pebble/assets/
plugin.rs

1use crate::{
2    app::SystemStage,
3    assets::{
4        deps::Dependencies,
5        storage::{Assets, ProcessedAssets},
6        upload::Asset,
7    },
8    ecs::{
9        plugin::Plugin,
10        resources::Resources,
11        system::{Res, ResMut},
12    },
13};
14
15/// Plugin that drives the source → processed conversion pipeline for a single
16/// asset type `T`.
17///
18/// `B` is the *backend* passed to [`Asset::upload`] and is intentionally
19/// generic — it need not be a GPU backend:
20/// - **GPU assets**: `B` = your graphics backend (e.g. wgpu `Device`).
21/// - **CPU-only / audio / other**: `B = ()` or any other service type.
22///
23/// Registering `AssetPlugin::<B, T>::new()` will:
24/// - Insert an [`Assets<T::Source>`] resource for raw source assets.
25/// - Insert a [`ProcessedAssets<T>`] resource for the converted results.
26/// - Add a system on [`SystemStage::AssetSync`] that flushes the dirty queue
27///   each tick, calling [`Asset::upload`] for every pending entry.
28///
29/// The sync system waits silently until both `B` and all of `T`'s
30/// [`Dependencies`] are present as resources before processing any uploads.
31pub struct AssetPlugin<B, T: Asset<B>> {
32    _marker: std::marker::PhantomData<(B, T)>,
33}
34
35impl<B, T: Asset<B>> AssetPlugin<B, T> {
36    pub fn new() -> Self {
37        Self {
38            _marker: std::marker::PhantomData,
39        }
40    }
41}
42
43impl<B, T> Plugin for AssetPlugin<B, T>
44where
45    B: 'static + Send + Sync,
46    T: Asset<B>,
47{
48    fn build(&self, app: &mut crate::app::App) {
49        app.try_insert_resource(Assets::<T::Source>::new());
50        app.try_insert_resource(ProcessedAssets::<T>::new());
51        app.add_system(SystemStage::AssetSync, sync_assets::<B, T>);
52        app.required.provides::<ProcessedAssets<T>>();
53    }
54}
55
56/// Per-tick system: flush the dirty queue and convert pending assets.
57///
58/// Skips processing if `B` or any dependency is not yet available as a
59/// resource. Assets whose [`Asset::upload`] returns `None` are re-queued for
60/// the next tick.
61fn sync_assets<B, T>(
62    mut cpu: ResMut<Assets<T::Source>>,
63    mut processed: ResMut<ProcessedAssets<T>>,
64    backend: Option<Res<B>>,
65    world: &hecs::World,
66    resources: &Resources,
67) where
68    B: 'static + Send + Sync,
69    T: Asset<B>,
70{
71    let Some(backend) = backend else {
72        log_waiting::<B, T>(&cpu, "backend");
73        return;
74    };
75    let Some(deps) = T::Deps::try_gather(world, resources) else {
76        log_waiting::<B, T>(&cpu, "dependencies");
77        return;
78    };
79
80    let mut still_pending = Vec::new();
81
82    for handle in cpu.take_dirty() {
83        let Some(source) = cpu.get(handle) else {
84            continue;
85        };
86        match T::upload(source, &backend, &deps) {
87            Some(value) => {
88                if let Some(name) = cpu.name_for_handle(handle) {
89                    processed.names.insert(name.to_string(), handle);
90                }
91                processed.insert(handle, value);
92            }
93            None => {
94                tracing::trace!(
95                    "{}: {handle:?} not ready yet (dependency exists but entry missing), requeued",
96                    std::any::type_name::<T>()
97                );
98                still_pending.push(handle);
99            }
100        }
101    }
102
103    if !still_pending.is_empty() {
104        tracing::trace!(
105            "{}: {} handle(s) requeued this tick",
106            std::any::type_name::<T>(),
107            still_pending.len()
108        );
109    }
110
111    cpu.requeue(still_pending);
112}
113
114fn log_waiting<D, T>(cpu: &Assets<T::Source>, what: &str)
115where
116    D: 'static + Send + Sync,
117    T: Asset<D>,
118{
119    if !cpu.dirty_is_empty() {
120        tracing::trace!(
121            "{}: waiting on {what}, {} pending",
122            std::any::type_name::<T>(),
123            cpu.dirty_len()
124        );
125    }
126}
pebble/assets/plugin.rs

pebble/assets/
plugin.rs
