Asset server load state not working for individual assets

[willcrichton]

Bevy version

0.4.0

Operating system & version

OSX

What you did

Patterned after this example, I tried to make an on-load event for a gLTF scene. The code:

use bevy::{asset::LoadState, prelude::*};

fn main() {
  App::build()
    .init_resource::<AssetHandles>()
    .add_plugins(DefaultPlugins)
    .add_resource(State::new(AssetState::Loading))
    .add_stage_after(stage::UPDATE, "assets", StateStage::<AssetState>::default())
    .on_state_enter("assets", AssetState::Loading, load_assets.system())
    .on_state_update("assets", AssetState::Loading, check_assets.system())
    .on_state_enter("assets", AssetState::Finished, init_assets.system())
    .run();
}

#[derive(Clone)]
enum AssetState {
  Loading,
  Finished,
}

[derive(Default)]
struct AssetHandles {
  scene: Handle<Scene>,
}

fn load_assets(
  commands: &mut Commands,
  mut asset_handles: ResMut<AssetHandles>,
  asset_server: Res<AssetServer>,
) {
  asset_handles.scene = asset_server.load("models/Monkey.gltf#Scene0");
  commands.spawn_scene(asset_handles.scene.clone());  
}

fn check_assets(
  mut state: ResMut<State<AssetState>>,
  asset_handles: ResMut<AssetHandles>,
  asset_server: Res<AssetServer>,
) {
  if let LoadState::Loaded = asset_server.get_load_state(&asset_handles.scene) {
    state.set_next(AssetState::Finished).unwrap();
  }
}

fn init_assets(
  asset_handles: Res<AssetHandles>,
  scenes: ResMut<Assets<Scene>>,
) {
  let scene = scenes.get(&asset_handles.scene).unwrap();
}

What you expected to happen

The scenes.get(...) call should return Some.

What actually happened

The scenes.get(...) call returned None, suggesting that the asset was not actually loaded (or that I'm using the API incorrectly somehow?).

[willcrichton]

After some debugging, if I use load_folder and HandleUntyped then the program works as expected. It seems the issue is not with gLTF, but rather loading individual assets vs. a folder of assets.

[mockersf]

This is working for me using current master.

Adding the #Scene0 to load a scene from a gltf file is a recent change, and was not needed in bevy 0.4, check the load_gltf.rs example from the release (instead of the current one - you can see the difference)

[willcrichton]

I think it was a version issue, I was able to get this working.