Migration guide:
# Objective
Currently there seems to be no way to enable picking through
render-to-texture cameras
## Solution
This PR allows casting rays from the game code quite easily.
## Testing
- I've tested these in my game and it seems to work
- I haven't tested edge cases
---
## Showcase
<details>
<summary>Click to view showcase</summary>
```rust
fn cast_rays_from_additional_camera(
cameras: Query<(&GlobalTransform, &Camera, Entity), With<RenderToTextureCamera>>,
mut rays: ResMut<RayMap>,
pointers: Query<(&PointerId, &PointerLocation)>,
) {
for (camera_global_transform, camera, camera_entity) in &cameras {
for (pointer_id, pointer_loc) in &pointers {
let Some(viewport_pos) = pointer_loc.location() else {
continue;
};
// if camera result is transformed in any way, the reverse transformation
// should be applied somewhere here
let ray = camera
.viewport_to_world(camera_global_transform, viewport_pos.position)
.ok();
if let Some(r) = ray {
rays.map.insert(RayId::new(camera_entity, *pointer_id), r);
}
}
}
}
```
</details>
## Migration Guide
The `bevy_picking::backend::ray::RayMap::map` method is removed as
redundant,
In systems using `Res<RayMap>` replace `ray_map.map()` with
`&ray_map.map`
# Objective
- The prepass pipeline has a generic bound on the specialize function
but 95% of it doesn't need it
## Solution
- Move most of the fields to an internal struct and use a separate
specialize function for those fields
## Testing
- Ran the 3d_scene and it worked like before
---
## Migration Guide
If you were using a field of the `PrepassPipeline`, most of them have
now been move to `PrepassPipeline::internal`.
## Notes
Here's the cargo bloat size comparison (from this tool
https://github.com/bevyengine/bevy/discussions/14864):
```
before:
(
"<bevy_pbr::prepass::PrepassPipeline<M> as bevy_render::render_resource::pipeline_specializer::SpecializedMeshPipeline>::specialize",
25416,
0.05582993,
),
after:
(
"<bevy_pbr::prepass::PrepassPipeline<M> as bevy_render::render_resource::pipeline_specializer::SpecializedMeshPipeline>::specialize",
2496,
0.005490916,
),
(
"bevy_pbr::prepass::PrepassPipelineInternal::specialize",
11444,
0.025175499,
),
```
The size for the specialize function that is generic is now much
smaller, so users won't need to recompile it for every material.
# Objective
- #18495
## Solution
- The code in the PR #18232 accidentally used a vertex index as a
triangle index, causing the wrong triangle to be used for normal
computation and if the triangle went out of bounds, it would skip the
ray-hit.
- Don't do that.
## Testing
- Run `cargo run --example mesh_picking`
# Objective
Enabling `serialize`, `critical-section`, or `async-executor` would
improperly enable `bevy_math`, `bevy_input`, and/or `bevy_transform`.
This was caused by those crates previously being required but are now
optional (gated behind `std` and/or `libm`).
## Solution
- Added `?` to features not intended to enable those crates
## Testing
- CI
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/11682
## Solution
- https://github.com/bevyengine/bevy/pull/4086 introduced an
optimization to not do redundant calculations, but did not take into
account changes to the resource `global_lights`. I believe that my patch
includes the optimization benefit but adds the required nuance to fix
said bug.
## Testing
The example originally given by
[@kirillsurkov](https://github.com/kirillsurkov) and then updated by me
to bevy 15.3 here:
https://github.com/bevyengine/bevy/issues/11682#issuecomment-2746287416
will not have shadows without this patch:
```rust
use bevy::prelude::*;
#[derive(Resource)]
struct State {
x: f32,
}
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, update)
.insert_resource(State { x: -40.0 })
.run();
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
commands.spawn((
Mesh3d(meshes.add(Circle::new(4.0))),
MeshMaterial3d(materials.add(Color::WHITE)),
));
commands.spawn((
Mesh3d(meshes.add(Cuboid::new(1.0, 1.0, 1.0))),
MeshMaterial3d(materials.add(Color::linear_rgb(0.0, 1.0, 0.0))),
));
commands.spawn((
PointLight {
shadows_enabled: true,
..default()
},
Transform::from_xyz(4.0, 8.0, 4.0),
));
commands.spawn(Camera3d::default());
}
fn update(mut state: ResMut<State>, mut camera: Query<&mut Transform, With<Camera3d>>) {
let mut camera = camera.single_mut().unwrap();
let t = Vec3::new(state.x, 0.0, 10.0);
camera.translation = t;
camera.look_at(t - Vec3::Z, Vec3::Y);
state.x = 0.0;
}
```
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
# Objective
When introduced, `Single` was intended to simply be silently skipped,
allowing for graceful and efficient handling of systems during invalid
game states (such as when the player is dead).
However, this also caused missing resources to *also* be silently
skipped, leading to confusing and very hard to debug failures. In
0.15.1, this behavior was reverted to a panic, making missing resources
easier to debug, but largely making `Single` (and `Populated`)
worthless, as they would panic during expected game states.
Ultimately, the consensus is that this behavior should differ on a
per-system-param basis. However, there was no sensible way to *do* that
before this PR.
## Solution
Swap `SystemParam::validate_param` from a `bool` to:
```rust
/// The outcome of system / system param validation,
/// used by system executors to determine what to do with a system.
pub enum ValidationOutcome {
/// All system parameters were validated successfully and the system can be run.
Valid,
/// At least one system parameter failed validation, and an error must be handled.
/// By default, this will result in1 a panic. See [crate::error] for more information.
///
/// This is the default behavior, and is suitable for system params that should *always* be valid,
/// either because sensible fallback behavior exists (like [`Query`] or because
/// failures in validation should be considered a bug in the user's logic that must be immediately addressed (like [`Res`]).
Invalid,
/// At least one system parameter failed validation, but the system should be skipped due to [`ValidationBehavior::Skip`].
/// This is suitable for system params that are intended to only operate in certain application states, such as [`Single`].
Skipped,
}
```
Then, inside of each `SystemParam` implementation, return either Valid,
Invalid or Skipped.
Currently, only `Single`, `Option<Single>` and `Populated` use the
`Skipped` behavior. Other params (like resources) retain their current
failing
## Testing
Messed around with the fallible_params example. Added a pair of tests:
one for panicking when resources are missing, and another for properly
skipping `Single` and `Populated` system params.
## To do
- [x] get https://github.com/bevyengine/bevy/pull/18454 merged
- [x] fix the todo!() in the macro-powered tuple implementation (please
help 🥺)
- [x] test
- [x] write a migration guide
- [x] update the example comments
## Migration Guide
Various system and system parameter validation methods
(`SystemParam::validate_param`, `System::validate_param` and
`System::validate_param_unsafe`) now return and accept a
`ValidationOutcome` enum, rather than a `bool`. The previous `true`
values map to `ValidationOutcome::Valid`, while `false` maps to
`ValidationOutcome::Invalid`.
However, if you wrote a custom schedule executor, you should now respect
the new `ValidationOutcome::Skipped` parameter, skipping any systems
whose validation was skipped. By contrast, `ValidationOutcome::Invalid`
systems should also be skipped, but you should call the
`default_error_handler` on them first, which by default will result in a
panic.
If you are implementing a custom `SystemParam`, you should consider
whether failing system param validation is an error or an expected
state, and choose between `Invalid` and `Skipped` accordingly. In Bevy
itself, `Single` and `Populated` now once again skip the system when
their conditions are not met. This is the 0.15.0 behavior, but stands in
contrast to the 0.15.1 behavior, where they would panic.
---------
Co-authored-by: MiniaczQ <xnetroidpl@gmail.com>
Co-authored-by: Dmytro Banin <banind@cs.washington.edu>
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
There are two related problems here:
1. Users should be able to change the fallback behavior of *all*
ECS-based errors in their application by setting the
`GLOBAL_ERROR_HANDLER`. See #18351 for earlier work in this vein.
2. The existing solution (#15500) for customizing this behavior is high
on boilerplate, not global and adds a great deal of complexity.
The consensus is that the default behavior when a parameter fails
validation should be set based on the kind of system parameter in
question: `Single` / `Populated` should silently skip the system, but
`Res` should panic. Setting this behavior at the system level is a
bandaid that makes getting to that ideal behavior more painful, and can
mask real failures (if a resource is missing but you've ignored a system
to make the Single stop panicking you're going to have a bad day).
I've removed the existing `ParamWarnPolicy`-based configuration, and
wired up the `GLOBAL_ERROR_HANDLER`/`default_error_handler` to the
various schedule executors to properly plumb through errors .
Additionally, I've done a small cleanup pass on the corresponding
example.
I've run the `fallible_params` example, with both the default and a
custom global error handler. The former panics (as expected), and the
latter spams the error console with warnings 🥲
1. Currently, failed system param validation will result in endless
console spam. Do you want me to implement a solution for warn_once-style
debouncing somehow?
2. Currently, the error reporting for failed system param validation is
very limited: all we get is that a system param failed validation and
the name of the system. Do you want me to implement improved error
reporting by bubbling up errors in this PR?
3. There is broad consensus that the default behavior for failed system
param validation should be set on a per-system param basis. Would you
like me to implement that in this PR?
My gut instinct is that we absolutely want to solve 2 and 3, but it will
be much easier to do that work (and review it) if we split the PRs
apart.
`ParamWarnPolicy` and the `WithParamWarnPolicy` have been removed
completely. Failures during system param validation are now handled via
the `GLOBAL_ERROR_HANDLER`: please see the `bevy_ecs::error` module docs
for more information.
---------
Co-authored-by: MiniaczQ <xnetroidpl@gmail.com>
# Objective
Fixes#18461
Apparently `RustRover` creates a temporary file with a tilde like
`load_scene_example.scn.ron~` and at the moment of calling
`.canonicalize()` the file does not exists anymore.
## Solution
Not call `.unwrap()` and return `None` fixes the issue.
## Testing
- `cargo ci`: OK
- Tested the `scene` example with `file_watcher` feature and it works as
expected.
Co-authored-by: François Mockers <mockersf@gmail.com>
Reduce dependencies on `bevy_render` by preferring `bevy_mesh` imports
over `bevy_render` re-exports.
```diff
- use bevy_render::mesh::Mesh;
+ use bevy_mesh::Mesh;
```
This is intended to help with #18423 (render crate restructure). Affects
`bevy_gltf`, `bevy_animation` and `bevy_picking`.
As part of #18423, I'm assuming there'll be a push to make crates less
dependent on the big render crates. This PR seemed like a small and safe
step along that path - it only changes imports and makes the `bevy_mesh`
crate dependency explicit in `Cargo.toml`. Any remaining dependencies on
`bevy_render` are true dependencies.
```
cargo run --example testbed_3d
cargo run --example mesh_picking
```
# Objective
- Fixes#18225
## Solution
- Updated `accesskit` version requirement from 0.17 to 0.18
- Updated `accesskit_winit` version requirement from 0.23 to 0.25
## Testing
- Ran CI checks locally.
---------
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Instead of extracting an individual sprite per glyph of a text spawn or
slice of a nine-patched sprite, add a buffer to store the extracted
slice geometry.
Fixes#16972
* New struct `ExtractedSlice` to hold sprite slice size, position and
atlas info (for text each glyph is a slice).
* New resource `ExtractedSlices` that wraps the `ExtractedSlice` buffer.
This is a separate resource so it can be used without sprites (with a
text material, for example).
* New enum `ExtractedSpriteKind` with variants `Single` and `Slices`.
`Single` represents a single sprite, `Slices` contains a range into the
`ExtractedSlice` buffer.
* Only queue a single `ExtractedSprite` for sets of glyphs or slices and
push the geometry for each individual slice or glyph into the
`ExtractedSlice` buffer.
* Modify `ComputedTextureSlices` to return an `ExtractedSlice` iterator
instead of `ExtractedSprites`.
* Modify `extract_text2d_sprite` to only queue new `ExtractedSprite`s on
font changes and otherwise push slices.
I don't like the name `ExtractedSpriteKind` much, it's a bit redundant
and too haskellish. But although it's exported, it's not something users
will interact with most of the time so don't want to overthink it.
yellow = this pr, red = main
```cargo run --example many_glyphs --release --features "trace_tracy" -- --no-ui```
<img width="454" alt="many-glyphs" src="https://github.com/user-attachments/assets/711b52c9-2d4d-43c7-b154-e81a69c94dce" />
```cargo run --example many_text2d --release --features "trace_tracy"```
<img width="415" alt="many-text2d"
src="https://github.com/user-attachments/assets/5ea2480a-52e0-4cd0-9f12-07405cf6b8fa"
/>
* `ExtractedSprite` has a new `kind: ExtractedSpriteKind` field with
variants `Single` and `Slices`.
- `Single` represents a single sprite. `ExtractedSprite`'s `anchor`,
`rect`, `scaling_mode` and `custom_size` fields have been moved into
`Single`.
- `Slices` contains a range that indexes into a new resource
`ExtractedSlices`. Slices are used to draw elements composed from
multiple sprites such as text or nine-patched borders.
* `ComputedTextureSlices::extract_sprites` has been renamed to
`extract_slices`. Its `transform` and `original_entity` parameters have
been removed.
---------
Co-authored-by: Kristoffer Søholm <k.soeholm@gmail.com>
Remove `critical-section` from required dependencies, allowing linking
without any features.
- Switched from `OnceCell` to `LazyLock`
- Removed `std` feature from `bevy_dylib` (proof that it works)
- CI
- building bevy_winit on linux fails with
```
error: The platform you're compiling for is not supported by winit
--> /home/runner/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/winit-0.30.9/src/platform_impl/mod.rs:78:1
|
78 | compile_error!("The platform you're compiling for is not supported by winit");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
- this blocks publishing Bevy from linux during the verification step
- Enable `x11` by default when building bevy_winit, and disable default
features of bevy_winit in bevy_internal
- This doesn't change anything when depending on Bevy
# Objective
- Some crates don't compile or have clippy warnings when building for
wasm32
## Solution
- bevy_asset: unused lifetime
- bevy_gltf: the error is not too large in wasm32
- bevy_remote: fails to compile as feature http is also gated on wasm32
- bevy_winit: unused import `error`
# Objective
`cargo clippy -p bevy_asset` warns on a pair of lints on my Windows 10
development machine (return from let binding).
## Solution
Addressed them!
## Testing
- CI
# Objective
Bevy 0.15 used to have methods on `Children` for sorting and reordering
them. This is very important, because in certain situations, the order
of children matters. For example, in the context of UI nodes.
These methods are missing/omitted/forgotten in the current version,
after the Relationships rework.
Without them, it is impossible for me to upgrade `iyes_perf_ui` to Bevy
0.16.
## Solution
Reintroduce the methods. This PR simply copy-pastes them from Bevy 0.15.
# Objective
- Compiling `bevy_time` without the `std`-feature results in a
`clippy::unnecessary-literal-unwrap`.
## Solution
- Fix lint error
## Testing
- CI
---
- Compiling `bevy_a11y` without default features fails because you need
to select a floating point backed. But you actually don't need it, this
requirement is from an unused linkage to `bevy_input_focus`
- Remove link
- CI
---------
Co-authored-by: François Mockers <mockersf@gmail.com>
- Compile failure with `bevy_anti_aliasing` due to `dds` feature not
enabling `bevy_core_pipeline/dds`, causing a public API desync.
- Ensured feature is enabled
- CI
# Objective
Noticed that `bevy_remote` fails to compile without default features.
## Solution
Adjusted offending method to avoid reliance on `http` module when it is
disabled.
## Testing
- CI
- `cargo clippy -p bevy_remote --no-default-features`
# Objective
Every time I run `cargo clippy -p bevy_ecs` it pops up and it's
distracting.
## Solution
Removed unnecessary returns. The blocks themselves are necessary or the
`#[cfg(...)]` doesn't apply properly
## Testing
`cargo clippy -p bevy_ecs` + ci build tests
# Objective
There are currently too many disparate ways to handle entity mapping,
especially after #17687. We now have MapEntities, VisitEntities,
VisitEntitiesMut, Component::visit_entities,
Component::visit_entities_mut.
Our only known use case at the moment for these is entity mapping. This
means we have significant consolidation potential.
Additionally, VisitEntitiesMut cannot be implemented for map-style
collections like HashSets, as you cant "just" mutate a `&mut Entity`.
Our current approach to Component mapping requires VisitEntitiesMut,
meaning this category of entity collection isn't mappable. `MapEntities`
is more generally applicable. Additionally, the _existence_ of the
blanket From impl on VisitEntitiesMut blocks us from implementing
MapEntities for HashSets (or any types we don't own), because the owner
could always add a conflicting impl in the future.
## Solution
Use `MapEntities` everywhere and remove all "visit entities" usages.
* Add `Component::map_entities`
* Remove `Component::visit_entities`, `Component::visit_entities_mut`,
`VisitEntities`, and `VisitEntitiesMut`
* Support deriving `Component::map_entities` in `#[derive(Coomponent)]`
* Add `#[derive(MapEntities)]`, and share logic with the
`Component::map_entities` derive.
* Add `ComponentCloneCtx::queue_deferred`, which is command-like logic
that runs immediately after normal clones. Reframe `FromWorld` fallback
logic in the "reflect clone" impl to use it. This cuts out a lot of
unnecessary work and I think justifies the existence of a pseudo-command
interface (given how niche, yet performance sensitive this is).
Note that we no longer auto-impl entity mapping for ` IntoIterator<Item
= &'a Entity>` types, as this would block our ability to implement cases
like `HashMap`. This means the onus is on us (or type authors) to add
explicit support for types that should be mappable.
Also note that the Component-related changes do not require a migration
guide as there hasn't been a release with them yet.
## Migration Guide
If you were previously implementing `VisitEntities` or
`VisitEntitiesMut` (likely via a derive), instead use `MapEntities`.
Those were almost certainly used in the context of Bevy Scenes or
reflection via `ReflectMapEntities`. If you have a case that uses
`VisitEntities` or `VisitEntitiesMut` directly, where `MapEntities` is
not a viable replacement, please let us know!
```rust
// before
#[derive(VisitEntities, VisitEntitiesMut)]
struct Inventory {
items: Vec<Entity>,
#[visit_entities(ignore)]
label: String,
}
// after
#[derive(MapEntities)]
struct Inventory {
#[entities]
items: Vec<Entity>,
label: String,
}
```
# Objective
Const values should be more ergonomic to insert, since this is too
verbose
``` rust
#[derive(Component)]
#[require(
LockedAxes(||LockedAxes::ROTATION_LOCKED),
)]
pub struct CharacterController;
```
instead, users can now abbreviate that nonsense like this
``` rust
#[derive(Component)]
#[require(
LockedAxes = ROTATION_LOCKED),
)]
pub struct CharacterController;
```
it also works for enum labels.
I chose to omit the type, since were trying to reduce typing here. The
alternative would have been this:
```rust
#[require(
LockedAxes = LockedAxes::ROTATION_LOCKED),
)]
```
This of course has its disadvantages, since the const has to be
associated, but the old closure method is still possible, so I dont
think its a problem.
- Fixes#16720
## Testing
I added one new test in the docs, which also explain the new change. I
also saw that the docs for the required components on line 165 was
missing an assertion, so I added it back in
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Contributes to #18238
Updates the `sprite_slice`, `spatial_audio_3d` and `spatial_audio_2d`
examples to use the `children!` macro.
## Solution
Updates examples to use the Improved Spawning API merged in
https://github.com/bevyengine/bevy/pull/17521
## Testing
- Did you test these changes? If so, how?
- Opened the examples before and after and verified the same behavior
was observed. I did this on Ubuntu 24.04.2 LTS using `--features
wayland`.
- Are there any parts that need more testing?
- Other OS's and features can't hurt, but this is such a small change it
shouldn't be a problem.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Run the examples yourself with and without these changes.
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
- see above
---
## Showcase
n/a
## Migration Guide
n/a
# Objective
Fixes#18429
## Solution
Add syncing to the render world for the `ColoredMesh2d` component
## Testing
Ran the example and it works as intended without the warning spam
# Objective
While working on #18058 I realized I could use
`RelationshipTargetCollection::new`, so I added it.
## Solution
- Add `RelationshipTargetCollection::new`
- Add `RelationshipTargetCollection::reserve`. Could generally be useful
when doing micro-optimizations.
- Add `RelationshipTargetCollection::shrink_to_fit`. Rust collections
generally don't shrink when removing elements. Might be a good idea to
call this once in a while.
## Testing
`cargo clippy`
---
## Showcase
`RelationshipSourceCollection` now implements `new`, `reserve` and
`shrink_to_fit` to give greater control over how much memory it
consumes.
## Migration Guide
Any type implementing `RelationshipSourceCollection` now needs to also
implement `new`, `reserve` and `shrink_to_fit`. `reserve` and
`shrink_to_fit` can be made no-ops if they conceptually mean nothing to
a collection.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
correctly load gltfs without explicit bindposes
## Solution
use identity matrices if bindposes are not found.
note: currently does nothing, as gltfs without explicit bindposes fail
to load, see <https://github.com/gltf-rs/gltf/pull/449>
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
Add a way to efficiently replace a set of specifically related entities
with a new set.
Closes#18041
## Solution
Add new `replace_(related/children)` to `EntityWorldMut` and friends.
## Testing
Added a new test to `hierarchy.rs` that specifically check if
`replace_children` actually correctly replaces the children on a entity
while keeping the original one.
---
## Showcase
`EntityWorldMut` and `EntityCommands` can now be used to efficiently
replace the entities a entity is related to.
```rust
/// `parent` has 2 children. `entity_a` and `entity_b`.
assert_eq!([entity_a, entity_b], world.entity(parent).get::<Children>());
/// Replace `parent`s children with `entity_a` and `entity_c`
world.entity_mut(parent).replace_related(&[entity_a, entity_c]);
/// `parent` now has 2 children. `entity_a` and `entity_c`.
///
/// `replace_children` has saved time by not removing and reading
/// the relationship between `entity_a` and `parent`
assert_eq!([entity_a, entity_c], world.entity(parent).get::<Children>());
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
## Objective
Fix `bevy_ecs` doc tests failing when used with `--all-features`.
```
---- crates\bevy_ecs\src\error\handler.rs - error::handler::GLOBAL_ERROR_HANDLER (line 87) stdout ----
error[E0425]: cannot find function `default_error_handler` in this scope
--> crates\bevy_ecs\src\error\handler.rs:92:24
|
8 | let error_handler = default_error_handler();
| ^^^^^^^^^^^^^^^^^^^^^ not found in this scope
```
I happened to come across this while testing #12207. I'm not sure it
actually needs fixing but seemed worth a go
## Testing
```
cargo test --doc -p bevy_ecs --all-features
```
## Side Notes
The CI misses this error as it doesn't use `--all-features`. Perhaps it
should?
I tried adding `--all-features` to `ci/src/commands/doc_tests.rs` but
this triggered a linker error:
```
Compiling bevy_dylib v0.16.0-dev (C:\Projects\bevy\crates\bevy_dylib)
error: linking with `link.exe` failed: exit code: 1189
= note: LINK : fatal error LNK1189: library limit of 65535 objects exceeded␍
```
# Objective
Separate example explanation (file docblock) and the code so they can be
layout differently in the website and we can give a higher importance to
the explanation on the [website search
tool](https://github.com/bevyengine/bevy-website/pull/1935). This would
also allow us to improve the examples so they become even more like a
cookbook.
## Solution
Update the `example-showcase` tool to extract the example file docblock
and write it as the example markdown content. This allows us to access
the explanation via `page.content` in Zola.
## Testing
I've checked that the output is correct after running the tool and it
doesn't throw any error. I've also validated that the approach will work
on the website.
## Showcase
This is a quick and dirty example of what we could do in the web
examples after the change. When we implement the real thing we can put
the explanation on a sidebar or explore other layout options.
<img width="1362" alt="image"
src="https://github.com/user-attachments/assets/6738542e-31c3-41cd-972a-7fa2e942e85d"
/>
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/18332
## Solution
- Move specialize_shadows to ManageViews so that it can run after
prepare_lights, so that shadow views exist for specialization.
- Unfortunately this means that specialize_shadows is no longer in
PrepareMeshes like the rest of the specialization systems.
## Testing
- Ran anti_aliasing example, switched between the different AA options,
observed no glitches.
# Objective
For materials that aren't being used or a visible entity doesn't have an
instance of, we were unnecessarily constantly checking whether they
needed specialization, saying yes (because the material had never been
specialized for that entity), and failing to look up the material
instance.
## Solution
If an entity doesn't have an instance of the material, it can't possibly
need specialization, so exit early before spending time doing the check.
Fixes#18388.
- bevy_dylib fails to build:
```
Compiling bevy_dylib v0.16.0-rc.1 (/bevy/crates/bevy_dylib)
error: linking with `cc` failed: exit status: 1
|
= note: some arguments are omitted. use `--verbose` to show all linker arguments
= note: Undefined symbols for architecture arm64:
"__critical_section_1_0_acquire", referenced from:
critical_section::with::h00cfbe529dea9dc9 in libbevy_tasks-53c9db6a3865f250.rlib[58](bevy_tasks-53c9db6a3865f250.evom2xwveqp508omiiqb25xig.rcgu.o)
"__critical_section_1_0_release", referenced from:
core::ptr::drop_in_place$LT$critical_section..with..Guard$GT$::hfa034e0208e1a49d in libbevy_tasks-53c9db6a3865f250.rlib[48](bevy_tasks-53c9db6a3865f250.d9dwgpd0156zfn2h5z5ff94zn.rcgu.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```
- enable `std` when building bevy_dylib
---------
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
- `collect_path` is only declared when feature `bevy_animation` is
enabled
- it is imported without checking for the feature, not compiling when
not enabled
## Solution
- Gate the import
# Objective
@cart noticed some issues with my work in
https://github.com/bevyengine/bevy/pull/17348#discussion_r2001815637,
which I somehow missed before merging the PR.
## Solution
- feature gate the UiPickingPlugin correctly
- don't manually add the picking plugins
## Testing
Ran the debug_picking and sprite_picking examples (for UI and sprites
respectively): both seem to work fine.
# Objective
The resources were converted via `clone_reflect_value` and the cloned
value was mapped. But the value that is inserted is the source of the
clone, which was not mapped.
I ran into this issue while working on #18380. Having non consecutive
entity allocations has caught a lot of bugs.
## Solution
Use the cloned value for insertion if it exists.
# Objective
- ECS error handling is a lovely flagship feature for Bevy 0.16, all in
the name of reducing panics and encouraging better error handling
(#14275).
- Currently though, command and system error handling are completely
disjoint and use different mechanisms.
- Additionally, there's a number of distinct ways to set the
default/fallback/global error handler that have limited value. As far as
I can tell, this will be cfg flagged to toggle between dev and
production builds in 99.9% of cases, with no real value in more granular
settings or helpers.
- Fixes#17272
## Solution
- Standardize error handling on the OnceLock global error mechanisms
ironed out in https://github.com/bevyengine/bevy/pull/17215
- As discussed there, there are serious performance concerns there,
especially for commands
- I also think this is a better fit for the use cases, as it's truly
global
- Move from `SystemErrorContext` to a more general purpose
`ErrorContext`, which can handle observers and commands more clearly
- Cut the superfluous setter methods on `App` and `SubApp`
- Rename the limited (and unhelpful) `fallible_systems` example to
`error_handling`, and add an example of command error handling
## Testing
Ran the `error_handling` example.
## Notes for reviewers
- Do you see a clear way to allow commands to retain &mut World access
in the per-command custom error handlers? IMO that's a key feature here
(allowing the ad-hoc creation of custom commands), but I'm not sure how
to get there without exploding complexity.
- I've removed the feature gate on the default_error_handler: contrary
to @cart's opinion in #17215 I think that virtually all apps will want
to use this. Can you think of a category of app that a) is extremely
performance sensitive b) is fine with shipping to production with the
panic error handler? If so, I can try to gather performance numbers
and/or reintroduce the feature flag. UPDATE: see benches at the end of
this message.
- ~~`OnceLock` is in `std`: @bushrat011899 what should we do here?~~
- Do you have ideas for more automated tests for this collection of
features?
## Benchmarks
I checked the impact of the feature flag introduced: benchmarks might
show regressions. This bears more investigation. I'm still skeptical
that there are users who are well-served by a fast always panicking
approach, but I'm going to re-add the feature flag here to avoid
stalling this out.

---------
Co-authored-by: Zachary Harrold <zac@harrold.com.au>