# Objective
A separate `tracing` span for running a system's commands is created, even if the system doesn't have commands. This is adding extra measuring overhead (see #4892) where it's not needed.
## Solution
Move the span into `ParallelCommandState` and `CommandQueue`'s `SystemParamState::apply`. To get the right metadata for the span, a additional `&SystemMeta` parameter was added to `SystemParamState::apply`.
---
## Changelog
Added: `SystemMeta::name`
Changed: Systems without `Commands` and `ParallelCommands` will no longer show a "system_commands" span when profiling.
Changed: `SystemParamState::apply` now takes a `&SystemMeta` parameter in addition to the provided `&mut World`.
# Objective
Change detection can be spuriously triggered by setting a field to the same value as before. As a result, a common pattern is to write:
```rust
if *foo != value {
*foo = value;
}
```
This is confusing to read, and heavy on boilerplate.
Adopted from #5373, but untangled and rebased to current `bevy/main`.
## Solution
1. Add a method to the `DetectChanges` trait that implements this boilerplate when the appropriate trait bounds are met.
2. Document this minor footgun, and point users to it.
## Changelog
* added the `set_if_neq` method to avoid triggering change detection when the new and previous values are equal. This will work on both components and resources.
## Migration Guide
If you are manually checking if a component or resource's value is equal to its new value before setting it to avoid triggering change detection, migrate to the clearer and more convenient `set_if_neq` method.
## Context
Related to #2363 as it avoids triggering change detection, but not a complete solution (as it still requires triggering it when real changes are made).
Co-authored-by: Zoey <Dessix@Dessix.net>
Add a section about install `vulkan-loader` on Gentoo.
# Objective
- Clarify the dependency about install on Gentoo with NVIDIA GPU and using a proprietary driver.
## Solution
- Emerge `vulkan-loader` to help Bevy to find the correct ICD.
# Objective
The following code:
```rs
use bevy::prelude::Image;
use image::{ DynamicImage, GenericImage, Rgba };
fn main() {
let mut dynamic_image = DynamicImage::new_rgb32f(1, 1);
dynamic_image.put_pixel(0, 0, Rgba([1, 1, 1, 1]));
let image = Image::from_dynamic(dynamic_image, false); // Panic!
println!("{image:?}");
}
```
Can cause an assertion failed:
```
thread 'main' panicked at 'assertion failed: `(left == right)`
left: `16`,
right: `14`: Pixel data, size and format have to match', .../bevy_render-0.9.1/src/texture/image.rs:209:9
stack backtrace:
...
4: core::panicking::assert_failed<usize,usize>
at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/panicking.rs:181
5: bevy_render::texture::image::Image::new
at .../bevy_render-0.9.1/src/texture/image.rs:209
6: bevy_render::texture::image::Image::from_dynamic
at .../bevy_render-0.9.1/src/texture/image_texture_conversion.rs:159
7: bevy_test::main
at ./src/main.rs:8
...
```
It seems to be cause by a copypasta in `crates/bevy_render/src/texture/image_texture_conversion.rs`. Let's fix it.
## Solution
```diff
// DynamicImage::ImageRgb32F(image) => {
- let a = u16::max_value();
+ let a = 1f32;
```
This will fix the conversion.
---
## Changelog
- Fixed the alpha channel of the `image::DynamicImage::ImageRgb32F` to `bevy_render::texture::Image` conversion in `bevy_render::texture::Image::from_dynamic()`.
# Objective
The feature doesn't have any use case in libraries or applications and many users use this feature incorrectly. See the issue for details.
Closes#5753.
## Solution
Remove it.
---
## Changelog
### Removed
- `render` feature group.
## Migration Guide
Instead of using `render` feature group use dependencies directly. This group consisted of `bevy_core_pipeline`, `bevy_pbr`, `bevy_gltf`, `bevy_render`, `bevy_sprite`, `bevy_text` and `bevy_ui`. You probably want to check if you need all of them.
# Objective
- https://github.com/bevyengine/bevy/pull/5364 Added a few features to the AsBindGroup derive, but if you don't know they exist they aren't documented anywhere.
## Solution
- Document the new arguments in the doc block for the derive.
# Objective
Speed up bundle insertion and spawning from a bundle.
## Solution
Use the same technique used in #6800 to remove the branch on storage type when writing components from a `Bundle` into storage.
- Add a `StorageType` argument to the closure on `Bundle::get_components`.
- Pass `C::Storage::STORAGE_TYPE` into that argument.
- Match on that argument instead of reading from a `Vec<StorageType>` in `BundleInfo`.
- Marked all implementations of `Bundle::get_components` as inline to encourage dead code elimination.
The `Vec<StorageType>` in `BundleInfo` was also removed as it's no longer needed. If users were reliant on this, they can either use the compile time constants or fetch the information from `Components`. Should save a rather negligible amount of memory.
## Performance
Microbenchmarks show a slight improvement to inserting components into existing entities, as well as spawning from a bundle. Ranging about 8-16% faster depending on the benchmark.
```
group main soft-constant-write-components
----- ---- ------------------------------
add_remove/sparse_set 1.08 1019.0±80.10µs ? ?/sec 1.00 944.6±66.86µs ? ?/sec
add_remove/table 1.07 1343.3±20.37µs ? ?/sec 1.00 1257.3±18.13µs ? ?/sec
add_remove_big/sparse_set 1.08 1132.4±263.10µs ? ?/sec 1.00 1050.8±240.74µs ? ?/sec
add_remove_big/table 1.02 2.6±0.05ms ? ?/sec 1.00 2.5±0.08ms ? ?/sec
get_or_spawn/batched 1.15 401.4±17.76µs ? ?/sec 1.00 349.3±11.26µs ? ?/sec
get_or_spawn/individual 1.13 732.1±43.35µs ? ?/sec 1.00 645.6±41.44µs ? ?/sec
insert_commands/insert 1.12 623.9±37.48µs ? ?/sec 1.00 557.4±34.99µs ? ?/sec
insert_commands/insert_batch 1.16 401.4±17.00µs ? ?/sec 1.00 347.4±12.87µs ? ?/sec
insert_simple/base 1.08 416.9±5.60µs ? ?/sec 1.00 385.2±4.14µs ? ?/sec
insert_simple/unbatched 1.06 934.5±44.58µs ? ?/sec 1.00 881.3±47.86µs ? ?/sec
spawn_commands/2000_entities 1.09 190.7±11.41µs ? ?/sec 1.00 174.7±9.15µs ? ?/sec
spawn_commands/4000_entities 1.10 386.5±25.33µs ? ?/sec 1.00 352.3±18.81µs ? ?/sec
spawn_commands/6000_entities 1.10 586.2±34.42µs ? ?/sec 1.00 535.3±27.25µs ? ?/sec
spawn_commands/8000_entities 1.08 778.5±45.15µs ? ?/sec 1.00 718.0±33.66µs ? ?/sec
spawn_world/10000_entities 1.04 1026.4±195.46µs ? ?/sec 1.00 985.8±253.37µs ? ?/sec
spawn_world/1000_entities 1.06 103.8±20.23µs ? ?/sec 1.00 97.6±18.22µs ? ?/sec
spawn_world/100_entities 1.15 11.4±4.25µs ? ?/sec 1.00 9.9±1.87µs ? ?/sec
spawn_world/10_entities 1.05 1030.8±229.78ns ? ?/sec 1.00 986.2±231.12ns ? ?/sec
spawn_world/1_entities 1.01 105.1±23.33ns ? ?/sec 1.00 104.6±31.84ns ? ?/sec
```
---
## Changelog
Changed: `Bundle::get_components` now takes a `FnMut(StorageType, OwningPtr)`. The provided storage type must be correct for the component being fetched.
# Objective
Partially address #3492.
## Solution
Document the remaining undocumented members of `bevy_utils` and set `warn(missing_docs)` on the crate level. Also enabled `clippy::undocumented_unsafe_blocks` as a warning on the crate to keep it in sync with `bevy_ecs`'s warnings.
# Objective
- Fixes#6630, fixes#6679
- Improve scene viewer in cases where there are more than one scene in a gltf file
## Solution
- Can select which scene to display using `#SceneN`, defaults to scene 0 if not present
- Display the number of scenes available if there are more than one
# Objective
```rust
// makes clippy complain about 'taking a mutable reference to a `const` item'
let color = *Color::RED.set_a(0.5);
// Now you can do
let color = Color::RED.with_a(0.5);
```
## Changelog
Added `with_r`, `with_g`, `with_b`, and `with_a` to `Color`.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/6417
## Solution
- clear_trackers was not being called on the render world. This causes the removed components vecs to continuously grow. This PR adds clear trackers to the end of RenderStage::Cleanup
## Migration Guide
The call to `clear_trackers` in `App` has been moved from the schedule to App::update for the main world and calls to `clear_trackers` have been added for sub_apps in the same function. This was due to needing stronger guarantees. If clear_trackers isn't called on a world it can lead to memory leaks in `RemovedComponents`.
# Objective
* Implementing a custom `SystemParam` by hand requires implementing three traits -- four if it is read-only.
* The trait `SystemParamFetch<'w, 's>` is a workaround from before we had generic associated types, and is no longer necessary.
## Solution
* Combine the trait `SystemParamFetch` with `SystemParamState`.
* I decided to remove the `Fetch` name and keep the `State` name, since the former was consistently conflated with the latter.
* Replace the trait `ReadOnlySystemParamFetch` with `ReadOnlySystemParam`, which simplifies trait bounds in generic code.
---
## Changelog
- Removed the trait `SystemParamFetch`, moving its functionality to `SystemParamState`.
- Replaced the trait `ReadOnlySystemParamFetch` with `ReadOnlySystemParam`.
## Migration Guide
The trait `SystemParamFetch` has been removed, and its functionality has been transferred to `SystemParamState`.
```rust
// Before
impl SystemParamState for MyParamState {
fn init(world: &mut World, system_meta: &mut SystemMeta) -> Self { ... }
}
impl<'w, 's> SystemParamFetch<'w, 's> for MyParamState {
type Item = MyParam<'w, 's>;
fn get_param(...) -> Self::Item;
}
// After
impl SystemParamState for MyParamState {
type Item<'w, 's> = MyParam<'w, 's>; // Generic associated types!
fn init(world: &mut World, system_meta: &mut SystemMeta) -> Self { ... }
fn get_param<'w, 's>(...) -> Self::Item<'w, 's>;
}
```
The trait `ReadOnlySystemParamFetch` has been replaced with `ReadOnlySystemParam`.
```rust
// Before
unsafe impl ReadOnlySystemParamFetch for MyParamState {}
// After
unsafe impl<'w, 's> ReadOnlySystemParam for MyParam<'w, 's> {}
```
# Objective
It's not clear to users how to handle `!Sync` types as components and resources in the absence of engine level support for them.
## Solution
Added a section to `Component`'s and `Resource`'s type level docs on available options for making a type `Sync` when it holds `!Sync` fields, linking `bevy_utils::synccell::SyncCell` and the currently unstable `std::sync::Exclusive`.
Also added a compile_fail doctest that illustrates how to apply `SyncCell`. These will break when/if #6572 gets merged, at which point these docs should be updated.
# Objective
- Make running animation fluid skipping 'idle' frame.
## Solution
- Loop through the specified indices instead of through the whole sprite sheet.
The example is correct, is just the feeling that the animation loop is not seamless.
Based on the solution suggested by @mockersf in #5429.
# Objective
This is an adoption of #5792. Fixes#5791.
## Solution
Implemented all the required reflection traits for `VecDeque`, taking from `Vec`'s impls.
---
## Changelog
Added: `std::collections::VecDeque` now implements `Reflect` and all relevant traits.
Co-authored-by: james7132 <contact@jamessliu.com>
# Objective
- Get rid of giant match statement to get PixelInfo.
- This will allow for supporting any texture that is uncompressed, instead of people needing to PR in any textures that are supported in wgpu, but not bevy.
## Solution
- More conservative alternative to https://github.com/bevyengine/bevy/pull/6788, where we don't try to make some of the calculations correct for compressed types.
- Delete `PixelInfo` and get the pixel_size directly from wgpu. Data from wgpu is here: https://docs.rs/wgpu-types/0.14.0/src/wgpu_types/lib.rs.html#2359
- Panic if the texture is a compressed type. An integer byte size of a pixel is no longer a valid concept when talking about compressed textures.
- All internal usages use `pixel_size` and not `pixel_info` and are on uncompressed formats. Most of these usages are on either explicit texture formats or slightly indirectly through `TextureFormat::bevy_default()`. The other uses are in `TextureAtlas` and have other calculations that assumes the texture is uncompressed.
## Changelog
- remove `PixelInfo` and get `pixel_size` from wgpu
## Migration Guide
`PixelInfo` has been removed. `PixelInfo::components` is equivalent to `texture_format.describe().components`. `PixelInfo::type_size` can be gotten from `texture_format.describe().block_size/ texture_format.describe().components`. But note this can yield incorrect results for some texture types like Rg11b10Float.
# Objective
Adds a cylinder shape. Fixes#2282.
## Solution
- I added a custom cylinder shape, taken from [here](https://github.com/rparrett/typey_birb/blob/main/src/cylinder.rs) with permission from @rparrett.
- I also added the cylinder shape to the `3d_shapes` example scene.
---
## Changelog
- Added cylinder shape
Co-Authored-By: Rob Parrett <robparrett@gmail.com>
Co-Authored-By: davidhof <7483215+davidhof@users.noreply.github.com>
# Objective
Fixes#6224, add ``dbg``, ``info``, ``warn`` and ``error`` system piping adapter variants to expand #5776, which call the corresponding re-exported [bevy_log macros](https://docs.rs/bevy/latest/bevy/log/macro.info.html) when the result is an error.
## Solution
* Added ``dbg``, ``info``, ``warn`` and ``error`` system piping adapter variants to ``system_piping.rs``.
* Modified and added tests for these under examples in ``system_piping.rs``.
# Objective
- Make `AudioOutput` a `Resource`.
## Solution
- Do not store `OutputStream` in the struct.
- `mem::forget` `OutputStream`.
---
## Changelog
### Added
- `AudioOutput` is now a `Resource`.
## Migration Guide
- Use `Res<AudioOutput<Source>>` instead of `NonSend<AudioOutput<Source>>`. Same for `Mut` variants.
# Objective
Resolves#4597 (based on the work from #6056 and a refresh of #4147)
When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime.
Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves.
## Solution
Add a `ReflectFromReflect` type data struct.
This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances.
```rust
#[derive(Reflect, FromReflect)]
#[reflect(FromReflect)] // <- Register `ReflectFromReflect`
struct MyStruct(String);
let type_id = TypeId::of::<MyStruct>();
// Register our type
let mut registry = TypeRegistry::default();
registry.register::<MyStruct>();
// Create a concrete instance
let my_struct = MyStruct("Hello world".to_string());
// `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types
let dynamic_value: Box<dyn Reflect> = my_struct.clone_value();
assert!(!dynamic_value.is::<MyStruct>());
// Get the `ReflectFromReflect` type data from the registry
let rfr: &ReflectFromReflect = registry
.get_type_data::<ReflectFromReflect>(type_id)
.unwrap();
// Call `FromReflect::from_reflect` on our Dynamic value
let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value);
assert!(concrete_value.is::<MyStruct>());
```
### Why this PR?
###### Why now?
The three main reasons I closed#4147 were that:
1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`)
2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect`
3. I didn't see a lot of desire from the community for such a feature
However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`.
I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users).
###### Why not just re-open #4147?
The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews.
---
## Changelog
* Added `ReflectFromReflect`
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
# Objective
#6547 accidentally broke change detection for SparseSet components by using `Ticks::from_tick_cells` with the wrong argument order.
## Solution
Use the right argument order. Add a regression test.
# Objective
The window event types currently don't support reflection. This PR adds support to them (as requested [here](https://github.com/bevyengine/bevy/issues/6223#issuecomment-1273852329)).
## Solution
Implement `Reflect` + `FromReflect` for window event types. Relevant traits are also being reflected with `#[reflect(...)]` attributes.
Additionally, this PR derives `Reflect` + `FromReflect` for `WindowDescriptor` and the types it depends on so that `CreateWindow` events can be fully manipulated through reflection.
Finally, this PR adds `FromReflect` for `PathBuf` as a value type, which is needed for `FileDragAndDrop`.
This adds the "glam" feature to the `bevy_reflect` dependency for package `bevy_window`. Since `bevy_window` transitively depends on `glam` already, all this brings in are the reflection `impl`s.
## Open questions
Should `app.register_type::<PathBuf>();` be moved to `CorePlugin`? I added it to `WindowPlugin` because that's where it's used and `CorePlugin` doesn't seem to register all the missing std types, but it would also make sense in `CorePlugin` I believe since it's a commonly used type.
---
## Changelog
Added:
- Implemented `Reflect` + `FromReflect` for window events and related types. These types are automatically registered when adding the `WindowPlugin`.
# Objective
- Fixes#6841
- In some case, the number of maximum storage buffers is `u32::MAX` which doesn't fit in a `i32`
## Solution
- Add an option to have a `u32` in a `ShaderDefVal`
having `doc(hidden)` on the read only version of a generated mutable world query leads to docs on the readonly item having a dead link. It also makes it annoying to have nice docs for libraries attempting to expose derived `WorldQuery` structs as re-exporting the read only item does not cause it to appear in docs even though it would be intended for users to know about the read only world query and use it.
# Objective
Fixes#6866.
## Solution
Docs now should describe what the _front_, _first_, _back_, and _last_ elements are for an implementor of the `bevy::reflect::list::List` Trait. Further, the docs should describe how `bevy::reflect::list::List::push` and `bevy::reflect::list::List::pop` should act on these elements.
Co-authored-by: Linus Käll <linus.kall.business@gmail.com>
# Objective
Links to `cargo-flamegraph`'s repo point to a [fork](https://github.com/killercup/cargo-flamegraph), not the actual upstream repo. We should point to the source of truth instead of a fork that hasn't been updated since 2019.
## Solution
Change links to point to the upstream repo at [flamegraph-rs/flamegraph](https://github.com/flamegraph-rs/flamegraph).
# Objective
Prevent future unsoundness that was seen in #6623.
## Solution
Newtype both indexes in `Archetype` and `Table` as `ArchetypeRow` and `TableRow`. This avoids weird numerical manipulation on the indices, and can be stored and treated opaquely. Also enforces the source and destination of where these indices at a type level.
---
## Changelog
Changed: `Archetype` indices and `Table` rows have been newtyped as `ArchetypeRow` and `TableRow`.
# Objective
`EntityRef::get` and friends all type erase calls to fetch the target components by using passing in the `TypeId` instead of using generics. This is forcing a lookup to `Components` to fetch the storage type. This adds an extra memory lookup and forces a runtime branch instead of allowing the compiler to optimize out the unused branch.
## Solution
Leverage `Component::Storage::STORAGE_TYPE` as a constant instead of fetching the metadata from `Components`.
## Performance
This has a near 2x speedup for all calls to `World::get`. Microbenchmark results from my local machine. `Query::get_component`, which uses `EntityRef::get` internally also show a slight speed up. This has closed the gap between `World::get` and `Query::get` for the same use case.
```
group entity-ref-generics main
----- ------------------- ----
query_get_component/50000_entities_sparse 1.00 890.6±40.42µs ? ?/sec 1.10 980.6±28.22µs ? ?/sec
query_get_component/50000_entities_table 1.00 968.5±73.73µs ? ?/sec 1.08 1048.8±31.76µs ? ?/sec
query_get_component_simple/system 1.00 703.2±4.37µs ? ?/sec 1.00 702.1±6.13µs ? ?/sec
query_get_component_simple/unchecked 1.02 855.8±8.98µs ? ?/sec 1.00 843.1±8.19µs ? ?/sec
world_get/50000_entities_sparse 1.00 202.3±3.15µs ? ?/sec 1.85 374.0±20.96µs ? ?/sec
world_get/50000_entities_table 1.00 193.0±1.78µs ? ?/sec 2.02 389.2±26.55µs ? ?/sec
world_query_get/50000_entities_sparse 1.01 162.4±2.23µs ? ?/sec 1.00 161.3±0.95µs ? ?/sec
world_query_get/50000_entities_table 1.00 199.9±0.63µs ? ?/sec 1.00 200.2±0.74µs ? ?/sec
```
This should also, by proxy, speed up the `ReflectComponent` APIs as most of those use `World::get` variants internally.
# Objective
- Fixes#3004
## Solution
- Replaced all the types with their fully quallified names
- Replaced all trait methods and inherent methods on dyn traits with their fully qualified names
- Made a new file `fq_std.rs` that contains structs corresponding to commonly used Structs and Traits from `std`. These structs are replaced by their respective fully qualified names when used inside `quote!`
# Objective
- Fixes#6711
## Solution
- Change the `path` function parameter of `dynamically_load_plugin` and `DynamicPluginExt::load_plugin` to a generic with `AsRef<OsStr>` bound
# Objective
`prepare_asset` for Image has an alternate path for texture creation that is used when the image is not compressed and does not contain mipmaps. This additional code path is unnecessary as `render_device.create_texture_with_data()` will handle both cases correctly.
## Solution
Use `render_device.create_texture_with_data()` in all cases.
Tested successfully with the following examples:
- load_gltf
- render_to_texture
- texture
- 3d_shapes
- sprite
- sprite_sheet
- array_texture
- shader_material_screenspace_texture
- skybox (though this already would use the `create_texture_with_data()` branch anyway)
# Objective
The methods `World::change_tick` and `World::read_change_tick` lack documentation and have confusingly similar behavior.
## Solution
Add documentation and clarify the distinction between the two functions.
The PR fixes the interface of `EventReader::clear`. Currently, the method consumes the reader, which makes it unusable.
## Changelog
- `EventReader::clear` now takes a mutable reference instead of consuming the event reader.
## Migration Guide
`EventReader::clear` now takes a mutable reference instead of consuming the event reader. This means that `clear` now needs explicit mutable access to the reader variable, which previously could have been omitted in some cases:
```rust
// Old (0.9)
fn clear_events(reader: EventReader<SomeEvent>) {
reader.clear();
}
// New (0.10)
fn clear_events(mut reader: EventReader<SomeEvent>) {
reader.clear();
}
```
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Fixes#6812.
## Solution
- Replaced `World::read_change_ticks` with `World::change_ticks` within `bevy_ecs` crate in places where `World` references were mutable.
---
# Objective
Partially addresses #5504. Allow users to get an `Iterator<Item = EntityRef<'a>>` over all entities in the `World`.
## Solution
Change `World::iter_entities` to return an iterator of `EntityRef` instead of `Entity`.
Not sure how to tackle making an `Iterator<Item = EntityMut<'_>>` without being horribly unsound. Might need to wait for `LendingIterator` to stabilize so we can ensure only one of them is valid at a given time.
---
## Changelog
Changed: `World::iter_entities` now returns an iterator of `EntityRef` instead of `Entity`.
# Objective
Currently, the `SystemParam` derive forces you to declare the lifetime parameters `<'w, 's>`, even if you don't use them.
If you don't follow this structure, the error message is quite nasty.
### Example (before):
```rust
#[derive(SystemParam)]
pub struct EventWriter<'w, 's, E: Event> {
events: ResMut<'w, Events<E>>,
// The derive forces us to declare the `'s` lifetime even though we don't use it,
// so we have to add this `PhantomData` to please rustc.
#[system_param(ignore)]
_marker: PhantomData<&'s ()>,
}
```
## Solution
* Allow the user to omit either lifetime.
* Emit a descriptive error if any lifetimes used are invalid.
### Example (after):
```rust
#[derive(SystemParam)]
pub struct EventWriter<'w, E: Event> {
events: ResMut<'w, Events<E>>,
}
```
---
## Changelog
* The `SystemParam` derive is now more flexible, allowing you to omit unused lifetime parameters.
Updates the requirements on [tracing-chrome](https://github.com/thoren-d/tracing-chrome) to permit the latest version.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/thoren-d/tracing-chrome/releases">tracing-chrome's releases</a>.</em></p>
<blockquote>
<h2>Release v0.7.0</h2>
<ul>
<li>Add <code>start_new</code> to <code>FlushGuard</code>. You can now generate multiple traces in one run!</li>
<li>Clean up dependencies</li>
<li>Make events thread-scoped</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
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<li><a href="8760d81206"><code>8760d81</code></a> Prepare for 0.7 (<a href="https://github-redirect.dependabot.com/thoren-d/tracing-chrome/issues/16">#16</a>)</li>
<li><a href="a30bfb78d2"><code>a30bfb7</code></a> Update documentation (<a href="https://github-redirect.dependabot.com/thoren-d/tracing-chrome/issues/15">#15</a>)</li>
<li><a href="3fe24ff44d"><code>3fe24ff</code></a> Save thread names for start_new (<a href="https://github-redirect.dependabot.com/thoren-d/tracing-chrome/issues/14">#14</a>)</li>
<li><a href="fa8a0ff8ba"><code>fa8a0ff</code></a> Adding "Start New" feature that allows a user to finalize writing to the (<a href="https://github-redirect.dependabot.com/thoren-d/tracing-chrome/issues/11">#11</a>)</li>
<li><a href="d3059d66b3"><code>d3059d6</code></a> Directly depend on crossbeam_channel (<a href="https://github-redirect.dependabot.com/thoren-d/tracing-chrome/issues/12">#12</a>)</li>
<li><a href="441dba5c21"><code>441dba5</code></a> change scope of instant events to thread (<a href="https://github-redirect.dependabot.com/thoren-d/tracing-chrome/issues/13">#13</a>)</li>
<li>See full diff in <a href="https://github.com/thoren-d/tracing-chrome/compare/v0.6.0...v0.7.0">compare view</a></li>
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# Objective
Fixes#6827
## Solution
Use the `Color::rgba_linear` function instead of the `Color::rgba` function to correctly interpret colors from glTF files in the linear color space rather than the incorrect sRGB color space
