/// <summary>
/// Checks if the current state of the game has potential for
/// Zugzwang. A zugzwang is a position where you are fine if you don't move, but
/// your position collapses if you are forced to move. We simply detect this by
/// checking if we are in an endgame.
/// </summary>
/// <param name="board">board to check.</param>
/// <returns>True if we are in an endgame and there is possabilety of zugzwang.</returns>
private bool ColorToPlayZugzwang(Board board)
{
switch (board.State.ColorToPlay)
{
case PieceColor.White:
{
int score = 0;
foreach (Square square in board.WhitePieceLocations)
{
if (board[square] == Piece.WhiteRook || board[square] == Piece.WhiteBishop ||
board[square] == Piece.WhiteKnight || board[square] == Piece.WhiteQueen)
{
score += m_evaluator.PieceValue(board[square]);
if (score > m_evaluator.PieceValue(Piece.WhiteRook))
{
return(false);
}
}
}
}
break;
case PieceColor.Black:
{
int score = 0;
foreach (Square square in board.BlackPieceLocations)
{
if (board[square] == Piece.BlackRook || board[square] == Piece.BlackBishop ||
board[square] == Piece.BlackKnight || board[square] == Piece.BlackQueen)
{
score += m_evaluator.PieceValue(board[square]);
if (score > m_evaluator.PieceValue(Piece.BlackRook))
{
return(false);
}
}
}
}
break;
}
return(true);
}
public int Compare(Move x, Move y)
{
if (x.IsCaptureMove && !y.IsCaptureMove)
{
return(-1);
}
if (!x.IsCaptureMove && y.IsCaptureMove)
{
return(1);
}
if (x.IsCaptureMove && y.IsCaptureMove)
{
int xCaptureVal = m_evaluator.PieceValue(x.Capture);
int yCaptureVal = m_evaluator.PieceValue(y.Capture);
if (xCaptureVal > yCaptureVal)
{
return(-1);
}
if (xCaptureVal < yCaptureVal)
{
return(1);
}
int xAttackerVal = m_evaluator.PieceValue(x.Piece);
int yAttackerVal = m_evaluator.PieceValue(y.Piece);
if (xAttackerVal < yAttackerVal)
{
return(-1);
}
if (xAttackerVal > yAttackerVal)
{
return(1);
}
}
//TODO: Also sort according to pawn promotion moves.
return(0);
}