fix: character ordering

src/game.rs

@@ -13,6 +13,7 @@ use bevy::{
 };
 use bevy_rapier2d::prelude::*;
 use rapier2d::geometry::CollisionEventFlags;
+use std::collections::BTreeSet;
 
 pub enum AudioMsg {
 	Color([f32; 3]),
@@ -33,6 +34,7 @@ impl Plugin for GamePlugin {
 		app.add_event::<LevelStartupEvent>()
 			.init_resource::<CharacterMeshes>()
 			.insert_resource(CurrentLevel(None))
+			.init_resource::<CharacterList>()
 			.add_system_set(SystemSet::on_enter(AppState::Game).with_system(setup))
 			.add_system_set(SystemSet::on_enter(AppState::Win).with_system(win_setup))
 			.add_system_set(
@@ -67,6 +69,9 @@ pub struct LevelStartupEvent;
 
 pub struct CurrentLevel(pub Option<LevelId>);
 
+#[derive(Default)]
+pub struct CharacterList(pub BTreeSet<Entity>);
+
 pub struct CharacterMeshes {
 	square: Mesh2dHandle,
 }
@@ -125,6 +130,7 @@ pub fn spawn_characters<I: IntoIterator<Item = (Transform, Color)>>(
 	character_meshes: &Res<CharacterMeshes>,
 	materials: &mut ResMut<Assets<ColorMaterial>>,
 	audio: &Res<crossbeam_channel::Sender<AudioMsg>>,
+	character_list: &mut ResMut<CharacterList>,
 
 	characters: I,
 ) {
@@ -134,6 +140,7 @@ pub fn spawn_characters<I: IntoIterator<Item = (Transform, Color)>>(
 			character_meshes,
 			materials,
 			audio,
+			character_list,
 			transform,
 			color,
 			i == 0,
@@ -146,6 +153,7 @@ pub fn spawn_character(
 	character_meshes: &Res<CharacterMeshes>,
 	materials: &mut ResMut<Assets<ColorMaterial>>,
 	audio: &Res<crossbeam_channel::Sender<AudioMsg>>,
+	character_list: &mut ResMut<CharacterList>,
 	mut transform: Transform,
 	color: Color,
 	is_player: bool,
@@ -185,6 +193,8 @@ pub fn spawn_character(
 			.insert(CollisionCount(0));
 		});
 
+	character_list.0.insert(entity_commands.id());
+
 	if is_player {
 		entity_commands.insert(Player);
 		audio
@@ -273,6 +283,7 @@ fn collision_event_system(
 	mut collision_counter_query: Query<&mut CollisionCount>,
 	mut app_state: ResMut<State<AppState>>,
 	audio: Res<crossbeam_channel::Sender<AudioMsg>>,
+	mut character_list: ResMut<CharacterList>,
 ) {
 	for collision_event in collision_events.iter() {
 		match collision_event {
@@ -283,6 +294,8 @@ fn collision_event_system(
 						Ok((c2_color, c2_transform, _c2_material, c2_player)),
 					) = (character_query.get(*e1), character_query.get(*e2))
 					{
+						character_list.0.remove(e1);
+						character_list.0.remove(e2);
 						commands.entity(*e1).despawn_recursive();
 						commands.entity(*e2).despawn_recursive();
 
@@ -301,6 +314,7 @@ fn collision_event_system(
 							&character_meshes,
 							&mut materials,
 							&audio,
+							&mut character_list,
 							if c1_player.is_some() {
 								*c1_transform
 							} else if c2_player.is_some() {
@@ -404,41 +418,32 @@ fn change_character_system(
 	keyboard_input: Res<Input<KeyCode>>,
 	characters: Query<(Entity, &CharacterColor, Option<&Player>)>,
 	audio: Res<crossbeam_channel::Sender<AudioMsg>>,
+	character_list: Res<CharacterList>,
 ) {
 	if !keyboard_input.just_pressed(KeyCode::Tab) {
 		return;
 	}
 
-	let mut player_idx: usize = 0;
-	let mut player_count: usize = 0;
-
-	// find player idx
-	for (_entity, _color, player) in characters.iter() {
-		if player.is_some() {
-			player_idx = player_count;
-		}
-		player_count += 1;
-	}
-
-	// calculate next player index
-	let next_player_idx = (player_idx + 1) % player_count;
-	player_count = 0;
-
-	// exchange `Player` component from old `player_idx` to new `next_player_idx`
-	for (entity, color, _player) in characters.iter() {
-		if player_count == player_idx {
-			commands.entity(entity).remove::<Player>();
-		}
-
-		if player_count == next_player_idx {
-			commands.entity(entity).insert(Player);
+	if let Some((player_entity, _color, _)) = characters
+		.iter()
+		.find(|(_entity, _color, player)| player.is_some())
+		.or_else(|| characters.iter().next())
+	{
+		commands.entity(player_entity).remove::<Player>();
+		if let Some(new_player_entity) = character_list
+			.0
+			.range(player_entity..)
+			.nth(1)
+			.or_else(|| character_list.0.iter().next())
+		{
+			commands.entity(*new_player_entity).insert(Player);
+			if let Ok((_entity, color, _player)) = characters.get(*new_player_entity) {
 				audio
 					.send(AudioMsg::Color([color.0.r(), color.0.g(), color.0.b()]))
 					.ok();
 				audio.send(AudioMsg::Switch).ok();
 			}
-
-		player_count += 1;
+		}
 	}
 }
 
@@ -557,6 +562,7 @@ fn level_keyboard_system(
 	mut level_startup_event: EventWriter<LevelStartupEvent>,
 	mut camera_query: Query<&mut Transform, With<Camera>>,
 	keyboard_input: Res<Input<KeyCode>>,
+	mut character_list: ResMut<CharacterList>,
 	level_query: Query<Entity, With<Level>>,
 	mut app_state: ResMut<State<AppState>>,
 ) {
@@ -568,6 +574,7 @@ fn level_keyboard_system(
 	}
 
 	if keyboard_input.just_pressed(KeyCode::R) {
+		character_list.0.clear();
 		for entity in level_query.iter() {
 			commands.entity(entity).despawn_recursive();
 		}

src/levels.rs

@@ -16,7 +16,12 @@ pub fn setup_level(
 	level_startup_event.send(LevelStartupEvent);
 }
 
-pub fn despawn_level(mut commands: Commands, level_query: Query<Entity, With<Level>>) {
+pub fn despawn_level(
+	mut commands: Commands,
+	mut character_list: ResMut<CharacterList>,
+	level_query: Query<Entity, With<Level>>,
+) {
+	character_list.0.clear();
 	for entity in level_query.iter() {
 		commands.entity(entity).despawn_recursive();
 	}
@@ -32,6 +37,7 @@ pub fn post_setup_level(
 	mut level_startup_event: EventReader<LevelStartupEvent>,
 	asset_server: Res<AssetServer>,
 	audio: Res<crossbeam_channel::Sender<AudioMsg>>,
+	mut character_list: ResMut<CharacterList>,
 	stored_levels_assets: Res<Assets<StoredLevels>>,
 	stored_levels_handle: Res<Handle<StoredLevels>>,
 ) {
@@ -50,6 +56,7 @@ pub fn post_setup_level(
 					&mut materials,
 					&asset_server,
 					&audio,
+					&mut character_list,
 					stored_level,
 				);
 			}
@@ -64,6 +71,7 @@ pub fn spawn_stored_level(
 	materials: &mut ResMut<Assets<ColorMaterial>>,
 	asset_server: &Res<AssetServer>,
 	audio: &Res<crossbeam_channel::Sender<AudioMsg>>,
+	character_list: &mut ResMut<CharacterList>,
 
 	stored_level: &StoredLevel,
 ) {
@@ -84,6 +92,7 @@ pub fn spawn_stored_level(
 		character_meshes,
 		materials,
 		audio,
+		character_list,
 		stored_level.characters.iter().map(|character| {
 			(
 				Transform::from_xyz(character.pos.x, character.pos.y, 0.),