Add naive pawn move generation

This commit is contained in:
Bruno BELANYI 2022-07-22 10:36:28 +02:00
parent bf23d0eaae
commit d3a84750f5
2 changed files with 140 additions and 0 deletions

View file

@ -2,4 +2,5 @@
mod bishop;
mod king;
mod knight;
mod pawn;
mod rook;

139
src/movegen/pawn.rs Normal file
View file

@ -0,0 +1,139 @@
use crate::board::{Bitboard, Color, Direction, Rank, Square};
/// Compute a pawn's movement given its color, and a set of blockers that cannot be moved past.
#[allow(unused)]
pub fn pawn_moves(color: Color, square: Square, blockers: Bitboard) -> Bitboard {
if (square.rank() == Rank::First) || (square.rank() == Rank::Eighth) {
return Bitboard::EMPTY;
}
let dir = color.forward_direction();
let first_push = dir.move_board(square.into_bitboard());
let second_push = if square.rank() == color.second_rank() {
Square::new(square.file(), color.fourth_rank()).into_bitboard()
} else {
Bitboard::EMPTY
};
if (first_push & blockers).is_empty() {
first_push | second_push
} else {
Bitboard::EMPTY
}
}
/// Computes the set of squares a pawn can capture, given its color.
#[allow(unused)]
pub fn pawn_captures(color: Color, square: Square) -> Bitboard {
if (square.rank() == Rank::First) || (square.rank() == Rank::Eighth) {
return Bitboard::EMPTY;
}
let dir = color.forward_direction();
let advanced = dir.move_board(square.into_bitboard());
let attack_west = Direction::West.move_board(advanced);
let attack_east = Direction::East.move_board(advanced);
attack_west | attack_east
}
/// Computes the set of squares that can capture this one *en-passant*.
#[allow(unused)]
pub fn en_passant_origins(square: Square) -> Bitboard {
let board = square.into_bitboard();
let origin_west = Direction::West.move_board(board);
let origin_east = Direction::East.move_board(board);
origin_west | origin_east
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn moves() {
assert_eq!(
pawn_moves(Color::White, Square::A2, Bitboard::EMPTY),
Square::A3 | Square::A4
);
assert_eq!(
pawn_moves(Color::Black, Square::A7, Bitboard::EMPTY),
Square::A5 | Square::A6
);
assert_eq!(
pawn_moves(Color::Black, Square::A2, Bitboard::EMPTY),
Square::A1.into_bitboard()
);
assert_eq!(
pawn_moves(Color::White, Square::A7, Bitboard::EMPTY),
Square::A8.into_bitboard()
);
}
#[test]
fn captures() {
assert_eq!(
pawn_captures(Color::White, Square::A2),
Square::B3.into_bitboard()
);
assert_eq!(
pawn_captures(Color::White, Square::B2),
Square::A3 | Square::C3
);
assert_eq!(
pawn_captures(Color::White, Square::H2),
Square::G3.into_bitboard()
);
assert_eq!(
pawn_captures(Color::Black, Square::A2),
Square::B1.into_bitboard()
);
assert_eq!(
pawn_captures(Color::Black, Square::B2),
Square::A1 | Square::C1
);
assert_eq!(
pawn_captures(Color::Black, Square::H2),
Square::G1.into_bitboard()
);
assert_eq!(
pawn_captures(Color::White, Square::A7),
Square::B8.into_bitboard()
);
assert_eq!(
pawn_captures(Color::White, Square::B7),
Square::A8 | Square::C8
);
assert_eq!(
pawn_captures(Color::Black, Square::H7),
Square::G6.into_bitboard()
);
assert_eq!(
pawn_captures(Color::Black, Square::A7),
Square::B6.into_bitboard()
);
assert_eq!(
pawn_captures(Color::Black, Square::B7),
Square::A6 | Square::C6
);
assert_eq!(
pawn_captures(Color::Black, Square::H7),
Square::G6.into_bitboard()
);
}
#[test]
fn en_passant() {
assert_eq!(en_passant_origins(Square::A4), Square::B4.into_bitboard());
assert_eq!(en_passant_origins(Square::A5), Square::B5.into_bitboard());
assert_eq!(en_passant_origins(Square::B4), Square::A4 | Square::C4);
assert_eq!(en_passant_origins(Square::B5), Square::A5 | Square::C5);
assert_eq!(en_passant_origins(Square::H4), Square::G4.into_bitboard());
assert_eq!(en_passant_origins(Square::H5), Square::G5.into_bitboard());
}
}