ffecb05a0a
This makes the [New Bevy Renderer](#2535) the default (and only) renderer. The new renderer isn't _quite_ ready for the final release yet, but I want as many people as possible to start testing it so we can identify bugs and address feedback prior to release. The examples are all ported over and operational with a few exceptions: * I removed a good portion of the examples in the `shader` folder. We still have some work to do in order to make these examples possible / ergonomic / worthwhile: #3120 and "high level shader material plugins" are the big ones. This is a temporary measure. * Temporarily removed the multiple_windows example: doing this properly in the new renderer will require the upcoming "render targets" changes. Same goes for the render_to_texture example. * Removed z_sort_debug: entity visibility sort info is no longer available in app logic. we could do this on the "render app" side, but i dont consider it a priority.
45 lines
1.5 KiB
Markdown
45 lines
1.5 KiB
Markdown
# B0002
|
|
|
|
To keep [Rust rules on references](https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#the-rules-of-references) (either one mutable reference or any number of immutable references) on a resource, it is not possible to have more than one resource of a kind if one is mutable in the same system. This can happen between [`Res<T>`](https://docs.rs/bevy/*/bevy/ecs/system/struct.Res.html) and [`ResMut<T>`](https://docs.rs/bevy/*/bevy/ecs/system/struct.ResMut.html) for the same `T`, or between [`NonSend<T>`](https://docs.rs/bevy/*/bevy/ecs/system/struct.NonSend.html) and [`NonSendMut<T>`](https://docs.rs/bevy/*/bevy/ecs/system/struct.NonSendMut.html) for the same `T`.
|
|
|
|
Erroneous code example:
|
|
|
|
```rust,should_panic
|
|
use bevy::prelude::*;
|
|
|
|
fn update_materials(
|
|
mut material_updater: ResMut<Assets<StandardMaterial>>,
|
|
current_materials: Res<Assets<StandardMaterial>>,
|
|
) {
|
|
// ...
|
|
}
|
|
|
|
fn main() {
|
|
App::new()
|
|
.add_plugins(DefaultPlugins)
|
|
.add_system(update_materials)
|
|
.run();
|
|
}
|
|
```
|
|
|
|
This will panic, as it's not possible to have both a mutable and an immutable resource on `State` at the same time.
|
|
|
|
As a mutable resource already provide access to the current resource value, you can remove the immutable resource.
|
|
|
|
```rust,no_run
|
|
use bevy::prelude::*;
|
|
|
|
fn update_materials(
|
|
mut material_updater: ResMut<Assets<StandardMaterial>>,
|
|
) {
|
|
// ...
|
|
}
|
|
|
|
fn main() {
|
|
App::new()
|
|
.add_plugins(DefaultPlugins)
|
|
.add_system(update_materials)
|
|
.run();
|
|
}
|
|
```
|