internal void EvaluateScan(
ref EvaluationValue evaluationValue,
int column,
int row,
int columnStep,
int rowStep,
Piece piece)
{
var targetColumn = column + (columnStep * StraightLength);
if (targetColumn < 0)
{
targetColumn = -1;
}
else if (targetColumn > Width)
{
targetColumn = Width;
}
var targetRow = row + (rowStep * StraightLength);
if (targetRow < 0)
{
targetRow = -1;
}
else if (targetRow > Height)
{
targetRow = Height;
}
column += columnStep;
row += rowStep;
for (int c = column, r = row;
(c != targetColumn || r != targetRow) &&
(c >= 0 && c < Width && r >= 0 && r < Height);
c += columnStep, r += rowStep)
{
if (GetPiece(c, r) == piece)
{
evaluationValue.Value += 1;
evaluationValue.Indexes.Add(c + (r * Width));
}
else
{
return;
}
}
}
internal EvaluationResult Evaluate(int column, int row)
{
var playerPiece = GetPiece(column, row);
var evaluationResult = new EvaluationResult(playerPiece);
if (playerPiece == Piece.Empty)
{
return(evaluationResult);
}
var opponentPiece = playerPiece == Piece.X ? Piece.O : Piece.X;
var moves = new List <int[]>()
{
new int[] { 1, 0 }, // East
new int[] { -1, 0 }, // West
new int[] { 0, 1 }, // South
new int[] { 0, -1 }, // North
new int[] { 1, -1 }, // North-East
new int[] { -1, 1 }, // South-West
new int[] { -1, -1 }, // North-West
new int[] { 1, 1 } // South-East
};
for (var i = 0; i < moves.Count; i += 2)
{
var evaluationValuePlayer = new EvaluationValue();
evaluationValuePlayer.Indexes.Add(column + (row * Width));
var evaluationValueOpponent = new EvaluationValue();
evaluationValueOpponent.Indexes.Add(column + (row * Width));
var move = moves[i];
EvaluateScan(
ref evaluationValuePlayer,
column,
row,
move[0] /* columnStep */,
move[1] /* rowStep */,
playerPiece);
EvaluateScan(
ref evaluationValueOpponent,
column,
row,
move[0] /* columnStep */,
move[1] /* rowStep */,
opponentPiece);
move = moves[i + 1];
EvaluateScan(
ref evaluationValuePlayer,
column,
row,
move[0] /* columnStep */,
move[1] /* rowStep */,
playerPiece);
EvaluateScan(
ref evaluationValueOpponent,
column,
row,
move[0] /* columnStep */,
move[1] /* rowStep */,
opponentPiece);
evaluationResult.Evaluations.Add(evaluationValuePlayer);
evaluationValueOpponent.Value = -evaluationValueOpponent.Value;
evaluationResult.Evaluations.Add(evaluationValueOpponent);
}
return(evaluationResult);
}