mirror of
https://github.com/bevyengine/bevy
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1efc762924
# Objective
- Introduce a stable alternative to
[`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html).
- Rewrite of #5805 with heavy inspiration in design.
- On the path to #5830.
- Part of solving #3327.
## Solution
- Add a `TypePath` trait for static stable type path/name information.
- Add a `TypePath` derive macro.
- Add a `impl_type_path` macro for implementing internal and foreign
types in `bevy_reflect`.
---
## Changelog
- Added `TypePath` trait.
- Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`.
- Added a `TypePath` derive macro.
- Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on
internal and foreign types in `bevy_reflect`.
- Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to
`(Non)GenericTypedCell<T>` which allows us to be generic over both
`TypeInfo` and `TypePath`.
- `TypePath` is now a supertrait of `Asset`, `Material` and
`Material2d`.
- `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be
specified.
- `impl_reflect_value` needs to either specify path starting with a
double colon (`::core::option::Option`) or an `in my_crate::foo`
declaration.
- Added `bevy_reflect_derive::ReflectTypePath`.
- Most uses of `Ident` in `bevy_reflect_derive` changed to use
`ReflectTypePath`.
## Migration Guide
- Implementors of `Asset`, `Material` and `Material2d` now also need to
derive `TypePath`.
- Manual implementors of `Reflect` will need to implement the new
`get_type_path` method.
## Open Questions
- [x] ~This PR currently does not migrate any usages of
`std::any::type_name` to use `bevy_reflect::TypePath` to ease the review
process. Should it?~ Migration will be left to a follow-up PR.
- [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to
satisfy new bounds, mostly when deriving `TypeUuid`. Should we make
`TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in
favour of
`TypePath`?](2afbd85532 (r961067892))
67 lines
1.7 KiB
Rust
67 lines
1.7 KiB
Rust
//! Implements loader for a custom asset type.
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use bevy::{
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asset::{AssetLoader, LoadContext, LoadedAsset},
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prelude::*,
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reflect::{TypePath, TypeUuid},
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utils::BoxedFuture,
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};
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use serde::Deserialize;
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#[derive(Debug, Deserialize, TypeUuid, TypePath)]
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#[uuid = "39cadc56-aa9c-4543-8640-a018b74b5052"]
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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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impl AssetLoader for CustomAssetLoader {
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fn load<'a>(
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&'a self,
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bytes: &'a [u8],
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load_context: &'a mut LoadContext,
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) -> BoxedFuture<'a, Result<(), bevy::asset::Error>> {
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Box::pin(async move {
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let custom_asset = ron::de::from_bytes::<CustomAsset>(bytes)?;
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load_context.set_default_asset(LoadedAsset::new(custom_asset));
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Ok(())
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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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.add_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: ResMut<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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