This example is running in WebGL2 and should work in most browsers. You can check the WebGPU examples here.
custom_asset.rs:
//! Implements loader for a custom asset type.
use bevy::{
asset::{io::Reader, AssetLoader, LoadContext},
prelude::*,
reflect::TypePath,
};
use serde::Deserialize;
use thiserror::Error;
#[derive(Asset, TypePath, Debug, Deserialize)]
struct CustomAsset {
#[allow(dead_code)]
value: i32,
}
#[derive(Default)]
struct CustomAssetLoader;
/// Possible errors that can be produced by [`CustomAssetLoader`]
#[non_exhaustive]
#[derive(Debug, Error)]
enum CustomAssetLoaderError {
/// An [IO](std::io) Error
#[error("Could not load asset: {0}")]
Io(#[from] std::io::Error),
/// A [RON](ron) Error
#[error("Could not parse RON: {0}")]
RonSpannedError(#[from] ron::error::SpannedError),
}
impl AssetLoader for CustomAssetLoader {
type Asset = CustomAsset;
type Settings = ();
type Error = CustomAssetLoaderError;
async fn load(
&self,
reader: &mut dyn Reader,
_settings: &(),
_load_context: &mut LoadContext<'_>,
) -> Result<Self::Asset, Self::Error> {
let mut bytes = Vec::new();
reader.read_to_end(&mut bytes).await?;
let custom_asset = ron::de::from_bytes::<CustomAsset>(&bytes)?;
Ok(custom_asset)
}
fn extensions(&self) -> &[&str] {
&["custom"]
}
}
#[derive(Asset, TypePath, Debug)]
struct Blob {
bytes: Vec<u8>,
}
#[derive(Default)]
struct BlobAssetLoader;
/// Possible errors that can be produced by [`BlobAssetLoader`]
#[non_exhaustive]
#[derive(Debug, Error)]
enum BlobAssetLoaderError {
/// An [IO](std::io) Error
#[error("Could not load file: {0}")]
Io(#[from] std::io::Error),
}
impl AssetLoader for BlobAssetLoader {
type Asset = Blob;
type Settings = ();
type Error = BlobAssetLoaderError;
async fn load(
&self,
reader: &mut dyn Reader,
_settings: &(),
_load_context: &mut LoadContext<'_>,
) -> Result<Self::Asset, Self::Error> {
info!("Loading Blob...");
let mut bytes = Vec::new();
reader.read_to_end(&mut bytes).await?;
Ok(Blob { bytes })
}
}
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.init_resource::<State>()
.init_asset::<CustomAsset>()
.init_asset::<Blob>()
.init_asset_loader::<CustomAssetLoader>()
.init_asset_loader::<BlobAssetLoader>()
.add_systems(Startup, setup)
.add_systems(Update, print_on_load)
.run();
}
#[derive(Resource, Default)]
struct State {
handle: Handle<CustomAsset>,
other_handle: Handle<CustomAsset>,
blob: Handle<Blob>,
printed: bool,
}
fn setup(mut state: ResMut<State>, asset_server: Res<AssetServer>) {
// Recommended way to load an asset
state.handle = asset_server.load("data/asset.custom");
// File extensions are optional, but are recommended for project management and last-resort inference
state.other_handle = asset_server.load("data/asset_no_extension");
// Will use BlobAssetLoader instead of CustomAssetLoader thanks to type inference
state.blob = asset_server.load("data/asset.custom");
}
fn print_on_load(
mut state: ResMut<State>,
custom_assets: Res<Assets<CustomAsset>>,
blob_assets: Res<Assets<Blob>>,
) {
let custom_asset = custom_assets.get(&state.handle);
let other_custom_asset = custom_assets.get(&state.other_handle);
let blob = blob_assets.get(&state.blob);
// Can't print results if the assets aren't ready
if state.printed {
return;
}
if custom_asset.is_none() {
info!("Custom Asset Not Ready");
return;
}
if other_custom_asset.is_none() {
info!("Other Custom Asset Not Ready");
return;
}
if blob.is_none() {
info!("Blob Not Ready");
return;
}
info!("Custom asset loaded: {:?}", custom_asset.unwrap());
info!("Custom asset loaded: {:?}", other_custom_asset.unwrap());
info!("Blob Size: {:?} Bytes", blob.unwrap().bytes.len());
// Once printed, we won't print again
state.printed = true;
}