public AIMove GetAIMove(ChessEngine.Engine.Engine engine)
{
PieceList.Clear();
Squares = engine.ChessBoard.Squares;
WhoseTurn = engine.WhoseMove;
//Find all pieces that can be moved on this turn
for (byte i = 0; i < Squares.Length; i++)
{
if (Squares[i].Piece != null && Squares[i].Piece.PieceColor == WhoseTurn && Squares[i].Piece.ValidMoves.Count > 0)
{
PieceList.Add(i);
}
}
//If piecelist is empty, no moves can be made
if (PieceList.Count == 0)
{
return(null);
}
//Randomly select Piece
byte Piece = PieceList[RandomGenerator.Next(0, PieceList.Count)];
//Calculate piece position
byte SquareCount = 7;
byte Row = 0;
while (SquareCount < 64)
{
if (Piece <= SquareCount)
{
break;
}
Row++;
SquareCount += 8;
}
byte Column = (byte)(Piece - Row * 8);
AIMove.SourceRow = Row;
AIMove.SourceColumn = Column;
//Randomly select a move
LegalMoves = engine.GetValidMoves(Column, Row);
int MoveIndex = RandomGenerator.Next(0, LegalMoves.Length);
AIMove.DestinationRow = LegalMoves[MoveIndex][1];
AIMove.DestinationColumn = LegalMoves[MoveIndex][0];
Console.WriteLine("(" + AIMove.SourceColumn + ", " + AIMove.SourceRow + ")" + " (" + AIMove.DestinationColumn + ", " + AIMove.DestinationRow + ")" + "\n---------------");
return(AIMove);
}
private ChessEngine.Engine.Engine ReturnNewState(ChessEngine.Engine.Engine engine, byte piece, byte move)
{
ChessEngine.Engine.Engine newState = new Engine.Engine();
newState.ChessBoard = new Board(engine.ChessBoard);
byte[] sourcePos = engine.CalculateColumnAndRow((byte)(piece));
byte[] destinationPos = engine.CalculateColumnAndRow(move);
if (!newState.MovePiece(sourcePos[0], sourcePos[1], destinationPos[0], destinationPos[1]))
{
return(null);
}
return(newState);
}
private DynamicArray ReturnAllMovablePieces(ChessEngine.Engine.Engine engine)
{
DynamicArray pieceList = new DynamicArray();
Square[] squares = engine.ChessBoard.Squares;
//Find all pieces that can be moved on this turn
for (byte i = 0; i < squares.Length; i++)
{
if (squares[i].Piece != null && squares[i].Piece.PieceColor == engine.WhoseMove && squares[i].Piece.ValidMoves.Count > 0)
{
pieceList.Add(i);
}
}
return(pieceList);
}
private void debugWrite(ChessEngine.Engine.Engine engine)
{
string line = "";
for (int i = 0; i < engine.ChessBoard.Squares.Length; i++)
{
if (i == 59)
{
}
Square square = engine.ChessBoard.Squares[i];
if (square.Piece != null)
{
if (square.Piece.PieceType == ChessPieceType.Knight)
{
line += "H";
}
else
{
line += square.Piece.PieceType.ToString().Substring(0, 1);
}
}
else
{
line += ".";
}
if ((i + 1) % 8 == 0)
{
Debug.WriteLine(line);
line = "";
}
}
Debug.WriteLine("\n\n\n");
}
public void NewGame()
{
//ChessEngine
engine = new Engine();
currentSource = new Selection();
currentDestination = new Selection();
if (engine.HumanPlayer != engine.WhoseMove)
{
EngineMove();
}
Refresh();
}
private double MaxValue(int depth, double alpha, double beta, ChessEngine.Engine.Engine engine)
{
//Check if stalemate
if (engine.IsStalemateBy50MoveRule())
{
return(0);
}
//Check if checkmate
if (engine.IsCheckMate())
{
return(Double.MinValue);
}
//A leaf node, return value of board state
if ((depth == 0 && maxDepth != 0) || (maxTime.Seconds != 0 && timer.Elapsed > maxTime))
{
if (maxTime.Seconds != 0 && timer.Elapsed > maxTime)
{
overTime = true;
}
double boardValue = evaluator.ValuateBoard(engine.ChessBoard.Squares);
return(boardValue);
}
double value = Double.MinValue;
//Find all pieces that can be moved on this turn
DynamicArray pieceList = ReturnAllMovablePieces(engine);
//Go through all possible moves
foreach (byte piece in pieceList)
{
foreach (byte move in engine.ChessBoard.Squares[piece].Piece.ValidMoves)
{
//Create the next board stage
ChessEngine.Engine.Engine newState = ReturnNewState(engine, piece, move);
//Invalid move, continue to next move
if (newState == null)
{
continue;
}
//Pass parameters to the next node
value = MinValue(depth - 1, alpha, beta, newState);
//Check if alpha can be given bigger value
if (value > alpha)
{
alpha = value;
if (depth == maxDepth)
{
//Back at the root node with a better move than the previous best
byte[] source = engine.CalculateColumnAndRow(piece);
byte[] destination = engine.CalculateColumnAndRow(move);
bestMove.SourceColumn = source[0];
bestMove.SourceRow = source[1];
bestMove.DestinationColumn = destination[0];
bestMove.DestinationRow = destination[1];
}
}
//If alpha is bigger than beta, don't investigate branch further
if (alpha > beta)
{
return(alpha);
}
if (overTime)
{
break;
}
}
if (overTime)
{
break;
}
}
return(alpha);
}
private double MinValue(int depth, double alpha, double beta, ChessEngine.Engine.Engine engine)
{
//Check if stalemate
if (engine.IsStalemateBy50MoveRule())
{
return(0);
}
//Check if checkmate
if (engine.IsCheckMate())
{
return(Double.MaxValue);
}
//A leaf node, return value of board state
if ((depth == 0 && maxDepth != 0) || (maxTime.Seconds != 0) && timer.Elapsed > maxTime)
{
if (maxTime.Seconds != 0 && timer.Elapsed > maxTime)
{
overTime = true;
}
double boardValue = evaluator.ValuateBoard(engine.ChessBoard.Squares);
return(boardValue);
}
double value = Double.MaxValue;
//Find all pieces that can be moved on this turn
DynamicArray pieceList = ReturnAllMovablePieces(engine);
//Go through all possible moves
foreach (byte piece in pieceList)
{
foreach (byte move in engine.ChessBoard.Squares[piece].Piece.ValidMoves)
{
//Create the next board stage and pass it to the next node
ChessEngine.Engine.Engine newState = ReturnNewState(engine, piece, move);
//Invalid move, continue to next move
if (newState == null)
{
continue;
}
value = MaxValue(depth - 1, alpha, beta, newState);
//Check if beta can be given smaller value
if (value < beta)
{
beta = value;
}
//If beta is smaller than alpha, don't investigate branch further
if (beta < alpha)
{
return(beta);
}
if (overTime)
{
break;
}
}
if (overTime)
{
break;
}
}
return(beta);
}
