Fix bug with move generation jumps

4 files changed, 41 insertions, 19 deletions

diff --git a/model/benches/bitboard.rs b/model/benches/bitboard.rs
index 7f64f2e..18d1a84 100644
--- a/model/benches/bitboard.rs
+++ b/model/benches/bitboard.rs
@@ -5,7 +5,7 @@ use std::hash::Hash;
 
 fn clone(c: &mut Criterion) {
 	let board = CheckersBitBoard::starting_position();
-	c.bench_function("clone", |b| b.iter(|| black_box(board.clone())));
+	c.bench_function("clone", |b| b.iter(|| black_box(board)));
 }
 
 fn hash(c: &mut Criterion) {
diff --git a/model/src/board.rs b/model/src/board.rs
index 1cc8d1c..7d61779 100644
--- a/model/src/board.rs
+++ b/model/src/board.rs
@@ -23,13 +23,13 @@ mod tests;
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct CheckersBitBoard {
 	/// If the space contains a piece, it's a 1
-	pieces: u32,
+	pub pieces: u32,
 	/// If the piece is black, 1, otherwise 0
-	color: u32,
+	pub color: u32,
 	/// 1 if the piece is a king
-	kings: u32,
+	pub kings: u32,
 	/// The player who has the next turn
-	turn: PieceColor,
+	pub turn: PieceColor,
 }
 
 impl Default for CheckersBitBoard {
diff --git a/model/src/board/tests.rs b/model/src/board/tests.rs
index c3ea2cd..f1009e7 100644
--- a/model/src/board/tests.rs
+++ b/model/src/board/tests.rs
@@ -127,7 +127,7 @@ proptest! {
 			kings: k,
 			turn: PieceColor::Dark
 		};
-		unsafe {board.move_piece_to_unchecked(s, e)};
+		let _ = unsafe {board.move_piece_to_unchecked(s, e)};
 	}
 
 	#[test]
@@ -136,7 +136,7 @@ proptest! {
 			let board = CheckersBitBoard {
 				pieces: p, color: c, kings: k, turn: PieceColor::Dark
 			};
-			unsafe {board.move_piece_forward_unchecked(v, a)};
+			let _ = unsafe {board.move_piece_forward_unchecked(v, a)};
 		}
 	}
 
@@ -145,7 +145,7 @@ proptest! {
 		let board = CheckersBitBoard {
 			pieces: p, color: c, kings: k, turn: PieceColor::Dark
 		};
-		unsafe {board.move_piece_backward_unchecked(v, a)};
+		let _ = unsafe {board.move_piece_backward_unchecked(v, a)};
 	}
 
 	#[test]
@@ -378,8 +378,8 @@ fn test_king_at_unchecked_one_king() {
 #[test]
 fn test_default_bitboard() {
 	let board = CheckersBitBoard::default();
-	let exemptions = vec![2, 28, 22, 16, 27, 21, 15, 9];
-	let black = vec![18, 12, 6, 0, 19, 13, 7, 1, 26, 20, 14, 8];
+	let exemptions = [2, 28, 22, 16, 27, 21, 15, 9];
+	let black = [18, 12, 6, 0, 19, 13, 7, 1, 26, 20, 14, 8];
 
 	for i in 0..32 {
 		if !exemptions.contains(&i) {
diff --git a/model/src/possible_moves.rs b/model/src/possible_moves.rs
index 5140bb7..9f9f5af 100644
--- a/model/src/possible_moves.rs
+++ b/model/src/possible_moves.rs
@@ -379,7 +379,6 @@ impl IntoIterator for PossibleMoves {
 impl PossibleMoves {
 	// TODO test
 	const fn slides_dark(board: CheckersBitBoard) -> Self {
-		// TODO maybe remove these?
 		const FORWARD_LEFT_MASK: u32 = 0b01111001111110111111001111011011;
 		const FORWARD_RIGHT_MASK: u32 = 0b01111101111111011111010111011101;
 		const BACKWARD_LEFT_MASK: u32 = 0b11111011111110111110101110111010;
@@ -389,14 +388,18 @@ impl PossibleMoves {
 		let friendly_pieces = board.pieces_bits() & board.color_bits();
 		let friendly_kings = friendly_pieces & board.king_bits();
 
-		let forward_left_movers = not_occupied.rotate_right(7) & friendly_pieces;
-		let forward_right_movers = not_occupied.rotate_right(1) & friendly_pieces;
+		let forward_left_movers =
+			not_occupied.rotate_right(7) & friendly_pieces & FORWARD_LEFT_MASK;
+		let forward_right_movers =
+			not_occupied.rotate_right(1) & friendly_pieces & FORWARD_RIGHT_MASK;
 		let backward_left_movers;
 		let backward_right_movers;
 
 		if friendly_kings > 0 {
-			backward_left_movers = not_occupied.rotate_left(1) & friendly_kings;
-			backward_right_movers = not_occupied.rotate_left(7) & friendly_kings;
+			backward_left_movers =
+				not_occupied.rotate_left(1) & friendly_kings & BACKWARD_LEFT_MASK;
+			backward_right_movers =
+				not_occupied.rotate_left(7) & friendly_kings & BACKWARD_RIGHT_MASK;
 		} else {
 			backward_left_movers = 0;
 			backward_right_movers = 0;
@@ -420,14 +423,17 @@ impl PossibleMoves {
 		let friendly_pieces = board.pieces_bits() & !board.color_bits();
 		let friendly_kings = friendly_pieces & board.king_bits();
 
-		let backward_left_movers = not_occupied.rotate_left(1) & friendly_pieces;
-		let backward_right_movers = not_occupied.rotate_left(7) & friendly_pieces;
+		let backward_left_movers =
+			not_occupied.rotate_left(1) & friendly_pieces & BACKWARD_LEFT_MASK;
+		let backward_right_movers =
+			not_occupied.rotate_left(7) & friendly_pieces & BACKWARD_RIGHT_MASK;
 		let forward_left_movers;
 		let forward_right_movers;
 
 		if friendly_kings > 0 {
-			forward_left_movers = not_occupied.rotate_right(7) & friendly_kings;
-			forward_right_movers = not_occupied.rotate_right(1) & friendly_kings;
+			forward_left_movers = not_occupied.rotate_right(7) & friendly_kings & FORWARD_LEFT_MASK;
+			forward_right_movers =
+				not_occupied.rotate_right(1) & friendly_kings & FORWARD_RIGHT_MASK;
 		} else {
 			forward_left_movers = 0;
 			forward_right_movers = 0;
@@ -1019,6 +1025,22 @@ mod tests {
 	}
 
 	#[test]
+	fn cant_jump_in_position_2_without_26() {
+		// This bug was bizarre, but it's caused by a white piece being in the
+		//second bit while there is no piece in the 26th bit. If you don't
+		// apply the bit mask for collision detection, then all of the light
+		// player moves become jumps.
+		let board = CheckersBitBoard {
+			pieces: 16908890,
+			color: 401395713,
+			kings: 50332352,
+			turn: PieceColor::Light,
+		};
+		let possible_moves = PossibleMoves::moves(board);
+		assert!(!possible_moves.can_jump())
+	}
+
+	#[test]
 	fn test_send() {
 		fn assert_send<T: Send>() {}
 		assert_send::<PossibleMoves>();