private Spot Minimax(Game G, int level, int maxLevel, char turn)
{
Spot BestSpot = new Spot();
//if current AI player
if (level % 2 == 0)
{
BestSpot.score = -1000000; // Negative infinity. Trying to maximize this score.
}
//if AI opponent
else
{
BestSpot.score = 1000000; // Positive infinity. Trying to minimize this score.
}
//if there is a winner or we are as deep as we are allowed to go
if (G.checkWinner().Item1 != ' ' || G.BoardIsFull() || level >= maxLevel)
{
BestSpot.score = scoreGame(G, level + 1, turn);
//MessageBox.Show(string.Format("Score is {0}, level is {1}", BestSpot.score, level));
}
else
{
//note that consts in C# are static, meaning that to access
//them you should use the class name
for (int i = 0; i < Game.ROWS; i++)
{
for (int j = 0; j < Game.COLS; j++)
{
if (G.CellIsPlayable(i, j))
{
Game TmpGame = new Game(G); // Create virtual games and pick the best one.
TmpGame.MarkGameBoard(i, j);
Spot TmpSpot = new Spot();
TmpSpot.row = i;
TmpSpot.col = j;
//if (TmpGame.checkWinner().Item1 != ' ')
//{
TmpSpot.score = Minimax(TmpGame, level + 1, maxLevel, turn).score;
//MessageBox.Show(string.Format("Score is {0}, level is {1}", TmpSpot.score, level));
//if current AI player
if (level % 2 == 0)
{
if (TmpSpot.score > BestSpot.score)
{
BestSpot = TmpSpot;
}
}
//if AI opponent
else
{
if (TmpSpot.score < BestSpot.score)
{
BestSpot = TmpSpot;
}
}
//}
}
}
}
}
//MessageBox.Show(string.Format("Score is {0}, level is {1}", BestSpot.score, level));
return(BestSpot);
}
private void PlayGrid_MouseLeftDown(object sender, MouseButtonEventArgs e)
{
var point = Mouse.GetPosition(PlayGrid);
int row = 0;
int col = 0;
double accumulatedHeight = 0.0;
double accumulatedWidth = 0.0;
// calc row mouse was over
foreach (var rowDefinition in PlayGrid.RowDefinitions)
{
accumulatedHeight += rowDefinition.ActualHeight;
if (accumulatedHeight >= point.Y)
{
break;
}
row++;
}
// calc col mouse was over
foreach (var columnDefinition in PlayGrid.ColumnDefinitions)
{
accumulatedWidth += columnDefinition.ActualWidth;
if (accumulatedWidth >= point.X)
{
break;
}
col++;
}
int rowIndexEmpty = -1;
for (int i = Game.ROWS - 1; i >= 0; i--)
{
if (TTT_Game.CellIsEmpty(Game.ROWS - i - 1, col))
{
rowIndexEmpty = i;
break;
}
}
if (rowIndexEmpty != -1)
{
if (TTT_Game.turn == 'X')
{
DrawX(rowIndexEmpty, col);
TTT_Game.MarkGameBoard(Game.ROWS - rowIndexEmpty - 1, col);
}
else if (TTT_Game.turn == 'O')
{
DrawO(rowIndexEmpty, col);
TTT_Game.MarkGameBoard(Game.ROWS - rowIndexEmpty - 1, col);
}
}
else
{
MessageBox.Show(string.Format("CANNOT PUT A TOKEN IN THAT COLUMN! IT'S NOT EMPTY!"));
return;
}
Tuple <char, List <Tuple <int, int> > > winResult = TTT_Game.checkWinner();
char winner = winResult.Item1;
if (txtPlayer1.Text == "")
{
txtPlayer1.Text = "Player 1";
}
if (txtPlayer2.Text == "")
{
txtPlayer2.Text = "Player 2";
}
if (winner != ' ')
{
List <Tuple <int, int> > winningSpots = winResult.Item2;
string winnerName = "";
if (winner == 'X')
{
winnerName = txtPlayer1.Text;
player1Wins++;
lblPlayer1Wins.Content = player1Wins.ToString();
}
else
{
winnerName = txtPlayer2.Text;
player2Wins++;
lblPlayer2Wins.Content = player2Wins.ToString();
}
string message = string.Format("Winner is {0}!", winnerName);
EndGame(message, winResult);
}
else if (TTT_Game.BoardIsFull())
{
ties++;
lblTie.Content = ties.ToString();
string message = string.Format("It's a TIE!");
EndGame(message, null);
}
else
{
if (PlayVsAi)
{
int difficulty = (int)sliderDifficulty.Value;
Game G = new Game(TTT_Game);
Spot spot = AiPlayer.GetBestMove(G, difficulty);
int r = spot.row;
int c = spot.col;
TTT_Game.MarkGameBoard(r, c);
Draw(Game.ROWS - r - 1, c, GetPlayerColor('O'));
winResult = TTT_Game.checkWinner();
if (TTT_Game.checkWinner().Item1 != ' ')
{
string message = string.Format("Winner is {0}!", txtPlayer2.Text);
EndGame(message, winResult);
}
else if (TTT_Game.BoardIsFull())
{
string message = string.Format("It's a TIE!");
EndGame(message, null);
}
}
}
}
public Spot GetBestMove(Game G, int difficulty)
{
Spot s = Minimax(G, 0, difficulty, G.getTurn());
return(s);
}