/// <summary>
/// Calculates attacks for the specified piece.
/// </summary>
/// <param name="pieceBitboard">The bitboard with set bit at piece position.</param>
/// <param name="excludedFields">The bitboard with excluded fields from attacks calculating.</param>
/// <param name="opt">The generator parameters.</param>
private static void CalculateAttacks(ulong pieceBitboard, ulong excludedFields, GeneratorParameters opt)
{
if ((opt.Mode & GeneratorMode.CalculateAttacks) == 0)
{
return;
}
var blockersToRemove = opt.Bitboard.Pieces[FastArray.GetPieceIndex(opt.FriendlyColor, PieceType.Rook)] |
opt.Bitboard.Pieces[FastArray.GetPieceIndex(opt.FriendlyColor, PieceType.Queen)];
var occupancyWithoutBlockers = opt.OccupancySummary & ~blockersToRemove;
var pieceIndex = BitOperations.GetBitIndex(pieceBitboard);
var pattern = MagicContainer.GetRookAttacks(pieceIndex, occupancyWithoutBlockers);
pattern ^= excludedFields;
while (pattern != 0)
{
var patternLSB = BitOperations.GetLSB(pattern);
pattern = BitOperations.PopLSB(pattern);
var patternIndex = BitOperations.GetBitIndex(patternLSB);
opt.Bitboard.Attacks[patternIndex] |= pieceBitboard;
opt.Bitboard.AttacksSummary[(int)opt.FriendlyColor] |= patternLSB;
}
}
/// <summary>
/// Calculates moves for the specified piece.
/// </summary>
/// <param name="pieceType">The piece type.</param>
/// <param name="pieceBitboard">The bitboard with set bit at piece position.</param>
/// <param name="opt">The generator parameters.</param>
/// <returns>The bitboard with available moves for the specified piece.</returns>
private static ulong CalculateMoves(PieceType pieceType, ulong pieceBitboard, GeneratorParameters opt)
{
if ((opt.Mode & GeneratorMode.CalculateMoves) == 0)
{
return(0);
}
var pieceIndex = BitOperations.GetBitIndex(pieceBitboard);
var piecePosition = BitPositionConverter.ToPosition(pieceIndex);
var pattern = MagicContainer.GetRookAttacks(pieceIndex, opt.OccupancySummary);
pattern &= ~opt.FriendlyOccupancy;
if (opt.QuiescenceSearch)
{
pattern &= opt.EnemyOccupancy;
}
var excludeFromAttacks = pattern;
while (pattern != 0)
{
var patternLSB = BitOperations.GetLSB(pattern);
pattern = BitOperations.PopLSB(pattern);
var patternIndex = BitOperations.GetBitIndex(patternLSB);
var to = BitPositionConverter.ToPosition(patternIndex);
if ((patternLSB & opt.EnemyOccupancy) == 0)
{
opt.Bitboard.Moves.AddLast(new QuietMove(piecePosition, to, pieceType, opt.FriendlyColor));
}
else
{
opt.Bitboard.Moves.AddLast(new KillMove(piecePosition, to, pieceType, opt.FriendlyColor));
}
if ((opt.Mode & GeneratorMode.CalculateAttacks) != 0)
{
opt.Bitboard.Attacks[patternIndex] |= pieceBitboard;
opt.Bitboard.AttacksSummary[(int)opt.FriendlyColor] |= patternLSB;
}
}
return(excludeFromAttacks);
}