Fire events when scenes spawn

crates/bevy_scene/src/lib.rs

@@ -29,6 +29,7 @@ impl Plugin for ScenePlugin {
     fn build(&self, app: &mut App) {
         app.add_asset::<DynamicScene>()
             .add_asset::<Scene>()
+            .add_event::<SceneSpawnedEvent>()
             .init_asset_loader::<SceneLoader>()
             .init_resource::<SceneSpawner>()
             .add_system_to_stage(

crates/bevy_scene/src/scene_spawner.rs

@@ -27,6 +27,11 @@ impl InstanceId {
     }
 }
 
+#[derive(Debug)]
+pub struct SceneSpawnedEvent {
+    pub instance_id: InstanceId,
+}
+
 #[derive(Default)]
 pub struct SceneSpawner {
     spawned_scenes: HashMap<Handle<Scene>, Vec<InstanceId>>,
@@ -108,6 +113,10 @@ impl SceneSpawner {
             .entry(scene_handle.clone())
             .or_insert_with(Vec::new);
         spawned.push(instance_id);
+        let mut scene_spawned_event_writer = world
+            .get_resource_mut::<Events<SceneSpawnedEvent>>()
+            .expect("SceneSpawnedEvent not found");
+        scene_spawned_event_writer.send(SceneSpawnedEvent { instance_id });
         Ok(())
     }
 
@@ -201,6 +210,11 @@ impl SceneSpawner {
                 .entry(scene_handle)
                 .or_insert_with(Vec::new);
             spawned.push(instance_id);
+            let mut scene_spawned_event_writer = world
+                .get_resource_mut::<Events<SceneSpawnedEvent>>()
+                .expect("SceneSpawnedEvent not found");
+            scene_spawned_event_writer.send(SceneSpawnedEvent { instance_id });
+
             Ok(instance_id)
         })
     }
@@ -242,7 +256,7 @@ impl SceneSpawner {
             match self.spawn_dynamic_sync(world, &scene_handle) {
                 Ok(_) => {}
                 Err(SceneSpawnError::NonExistentScene { .. }) => {
-                    self.dynamic_scenes_to_spawn.push(scene_handle)
+                    self.dynamic_scenes_to_spawn.push(scene_handle);
                 }
                 Err(err) => return Err(err),
             }

examples/scene/scene.rs

@@ -1,4 +1,4 @@
-use bevy::{prelude::*, reflect::TypeRegistry, utils::Duration};
+use bevy::{prelude::*, reflect::TypeRegistry, scene::SceneSpawnedEvent, utils::Duration};
 
 /// This example illustrates loading and saving scenes from files
 fn main() {
@@ -10,6 +10,7 @@ fn main() {
         .add_startup_system(load_scene_system)
         .add_startup_system(infotext_system)
         .add_system(log_system)
+        .add_system(scene_spawned_listener.system())
         .run();
 }
 
@@ -121,3 +122,9 @@ fn infotext_system(mut commands: Commands, asset_server: Res<AssetServer>) {
         ..Default::default()
     });
 }
+
+fn scene_spawned_listener(mut events: EventReader<SceneSpawnedEvent>) {
+    for event in events.iter() {
+        info!("{:?}", event);
+    }
+}