private void PawnMoves(ref List <Move> list, BitBoard active)
{
int direction = player ? -1 : 1;
//moving 1
BitBoard finalPos = active.Offset(0, direction) & ~AllPieces;
list.AddRange(Move.GetMoves(Category.Pawn, 0, direction, finalPos, false));
//moving 2
finalPos.Move(0, direction);
list.AddRange(Move.GetMoves(Category.Pawn, 0, direction * 2, finalPos & ~AllPieces & (player ? BlackPawns : WhitePawns), false));
//kill right
finalPos = active.Offset(1, direction);
list.AddRange(Move.GetMoves(Category.Pawn, 1, direction, finalPos & (player ? white : black), true));
//kill left
finalPos = active.Offset(-1, direction);
list.AddRange(Move.GetMoves(Category.Pawn, -1, direction, finalPos & (player ? white : black), true));
//en passant
if (lastMove.Category == Category.Pawn && Math.Abs(lastMove.Start.Y - lastMove.End.Y) == 2)
{
//kill right
finalPos = active.Offset(1, direction) & new BitBoard(lastMove.End).Offset(0, direction);
list.AddRange(Move.GetMoves(Category.Pawn, 1, direction, finalPos, true));
//kill left
finalPos = active.Offset(-1, direction) & new BitBoard(lastMove.End).Offset(0, direction);
list.AddRange(Move.GetMoves(Category.Pawn, -1, direction, finalPos, true));
}
}
//private functions
private void TryMoveOrKill(ref List <Move> list, ref BitBoard active, int dx, int dy, Category c)
{
if (!active.Empty)
{
BitBoard coll, move, finalPos;
//pieces that are out of bounce are no more active
active.Move(dx, dy); active.Move(-dx, -dy);
finalPos = active.Offset(dx, dy);
//marks all collisions points
coll = finalPos & AllPieces;
if (!coll.Empty)
{
//are there pieces that dont collide?
if (coll != finalPos)
{ //add all pieces that are active and dont collide
list.AddRange(Move.GetMoves(c, dx, dy, finalPos & ~coll, false));
//remove all not colliding pieces from collider
coll.RemoveAt(finalPos & ~coll);
}
//colliding with opposite color?
move = coll & (player ? white : black);
if (!move.Empty)
{
//adding all pieces that kill another
list.AddRange(Move.GetMoves(c, dx, dy, move, true));
//pieces that collide here are no more active
active.RemoveAt(move.Offset(-dx, -dy));
}
//pieces that collide with the same color are no more active
active.RemoveAt((coll & (player ? black : white)).Offset(-dx, -dy));
}
else
{
list.AddRange(Move.GetMoves(c, dx, dy, finalPos, false)); //no collision at all
}
}
}