/// <summary>
/// Sets a piece in the hash.
/// </summary>
///
/// <exception cref="System.ArgumentOutOfRangeException">If index is >= `Board.pieceCount`</exception>
/// <exception cref="CS_Project.Game.HashException">If `allowOverwrite` is false, and there is a non-empty piece at 'index'</exception>
///
/// <param name="piece">The piece to use</param>
/// <param name="index">The index to place the piece</param>
/// <param name="allowOverwrite">See the `HashException` part of this documentation</param>
public void setPiece(Board.Piece piece, int index, bool allowOverwrite = false)
{
// Enforce the behaviour of `allowOverwrite`
if (this.getPieceChar(index) != Hash.emptyChar && !allowOverwrite)
{
throw new HashException($"Attempted to place {piece} at index {index}, however a non-null piece is there and allowOverwrite is false. Hash = {this._hash}");
}
// Figure out which character to use to represent `piece`.
char pieceChar = '\0';
if (piece == this.myPiece)
{
pieceChar = Hash.myChar;
}
else if (piece == this.otherPiece)
{
pieceChar = Hash.otherChar;
}
else
{
pieceChar = Hash.emptyChar;
}
// Then place that character into the hash.
this._hash[index] = pieceChar;
this.checkCorrectness();
}
/// <summary>
/// Updates the GUI to reflect the new state of the board.
/// </summary>
///
/// <param name="boardState">The new state of the baord.</param>
/// <param name="turn">Who's turn it currently is.</param>
private void updateGUI(Board.Hash boardState, Board.Piece turn)
{
this._window.Dispatcher.Invoke(() =>
{
this._window.updateBoard(boardState);
this._window.updateText(null, (turn == base.piece) ? "It is your turn" : "The AI is thinking...");
});
}
// implement Controller.onMatchStart
public override void onMatchStart(Board board, Board.Piece myPiece)
{
base.onMatchStart(board, myPiece);
// When the match starts, tell the player which piece they're using.
this._window.Dispatcher.Invoke(() =>
{
this._window.updateText($"[You are {myPiece}]");
});
}
/// <summary>
/// Creates a hash of the board, using a given piece as the "myPiece".
/// </summary>
///
/// <param name="piece">The piece that should be used as the "myPiece"</param>
private Hash createHashFor(Board.Piece piece)
{
var hash = new Hash(piece);
for (var i = 0; i < this._board.Length; i++)
{
hash.setPiece(this._board[i], i);
}
return(hash);
}
// implement Controller.onMatchStart
public override void onMatchStart(Board board, Board.Piece myPiece)
{
base.onMatchStart(board, myPiece);
// Reset some variables.
this._localTree = Node.root;
this._useRandom = false;
// Update the global tree debugger
this.doDebugAction(() => this._globalDebug.updateNodeData(this._globalTree));
this.doDebugAction(() => this._globalDebug.updateStatusText("[GLOBAL MOVE TREE DEBUGGER]"));
}
private Hash(Board.Piece myPiece, bool dummyParam)
{
if (myPiece == Board.Piece.Empty)
{
throw new HashException("myPiece must not be Board.Piece.empty");
}
// Figure out who is using what piece.
this.myPiece = myPiece;
this.otherPiece = (myPiece == Board.Piece.O) ? Board.Piece.X
: Board.Piece.O;
}
/// <summary>
/// Evaluates the board based on how many pieces of a kind there are in a row. The more a player has in a row, the greater their score will be.
/// </summary>
/// <param name="b">The board that will be evaluated for a score.</param>
/// <param name="p">The piece on the board in which the score is taken in respect to.</param>
/// <returns>The total score of the board in respect to the piece.</returns>
private float EvaluateScore(Board b, Board.Piece p)
{
float score = 0;
//The opposing piece is called other. If the parameter p is Player 1, then other is Player 2. If p is Player 2, then other is player 1.
Board.Piece other = (p == Board.Piece.Player1 ? Board.Piece.Player2 : Board.Piece.Player1);
//The score from each type of pairing. The count of p is positive and the opponent is negative.
score += (b.countSingles(p) - b.countSingles(other)) * (int)Point.One;
score += (b.countDoubles(p) - b.countDoubles(other)) * (int)Point.Two;
score += (b.countTriples(p) - b.countTriples(other)) * (int)Point.Three;
score += (b.countQuadruples(p) - b.countQuadruples(other)) * (int)Point.Four;
return(score);
}
/// <summary>
/// Gets the board piece at a certain index.
/// </summary>
///
/// <exception cref="System.ArgumentOutOfRangeException">If index is >= `Board.pieceCount`</exception>
///
/// <param name="index">The index to use</param>
///
/// <returns>The board piece at 'index'</returns>
public Board.Piece getPiece(int index)
{
Board.Piece piece = Board.Piece.Empty;
var pieceChar = this.getPieceChar(index);
// Convert the character into a Board.Piece
switch (pieceChar)
{
case Hash.emptyChar: piece = Board.Piece.Empty; break;
case Hash.myChar: piece = this.myPiece; break;
case Hash.otherChar: piece = this.otherPiece; break;
default: Debug.Assert(false, "This should not have happened"); break;
}
return(piece);
}
// --------------------------------------------------------------------------------------------------------------
/// <summary>
/// The AI managing method that uses Alphabeta Minimax. Will set the bestMove field.
/// </summary>
/// <param name="alpha">Lower bound of the optimal score.</param>
/// <param name="beta">Upper bound of the optimal score.</param>
/// <param name="maxDepth">The maximum number of levels deep in the recursion.</param>
/// <param name="currentDepth">The current number of the level in the recursion. Set to 0 initially to start.</param>
/// <param name="player">The bestMove in respect to the player.</param>
/// <param name="tempBoard">The current board state.</param>
/// <returns>End result of the recursion of the bestScore, ie. the best score possible.</returns>
private float ComputerMove(float alpha, float beta, int maxDepth, int currentDepth, Board.Piece player, Board tempBoard)
{
// base case
if (board.countQuadruples(player) > 0 || currentDepth == maxDepth)
{
//Debug.Log("Board Score : " + EvaluateScore(tempBoard, player));
return(EvaluateScore(tempBoard, player));
}
// set initial values
float bestScore;
float tempScore;
int row;
Board.Piece other = (player == Board.Piece.Player1 ? Board.Piece.Player2 : Board.Piece.Player1);
//If this is true then it means that it is the maximizing player's turn.
if (currentDepth % 2 == 0)
{
//bestScore has to be overwritten with a larger number, therefore it starts at smallest possible.
bestScore = Mathf.NegativeInfinity;
foreach (int move in board.getPossibleMoves())
{
tempScore = bestScore;
row = tempBoard.getEmptyCell(move);
alpha = Mathf.Max(alpha, bestScore);
tempBoard.setCell(move, row, player);
bestScore = Mathf.Max(bestScore, ComputerMove(-beta, -alpha, maxDepth, currentDepth + 1, player, tempBoard));
if (currentDepth == 0)
{
bestMove = tempScore == bestScore ? bestMove : move;
}
tempBoard.setCell(move, row, Board.Piece.Empty);
if (beta <= alpha)
{
break;
}
}
}
//The opponent's turn or the minimizing player's turn.
else
{
//bestScore has to be overwritten with a smaller number, therefore it starts at the largest number possible.
bestScore = Mathf.Infinity;
foreach (int move in board.getPossibleMoves())
{
tempScore = bestScore;
row = tempBoard.getEmptyCell(move);
tempBoard.setCell(move, row, other);
bestScore = Mathf.Min(bestScore, ComputerMove(-beta, -alpha, maxDepth, currentDepth + 1, player, tempBoard));
if (currentDepth == 0)
{
bestMove = bestMove = tempScore == bestScore ? bestMove : move;
}
beta = Mathf.Min(beta, bestScore);
tempBoard.setCell(move, row, Board.Piece.Empty);
if (beta <= alpha)
{
break;
}
}
}
Debug.Log("Best Move : " + bestMove);
//Debug.Log("Best Score : " + bestScore);
return(bestScore);
}
/// <summary>
/// Called whenever the match has ended.
///
/// Notes for inheriting classes: Call 'super.onMatchEnd' only at the end of the function.
/// </summary>
///
/// <param name="boardState">The final state of the board.</param>
/// <param name="index">The index of where the last piece was placed on the board.</param>
/// <param name="result">Contains the match result.</param>
public virtual void onMatchEnd(Board.Hash boardState, int index, MatchResult result)
{
this.board = null;
this.piece = Board.Piece.Empty;
}
/// <summary>
/// Called whenever a new match is started.
/// </summary>
///
/// <param name="board">The board that is using this controller.</param>
/// <param name="myPiece">Which piece this controller has been given.</param>
public virtual void onMatchStart(Board board, Board.Piece myPiece)
{
this.board = board;
this.piece = myPiece;
}
// implement ISerialiseable.deserialise
public void deserialise(BinaryReader input, uint version)
{
// TREE version 1
if (version == 1)
{
var length = input.ReadByte();
this._hash = input.ReadChars(length);
this.myPiece = (Board.Piece)input.ReadByte();
this.otherPiece = (Board.Piece)input.ReadByte();
}
/**
* Format of a hash: (TREE version 2)
* [3 bytes]
* byte 1: 4433 2211
* byte 2: 8877 6655
* byte 3: 0000 MO99
*
* Numbers such as '11' and '55' represent the Board.Piece in slot '1' and '5', respectively.
* 'M' and 'O' represent the Board.Piece of 'My' piece and 'Other' piece, respectively.
* '0' Represents 'unused'
*
* For 'M' and 'O':
* 0 = Board.Piece.O
* 1 = Board.Piece.X
*
* So if the 'MO' bits were 0x40: M = O, O = X
* If 'MO' were 0x80: M = X, O = O
*
* For '11' to '99':
* 0 = Empty
* 1 = M
* 2 = O
* **/
if (version == 2)
{
var bytes = input.ReadBytes(3);
var identityBits = bytes[2] & 0xC; // Identity = The bits defining 'myPiece' and 'otherPiece'. 0xC = 1100
this.myPiece = (identityBits & 0x4) == 0x4 ? Piece.O : Piece.X;
this.otherPiece = (identityBits & 0x4) == 0x4 ? Piece.X : Piece.O;
for (int i = 0; i < Board.pieceCount; i++)
{
var byteIndex = (i * 2) / 8; // Index into 'bytes' for which byte to use.
var bitOffset = (i * 2) % 8; // The offset into the byte to write the data to.
var byte_ = bytes[byteIndex];
var piece = (byte_ >> bitOffset) & 0x3; // 0x3 == 0000 0011
switch (piece)
{
case 0: this._hash[i] = Hash.emptyChar; break;
case 1: this._hash[i] = Hash.myChar; break;
case 2: this._hash[i] = Hash.otherChar; break;
default:
throw new IOException("");
}
}
}
this.checkCorrectness();
}
/// <summary>
/// Constructs a new Hash from a given hash string.
/// </summary>
///
/// <exception cref="CS_Project.Game.HashException">If `myPiece` is `Board.Piece.empty`</exception>
///
/// <param name="myPiece">The piece that you are using, this is needed so the class knows how to correctly format the hash.</param>
/// <param name="hash">
/// The hash string to use.
///
/// An internal check is made with every function call, that determines if the hash is still correct:
/// * The hash's length must be the same as 'Board.pieceCount'
/// * The hash's characters must only be made up of 'Hash.myChar', 'Hash.otherChar', and 'Hash.emptyChar'.
///
/// If the given hash fails to meet any of these checks, then an error box will be displayed.
/// In the future, when I can be bothered, exceptions will be thrown instead so the errors can actually be handled.
/// </param>
public Hash(Board.Piece myPiece, IEnumerable <char> hash) : this(myPiece, false)
{
this._hash = hash.ToArray();
this.checkCorrectness();
}
/// <summary>
/// Constructs a new Hash.
/// </summary>
///
/// <exception cref="CS_Project.Game.HashException">If `myPiece` is `Board.Piece.empty`</exception>
///
/// <param name="myPiece">The piece that you are using, this is needed so the class knows how to correctly format the hash.</param>
public Hash(Board.Piece myPiece) : this(myPiece, new string(Hash.emptyChar, 9))
{
}
/// <summary>
/// Starts a match between two controllers.
///
/// Note to self: Run all of this stuff in a seperate thread, otherwise the GUI will freeze.
/// Use System.Collections.Concurrent.ConcurrentQueue to talk between the two threads.
/// </summary>
///
/// <param name="xCon">The controller for the X piece.</param>
/// <param name="oCon">The controller for the O piece.</param>
public void startMatch(Controller xCon, Controller oCon)
{
Debug.Assert(this._stage == Stage.NoMatch, "Attempted to start a match while another match is in progress.");
#region Setup controllers.
Debug.Assert(xCon != null, "The X controller is null.");
Debug.Assert(oCon != null, "The O controller is null.");
this._stage = Stage.Initialisation;
// Inform the controllers what piece they're using.
xCon.onMatchStart(this, Piece.X);
oCon.onMatchStart(this, Piece.O);
// Reset some stuff
this._lastIndex = int.MaxValue;
#endregion
#region Match turn logic
Board.Piece turnPiece = Piece.O; // The piece of who's turn it is.
Board.Piece wonPiece = Piece.Empty; // The piece of who's won. Empty for no win.
bool isTie = false;
while (wonPiece == Piece.Empty && !isTie) // While there hasn't been a tie, and no one has won yet.
{
// Unset some flags
this._flags &= ~Flags.HasSetPiece;
#region Do controller turn
this._stage = Stage.InControllerTurn;
var hash = this.createHashFor(turnPiece); // Create a hash from the point of view of who's turn it is.
var controller = (turnPiece == Piece.X) ? xCon : oCon; // Figure out which controller to use this turn.
this._current = controller;
controller.onDoTurn(hash, this._lastIndex); // Allow the controller to perform its turn.
Debug.Assert((this._flags & Flags.HasSetPiece) != 0,
$"The controller using the {turnPiece} piece didn't place a piece.");
#endregion
#region Do after controller turn
this._stage = Stage.AfterControllerTurn;
hash = this.createHashFor(turnPiece); // Create another hash for the controller
controller.onAfterTurn(hash, this._lastIndex); // And let the controller handle its 'after move' logic
#endregion
#region Misc stuff
wonPiece = this.checkForWin(out isTie); // See if someone's won/tied yet.
turnPiece = (turnPiece == Piece.X) ? Piece.O : Piece.X; // Change who's turn it is
#endregion
}
#endregion
Debug.Assert(wonPiece != Piece.Empty || isTie, "There was no win condition, but the loop still ended.");
#region Process the win
// Create a hash for both controllers, then tell them whether they tied, won, or lost.
var stateX = this.createHashFor(Piece.X);
var stateO = this.createHashFor(Piece.O);
if (isTie)
{
xCon.onMatchEnd(stateX, this._lastIndex, MatchResult.Tied);
oCon.onMatchEnd(stateO, this._lastIndex, MatchResult.Tied);
}
else if (wonPiece == Piece.O)
{
xCon.onMatchEnd(stateX, this._lastIndex, MatchResult.Lost);
oCon.onMatchEnd(stateO, this._lastIndex, MatchResult.Won);
}
else
{
xCon.onMatchEnd(stateX, this._lastIndex, MatchResult.Won);
oCon.onMatchEnd(stateO, this._lastIndex, MatchResult.Lost);
}
#endregion
#region Reset variables
this._stage = Stage.NoMatch;
this._current = null;
for (var i = 0; i < this._board.Length; i++)
{
this._board[i] = Piece.Empty;
}
#endregion
}
