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refactor: en passant target square calculation

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This commit is contained in:
dogeystamp 2024-10-04 23:00:58 -04:00
parent ecda71f176
commit 4acdf8063e
1 changed files with 22 additions and 22 deletions
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44
src/movegen.rs
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@ -110,19 +110,25 @@ impl Move {
MoveType::Normal => {
let pc_src = pc_src!(self);
pc_asserts!(pc_src, self);
let pc_dest: Option<ColPiece> = node.pos.get_piece(self.dest);
if matches!(pc_src.pc, Piece::Pawn) {
// pawn moves are irreversible
node.pos.half_moves = 0;
// en-passant
if self.src.0 + (BOARD_WIDTH) * 2 == self.dest.0 {
let (src_row, src_col) = self.src.to_row_col();
let (dest_row, dest_col) = self.dest.to_row_col();
// set en-passant target square
if src_row.abs_diff(dest_row) == 2 {
let new_idx = match pc_src.col {
Color::White => { self.src.0 + BOARD_WIDTH },
Color::Black => { self.src.0 - BOARD_WIDTH },
};
node.pos.ep_square = Some(
Square::try_from(self.src.0 + BOARD_WIDTH)
.expect("En-passant target should be valid."),
)
} else if self.dest.0 + (BOARD_WIDTH) * 2 == self.src.0 {
node.pos.ep_square = Some(
Square::try_from(self.src.0 - BOARD_WIDTH)
// TODO: fix the en passant targetsquare
Square::try_from(new_idx)
.expect("En-passant target should be valid."),
)
} else {
@ -133,6 +139,11 @@ impl Move {
node.pos.ep_square = None;
}
if pc_dest.is_some() {
// captures are irreversible
node.pos.half_moves = 0;
}
let castle = &mut node.pos.castle.0[pc_src.col as usize];
// forfeit castling rights
if matches!(pc_src.pc, Piece::King) {
@ -157,11 +168,6 @@ impl Move {
}
}
if let Some(_pc_dest) = node.pos.get_piece(self.dest) {
// captures are irreversible
node.pos.half_moves = 0;
}
node.pos.del_piece(self.src);
node.pos.set_piece(self.dest, pc_src);
}
@ -243,7 +249,7 @@ impl FromUCIAlgebraic for Move {
#[cfg(test)]
mod tests {
use super::*;
use crate::fen::{START_POSITION, ToFen};
use crate::fen::{ToFen, START_POSITION};
/// Test that make move and unmake move work as expected.
///
@ -321,14 +327,8 @@ mod tests {
(
"4k3/6P1/8/8/8/8/1p6/4K3 w - - 0 1",
vec![
(
"g7g8n",
"4k1N1/8/8/8/8/8/1p6/4K3 b - - 0 1",
),
(
"b2b1q",
"4k1N1/8/8/8/8/8/8/1q2K3 w - - 0 2",
),
("g7g8n", "4k1N1/8/8/8/8/8/1p6/4K3 b - - 0 1"),
("b2b1q", "4k1N1/8/8/8/8/8/8/1q2K3 w - - 0 2"),
],
),
];