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feat: castle movegen

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This commit is contained in:
dogeystamp 2024-10-20 14:53:55 -04:00
parent f0f73bb656
commit 605ce75f42
2 changed files with 114 additions and 3 deletions
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10
src/lib.rs
View File

@ -425,6 +425,16 @@ impl BoardState {
&self.players[col as usize]
}
/// Get immutable reference to castling rights.
fn pl_castle(&self, col: Color) -> &CastlePlayer {
&self.castle.0[col as usize]
}
/// Get mutable reference to castling rights.
fn pl_castle_mut(&mut self, col: Color) -> &mut CastlePlayer {
&mut self.castle.0[col as usize]
}
/// Create a new piece in a location.
fn set_piece(&mut self, idx: Square, pc: ColPiece) {
let pl = self.pl_mut(pc.col);

107
src/movegen.rs
View File

@ -157,7 +157,7 @@ impl Move {
node.pos.half_moves = 0;
}
let castle = &mut node.pos.castle.0[pc_src.col as usize];
let castle = &mut node.pos.pl_castle_mut(pc_src.col);
if matches!(pc_src.pc, Piece::King) {
// forfeit castling rights
castle.k = false;
@ -389,8 +389,49 @@ impl PseudoMoveGen for BoardState {
for sq in squares!(Queen) {
move_slider(&self, sq, &mut ret, SliderDirection::Star, true);
}
for sq in squares!(King) {
move_slider(&self, sq, &mut ret, SliderDirection::Star, false);
for src in squares!(King) {
move_slider(&self, src, &mut ret, SliderDirection::Star, false);
let (r, c) = src.to_row_col();
let rights = self.pl_castle(self.turn);
let castle_sides = [(rights.k, 2, BOARD_WIDTH - 1), (rights.q, -2, 0)];
for (is_allowed, move_offset, endpoint) in castle_sides {
if !is_allowed {
continue;
}
let range = if c < endpoint {
(c + 1)..endpoint
} else {
(endpoint + 1)..c
};
debug_assert_ne!(
range.len(),
0,
"c {:?}, endpoint {:?}, range {:?}",
c,
endpoint,
range
);
let mut range_squares = range.map(|nc| Square::from_row_col(r, nc).unwrap());
debug_assert_ne!(range_squares.len(), 0);
// find first blocking piece
let is_path_blocked = range_squares.find_map(|sq| self.get_piece(sq)).is_some();
if is_path_blocked {
continue;
}
let nc: isize = c.try_into().unwrap();
let dest = Square::from_row_col_signed(r.try_into().unwrap(), nc + move_offset)
.expect("Castle destination square should be valid");
ret.push(Move {
src,
dest,
move_type: MoveType::Normal,
})
}
}
for src in squares!(Pawn) {
let (r, c) = src.to_row_col();
@ -528,6 +569,66 @@ mod tests {
MoveType::Normal,
)],
),
// white castle test (blocked)
(
"8/8/8/8/8/8/r6r/R3Kn1R w KQ - 0 1",
vec![
// NOTE: pseudo-legal e1
("a1", vec!["b1", "a2", "c1", "d1", "e1"], MoveType::Normal),
// NOTE: pseudo-legal f1
("h1", vec!["g1", "f1", "h2"], MoveType::Normal),
// NOTE: pseudo-legal d2, e2, f2, f1
(
"e1",
vec!["c1", "d1", "f1", "d2", "e2", "f2"],
MoveType::Normal,
),
],
),
// white castle test (no rights, blocked)
(
"8/8/8/8/8/8/r6r/R3Kn1R w K - 0 1",
vec![
// NOTE: pseudo-legal e1
("a1", vec!["b1", "a2", "c1", "d1", "e1"], MoveType::Normal),
// NOTE: pseudo-legal f1
("h1", vec!["g1", "f1", "h2"], MoveType::Normal),
// NOTE: pseudo-legal d2, e2, f2, f1
("e1", vec!["d1", "f1", "d2", "e2", "f2"], MoveType::Normal),
],
),
// white castle test
(
"8/8/8/8/8/8/r6r/R3K2R w KQ - 0 1",
vec![
// NOTE: pseudo-legal e1
("a1", vec!["b1", "a2", "c1", "d1", "e1"], MoveType::Normal),
// NOTE: pseudo-legal e1
("h1", vec!["g1", "f1", "e1", "h2"], MoveType::Normal),
// NOTE: pseudo-legal d2, e2, f2
(
"e1",
vec!["g1", "c1", "d1", "f1", "d2", "e2", "f2"],
MoveType::Normal,
),
],
),
// black castle test
(
"r3k2r/R6R/8/8/8/8/8/8 b kq - 0 1",
vec![
// NOTE: pseudo-legal e8
("a8", vec!["b8", "a7", "c8", "d8", "e8"], MoveType::Normal),
// NOTE: pseudo-legal e8
("h8", vec!["g8", "f8", "e8", "h7"], MoveType::Normal),
// NOTE: pseudo-legal d7, e7, f7
(
"e8",
vec!["g8", "c8", "d8", "f8", "d7", "e7", "f7"],
MoveType::Normal,
),
],
),
// horse test
(
"8/2r1r3/1n3q2/3N4/8/2p5/8/8 w - - 0 1",