Do not send despawns for hidden entities (#366)

src/core/replication/replicated_clients.rs

@@ -345,7 +345,7 @@ impl ReplicatedClient {
     ///
     /// Internal cleanup happens lazily during the iteration.
     pub(crate) fn drain_lost_visibility(&mut self) -> impl Iterator<Item = Entity> + '_ {
-        self.visibility.drain_lost_visibility().inspect(|entity| {
+        self.visibility.drain_lost().inspect(|entity| {
             self.mutation_ticks.remove(entity);
         })
     }

src/core/replication/replicated_clients/client_visibility.rs

@@ -121,7 +121,7 @@ impl ClientVisibility {
     }
 
     /// Drains all entities for which visibility was lost during this tick.
-    pub(super) fn drain_lost_visibility(&mut self) -> impl Iterator<Item = Entity> + '_ {
+    pub(super) fn drain_lost(&mut self) -> impl Iterator<Item = Entity> + '_ {
         match &mut self.filter {
             VisibilityFilter::All { .. } => VisibilityLostIter::AllVisible,
             VisibilityFilter::Blacklist { added, .. } => VisibilityLostIter::Lost(added.drain()),
@@ -219,14 +219,14 @@ impl ClientVisibility {
 
     /// Checks if a specific entity is visible.
     pub fn is_visible(&self, entity: Entity) -> bool {
-        match self.visibility_state(entity) {
+        match self.state(entity) {
             Visibility::Hidden => false,
             Visibility::Gained | Visibility::Visible => true,
         }
     }
 
     /// Returns visibility of a specific entity.
-    pub(crate) fn visibility_state(&self, entity: Entity) -> Visibility {
+    pub(crate) fn state(&self, entity: Entity) -> Visibility {
         match &self.filter {
             VisibilityFilter::All => Visibility::Visible,
             VisibilityFilter::Blacklist { list, .. } => match list.get(&entity) {

src/server.rs

@@ -420,8 +420,11 @@ fn collect_despawns(
     for entity in despawn_buffer.drain(..) {
         let entity_range = serialized.write_entity(entity)?;
         for ((message, _), client) in messages.iter_mut().zip(replicated_clients.iter_mut()) {
+            let visibility = client.visibility().state(entity);
+            if visibility != Visibility::Hidden {
+                message.add_despawn(entity_range.clone());
+            }
             client.remove_despawned(entity);
-            message.add_despawn(entity_range.clone());
         }
     }
 
@@ -487,7 +490,7 @@ fn collect_changes(
             for ((change_message, mutate_message), client) in
                 messages.iter_mut().zip(replicated_clients.iter())
             {
-                let visibility = client.visibility().visibility_state(entity.id());
+                let visibility = client.visibility().state(entity.id());
                 change_message.start_entity_changes(visibility);
                 mutate_message.start_entity_mutations();
             }