reimplement marble behavior, making it more consistent in different directions. Triggers no longer activate from blocked marbles, and bounces take the same amount of time to travel through a chain of marbles in all directions

README.md

@@ -4,10 +4,12 @@
 logic mostly like https://git.crispypin.cc/CrispyPin/marble
 
 ## todo
-make marble movement not order-dependent (`>ooo <` does not behave symmetrically)
+(more levels)
+story/lore
 blueprints
 scroll level list
-
+should the output tile consume marbles like the bag instead of needing power? then input and output could be merged to one tile type
+make marble movement more consistent (`>o o<` depends on internal marble order)
 decide on marble data size (u32 or byte?)
 blueprint rotation
 

src/marble_engine.rs

@@ -108,110 +108,179 @@ impl Machine {
 				}
 			}
 		}
-		let mut to_remove = Vec::new();
-		let mut triggers = Vec::new();
-		for i in 0..self.marbles.len() {
-			let marble_pos = self.marbles[i];
-			let tile = self.board.get_or_blank(marble_pos);
 
-			let Tile::Marble { value, dir } = tile else {
-				continue;
+		#[derive(Debug, Clone, Copy)]
+		enum Event {
+			Stay,
+			/// (new_pos, new_dir)
+			MoveTo(Pos, Direction),
+			/// (new_pos, new_dir, trigger_pos)
+			Trigger(Pos, Direction, Pos),
+			/// (other, new_dir)
+			/// other marble should be set to reverse of new_dir
+			/// and should be cancelled if it had a movement event planned
+			Bounce(usize, Direction),
+			Remove,
+		}
+
+		let mut marble_events: Vec<Event> = self
+			.marbles
+			.iter()
+			.map(|&pos| {
+				let marble = self.board.get(pos).unwrap();
+				let Tile::Marble { value: _, dir } = marble else {
+					panic!("broken marble");
 				};
-			let next_pos = dir.step(marble_pos);
-			if !self.board.pos_in_bounds(next_pos) {
-				continue;
-			}
-			let mut new_tile = None;
-			let Some(target) = self.board.get_mut(next_pos) else {
-				continue;
+				let front_pos = dir.step(pos);
+				let Some(front_tile) = self.board.get(front_pos) else {
+					return Event::Stay;
 				};
-			match target {
-				Tile::Blank => {
-					*target = tile;
-					self.marbles[i] = next_pos;
-					new_tile = Some(Tile::Blank);
-				}
-				Tile::Digit(d) => {
-					let new_val = value.wrapping_mul(10).wrapping_add(*d as MarbleValue);
-					*target = Tile::Marble {
-						value: new_val,
-						dir,
-					};
-					self.marbles[i] = next_pos;
-					new_tile = Some(Tile::Blank);
-				}
-				Tile::Powerable(PTile::Bag, _) => {
-					to_remove.push(i);
-					new_tile = Some(Tile::Blank);
-				}
-				Tile::Marble {
-					value: _other_value,
-					dir: other_dir,
-				} => {
-					// bounce off other marbles
-					if *other_dir != dir {
-						new_tile = Some(Tile::Marble {
-							value,
-							dir: dir.opposite(),
-						});
-						*other_dir = dir;
-					}
-				}
-				Tile::Powerable(PTile::Trigger, state) => {
-					// triggers activate even if the marble can't move past it
-					// making it stay on permanently (or until the marble is knocked away)
-					*state = true;
-					triggers.push(next_pos);
-					let far_pos = dir.step(next_pos);
-					if let Some(target) = self.board.get_blank_mut(far_pos) {
-						*target = tile;
-						self.marbles[i] = far_pos;
-						new_tile = Some(Tile::Blank);
-					}
-				}
-				Tile::Arrow(arrow_dir) => {
-					let far_pos = arrow_dir.step(next_pos);
-					let arrow_dir = *arrow_dir;
-					if let Some(target) = self.board.get_blank_mut(far_pos) {
-						self.marbles[i] = far_pos;
-						*target = Tile::Marble {
-							value,
-							dir: arrow_dir,
-						};
-						new_tile = Some(Tile::Blank);
-					} else if far_pos == marble_pos {
-						// always bounce on reverse arrow
-						new_tile = Some(Tile::Marble {
-							value,
-							dir: dir.opposite(),
-						});
-					}
+
+				if let Tile::Powerable(PTile::Bag, _) = front_tile {
+					return Event::Remove;
 				}
+
+				let can_move_to = |tile| matches!(tile, Some(Tile::Blank | Tile::Digit(_)));
+
+				let can_move_over = |tile| match tile {
 					Tile::Mirror(mirror) => {
 						let new_dir = mirror.new_dir(dir);
-					let far_pos = new_dir.step(next_pos);
-					if let Some(far_target) = self.board.get_blank_mut(far_pos) {
-						*far_target = Tile::Marble {
+						let target_pos = new_dir.step(front_pos);
+						let target = self.board.get(target_pos);
+						if can_move_to(target) {
+							Some((target_pos, new_dir))
+						} else {
+							None
+						}
+					}
+					Tile::Arrow(new_dir) => {
+						let target_pos = new_dir.step(front_pos);
+						let target = self.board.get(target_pos);
+						if target_pos == pos || can_move_to(target) {
+							Some((target_pos, new_dir))
+						} else {
+							None
+						}
+					}
+					_ => None,
+				};
+
+				if can_move_to(Some(front_tile)) {
+					Event::MoveTo(front_pos, dir)
+				} else if let Tile::Powerable(PTile::Trigger, _) = front_tile {
+					let target_pos = dir.step(front_pos);
+					let target = self.board.get(target_pos);
+					if can_move_to(target) {
+						Event::Trigger(target_pos, dir, front_pos)
+					} else {
+						Event::Stay
+					}
+				} else if let Some((new_pos, new_dir)) = can_move_over(front_tile) {
+					Event::MoveTo(new_pos, new_dir)
+				} else if let Tile::Marble {
+					value: _,
+					dir: other_dir,
+				} = front_tile
+				{
+					if other_dir != dir {
+						Event::Bounce(
+							self.marbles.iter().position(|m| m == &front_pos).unwrap(),
+							dir.opposite(),
+						)
+					} else {
+						Event::Stay
+					}
+				} else {
+					Event::Stay
+				}
+			})
+			.collect();
+
+		// resolve bounces
+		for i in 0..marble_events.len() {
+			let event = marble_events[i];
+			if let Event::Bounce(other_index, dir) = event {
+				match marble_events[other_index] {
+					// cancel bounces on marble that are about to disappear
+					Event::Remove => {
+						marble_events[i] = Event::MoveTo(self.marbles[other_index], dir.opposite())
+					}
+					// let already bouncing marbles continue
+					Event::Bounce(_, _) => (),
+					// interrupt any other movement/staying to bounce
+					_ => marble_events[other_index] = Event::Bounce(i, dir.opposite()),
+				}
+			}
+		}
+
+		// resolve deletions of tiles
+		for (i, event) in marble_events.iter().enumerate() {
+			if let Event::Remove = event {
+				self.board.set(self.marbles[i], Tile::Blank);
+			}
+		}
+
+		// resolve triggers
+		let mut triggers_activated = Vec::new();
+		for event in &mut marble_events {
+			if let Event::Trigger(new_pos, dir, trigger_pos) = event {
+				triggers_activated.push(*trigger_pos);
+				*event = Event::MoveTo(*new_pos, *dir);
+			}
+		}
+
+		// resolve collisions (multiple marbles entering the same space)
+		for i in 0..(marble_events.len() - 1) {
+			let event = marble_events[i];
+			if let Event::MoveTo(new_pos, _dir) = event {
+				for other_event in &mut marble_events[(i + 1)..] {
+					if let Event::MoveTo(other_pos, _other_dir) = other_event {
+						// todo: maybe sort by direction so the sucessful direction is consistent
+						if other_pos == &new_pos {
+							*other_event = Event::Stay;
+						}
+					}
+				}
+			}
+		}
+
+		// resolve movement
+		for (i, &event) in marble_events.iter().enumerate() {
+			if let Event::Remove = event {
+				continue;
+			}
+			let marble = self.board.get_mut(self.marbles[i]).unwrap();
+			let Tile::Marble { value, dir } = marble else {
+				panic!("invalid marble");
+			};
+			match event {
+				Event::MoveTo(new_pos, new_dir) => {
+					let mut value = *value;
+					self.board.set(self.marbles[i], Tile::Blank);
+					self.marbles[i] = new_pos;
+					let new_tile = self.board.get_mut(new_pos).unwrap();
+					if let Tile::Digit(n) = new_tile {
+						value = value.wrapping_mul(10).wrapping_add(*n as MarbleValue);
+					}
+					*new_tile = Tile::Marble {
 						value,
 						dir: new_dir,
 					};
-						self.marbles[i] = far_pos;
-						new_tile = Some(Tile::Blank);
-					}
 				}
+				Event::Bounce(_other, new_dir) => *dir = new_dir,
 				_ => (),
 			}
+		}
 
-			if let Some(t) = new_tile {
-				*self.board.get_mut(marble_pos).unwrap() = t;
+		// resolve deletions of marbles
+		for (i, event) in marble_events.iter().enumerate().rev() {
+			if let Event::Remove = event {
+				self.marbles.remove(i);
 			}
 		}
-		let mut offset = 0;
-		for i in to_remove {
-			self.marbles.remove(i - offset);
-			offset += 1;
-		}
-		for pos in triggers {
+
+		// process triggers
+		for pos in triggers_activated {
 			for dir in Direction::ALL {
 				self.propagate_power(dir, dir.step(pos));
 			}

src/marble_engine/board.rs

@@ -118,10 +118,6 @@ impl Board {
 		sum
 	}
 
-	pub fn pos_in_bounds(&self, p: Pos) -> bool {
-		self.in_bounds(p)
-	}
-
 	fn in_bounds(&self, p: Pos) -> bool {
 		p.x >= 0 && p.y >= 0 && p.x < self.width as isize && p.y < self.height as isize
 	}

src/solution.rs

@@ -10,7 +10,7 @@ use crate::{level::Level, userdata_dir};
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Solution {
 	solution_id: String,
-	level_id: String, // redundant?
+	level_id: String,
 	pub name: String,
 	pub board: String,
 	#[serde(default)]