# Objective
- The time update is currently done in the wrong part of the schedule. For a single frame the current order of things is update input, update time (First stage), other stages, render stage (frame presentation). So when we update the time it includes the input processing of the current frame and the frame presentation of the previous frame. This is a problem when vsync is on. When input processing takes a longer amount of time for a frame, the vsync wait time gets shorter. So when these are not paired correctly we can potentially have a long input processing time added to the normal vsync wait time in the previous frame. This leads to inaccurate frame time reporting and more variance of the time than actually exists. For more details of why this is an issue see the linked issue below.
- Helps with https://github.com/bevyengine/bevy/issues/4669
- Supercedes https://github.com/bevyengine/bevy/pull/4728 and https://github.com/bevyengine/bevy/pull/4735. This PR should be less controversial than those because it doesn't add to the API surface.
## Solution
- The most accurate frame time would come from hardware. We currently don't have access to that for multiple reasons, so the next best thing we can do is measure the frame time as close to frame presentation as possible. This PR gets the Instant::now() for the time immediately after frame presentation in the render system and then sends that time to the app world through a channel.
- implements suggestion from @aevyrie from here https://github.com/bevyengine/bevy/pull/4728#discussion_r872010606
## Statistics
![image](https://user-images.githubusercontent.com/2180432/168410265-f249f66e-ea9d-45d1-b3d8-7207a7bc536c.png)
---
## Changelog
- Make frame time reporting more accurate.
## Migration Guide
`time.delta()` now reports zero for 2 frames on startup instead of 1 frame.
Remove unnecessary calls to `iter()`/`iter_mut()`.
Mainly updates the use of queries in our code, docs, and examples.
```rust
// From
for _ in list.iter() {
for _ in list.iter_mut() {
// To
for _ in &list {
for _ in &mut list {
```
We already enable the pedantic lint [clippy::explicit_iter_loop](https://rust-lang.github.io/rust-clippy/stable/) inside of Bevy. However, this only warns for a few known types from the standard library.
## Note for reviewers
As you can see the additions and deletions are exactly equal.
Maybe give it a quick skim to check I didn't sneak in a crypto miner, but you don't have to torture yourself by reading every line.
I already experienced enough pain making this PR :)
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Resolves#5004. As suggested in the original issue, change tuple types to their corresponding vector type.
## migration guide
Changed the following fields
- `WindowCommand::SetWindowMode.resolution` from `(u32, u32)` to `UVec2`
- `WindowCommand::SetResolution.logical_resolution` from `(f32, f32)` to `Vec2`
Co-authored-by: Daniel Liu <mr.picklepinosaur@gmail.com>
# Objective
- Reduce confusion as the example opens a window and isn't truly "headless"
- Fixes https://github.com/bevyengine/bevy/issues/5260.
## Solution
- Rename the example and add to the docs that the window is expected.
# Objective
- Validate the format of the values with the expected attribute format.
- Currently, if you pass the wrong format, it will crash somewhere unrelated with a very cryptic error message, so it's really hard to debug for beginners.
## Solution
- Compare the format and panic when unexpected format is passed
## Note
- I used a separate `error!()` for a human friendly message because the panic message is very noisy and hard to parse for beginners. I don't mind changing this to only a panic if people prefer that.
- This could potentially be something that runs only in debug mode, but I don't think inserting attributes is done often enough for this to be an issue.
Co-authored-by: Charles <IceSentry@users.noreply.github.com>
Small optimization. `.collect()` from arrays generates very nice code without reallocations: https://rust.godbolt.org/z/6E6c595bq
Co-authored-by: Kornel <kornel@geekhood.net>
# Objective
Currently some TextureFormats are not supported by the Image type.
The `TextureFormat::R16Unorm` format is useful for storing heightmaps.
This small change would unblock releasing my terrain plugin on bevy 0.8.
## Solution
Added `TextureFormat::R16Unorm` support to Image.
This is an alternative (short term solution) to the large texture format issue https://github.com/bevyengine/bevy/pull/4124.
# Objective
- Slight documentation tweak to make it more clear that `FloatOrd` also implements `Hash` and `Eq`, not just `Ord`.
- I know that it does show that Hash is implemented in the docs, but I had missed it after reading the description and assuming it didn't do it, so hopefully this helps other people who might miss it like I did. :)
## Solution
- Just mention in the Hash and Eq implementation in the docstring.
# Objective
- Currently bevy_ui only checks for primary window cursor position to determine `Interaction` behavior.
- Added checks for focused window where cursor position is available.
- Fixes#5224.
## Solution
- Added checks for focused windows in `Interaction` focus system.
## Follow Up
- All windows with camera will be rendering the UI elements right now.
- We will need some way to tell which camera to render which UI.
---
Co-authored-by: fadhliazhari <44402264+fadhliazhari@users.noreply.github.com>
# Objective
- Enable the `axis_dpad_to_button` gilrs filter to map hats to dpad buttons on supported remotes.
- Fixes https://github.com/Leafwing-Studios/leafwing-input-manager/issues/149
- Might have fixed the confusion related to https://github.com/bevyengine/bevy/issues/3229
## Solution
- Enables the `axis_dpad_to_button` filter in `gilrs` which will use it's remote mapping information to see if there are hats mapped to dpads for that remote model. I don't really understand the logic it uses exactly, but it is usually enabled by default in gilrs and I believe it probably leads to more intuitive mapping compared to the current situation of dpad buttons being mapped to an axis.
- Removes the `GamepadAxisType::DPadX` and `GamepadAxisType::DPadY` enum variants to avoid user confusion. Those variants should never be emitted anyway, for all supported remotes.
---
## Changelog
### Changed
- Removed `GamepadAxisType::DPadX` and `GamepadAxisType::DPadY` in favor of using `GamepadButtonType::DPad[Up/Down/Left/Right]` instead.
## Migration Guide
If your game reads gamepad events or queries the axis state of `GamePadAxisType::DPadX` or `GamePadAxisType::DPadY`, then you must migrate your code to check whether or not the `GamepadButtonType::DPadUp`, `GamepadButtonType::DPadDown`, etc. buttons were pressed instead.
# Objective
`ReflectResource` and `ReflectComponent` will panic on `apply` method if there is no such component. It's not very ergonomic. And not very good for performance since I need to check if such component exists first.
## Solution
* Add `ReflectComponent::apply_or_insert` and `ReflectResource::apply_or_insert` functions.
* Rename `ReflectComponent::add` into `ReflectComponent::insert` for consistency.
---
## Changelog
### Added
* `ReflectResource::apply_or_insert` and `ReflectComponent::apply_on_insert`.
### Changed
* Rename `ReflectComponent::add` into `ReflectComponent::insert` for consistency.
* Use `ReflectComponent::apply_on_insert` in `DynamicScene` instead of manual checking.
## Migration Guide
* Rename `ReflectComponent::add` into `ReflectComponent::insert`.
# Objective
- Extracting resources currently always uses commands, which requires *at least* one additional move of the extracted value, as well as dynamic dispatch.
- Addresses https://github.com/bevyengine/bevy/pull/4402#discussion_r911634931
## Solution
- Write the resource into a `ResMut<R>` directly.
- Fall-back to commands if the resource hasn't been added yet.
## Objective
Implement absolute minimum viable product for the changes proposed in bevyengine/rfcs#53.
## Solution
- Remove public mutative access to `Parent` (Children is already publicly read-only). This includes public construction methods like `Copy`, `Clone`, and `Default`.
- Remove `PreviousParent`
- Remove `parent_update_system`
- Update all hierarchy related commands to immediately update both `Parent` and `Children` references.
## Remaining TODOs
- [ ] Update documentation for both `Parent` and `Children`. Discourage using `EntityCommands::remove`
- [x] Add `HierarchyEvent` to notify listeners of hierarchy updates. This is meant to replace listening on `PreviousParent`
## Followup
- These changes should be best moved to the hooks mentioned in #3742.
- Backing storage for both might be best moved to indexes mentioned in the same relations.
# Objective
- The libraries used section of the README is outdated and is missing a lot of libraries
- The README isn't really the place for that anyway
## Solution
- Remove the section
# Objective
- Currently, the `Extract` `RenderStage` is executed on the main world, with the render world available as a resource.
- However, when needing access to resources in the render world (e.g. to mutate them), the only way to do so was to get exclusive access to the whole `RenderWorld` resource.
- This meant that effectively only one extract which wrote to resources could run at a time.
- We didn't previously make `Extract`ing writing to the world a non-happy path, even though we want to discourage that.
## Solution
- Move the extract stage to run on the render world.
- Add the main world as a `MainWorld` resource.
- Add an `Extract` `SystemParam` as a convenience to access a (read only) `SystemParam` in the main world during `Extract`.
## Future work
It should be possible to avoid needing to use `get_or_spawn` for the render commands, since now the `Commands`' `Entities` matches up with the world being executed on.
We need to determine how this interacts with https://github.com/bevyengine/bevy/pull/3519
It's theoretically possible to remove the need for the `value` method on `Extract`. However, that requires slightly changing the `SystemParam` interface, which would make it more complicated. That would probably mess up the `SystemState` api too.
## Todo
I still need to add doc comments to `Extract`.
---
## Changelog
### Changed
- The `Extract` `RenderStage` now runs on the render world (instead of the main world as before).
You must use the `Extract` `SystemParam` to access the main world during the extract phase.
Resources on the render world can now be accessed using `ResMut` during extract.
### Removed
- `Commands::spawn_and_forget`. Use `Commands::get_or_spawn(e).insert_bundle(bundle)` instead
## Migration Guide
The `Extract` `RenderStage` now runs on the render world (instead of the main world as before).
You must use the `Extract` `SystemParam` to access the main world during the extract phase. `Extract` takes a single type parameter, which is any system parameter (such as `Res`, `Query` etc.). It will extract this from the main world, and returns the result of this extraction when `value` is called on it.
For example, if previously your extract system looked like:
```rust
fn extract_clouds(mut commands: Commands, clouds: Query<Entity, With<Cloud>>) {
for cloud in clouds.iter() {
commands.get_or_spawn(cloud).insert(Cloud);
}
}
```
the new version would be:
```rust
fn extract_clouds(mut commands: Commands, mut clouds: Extract<Query<Entity, With<Cloud>>>) {
for cloud in clouds.value().iter() {
commands.get_or_spawn(cloud).insert(Cloud);
}
}
```
The diff is:
```diff
--- a/src/clouds.rs
+++ b/src/clouds.rs
@@ -1,5 +1,5 @@
-fn extract_clouds(mut commands: Commands, clouds: Query<Entity, With<Cloud>>) {
- for cloud in clouds.iter() {
+fn extract_clouds(mut commands: Commands, mut clouds: Extract<Query<Entity, With<Cloud>>>) {
+ for cloud in clouds.value().iter() {
commands.get_or_spawn(cloud).insert(Cloud);
}
}
```
You can now also access resources from the render world using the normal system parameters during `Extract`:
```rust
fn extract_assets(mut render_assets: ResMut<MyAssets>, source_assets: Extract<Res<MyAssets>>) {
*render_assets = source_assets.clone();
}
```
Please note that all existing extract systems need to be updated to match this new style; even if they currently compile they will not run as expected. A warning will be emitted on a best-effort basis if this is not met.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Support removing attributes from meshes. For an example use case, meshes created using the bevy::predule::shape types or loaded from external files may have attributes that are not needed for the materials they will be rendered with.
This was extracted from PR #5222.
## Solution
Implement Mesh::remove_attribute().
# Objective
Bevy requires meshes to include UV coordinates, even if the material does not use any textures, and will fail with an error `ERROR bevy_pbr::material: Mesh is missing requested attribute: Vertex_Uv (MeshVertexAttributeId(2), pipeline type: Some("bevy_pbr::material::MaterialPipeline<bevy_pbr::pbr_material::StandardMaterial>"))` otherwise. The objective of this PR is to permit this.
## Solution
This PR follows the design of #4528, which added support for per-vertex colours. It adds a shader define called VERTEX_UVS which indicates the presence of UV coordinates to the shader.
# Objective
add spotlight support
## Solution / Changelog
- add spotlight angles (inner, outer) to ``PointLight`` struct. emitted light is linearly attenuated from 100% to 0% as angle tends from inner to outer. Direction is taken from the existing transform rotation.
- add spotlight direction (vec3) and angles (f32,f32) to ``GpuPointLight`` struct (60 bytes -> 80 bytes) in ``pbr/render/lights.rs`` and ``mesh_view_bind_group.wgsl``
- reduce no-buffer-support max point light count to 204 due to above
- use spotlight data to attenuate light in ``pbr.wgsl``
- do additional cluster culling on spotlights to minimise cost in ``assign_lights_to_clusters``
- changed one of the lights in the lighting demo to a spotlight
- also added a ``spotlight`` demo - probably not justified but so reviewers can see it more easily
## notes
increasing the size of the GpuPointLight struct on my machine reduces the FPS of ``many_lights -- sphere`` from ~150fps to 140fps.
i thought this was a reasonable tradeoff, and felt better than handling spotlights separately which is possible but would mean introducing a new bind group, refactoring light-assignment code and adding new spotlight-specific code in pbr.wgsl. the FPS impact for smaller numbers of lights should be very small.
the cluster culling strategy reintroduces the cluster aabb code which was recently removed... sorry. the aabb is used to get a cluster bounding sphere, which can then be tested fairly efficiently using the strategy described at the end of https://bartwronski.com/2017/04/13/cull-that-cone/. this works well with roughly cubic clusters (where the cluster z size is close to the same as x/y size), less well for other cases like single Z slice / tiled forward rendering. In the worst case we will end up just keeping the culling of the equivalent point light.
Co-authored-by: François <mockersf@gmail.com>
This gives users a hint to use the GitHub "Discussions" for questions about bevy, instead of filing an issue.
## Objective
> Users sometimes file unhelpful issues when asking questions about how to use Bevy.
We should provide a link to the Discussion board in the list of "new Issue" options. This hopefully allows users to better find this option and reduces the number of question-issues.
- fixes#5150
## Solution
- add a small config.yml that configures the link
Looks like this (currently live on my local fork https://github.com/themasch/bevy/issues/new/choose):
![grafik](https://user-images.githubusercontent.com/170171/176940564-cd3a4ad1-731b-4417-95c2-3b5285120c88.png)
---
## Open questsions
- I am unsure about the wording.
# Objective
`EntityMap` lacks documentation, don't have `len()` / `is_empty` and `insert` doesn't work as in the regular HashMap`.
## Solution
* Add `len()` method.
* Return previously mapped entity from `insert()` as in the regular `HashMap`.
* Add documentation.
---
## Changelog
* Add `EntityMap::len()`.
* Return previously mapped entity from `EntityMap::insert()` as in the regular `HashMap`.
* Add documentation for `EntityMap` methods.
# Objective
It is currently hard to configure the `WindowPlugin`, as it is added as part of the `DefaultPlugins`. Ideally this should not be difficult.
## Solution
Remove the configuration from the plugin itself and put it as a `Resource`, similar to how it is done for almost all other plugins.
## Migration Guide
If you are currently configuring the behavior of the `WindowPlugin`, by constructing it manually, then you will need to instead create add the `WindowSettings` as a resource.
# Objective
Add texture sampling to the GLSL shader example, as naga does not support the commonly used sampler2d type.
Fixes#5059
## Solution
- Align the shader_material_glsl example behaviour with the shader_material example, as the later includes texture sampling.
- Update the GLSL shader to do texture sampling the way naga supports it, and document the way naga does not support it.
## Changelog
- The shader_material_glsl example has been updated to demonstrate texture sampling using the GLSL shading language.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
In bevy 0.7, `CameraUi` was a component specifically added to cameras
that display the UI. Since camera-driven rendering was merged, it
actually does the opposite! This will make it difficult for current
users to adapt to 0.8.
## Solution
To avoid unnecessary confusion, we rename `CameraUi` into
`UiCameraConfig`.
---
## Changelog
- Rename `CameraUi` to `UiCameraConfig`
# Objective
Remove suffixes from reflect component and resource methods to closer match bevy norms.
## Solution
removed suffixes and also fixed a spelling error
---
# Objective
When `miri` runs in our build system to detect unsoundness, its output can be very unhelpful, as the tests are all run in parallel.
## Solution
Add a comment documenting the extremely obvious 10/10 command used by @BoxyUwU in #4959.
I've stuck this in the CI file, as it seems like the most obvious place to check when frustrated. I didn't put it in CONTRIBUTING.md because this is an eldritch abomination and will never be useful to new contributors.
# Objective
- Help users fix issue when their app panic when executing a command on a despawned entity
## Solution
- Add an error code and a page describing how to debug the issue
# Objective
Make it easier to create pipelines derived from the `Material2dPipeline`. Currently this is made difficult because the fields of `Material2dKey` are private.
## Solution
Make the fields public.
# Objective
- To implement `Reflect` for more glam types.
## Solution
insert `impl_reflect_struct` invocations for more glam types. I am not sure about the boolean vectors, since none of them implement `Serde::Serialize/Deserialize`, and the SIMD versions don't have public fields.
I do still think implementing reflection is useful for BVec's since then they can be incorporated into `Reflect`'ed components and set dynamically even if as a whole + it's more consistent.
## Changelog
Implemented `Reflect` for the following types
- BVec2
- BVec3
- **BVec3A** (on simd supported platforms only)
- BVec4
- **BVec4A** (on simd supported platforms only)
- Mat2
- Mat3A
- DMat2
- Affine2
- Affine3A
- DAffine2
- DAffine3
- EulerRot
# Objective
Reduce the boilerplate code needed to make draw order sorting work correctly when queuing items through new common functionality. Also fix several instances in the bevy code-base (mostly examples) where this boilerplate appears to be incorrect.
## Solution
- Moved the logic for handling back-to-front vs front-to-back draw ordering into the PhaseItems by inverting the sort key ordering of Opaque3d and AlphaMask3d. The means that all the standard 3d rendering phases measure distance in the same way. Clients of these structs no longer need to know to negate the distance.
- Added a new utility struct, ViewRangefinder3d, which encapsulates the maths needed to calculate a "distance" from an ExtractedView and a mesh's transform matrix.
- Converted all the occurrences of the distance calculations in Bevy and its examples to use ViewRangefinder3d. Several of these occurrences appear to be buggy because they don't invert the view matrix or don't negate the distance where appropriate. This leads me to the view that Bevy should expose a facility to correctly perform this calculation.
## Migration Guide
Code which creates Opaque3d, AlphaMask3d, or Transparent3d phase items _should_ use ViewRangefinder3d to calculate the distance value.
Code which manually calculated the distance for Opaque3d or AlphaMask3d phase items and correctly negated the z value will no longer depth sort correctly. However, incorrect depth sorting for these types will not impact the rendered output as sorting is only a performance optimisation when drawing with depth-testing enabled. Code which manually calculated the distance for Transparent3d phase items will continue to work as before.
# Objective
- Document how to do profiling with Tracy
# Solution
- The documentation of setting `RUST_LOG=info` in order to capture `wgpu` spans depends on https://github.com/bevyengine/bevy/pull/5182
# Objective
`SAFETY` comments are meant to be placed before `unsafe` blocks and should contain the reasoning of why in this case the usage of unsafe is okay. This is useful when reading the code because it makes it clear which assumptions are required for safety, and makes it easier to spot possible unsoundness holes. It also forces the code writer to think of something to write and maybe look at the safety contracts of any called unsafe methods again to double-check their correct usage.
There's a clippy lint called `undocumented_unsafe_blocks` which warns when using a block without such a comment.
## Solution
- since clippy expects `SAFETY` instead of `SAFE`, rename those
- add `SAFETY` comments in more places
- for the last remaining 3 places, add an `#[allow()]` and `// TODO` since I wasn't comfortable enough with the code to justify their safety
- add ` #![warn(clippy::undocumented_unsafe_blocks)]` to `bevy_ecs`
### Note for reviewers
The first commit only renames `SAFETY` to `SAFE` so it doesn't need a thorough review.
cb042a416e..55cef2d6fa is the diff for all other changes.
### Safety comments where I'm not too familiar with the code
774012ece5/crates/bevy_ecs/src/entity/mod.rs (L540-L546)774012ece5/crates/bevy_ecs/src/world/entity_ref.rs (L249-L252)
### Locations left undocumented with a `TODO` comment
5dde944a30/crates/bevy_ecs/src/schedule/executor_parallel.rs (L196-L199)5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L287-L289)5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L413-L415)
Co-authored-by: Jakob Hellermann <hellermann@sipgate.de>
# Objective
`glam` is an optional feature in `bevy_reflect` and there is a separate `mod test { #[cfg(feature = "glam")] mod glam { .. }}`.
The `reflect_downcast` test is not in that module and doesn't depend on glam, which breaks `cargo test -p bevy_reflect` without the `glam` feature.
## Solution
- Remove the glam types from the test, they're not relevant to it
## Objective
Fixes: #5110
## Solution
- Moved benches into separate modules according to the part of ECS they are testing.
- Made so all ECS benches are included in one `benches.rs` so they don’t need to be added separately in `Cargo.toml`.
- Renamed a bunch of files to have more coherent names.
- Merged `schedule.rs` and `system_schedule.rs` into one file.
@BoxyUwU says that she always looks for this here, following the example of [tetra](https://github.com/17cupsofcoffee/tetra).
I think this is a pretty sensible idea!
# Objective
We don't have reflection for resources.
## Solution
Introduce reflection for resources.
Continues #3580 (by @Davier), related to #3576.
---
## Changelog
### Added
* Reflection on a resource type (by adding `ReflectResource`):
```rust
#[derive(Reflect)]
#[reflect(Resource)]
struct MyResourse;
```
### Changed
* Rename `ReflectComponent::add_component` into `ReflectComponent::insert_component` for consistency.
## Migration Guide
* Rename `ReflectComponent::add_component` into `ReflectComponent::insert_component`.
# Objective
This is a rebase of #3701 which is currently scheduled for 0.8 but is marked for adoption.
> Fixes https://github.com/bevyengine/bevy/discussions/3609
## Solution
> - add an `insert_boxed()` method on the `Map` trait
> - implement it for `HashMap` using a new `FromReflect` generic bound
> - add a `map_apply()` helper method to implement `Map::apply()`, that inserts new values instead of ignoring them
---
## Changelog
TODO
Co-authored-by: james7132 <contact@jamessliu.com>
# Objective
- I think our codebase is hit badly by rust-lang/rust-analyzer#11410
- None of our uses of cyclic dependencies are remotely necessary
- Note that these are false positives in rust-analyzer, however it's probably easier for us to work around this
- Note also that I haven't confirmed that this is causing rust-analyzer to not work very well, but it's not a bad guess.
## Solution
- Remove our cyclic dependencies
- Import the trick from #2851 for no-op plugin groups.
# Objective
This is a common and useful type. I frequently use this when working with `Events` resource directly, typically when caching the data or manipulating the `World` directly.
This is also useful when manually configuring the cleanup strategy for events.
# Objective
Transform screen-space coordinates into world space in shaders. (My use case is for generating rays for ray tracing with the same perspective as the 3d camera).
## Solution
Add `inverse_projection` and `inverse_view_proj` fields to shader view uniform
---
## Changelog
### Added
`inverse_projection` and `inverse_view_proj` fields to shader view uniform
## Note
It'd probably be good to double-check that I did the matrix multiplication in the right order for `inverse_proj_view`. Thanks!
# Objective
Intended to close#5073
## Solution
Adds a stress test that use TextureAtlas based on the existing many_sprites test using the animated sprite implementation from the sprite_sheet example.
In order to satisfy the goals described in #5073 the animations are all slightly offset.
Of note is that the original stress test was designed to test fullstrum culling. I kept this test similar as to facilitate easy comparisons between the use of TextureAtlas and without.
# Objective
- Fixes#4993
## Solution
- ~~Add `centered` property to `WindowDescriptor`~~
- Add `WindowPosition` enum
- `WindowDescriptor.position` is now `WindowPosition` instead of `Option<Vec2>`
- Add `center_window` function to `Window`
## Migration Guide
- If using `WindowDescriptor`, replace `position: None` with `position: WindowPosition::Default` and `position: Some(vec2)` with `WindowPosition::At(vec2)`.
I'm not sure if this is the best approach, so feel free to give any feedback.
Also I'm not sure how `Option`s should be handled in `bevy_winit/src/lib.rs:161`.
Also, on window creation we can't (or at least I couldn't) get `outer_size`, so this doesn't include decorations in calculations.
* Cleanup redundant code
* Use a type alias to make sure the `caster_query` and
`not_caster_query` really do the same thing and access the same things
**Objective**
Cleanup code that would otherwise be difficult to understand
**Solution**
* `extract_meshes` had two for loops which are functionally identical,
just copy-pasted code. I extracted the common code between the two
and put them into an anonymous function.
* I flattened the tuple literal for the bundle batch, it looks much
less nested and the code is much more readable as a result.
* The parameters of `extract_meshes` were also very daunting, but they
turned out to be the same query repeated twice. I extracted the query
into a type alias.
EDIT: I reworked the PR to **not do anything breaking**, and keep the old allocation behavior. Removing the memorized length was clearly a performance loss, so I kept it.
# Objective
- Enable `wgpu` profiling spans
## Solution
- `wgpu` uses the `profiling` crate to add profiling span instrumentation to their code
- `profiling` offers multiple 'backends' for profiling, including `tracing`
- When the `bevy` `trace` feature is used, add the `profiling` crate with its `profile-with-tracing` feature to enable appropriate profiling spans in `wgpu` using `tracing` which fits nicely into our infrastructure
- Bump our default `tracing` subscriber filter to `wgpu=info` from `wgpu=error` so that the profiling spans are not filtered out as they are created at the `info` level.
---
## Changelog
- Added: `tracing` profiling support for `wgpu` when using bevy's `trace` feature
- Changed: The default `tracing` filter statement for `wgpu` has been changed from the `error` level to the `info` level to not filter out the wgpu profiling spans