Multiplayer: Handle peer left events (#733)

crates/messages/src/lib.rs

@@ -4,7 +4,7 @@
 pub use game::{FromGame, JoinError, Readiness, ToGame};
 pub use players::{
     BorrowedFromPlayers, ChatMessage, ChatMessageError, EntityNet, FromPlayers, HealthDelta,
-    ToPlayers, MAX_CHAT_LEN,
+    NetEntityIndex, ToPlayers, MAX_CHAT_LEN,
 };
 pub use server::{FromServer, GameOpenError, ToServer};
 

crates/messages/src/players/entity.rs

@@ -1,11 +1,13 @@
+#[cfg(feature = "bevy")]
+use bevy::ecs::entity::Entity;
 use bincode::{Decode, Encode};
 use de_types::player::Player;
 
 /// Bevy ECS Entity derived identification of an entity.
 #[derive(Clone, Copy, Debug, Encode, Decode, Hash, PartialEq, Eq)]
 pub struct EntityNet {
     player: Player,
-    index: u32,
+    index: NetEntityIndex,
 }
 
 impl EntityNet {
@@ -15,11 +17,31 @@ impl EntityNet {
     ///   instance.
     ///
     /// * `index` - locally unique index of the entity.
-    pub fn new(player: Player, index: u32) -> Self {
+    pub fn new(player: Player, index: NetEntityIndex) -> Self {
         Self { player, index }
     }
 
-    pub fn index(&self) -> u32 {
+    pub fn player(&self) -> Player {
+        self.player
+    }
+
+    pub fn index(&self) -> NetEntityIndex {
         self.index
     }
 }
+
+#[derive(Clone, Copy, Debug, Encode, Decode, Hash, PartialEq, Eq)]
+pub struct NetEntityIndex(u32);
+
+impl From<NetEntityIndex> for u32 {
+    fn from(index: NetEntityIndex) -> u32 {
+        index.0
+    }
+}
+
+#[cfg(feature = "bevy")]
+impl From<Entity> for NetEntityIndex {
+    fn from(entity: Entity) -> Self {
+        Self(entity.index())
+    }
+}

crates/messages/src/players/mod.rs

@@ -1,7 +1,7 @@
 use bincode::{Decode, Encode};
 pub use chat::{ChatMessage, ChatMessageError, MAX_CHAT_LEN};
 use de_types::{objects::ActiveObjectType, player::Player};
-pub use entity::EntityNet;
+pub use entity::{EntityNet, NetEntityIndex};
 pub use geom::{TransformNet, Vec2Net, Vec3Net, Vec4Net};
 pub use path::{PathError, PathNet};
 

crates/multiplayer/src/lib.rs

@@ -24,7 +24,7 @@ pub use crate::{
     messages::{MessagesSet, ToPlayersEvent},
     netstate::NetState,
     playermsg::{
-        GameNetSet, NetEntities, NetRecvDespawnActiveEvent, NetRecvHealthEvent,
+        GameNetSet, NetEntities, NetEntityCommands, NetRecvDespawnActiveEvent, NetRecvHealthEvent,
         NetRecvSpawnActiveEvent,
     },
 };

crates/multiplayer/src/playermsg.rs

@@ -4,7 +4,7 @@ use bevy::{
     prelude::*,
 };
 use de_core::{gconfig::GameConfig, schedule::PreMovement, state::AppState};
-use de_messages::{EntityNet, ToPlayers};
+use de_messages::{EntityNet, NetEntityIndex, ToPlayers};
 use de_types::{objects::ActiveObjectType, player::Player};
 
 use crate::messages::{FromPlayersEvent, MessagesSet};
@@ -148,7 +148,7 @@ impl<'w> NetEntities<'w> {
     /// It is assumed that the entity exists.
     pub fn local_net_id(&self, entity: Entity) -> EntityNet {
         let player = self.config.locals().playable();
-        EntityNet::new(player, entity.index())
+        EntityNet::new(player, entity.into())
     }
 }
 
@@ -159,6 +159,10 @@ pub struct NetEntityCommands<'w> {
 }
 
 impl<'w> NetEntityCommands<'w> {
+    pub fn remove_player(&mut self, player: Player) -> Option<PlayerNetToLocal> {
+        self.map.remove_player(player)
+    }
+
     fn register(&mut self, remote: EntityNet, local: Entity) {
         self.map.register(remote, local)
     }
@@ -170,15 +174,15 @@ impl<'w> NetEntityCommands<'w> {
     fn local_id(&self, entity: EntityNet) -> Option<Entity> {
         self.map
             .translate_remote(entity)
-            .or_else(|| self.entities.resolve_from_id(entity.index()))
+            .or_else(|| self.entities.resolve_from_id(entity.index().into()))
     }
 }
 
 /// Mapping between remote and local entity IDs for non-locally simulated
 /// entities.
 #[derive(Resource)]
 struct EntityIdMapRes {
-    remote_to_local: AHashMap<EntityNet, Entity>,
+    remote_to_local: AHashMap<Player, PlayerNetToLocal>,
     local_to_remote: AHashMap<Entity, EntityNet>,
 }
 
@@ -202,8 +206,10 @@ impl EntityIdMapRes {
     ///
     /// Panics if the remote entity is already registered.
     fn register(&mut self, remote: EntityNet, local: Entity) {
-        let result = self.remote_to_local.insert(remote, local);
-        assert!(result.is_none());
+        self.remote_to_local
+            .entry(remote.player())
+            .or_default()
+            .insert(remote.index(), local);
         let result = self.local_to_remote.insert(local, remote);
         assert!(result.is_none());
     }
@@ -216,7 +222,8 @@ impl EntityIdMapRes {
     ///
     /// Panics if the entity is not registered.
     fn deregister(&mut self, remote: EntityNet) -> Entity {
-        let local = self.remote_to_local.remove(&remote).unwrap();
+        let player_entities = self.remote_to_local.get_mut(&remote.player()).unwrap();
+        let local = player_entities.remove(remote.index()).unwrap();
         self.local_to_remote.remove(&local).unwrap();
         local
     }
@@ -230,7 +237,57 @@ impl EntityIdMapRes {
     /// Translates remote entity ID to a local entity ID in case the entity is
     /// not locally simulated.
     fn translate_remote(&self, remote: EntityNet) -> Option<Entity> {
-        self.remote_to_local.get(&remote).copied()
+        self.remote_to_local
+            .get(&remote.player())
+            .and_then(|h| h.translate(remote.index()))
+    }
+
+    /// Removes entity mapping for the player.
+    ///
+    /// This should not be called unless the player leaves the multiplayer
+    /// game.
+    fn remove_player(&mut self, player: Player) -> Option<PlayerNetToLocal> {
+        let Some(map) = self.remote_to_local.remove(&player) else {
+            return None;
+        };
+
+        for local in map.locals() {
+            self.local_to_remote.remove(&local).unwrap();
+        }
+
+        Some(map)
+    }
+}
+
+/// Mapping from remote entity indices to local ECS entities.
+#[derive(Default)]
+pub struct PlayerNetToLocal(AHashMap<NetEntityIndex, Entity>);
+
+impl PlayerNetToLocal {
+    /// Inserts a new remote to local entity link.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the remote entity is already registered.
+    fn insert(&mut self, remote: NetEntityIndex, local: Entity) {
+        let result = self.0.insert(remote, local);
+        debug_assert!(result.is_none());
+    }
+
+    /// Removes a remote to local entity link and returns the local entity if
+    /// it was registered.
+    fn remove(&mut self, index: NetEntityIndex) -> Option<Entity> {
+        self.0.remove(&index)
+    }
+
+    /// Translates a remote entity to a local entity.
+    fn translate(&self, remote: NetEntityIndex) -> Option<Entity> {
+        self.0.get(&remote).copied()
+    }
+
+    /// Returns an iterator over all local entities from the mapping.
+    pub fn locals(&self) -> impl Iterator<Item = Entity> + '_ {
+        self.0.values().copied()
     }
 }
 

crates/spawner/src/despawner.rs

@@ -6,10 +6,12 @@ use de_audio::spatial::{PlaySpatialAudioEvent, Sound};
 use de_core::gconfig::GameConfig;
 use de_core::{objects::ObjectTypeComponent, player::PlayerComponent, state::AppState};
 use de_messages::ToPlayers;
-use de_multiplayer::{NetEntities, NetRecvDespawnActiveEvent, ToPlayersEvent};
+use de_multiplayer::{
+    NetEntities, NetEntityCommands, NetRecvDespawnActiveEvent, PeerLeftEvent, ToPlayersEvent,
+};
 use de_types::objects::{ActiveObjectType, ObjectType};
 
-use crate::ObjectCounter;
+use crate::{ObjectCounter, SpawnerSet};
 
 pub(crate) struct DespawnerPlugin;
 
@@ -22,11 +24,16 @@ impl Plugin for DespawnerPlugin {
                 despawn_active_remote
                     .run_if(on_event::<NetRecvDespawnActiveEvent>())
                     .before(despawn_active),
+                despawn_active_peer_left
+                    .run_if(on_event::<PeerLeftEvent>())
+                    .after(despawn_active_remote)
+                    .before(despawn_active),
                 despawn_active.before(despawn),
                 despawn,
             )
                 .run_if(in_state(AppState::InGame))
-                .in_set(DespawnerSet::Despawn),
+                .in_set(DespawnerSet::Despawn)
+                .after(SpawnerSet::Spawner),
         )
         .add_event::<DespawnActiveLocalEvent>()
         .add_event::<DespawnActiveEvent>()
@@ -84,6 +91,20 @@ fn despawn_active_remote(
     }
 }
 
+fn despawn_active_peer_left(
+    mut net_commands: NetEntityCommands,
+    mut peer_left_events: EventReader<PeerLeftEvent>,
+    mut event_writer: EventWriter<DespawnActiveEvent>,
+) {
+    for event in peer_left_events.iter() {
+        if let Some(entity_map) = net_commands.remove_player(event.id()) {
+            for entity in entity_map.locals() {
+                event_writer.send(DespawnActiveEvent(entity));
+            }
+        }
+    }
+}
+
 fn despawn_active(
     mut counter: ResMut<ObjectCounter>,
     entities: Query<(&PlayerComponent, &ObjectTypeComponent, &Transform)>,