Piece.NONE;
if (enpassant)
{
// if kill was through enpassant determine which direction and remove the killed pawn
int step = (b.Grid[m.from.number][m.from.letter].player == Player.WHITE) ? -1 : 1;
b2.Grid[m.to.number + step][m.to.letter].piece = Piece.NONE;
}
else if (castle)
{
// if no kill but enpassant, update the rook position
if (m.to.letter == 6)
{
b2.Grid[m.to.number][5] = new piece_t(b2.Grid[m.to.number][7]);
b2.Grid[m.to.number][7].piece = Piece.NONE;
}
else
{
b2.Grid[m.to.number][3] = new piece_t(b2.Grid[m.to.number][0]);
b2.Grid[m.to.number][0].piece = Piece.NONE;
}
}
//promotion
if (b2.Grid[m.to.number][m.to.letter].piece == Piece.PAWN)
{
for (int i = 0; i < 8; i++)
{
if (b2.Grid[0][i].piece == Piece.PAWN)
b2.Grid[0][i].piece = Piece.QUEEN;
if (b2.Grid[7][i].piece == Piece.PAWN)
b2.Grid[7][i].piece = Piece.QUEEN;
}
}
// update king position
if (b2.Grid[m.to.number][m.to.letter].piece == Piece.KING)
{
b2.Kings[b2.Grid[m.to.number][m.to.letter].player] = m.to;
}
// update last move
b2.LastMove[b2.Grid[m.to.number][m.to.letter].player] = m.to;
return b2;
}