Be explicit that extraction is to RenderApp for SyncComponent / ExtractComponent / ExtractResource

[Zeophlite]

Objective

• Bevy's extraction process is implicitly for copying data from the main sub-app to the RenderApp sub-app
• There is two user facing ways to set a component as extractable from the main world to the render world, #[derive(ExtractComponent)] (this is preferential) , or impl ExtractComponent for Foo {} (similarly for ExtractResource and SyncComponent ) .
• To make extraction possible to different sub-apps, we need to mark all these as explicitly for RenderApp
• Step towards making the extract infra is reusable for non-rendering crates (see bevy_extract tracking #24483 )

Solution

• Allow ExtractComponent , ExtractResource and SyncComponent to specify the AppLabel the trait is implemented for. The corresponding plugin is only implemented for RenderApp .
• For each explicit impl, specify RenderApp , e.g. impl ExtractComponent<RenderApp> for Foo {}
• For each derive ExtractComponent and ExtractResource , specify the AppLabel with the attribute #[extract_app(RenderApp)]
• This PR has no functionality change, that comes in the followup PRs (see above issue, next PR is Make ExtractComponentPlugin etc. generic on AppLabel #24423 )

Reviewer Notes

Wow 64 files changed! But it's really just 7 files, the rest is mechanical

• _release-content/migration-guides/extract-extract-b.md - summarises the changes in the rest of the files
• crates/bevy_render/macros/src/extract_component.rs - changes to derive(ExtractComponent)
• crates/bevy_render/macros/src/extract_resource.rs - changes to derive(ExtractResource)
• crates/bevy_render/macros/src/lib.rs - changes to macro call sites
• crates/bevy_render/src/extract_component.rs - changes to ExtractComponent trait
• crates/bevy_render/src/extract_resource.rs - changes to ExtractResource trait
• crates/bevy_render/src/sync_component.rs - changes to SyncComponent trait

I suggest first reading the ExtractResource changes as a starting point

Testing

• CI
• cargo run --example animated_mesh
• Follow up PRs (see tracking issue) extend this all the way to multiple extraction

[kfc35]

looks good to me

[kfc35]

Approving but trusting you’ll clean up some of the docs that might be outdated for the affected structs

[Zeophlite]

https://pixel-eagle.com/project/b25a040a-a980-4602-b90c-d480ab84076d/run/18220/compare/18213
So Pixel eagle is being weird, there's some changes due to entity number changes, and that's fine, but then there's weird things like pcss and tonemapping rendering incorrectly in pixel eagle (renders correctly on my mac).

[IceSentry]

LGTM

[kristoff3r]

I got distracted by other stuff, I'll take a look at this soon