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Don't use ScenePatchInstance for queued scenes #24474

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Merged
cart merged 2 commits into from
Jun 1, 2026
+34 −23
Merged

Don't use ScenePatchInstance for queued scenes #24474

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3b3e42c
Don't use ScenePatchInstance for queued scenes
cart May 28, 2026
29d4fd8
Use QueuedScenes instead of WaitingScenes
cart May 29, 2026
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57 changes: 34 additions & 23 deletions crates/bevy_scene/src/spawn.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -196,7 +196,13 @@ impl WorldSceneExt for World {
let assets = self.resource::<AssetServer>();
let patch = ScenePatch::load(assets, scene);
let handle = assets.add(patch);
self.spawn(ScenePatchInstance(handle))
let mut entity = self.spawn_empty();
let id = entity.id();
entity
.resource_mut::<QueuedScenes>()
.new_scene_entities
.push((id, handle));
entity
}

fn spawn_scene_list<L: SceneList>(
Expand Down Expand Up @@ -501,7 +507,10 @@ impl EntityWorldMutSceneExt for EntityWorldMut<'_> {
let assets = self.resource::<AssetServer>();
let patch = ScenePatch::load(assets, scene);
let handle = assets.add(patch);
self.insert(ScenePatchInstance(handle));
let id = self.id();
self.resource_mut::<QueuedScenes>()
.new_scene_entities
.push((id, handle));
}
}

Expand Down Expand Up @@ -660,7 +669,7 @@ pub fn resolve_scene_patches(
/// A [`Resource`] that tracks entities / scenes that have been queued to spawn.
#[derive(Resource, Default)]
pub struct QueuedScenes {
new_scene_entities: Vec<Entity>,
new_scene_entities: Vec<(Entity, Handle<ScenePatch>)>,
related_scene_list_spawns: Vec<(RelatedSceneListSpawn, Handle<SceneListPatch>)>,
scene_list_spawns: Vec<Handle<SceneListPatch>>,
}
Expand All @@ -682,8 +691,13 @@ pub(crate) struct RelatedSceneListSpawn {
pub fn on_add_scene_patch_instance(
add: On<Add, ScenePatchInstance>,
mut queued_scenes: ResMut<QueuedScenes>,
instances: Query<&ScenePatchInstance>,
) {
queued_scenes.new_scene_entities.push(add.entity);
if let Ok(instance) = instances.get(add.entity) {
queued_scenes
.new_scene_entities
.push((add.entity, instance.0.clone()));
}
}

/// A system that spawns queued scenes when they are loaded.
Expand All @@ -695,22 +709,8 @@ pub fn spawn_queued(
mut reader: Local<MessageCursor<AssetEvent<ScenePatch>>>,
mut list_reader: Local<MessageCursor<AssetEvent<SceneListPatch>>>,
) {
core::mem::swap(&mut *world.resource_mut::<QueuedScenes>(), &mut queued);
world.resource_scope(|world, mut list_patches: Mut<Assets<SceneListPatch>>| {
world.resource_scope(|world, mut waiting: Mut<WaitingScenes>| {
loop {
if queued.is_empty() {
break;
}
queued.spawn_queued(
world,
&mut waiting,
scene_patch_instances,
&mut bundle_scratch,
&list_patches,
);
}

world.resource_scope(|world, events: Mut<Messages<AssetEvent<ScenePatch>>>| {
for event in reader.read(&events) {
let patches = world.resource::<Assets<ScenePatch>>();
Expand Down Expand Up @@ -765,6 +765,20 @@ pub fn spawn_queued(
}
},
);

loop {
core::mem::swap(&mut *world.resource_mut::<QueuedScenes>(), &mut queued);
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@cart cart May 29, 2026

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I moved this loop until after the "asset load event" processing to ensure that we spawn queued scenes that are produced from the spawning of those scene asset loads now rather than waiting a frame.

I've also moved the mem::swap into the loop to ensure we check for newly queued spawns after spawning the current queue.

if queued.is_empty() {
break;
}
queued.spawn_queued(
world,
&mut waiting,
scene_patch_instances,
&mut bundle_scratch,
&list_patches,
);
}
});
});
}
Expand All @@ -784,12 +798,9 @@ impl QueuedScenes {
bundle_scratch: &mut BundleScratch,
list_patches: &Assets<SceneListPatch>,
) {
for entity in core::mem::take(&mut self.new_scene_entities) {
let Ok(handle) = scene_patch_instances.get(world, entity).map(|h| &h.0) else {
continue;
};
for (entity, handle) in core::mem::take(&mut self.new_scene_entities) {
let patches = world.resource::<Assets<ScenePatch>>();
if let Some(resolved) = patches.get(handle).and_then(|p| p.resolved.clone()) {
if let Some(resolved) = patches.get(&handle).and_then(|p| p.resolved.clone()) {
let mut entity_mut = world.get_entity_mut(entity).unwrap();
if let Err(err) = resolved.apply(&mut entity_mut, bundle_scratch) {
let scene_patch_instance = scene_patch_instances.get(world, entity).unwrap();
Expand Down
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