f90248b052
# Objective - Examples containing `ResMut`s that are never mutated can be confusing for readers. ## Solution - Changes them to `Res`.
86 lines
2.2 KiB
Rust
86 lines
2.2 KiB
Rust
//! Implements loader for a custom asset type.
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use bevy::utils::thiserror;
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use bevy::{
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asset::{io::Reader, ron, AssetLoader, AsyncReadExt, LoadContext},
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prelude::*,
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reflect::TypePath,
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utils::BoxedFuture,
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};
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use serde::Deserialize;
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use thiserror::Error;
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#[derive(Asset, TypePath, Debug, Deserialize)]
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pub struct CustomAsset {
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pub value: i32,
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}
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#[derive(Default)]
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pub struct CustomAssetLoader;
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/// Possible errors that can be produced by [`CustomAssetLoader`]
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#[non_exhaustive]
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#[derive(Debug, Error)]
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pub enum CustomAssetLoaderError {
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/// An [IO](std::io) Error
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#[error("Could not load asset: {0}")]
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Io(#[from] std::io::Error),
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/// A [RON](ron) Error
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#[error("Could not parse RON: {0}")]
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RonSpannedError(#[from] ron::error::SpannedError),
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}
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impl AssetLoader for CustomAssetLoader {
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type Asset = CustomAsset;
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type Settings = ();
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type Error = CustomAssetLoaderError;
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fn load<'a>(
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&'a self,
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reader: &'a mut Reader,
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_settings: &'a (),
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_load_context: &'a mut LoadContext,
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) -> BoxedFuture<'a, Result<Self::Asset, Self::Error>> {
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Box::pin(async move {
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let mut bytes = Vec::new();
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reader.read_to_end(&mut bytes).await?;
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let custom_asset = ron::de::from_bytes::<CustomAsset>(&bytes)?;
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Ok(custom_asset)
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})
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}
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fn extensions(&self) -> &[&str] {
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&["custom"]
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}
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}
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.init_resource::<State>()
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.init_asset::<CustomAsset>()
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.init_asset_loader::<CustomAssetLoader>()
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.add_systems(Startup, setup)
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.add_systems(Update, print_on_load)
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.run();
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}
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#[derive(Resource, Default)]
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struct State {
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handle: Handle<CustomAsset>,
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printed: bool,
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}
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fn setup(mut state: ResMut<State>, asset_server: Res<AssetServer>) {
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state.handle = asset_server.load("data/asset.custom");
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}
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fn print_on_load(mut state: ResMut<State>, custom_assets: Res<Assets<CustomAsset>>) {
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let custom_asset = custom_assets.get(&state.handle);
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if state.printed || custom_asset.is_none() {
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return;
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}
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info!("Custom asset loaded: {:?}", custom_asset.unwrap());
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state.printed = true;
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}
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