01649f13e2
# Objective This is a necessary precursor to #9122 (this was split from that PR to reduce the amount of code to review all at once). Moving `!Send` resource ownership to `App` will make it unambiguously `!Send`. `SubApp` must be `Send`, so it can't wrap `App`. ## Solution Refactor `App` and `SubApp` to not have a recursive relationship. Since `SubApp` no longer wraps `App`, once `!Send` resources are moved out of `World` and into `App`, `SubApp` will become unambiguously `Send`. There could be less code duplication between `App` and `SubApp`, but that would break `App` method chaining. ## Changelog - `SubApp` no longer wraps `App`. - `App` fields are no longer publicly accessible. - `App` can no longer be converted into a `SubApp`. - Various methods now return references to a `SubApp` instead of an `App`. ## Migration Guide - To construct a sub-app, use `SubApp::new()`. `App` can no longer convert into `SubApp`. - If you implemented a trait for `App`, you may want to implement it for `SubApp` as well. - If you're accessing `app.world` directly, you now have to use `app.world()` and `app.world_mut()`. - `App::sub_app` now returns `&SubApp`. - `App::sub_app_mut` now returns `&mut SubApp`. - `App::get_sub_app` now returns `Option<&SubApp>.` - `App::get_sub_app_mut` now returns `Option<&mut SubApp>.`
64 lines
2.1 KiB
Rust
64 lines
2.1 KiB
Rust
use std::marker::PhantomData;
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use bevy_app::{App, Plugin};
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use bevy_ecs::prelude::*;
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pub use bevy_render_macros::ExtractResource;
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use crate::{Extract, ExtractSchedule, RenderApp};
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/// Describes how a resource gets extracted for rendering.
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///
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/// Therefore the resource is transferred from the "main world" into the "render world"
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/// in the [`ExtractSchedule`] step.
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pub trait ExtractResource: Resource {
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type Source: Resource;
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/// Defines how the resource is transferred into the "render world".
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fn extract_resource(source: &Self::Source) -> Self;
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}
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/// This plugin extracts the resources into the "render world".
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///
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/// Therefore it sets up the[`ExtractSchedule`] step
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/// for the specified [`Resource`].
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pub struct ExtractResourcePlugin<R: ExtractResource>(PhantomData<R>);
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impl<R: ExtractResource> Default for ExtractResourcePlugin<R> {
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fn default() -> Self {
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Self(PhantomData)
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}
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}
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impl<R: ExtractResource> Plugin for ExtractResourcePlugin<R> {
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fn build(&self, app: &mut App) {
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if let Some(render_app) = app.get_sub_app_mut(RenderApp) {
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render_app.add_systems(ExtractSchedule, extract_resource::<R>);
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}
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}
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}
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/// This system extracts the resource of the corresponding [`Resource`] type
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pub fn extract_resource<R: ExtractResource>(
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mut commands: Commands,
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main_resource: Extract<Option<Res<R::Source>>>,
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target_resource: Option<ResMut<R>>,
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) {
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if let Some(main_resource) = main_resource.as_ref() {
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if let Some(mut target_resource) = target_resource {
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if main_resource.is_changed() {
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*target_resource = R::extract_resource(main_resource);
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}
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} else {
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#[cfg(debug_assertions)]
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if !main_resource.is_added() {
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bevy_utils::warn_once!(
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"Removing resource {} from render world not expected, adding using `Commands`.
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This may decrease performance",
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std::any::type_name::<R>()
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);
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}
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commands.insert_resource(R::extract_resource(main_resource));
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}
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}
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}
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