custom_asset_reader/
custom_asset_reader.rs

1//! Implements a custom asset io loader.
2//! An [`AssetReader`] is what the asset server uses to read the raw bytes of assets.
3//! It does not know anything about the asset formats, only how to talk to the underlying storage.
4
5use bevy::{
6    asset::io::{
7        AssetReader, AssetReaderError, AssetSource, AssetSourceId, ErasedAssetReader, PathStream,
8        Reader,
9    },
10    prelude::*,
11};
12use std::path::Path;
13
14/// A custom asset reader implementation that wraps a given asset reader implementation
15struct CustomAssetReader(Box<dyn ErasedAssetReader>);
16
17impl AssetReader for CustomAssetReader {
18    async fn read<'a>(&'a self, path: &'a Path) -> Result<impl Reader + 'a, AssetReaderError> {
19        info!("Reading {}", path.display());
20        self.0.read(path).await
21    }
22    async fn read_meta<'a>(&'a self, path: &'a Path) -> Result<impl Reader + 'a, AssetReaderError> {
23        self.0.read_meta(path).await
24    }
25
26    async fn read_directory<'a>(
27        &'a self,
28        path: &'a Path,
29    ) -> Result<Box<PathStream>, AssetReaderError> {
30        self.0.read_directory(path).await
31    }
32
33    async fn is_directory<'a>(&'a self, path: &'a Path) -> Result<bool, AssetReaderError> {
34        self.0.is_directory(path).await
35    }
36}
37
38/// A plugins that registers our new asset reader
39struct CustomAssetReaderPlugin;
40
41impl Plugin for CustomAssetReaderPlugin {
42    fn build(&self, app: &mut App) {
43        app.register_asset_source(
44            AssetSourceId::Default,
45            AssetSource::build().with_reader(|| {
46                Box::new(CustomAssetReader(
47                    // This is the default reader for the current platform
48                    AssetSource::get_default_reader("assets".to_string())(),
49                ))
50            }),
51        );
52    }
53}
54
55fn main() {
56    App::new()
57        .add_plugins((CustomAssetReaderPlugin, DefaultPlugins))
58        .add_systems(Startup, setup)
59        .run();
60}
61
62fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
63    commands.spawn(Camera2d);
64    commands.spawn(Sprite::from_image(asset_server.load("branding/icon.png")));
65}
custom_asset_reader/custom_asset_reader.rs

custom_asset_reader/
custom_asset_reader.rs
