2 unstable releases
0.2.0 | Jul 10, 2024 |
---|---|
0.1.0 | Apr 16, 2024 |
#1357 in Game dev
7KB
59 lines
seldom_singleton
seldom_singleton
adds a helper SystemParam
for when you have a resource containing a handle. If
you're using Bevy's asset system to, for example, load a list of items in the game and their
properties, you'd end up with a handle in a resource, and you'd need to get Res<Assets<MyItems>>
to get the asset you need. This crate adds a helper that lets you avoid the additional system param.
This is a very small crate. You can just copy the source code into your project to avoid adding a dependency.
Before:
#[derive(Asset, TypePath)]
struct MyAsset;
#[derive(Resource, Deref)]
struct MySingleton(Handle<MyAsset>);
fn my_system(my_assets: Res<Assets<MyAsset>>, my_singleton: Res<MySingleton>) {
// Return if the asset doesn't exist
let Some(my_asset) = my_assets.get(&**my_singleton) else {
return;
};
// or panic
let my_asset = my_assets.get(&**my_singleton).unwrap();
}
After:
#[derive(Asset, TypePath)]
struct MyAsset;
// Your resource. Add it to the world yourself.
#[derive(Resource, Deref)]
struct MySingleton(Handle<MyAsset>);
// `AssetSingleton` is this crate's `SystemParam`. This type definition can help reduce boilerplate
// a bit, but it's optional. There's also `AssetSingletonMut`.
type MySingletonParam<'w> = AssetSingleton<'w, MySingleton>;
fn my_system(my_singleton: MySingletonParam) {
// Return if the asset doesn't exist
let Some(my_asset) = my_singleton.get() else {
return;
};
// or panic
let my_asset = my_singleton.unwrap();
// `AssetSingletonMut` has `get_mut` and `unwrap_mut`
}
Usage
Add to your Cargo.toml
# Replace * with your desired version
[dependencies]
seldom_singleton = "*"
Compatibility
Bevy | seldom_singleton |
---|---|
0.14 | 0.2 |
0.13 | 0.1 |
License
seldom_singleton
is dual-licensed under MIT and Apache 2.0 at your option.
Contributing
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
Dependencies
~23–57MB
~1M SLoC