2025-02-06 18:34:54 +01:00

82 lines
2.9 KiB
C++

#include "../board/board.hpp"
#include "../utils/coords.hpp"
#include "../utils/move.hpp"
#include "piece.hpp"
std::vector<Move> pawn_moves(const Board& b, const Coords xy) {
std::vector<Move> ret{};
Colour my_colour = b.colour_at(xy);
// -- Capture to the left
if (xy.x > 0) {
int dy = my_colour == Colour::White ? 1 : -1;
Coords left{xy.x - 1, xy.y + dy};
int8_t capturable_piece = b.squares[left.to_index()];
if (capturable_piece != 0 && my_colour != b.colour_at(left)) {
if ((my_colour == White && left.y == 7)
|| (my_colour == Black && left.y == 0))
for (auto piece : {Rook, Knigt, Bishop, Queen})
ret.push_back(Move{
xy.to_index(),
left.to_index(),
(int8_t) (my_colour | piece)
});
else
ret.push_back(Move{xy.to_index(), left.to_index()});
}
}
// -- Capture to the right
if (xy.x < 7) {
int dy = my_colour == Colour::White ? 1 : -1;
Coords right{xy.x + 1, xy.y + dy};
int8_t capturable_piece = b.squares[right.to_index()];
if (capturable_piece != 0 && my_colour != b.colour_at(right)) {
if ((my_colour == White && right.y == 7)
|| (my_colour == Black && right.y == 0))
for (auto piece : {Rook, Knigt, Bishop, Queen})
ret.push_back(Move{
xy.to_index(),
right.to_index(),
(int8_t) (my_colour | piece)
});
else
ret.push_back(Move{xy.to_index(), right.to_index()});
}
}
// -- Capture en passant
if (b.en_passant_target != -1) {
Coords c = Coords::from_index(b.en_passant_target);
int dy = my_colour == Colour::White ? 1 : -1;
if (c.y == xy.y + dy && (c.x == xy.x - 1 || c.x == xy.x + 1))
ret.push_back(Move{xy.to_index(), c.to_index()});
}
// -- Normal move + promotion
bool is_on_starting_rank =
my_colour == Colour::White ? xy.y == 1 : xy.y == 6;
int max_dy = is_on_starting_rank ? 3 : 2;
for (int dy = 1; dy < max_dy; dy++) {
int actual_dy = my_colour == Colour::White ? dy : -dy;
Coords new_xy{xy.x, xy.y + actual_dy};
if (b.squares[new_xy.to_index()] != Piece::None)
break;
if (new_xy.y == 7 || new_xy.y == 0)
for (auto piece : {Rook, Knigt, Bishop, Queen})
ret.push_back(Move{
xy.to_index(),
new_xy.to_index(),
.promoting_to = (int8_t) (my_colour | piece)
});
else
ret.push_back(Move{
xy.to_index(),
new_xy.to_index(),
});
}
return ret;
}