public bool IsUnderAttack(Board board)
{
var underAttack = IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(0, 1))), PieceType.Rook, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(1, 0))), PieceType.Rook, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(0, -1))), PieceType.Rook, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(-1, 0))), PieceType.Rook, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(1, 1))), PieceType.Bishop, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(-1, -1))), PieceType.Bishop, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(-1, 1))), PieceType.Bishop, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackAlongSlope(board, new Move(Location, new Coordinate(1, -1))), PieceType.Bishop, PieceType.Queen);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 2, Location.Y - 1))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 2, Location.Y + 1))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 2, Location.Y - 1))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 2, Location.Y + 1))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 1, Location.Y + 2))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 1, Location.Y + 2))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 1, Location.Y - 2))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 1, Location.Y - 2))), PieceType.Knight);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 1, Location.Y + Direction))), PieceType.King, PieceType.Pawn);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X, Location.Y + Direction))), PieceType.King);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 1, Location.Y + Direction))), PieceType.King, PieceType.Pawn);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 1, Location.Y))), PieceType.King);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 1, Location.Y))), PieceType.King);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X - 1, Location.Y - Direction))), PieceType.King);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X, Location.Y - Direction))), PieceType.King);
underAttack = underAttack || IsResultValid(TryAttackSquare(board, new Move(Location, new Coordinate(Location.X + 1, Location.Y - Direction))), PieceType.King);
return underAttack;
}
public IEnumerable<Move> GetPossibleMoves(Board board)
{
var result = new List<Move>();
short x = -1;
short y = -1;
for (x = -1; x <= 1; x++)
{
for (y = -1; y <= 1; y++)
{
if (!(x == 0 && y == 0))
{
TryMoveToSquare(board, result, new Move(this.Location, new Coordinate(Location.X + x, Location.Y + y)), MoveType.CanAttack);
}
}
}
if (!HasMoved)
{
// Can't move to escape check
if (!IsUnderAttack(board))
{
var oneRight = new Coordinate(Location.X + 1, Location.Y);
var twoRight = new Coordinate(Location.X + 2, Location.Y);
var rook = board.GetPiece((short)(Location.X + 3), Location.Y);
if(board.GetPiece(oneRight.X, oneRight.Y) == null && board.GetPiece(twoRight.X, twoRight.Y) == null &&
rook != null && rook.PieceType == PieceType.Rook && rook.HasMoved == false)
{
if(!board.CheckMoveForCheck(new Move(Location, oneRight)) &&
!board.CheckMoveForCheck(new Move(Location, twoRight)))
{
result.Add(new Move(Location, twoRight, rook.Location, oneRight));
}
}
var oneLeft = new Coordinate(Location.X - 1, Location.Y);
var twoLeft = new Coordinate(Location.X - 2, Location.Y);
var threeLeft = new Coordinate(Location.X - 3, Location.Y);
rook = board.GetPiece((short)(Location.X - 4), Location.X);
if (board.GetPiece(oneLeft.X, oneLeft.Y) == null && board.GetPiece(twoLeft.X, twoLeft.Y) == null && board.GetPiece(threeLeft.X, threeLeft.Y) == null
&& rook != null && rook.PieceType == PieceType.Rook && rook.HasMoved == false)
{
if (!board.CheckMoveForCheck(new Move(Location, oneLeft)) &&
!board.CheckMoveForCheck(new Move(Location, twoLeft)) &&
!board.CheckMoveForCheck(new Move(Location, threeLeft)))
{
result.Add(new Move(Location, twoLeft, rook.Location, oneLeft));
}
}
}
}
return result;
}
private TreeNode MiniMax(Board board, Double depth, Double alpha, Double beta, Boolean maximizer)
{
if(depth == 0)
{
return GetLeafNode(board, maximizer);
}
var pieces = board.GetPiecesForPlayer(board.PlayerTurn);
var bestScore = maximizer ? _minScore : _maxScore;
var bestMove = default(Move);
var moves = pieces.SelectMany(x => x.GetPossibleMoves(board));
if (!moves.Any())
{
if (board.PlayerHasCheck(board.PlayerTurn))
{
return new TreeNode(null, maximizer ? _maxScore : _minScore);
}
}
foreach (var mv in moves)
{
var newBoard = board.Copy();
newBoard.MakeMove(mv);
var newNode = MiniMax(newBoard, depth - 1, alpha, beta, !maximizer);
if (maximizer)
{
if(newNode.Score > bestScore)
{
bestScore = newNode.Score;
bestMove = mv;
}
alpha = Math.Max(alpha, bestScore);
if(beta <= alpha)
{
return new TreeNode(bestMove, bestScore);
}
}
else
{
if(newNode.Score < bestScore)
{
bestScore = newNode.Score;
bestMove = mv;
}
beta = Math.Min(beta, bestScore);
if(beta <= alpha)
{
return new TreeNode(bestMove, bestScore);
}
}
}
return new TreeNode(bestMove, bestScore);
}
public void GetNextMoveMustNotAlterBoard()
{
_board = new Board();
_board.Initialize();
for(int i = 0; i < 10; i++)
{
var origBoard = _board.Copy();
var mv = _miniMaxService.GetNextMove(_board);
Assert.IsTrue(_board.Equals(origBoard));
_board.MakeMove(mv);
}
}
public IEnumerable<Move> GetPossibleMoves(Board board)
{
var result = new List<Move>();
//straight forward
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(0, 1)));
// straight left
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(-1, 0)));
//straight right
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(1, 0)));
//straigh back
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(0, -1)));
return result;
}
public Move GetNextMove(Board board)
{
var allMoves = new List<Move>();
var pcs = board.GetPiecesForPlayer(board.PlayerTurn);
foreach(var pc in pcs)
{
var moves = pc.GetPossibleMoves(board);
allMoves.AddRange(moves);
}
var randomIndex = new Random().Next(allMoves.Count);
return allMoves[randomIndex];
}
public IEnumerable<Move> GetPossibleMoves(Board board)
{
var result = new List<Move>();
//diag forward left;
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(-1, 1)));
//diag forward right;
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(1, 1)));
//diag backward left;
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(-1, -1)));
//diag backward right;
TryMoveAlongSlope(board, result, new Move(Location, new Coordinate(1, -1)));
return result;
}
private double GetScore(List<IPiece> playerPieces, Board board)
{
Dictionary<short, short> pawnCoords = new Dictionary<short, short>();
Double score = 0;
foreach (var pc in playerPieces)
{
switch (pc.PieceType)
{
case PieceType.Queen:
score += queenMaterial;
score += queenKingProximity * (7 - GetChebyShevDistance(pc.Location, board.GetKingPosition(board.OpposingPlayer())));
score += queenCenterProximity * (3 - GetChebyShevDistance(pc.Location, board.GetCenter()));
break;
case PieceType.Bishop:
score += bishopMaterial;
score += bishopDistanceToCenterWeight * (4 - GetChebyShevDistance(pc.Location, board.GetCenter()));
// mobility and xray mobility
break;
case PieceType.Knight:
score += knightMaterial;
score += knightDistanceToKingWeight * GetManhattanDistance(pc.Location, board.GetKingPosition(board.OpposingPlayer()));
score += knightDistanceToKingWeight * GetManhattanDistance(pc.Location, board.GetKingPosition(board.PlayerTurn));
score += knightDistanceToCenterWeight * (4 - GetChebyShevDistance(pc.Location, board.GetCenter()));
break;
case PieceType.Rook:
score += rookMaterial;
score += rookKingProximity * (14 - GetManhattanDistance(pc.Location, board.GetKingPosition(board.OpposingPlayer())));
//mobility and xray mobility
// friendly pawns.
break;
case PieceType.Pawn:
score += pawnMaterial;
score += pawnRankWeight * pc.Rank;
if (pawnCoords.ContainsKey(pc.Location.X))
{
pawnCoords[pc.Location.X] = Math.Min(pc.Location.Y, pawnCoords[pc.Location.X]);
score -= doubledPawnPenalty;
}
else
{
pawnCoords.Add(pc.Location.X, pc.Location.Y);
}
break;
}
}
score += IsolatedPawns(pawnCoords);
return score;
}
public IEnumerable<Move> GetPossibleMoves(Board board)
{
var result = new List<Move>();
if (TryMoveToSquare(board, result, new Move(this.Location, new Coordinate(Location.X, Location.Y + Direction)), MoveType.CannotAttack).Type == MoveResultType.Move) {
if ((Player == Player.Light && Location.Y == 6)|| (Player == Player.Dark && Location.Y == 1))
{
TryMoveToSquare(board, result, new Move(this.Location, new Coordinate(Location.X, Location.Y + (2 * Direction))), MoveType.CannotAttack);
}
}
TryMoveToSquare(board, result, new Move(this.Location, new Coordinate(Location.X - 1, Location.Y + Direction)), MoveType.MustAttack);
TryMoveToSquare(board, result, new Move(this.Location, new Coordinate(Location.X + 1, Location.Y + Direction)), MoveType.MustAttack);
return result;
}
public IEnumerable<Move> GetPossibleMoves(Board board)
{
var result = new List<Move>();
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X - 1, Location.Y + 2)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X + 1, Location.Y + 2)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X - 1, Location.Y - 2)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X + 1, Location.Y - 2)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X - 2, Location.Y + 1)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X - 2, Location.Y - 1)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X + 2, Location.Y + 1)), MoveType.CanAttack);
TryMoveToSquare(board, result, new Move(Location, new Coordinate(Location.X + 2, Location.Y - 1)), MoveType.CanAttack);
return result;
}
public void GetNextMoveMustReturnIn15Seconds()
{
var totalMoves = 3d;
_board = new Board();
_board.Initialize();
var stopWatch = new Stopwatch();
stopWatch.Start();
for (int i = 0; i < totalMoves; i++)
{
var mv = _miniMaxService.GetNextMove(_board);
_board.MakeMove(mv);
}
stopWatch.Stop();
var secondsPer = stopWatch.ElapsedMilliseconds / totalMoves / 1000d;
Assert.IsTrue(secondsPer < 15);
}
private TreeNode GetLeafNode(Board board, Boolean maximizer)
{
var status = board.GetBoardStatus();
var score = 0d;
if (status == Enums.BoardStatus.Checkmate)
{
score = maximizer ? _maxScore : _minScore;
}
else if (status == Enums.BoardStatus.Stalemate)
{
score = 0;
}
else
{
score = _evalService.Evaluate(board);
}
return new TreeNode(null, score);
}
public double Evaluate(Board board)
{
Double score = 0;
var playerPieces = board.GetPiecesForPlayer(board.PlayerTurn);
var opposingPieces = board.GetPiecesForPlayer(board.OpposingPlayer());
score = GetScore(playerPieces, board);
score -= GetScore(opposingPieces, board);
//score = 200 * (CountPiecesByType(playerPieces, PieceType.King) - CountPiecesByType(opposingPieces, PieceType.King));
//score += 9 * (CountPiecesByType(playerPieces, PieceType.Queen) - CountPiecesByType(opposingPieces, PieceType.Queen));
//score += 5 * (CountPiecesByType(playerPieces, PieceType.Rook) - CountPiecesByType(opposingPieces, PieceType.Rook));
//score += 3 * ((CountPiecesByType(playerPieces, PieceType.Bishop) - CountPiecesByType(opposingPieces, PieceType.Bishop)) +
// (CountPiecesByType(playerPieces, PieceType.Knight) - CountPiecesByType(opposingPieces, PieceType.Knight)));
//score += 1 * (CountPiecesByType(playerPieces, PieceType.Pawn) - (CountPiecesByType(opposingPieces, PieceType.Pawn)));
//score -= .5 * ((DoubledPawns(playerPieces) - DoubledPawns(opposingPieces)) +
// (BlockedPawns(playerPieces) - BlockedPawns(opposingPieces)) +
// (IsolatedPawns(playerPieces) - IsolatedPawns(opposingPieces)));
//score += .1 * (CountMoves(board, playerPieces) - CountMoves(board, opposingPieces));
return score;
}
public void Setup()
{
_board = new Board(true);
_board.SetPlayer(Player.Light);
}
public Board Copy()
{
var dest = new Board();
foreach (var sq in Squares)
{
IPiece pc = null;
if (sq.Piece != null)
{
pc = Piece.GetPiece(sq.Piece.PieceType, sq.Piece.Player, sq.Piece.Location);
pc.HasMoved = sq.Piece.HasMoved;
}
dest.AddPieceToBoard(sq.Location.X, sq.Location.Y, pc);
}
dest.PlayerTurn = PlayerTurn;
return dest;
}
public Board Get()
{
var board = new Board();
board.Initialize();
return board;
}
public Move GetNextMove(Board board)
{
var newBoard = board.Copy();
return MiniMax(board, _maxDepth, _minScore, _maxScore, true).Move;
}
public bool Equals(Board brd)
{
if (PlayerTurn != brd.PlayerTurn) { return false; }
for (short y = 0; y < 8; y++)
{
for (short x = 0; x < 8; x++)
{
var o = GetSquare(x, y);
var n = brd.GetSquare(x, y);
if (o.Piece == null && n.Piece == null)
{
continue;
}
if (o.Piece == null || n.Piece == null)
{
return false;
}
if ((o.Piece.PieceType != n.Piece.PieceType) || (o.Piece.HasMoved != n.Piece.HasMoved) ||
(o.Piece.Location.X != n.Piece.Location.X) || (o.Piece.Location.Y != n.Piece.Location.Y) ||
(o.Piece.Player != n.Piece.Player))
{
return false;
}
}
}
return true;
}
protected MoveResult TryAttackSquare(Board board, Move move)
{
if (move.To.IsValid)
{
var targetPiece = board.GetPiece(move.To.X, move.To.Y);
if(targetPiece != null)
{
if(targetPiece.Player != Player)
{
return new MoveResult() { Type = MoveResultType.Attack, CapturedPiece = targetPiece };
}
}
else
{
return new MoveResult() { Type = MoveResultType.Move };
}
}
return new MoveResult() { Type = MoveResultType.Invalid };
}
protected void TryMoveAlongSlope(Board board, List<Move> possibleMoves, Move slope)
{
var curX = slope.From.X;
var curY = slope.From.Y;
do
{
curX += slope.To.X;
curY += slope.To.Y;
} while (TryMoveToSquare(board, possibleMoves, new Move(slope.From, new Coordinate(curX, curY)), MoveType.CanAttack).Type == MoveResultType.Move);
}
public void Setup()
{
_board = new Board();
}
protected MoveResult TryMoveToSquare(Board board, List<Move> possibleMoves, Move move, MoveType moveType)
{
if (move.To.IsValid)
{
var targetPiece = board.GetPiece(move.To.X, move.To.Y);
if (moveType != MoveType.MustAttack && targetPiece == null)
{
if(!board.CheckMoveForCheck(move))
{
possibleMoves.Add(move);
}
return new MoveResult() { Type = MoveResultType.Move };
}
else if(moveType != MoveType.CannotAttack && targetPiece != null && targetPiece.Player != Player)
{
if(!board.CheckMoveForCheck(move))
{
possibleMoves.Add(move);
}
return new MoveResult() { Type = MoveResultType.Attack, CapturedPiece = targetPiece };
}
}
return new MoveResult() { Type = MoveResultType.Invalid };
}
protected MoveResult TryAttackAlongSlope(Board board, Move slope)
{
var curX = slope.From.X;
var curY = slope.From.Y;
var result = default(MoveResult);
do
{
curX += slope.To.X;
curY += slope.To.Y;
result = TryAttackSquare(board, new Move(slope.From, new Coordinate(curX, curY)));
} while (result.Type == MoveResultType.Move);
return result;
}
