Remove audio + assets modules in favor of raw Bevy APIs and thin …

…LoadResource API (#264)

Co-authored-by: Ben Frankel <[email protected]>
Co-authored-by: Jan Hohenheim <[email protected]>

README.md

@@ -46,15 +46,15 @@ The best way to get started is to play around with what you find in [`src/demo/`
 
 This template comes with a basic project structure that you may find useful:
 
-| Path                                     | Description                                                                    |
-|------------------------------------------|--------------------------------------------------------------------------------|
-| [`src/lib.rs`](./src/lib.rs)             | App setup                                                                      |
-| [`src/assets.rs`](./src/assets.rs)       | Definition of assets that will be preloaded before the game starts             |
-| [`src/audio/`](./src/audio)              | Commands for playing SFX and music                                             |
-| [`src/demo/`](./src/demo)                | Example game mechanics & content (replace with your own code)                  |
-| [`src/dev_tools.rs`](./src/dev_tools.rs) | Dev tools for dev builds (press \` aka backtick to toggle)                     |
-| [`src/screens/`](./src/screens)          | Splash screen, title screen, playing screen, etc.                              |
-| [`src/theme/`](./src/theme)              | Reusable UI widgets & theming                                                  |
+| Path                                               | Description                                                                |
+| -------------------------------------------------- | -------------------------------------------------------------------------- |
+| [`src/lib.rs`](./src/lib.rs)                       | App setup                                                                  |
+| [`src/asset_tracking.rs`](./src/asset_tracking.rs) | A simple, high-level way to load collections of asset handles as resources |
+| [`src/audio/`](./src/audio)                        | Commands for playing SFX and music                                         |
+| [`src/demo/`](./src/demo)                          | Example game mechanics & content (replace with your own code)              |
+| [`src/dev_tools.rs`](./src/dev_tools.rs)           | Dev tools for dev builds (press \` aka backtick to toggle)                 |
+| [`src/screens/`](./src/screens)                    | Splash screen, title screen, playing screen, etc.                          |
+| [`src/theme/`](./src/theme)                        | Reusable UI widgets & theming
 
 Feel free to move things around however you want, though.
 

src/asset_tracking.rs

@@ -0,0 +1,59 @@
+//! A simple, high-level way to load collections of asset handles as resources
+
+use bevy::prelude::*;
+
+pub(super) fn plugin(app: &mut App) {
+    app.init_resource::<ResourceHandles>()
+        .add_systems(PreUpdate, load_resource_assets);
+}
+
+pub trait LoadResource {
+    /// This will load the [`Resource`] as an [`Asset`]. When all of its asset dependencies
+    /// have been loaded, it will be inserted as a resource. This ensures that the resource only
+    /// exists when the assets are ready.
+    fn load_resource<T: Resource + Asset + Clone + FromWorld>(&mut self) -> &mut Self;
+}
+
+impl LoadResource for App {
+    fn load_resource<T: Resource + Asset + Clone + FromWorld>(&mut self) -> &mut Self {
+        self.init_asset::<T>();
+        let world = self.world_mut();
+        let value = T::from_world(world);
+        let assets = world.resource::<AssetServer>();
+        let handle = assets.add(value);
+        let mut handles = world.resource_mut::<ResourceHandles>();
+        handles.waiting.push((handle.untyped(), |world, handle| {
+            let assets = world.resource::<Assets<T>>();
+            if let Some(value) = assets.get(handle.id().typed::<T>()) {
+                world.insert_resource(value.clone());
+            }
+        }));
+        self
+    }
+}
+
+/// A function that inserts a loaded resource.
+type InsertLoadedResource = fn(&mut World, &UntypedHandle);
+
+#[derive(Resource, Default)]
+struct ResourceHandles {
+    waiting: Vec<(UntypedHandle, InsertLoadedResource)>,
+    #[allow(unused)]
+    finished: Vec<UntypedHandle>,
+}
+
+fn load_resource_assets(world: &mut World) {
+    world.resource_scope(|world, mut resource_handles: Mut<ResourceHandles>| {
+        world.resource_scope(|world, assets: Mut<AssetServer>| {
+            for _ in 0..resource_handles.waiting.len() {
+                let (handle, insert_fn) = resource_handles.waiting.pop().unwrap();
+                if assets.is_loaded_with_dependencies(&handle) {
+                    insert_fn(world, &handle);
+                    resource_handles.finished.push(handle);
+                } else {
+                    resource_handles.waiting.push((handle, insert_fn));
+                }
+            }
+        });
+    });
+}

src/audio.rs

@@ -0,0 +1,37 @@
+use bevy::prelude::*;
+
+/// An organizational marker component that should be added to a spawned [`AudioBundle`] if it is in the
+/// general "music" category (ex: global background music, soundtrack, etc).
+///
+/// This can then be used to query for and operate on sounds in that category. For example:
+///
+/// ```
+/// use bevy::prelude::*;
+/// use bevy_quickstart::audio::Music;
+///
+/// fn set_music_volume(sink_query: Query<&AudioSink, With<Music>>) {
+///     for sink in &sink_query {
+///         sink.set_volume(0.5);
+///     }
+/// }
+/// ```
+#[derive(Component, Default)]
+pub struct Music;
+
+/// An organizational marker component that should be added to a spawned [`AudioBundle`] if it is in the
+/// general "sound effect" category (ex: footsteps, the sound of a magic spell, a door opening).
+///
+/// This can then be used to query for and operate on sounds in that category. For example:
+///
+/// ```
+/// use bevy::prelude::*;
+/// use bevy_quickstart::audio::SoundEffect;
+///
+/// fn set_sound_effect_volume(sink_query: Query<&AudioSink, With<SoundEffect>>) {
+///     for sink in &sink_query {
+///         sink.set_volume(0.5);
+///     }
+/// }
+/// ```
+#[derive(Component, Default)]
+pub struct SoundEffect;