# Objective
- Update `tracing-tracy`.
- Closes#11598.
## Solution
- Bump `tracing-tracy` to 0.11.0 and `tracy-client` alongside it to
0.17.0 to avoid duplicating that dependency in the deps tree.
- `TracyLayer` is now configurable on creation, so use the default
config.
---------
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
# Objective
Currently the `missing_docs` lint is allowed-by-default and enabled at
crate level when their documentations is complete (see #3492).
This PR proposes to inverse this logic by making `missing_docs`
warn-by-default and mark crates with imcomplete docs allowed.
## Solution
Makes `missing_docs` warn at workspace level and allowed at crate level
when the docs is imcomplete.
# Objective
- Allow prepare windows to run off of the main thread on all platforms.
- Fixes https://github.com/bevyengine/bevy/issues/9964 on all platforms.
## Solution
- Running `prepare_windows` on the main thread on apple platforms is
only mandatory to create surface, which is only needed during window
creation. Split that part into its own system that happens before
`prepare_windows`
- Tested on macOS and iOS
---
## Changelog
- Allow prepare windows to run off main thread on all platforms.
# Objective
- Create an example for bounding volumes and intersection tests
## Solution
- Add an example with a few bounding volumes, created from primitives
- Allow the user to cycle trough the different intersection tests
# Objective
Add interactive system debugging capabilities to bevy, providing
step/break/continue style capabilities to running system schedules.
* Original implementation: #8063
- `ignore_stepping()` everywhere was too much complexity
* Schedule-config & Resource discussion: #8168
- Decided on selective adding of Schedules & Resource-based control
## Solution
Created `Stepping` Resource. This resource can be used to enable
stepping on a per-schedule basis. Systems within schedules can be
individually configured to:
* AlwaysRun: Ignore any stepping state and run every frame
* NeverRun: Never run while stepping is enabled
- this allows for disabling of systems while debugging
* Break: If we're running the full frame, stop before this system is run
Stepping provides two modes of execution that reflect traditional
debuggers:
* Step-based: Only execute one system at a time
* Continue/Break: Run all systems, but stop before running a system
marked as Break
### Demo
https://user-images.githubusercontent.com/857742/233630981-99f3bbda-9ca6-4cc4-a00f-171c4946dc47.mov
Breakout has been modified to use Stepping. The game runs normally for a
couple of seconds, then stepping is enabled and the game appears to
pause. A list of Schedules & Systems appears with a cursor at the first
System in the list. The demo then steps forward full frames using the
spacebar until the ball is about to hit a brick. Then we step system by
system as the ball impacts a brick, showing the cursor moving through
the individual systems. Finally the demo switches back to frame stepping
as the ball changes course.
### Limitations
Due to architectural constraints in bevy, there are some cases systems
stepping will not function as a user would expect.
#### Event-driven systems
Stepping does not support systems that are driven by `Event`s as events
are flushed after 1-2 frames. Although game systems are not running
while stepping, ignored systems are still running every frame, so events
will be flushed.
This presents to the user as stepping the event-driven system never
executes the system. It does execute, but the events have already been
flushed.
This can be resolved by changing event handling to use a buffer for
events, and only dropping an event once all readers have read it.
The work-around to allow these systems to properly execute during
stepping is to have them ignore stepping:
`app.add_systems(event_driven_system.ignore_stepping())`. This was done
in the breakout example to ensure sound played even while stepping.
#### Conditional Systems
When a system is stepped, it is given an opportunity to run. If the
conditions of the system say it should not run, it will not.
Similar to Event-driven systems, if a system is conditional, and that
condition is only true for a very small time window, then stepping the
system may not execute the system. This includes depending on any sort
of external clock.
This exhibits to the user as the system not always running when it is
stepped.
A solution to this limitation is to ensure any conditions are consistent
while stepping is enabled. For example, all systems that modify any
state the condition uses should also enable stepping.
#### State-transition Systems
Stepping is configured on the per-`Schedule` level, requiring the user
to have a `ScheduleLabel`.
To support state-transition systems, bevy generates needed schedules
dynamically. Currently it’s very difficult (if not impossible, I haven’t
verified) for the user to get the labels for these schedules.
Without ready access to the dynamically generated schedules, and a
resolution for the `Event` lifetime, **stepping of the state-transition
systems is not supported**
---
## Changelog
- `Schedule::run()` updated to consult `Stepping` Resource to determine
which Systems to run each frame
- Added `Schedule.label` as a `BoxedSystemLabel`, along with supporting
`Schedule::set_label()` and `Schedule::label()` methods
- `Stepping` needed to know which `Schedule` was running, and prior to
this PR, `Schedule` didn't track its own label
- Would have preferred to add `Schedule::with_label()` and remove
`Schedule::new()`, but this PR touches enough already
- Added calls to `Schedule.set_label()` to `App` and `World` as needed
- Added `Stepping` resource
- Added `Stepping::begin_frame()` system to `MainSchedulePlugin`
- Run before `Main::run_main()`
- Notifies any `Stepping` Resource a new render frame is starting
## Migration Guide
- Add a call to `Schedule::set_label()` for any custom `Schedule`
- This is only required if the `Schedule` will be stepped
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- In #9822 I forgot to disable auto sync points on the Extract Schedule.
We want to do this because the Commands on the Extract Schedule should
be applied on the render thread.
# Objective
- Allow prepare windows to run off of the main thread on platforms that
allow it.
- Fixes https://github.com/bevyengine/bevy/issues/9964 on most
platforms.
## Solution
- Conditionally compile prepare windows for different OS's
- Seems like it's only the call to `create_surface` that needs to run on
the main thread here.
- I've only tested this on windows, but I do see prepare windows running
on other threads.
---
## Changelog
- Allow prepare windows to run off main thread on platforms that allow
it.
# Objective
Allow animation of types other than translation, scale, and rotation on
`Transforms`.
## Solution
Add a base trait for all values that can be animated by the animation
system. This provides the basic operations for sampling and blending
animation values for more than just translation, rotation, and scale.
This implements part of bevyengine/rfcs#51, but is missing the
implementations for `Range<T>` and `Color`. This also does not fully
integrate with the existing `AnimationPlayer` yet, just setting up the
trait.
---------
Co-authored-by: Kirillov Kirill <kirusfg@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: irate <JustTheCoolDude@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
# Objective
Fix an issue where events are not being dropped after being read. I
believe #10077 introduced this issue. The code currently works as
follows:
1. `EventUpdateSignal` is **shared for all event types**
2. During the fixed update phase, `EventUpdateSignal` is set to true
3. `event_update_system`, **unique per event type**, runs to update
Events<T>
4. `event_update_system` reads value of `EventUpdateSignal` to check if
it should update, and then **resets** the value to false
If there are multiple event types, the first `event_update_system` run
will reset the shared `EventUpdateSignal` signal, preventing other
events from being cleared.
## Solution
I've updated the code to have separate signals per event type and added
a shared signal to notify all systems that the time plugin is installed.
## Changelog
- Fixed bug where events were not being dropped
The PR is in a reviewable state now in the sense that the basic
implementations are there. There are still some ToDos that I'm aware of:
- [x] docs for all the new structs and traits
- [x] implement `Default` and derive other useful traits for the new
structs
- [x] Take a look at the notes again (Do this after a first round of
reviews)
- [x] Take care of the repetition in the circle drawing functions
---
# Objective
- TLDR: This PR enables us to quickly draw all the newly added
primitives from `bevy_math` in immediate mode with gizmos
- Addresses #10571
## Solution
- This implements the first design idea I had that covered everything
that was mentioned in the Issue
https://github.com/bevyengine/bevy/issues/10571#issuecomment-1863646197
---
## Caveats
- I added the `Primitive(2/3)d` impls for `Direction(2/3)d` to make them
work with the current solution. We could impose less strict requirements
for the gizmoable objects and remove the impls afterwards if the
community doesn't like the current approach.
---
## Changelog
- implement capabilities to draw ellipses on the gizmo in general (this
was required to have some code which is able to draw the ellipse
primitive)
- refactored circle drawing code to use the more general ellipse drawing
code to keep code duplication low
- implement `Primitive2d` for `Direction2d` and impl `Primitive3d` for
`Direction3d`
- implement trait to draw primitives with specialized details with
gizmos
- `GizmoPrimitive2d` for all the 2D primitives
- `GizmoPrimitive3d` for all the 3D primitives
- (question while writing this: Does it actually matter if we split this
in 2D and 3D? I guess it could be useful in the future if we do
something based on the main rendering mode even though atm it's kinda
useless)
---
---------
Co-authored-by: nothendev <borodinov.ilya@gmail.com>
# Objective
Glyph positions don't account for padding added to the font texture
atlas, resulting in them being off by one physical pixel in both axis.
## Example
```rust
use bevy::{
prelude::*, window::WindowResolution
};
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
resolution: WindowResolution::default().with_scale_factor_override(1.),
..Default::default()
}),
..Default::default()
}))
.add_systems(Startup, setup)
.run();
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(Camera2dBundle::default());
commands.spawn(
TextBundle::from_section(
"QQQQQ",
TextStyle {
font: asset_server.load("FiraMono-Medium.ttf"),
font_size: 14.0,
..default()
},
)
.with_style(Style {
left:Val::Px(10.),
top: Val::Px(10.),
..default()
})
.with_background_color(Color::RED)
);
}
```
<img width="350" alt="QQQQQ-bad"
src="https://github.com/bevyengine/bevy/assets/27962798/6a509aee-64c8-4ee8-a8c1-77ee65355898">
The coordinates are off by one in physical coordinates, not logical. So
the difference only becomes obvious with `UiScale` and the window scale
factor set to low values.
## Solution
Translate glyph positions by -1 in both axes.
<img width="300" alt="QQQQQ-good"
src="https://github.com/bevyengine/bevy/assets/27962798/16e3f6d9-1223-48e0-9fdd-b682a3e8ade4">
---
## Changelog
* Translate the positions for each glyph by -1 in both axes in
`bevy_text::glyph_brush::process_glyphs`
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Drawing a `Gizmos::circle` whose normal is derived from a Transform's
local axes now requires converting a Vec3 to a Direction3d and
unwrapping the result, and I think we shold move the conversion into
Bevy.
## Solution
We can make
`Transform::{left,right,up,down,forward,back,local_x,local_y,local_z}`
return a Direction3d, because they know that their results will be of
finite non-zero length (roughly 1.0).
---
## Changelog
`Transform::up()` and similar functions now return `Direction3d` instead
of `Vec3`.
## Migration Guide
Callers of `Transform::up()` and similar functions may have to
dereference the returned `Direction3d` to get to the inner `Vec3`.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
# Objective
- Address #10338
## Solution
- When implementing specular and diffuse transmission, I inadvertently
introduced a performance regression. On high-end hardware it is barely
noticeable, but **for lower-end hardware it can be pretty brutal**. If I
understand it correctly, this is likely due to use of masking by the GPU
to implement control flow, which means that you still pay the price for
the branches you don't take;
- To avoid that, this PR introduces new shader defs (controlled via
`StandardMaterialKey`) that conditionally include the transmission
logic, that way the shader code for both types of transmission isn't
even sent to the GPU if you're not using them;
- This PR also renames ~~`STANDARDMATERIAL_NORMAL_MAP`~~ to
`STANDARD_MATERIAL_NORMAL_MAP` for consistency with the naming
convention used elsewhere in the codebase. (Drive-by fix)
---
## Changelog
- Added new shader defs, set when using transmission in the
`StandardMaterial`:
- `STANDARD_MATERIAL_SPECULAR_TRANSMISSION`;
- `STANDARD_MATERIAL_DIFFUSE_TRANSMISSION`;
- `STANDARD_MATERIAL_SPECULAR_OR_DIFFUSE_TRANSMISSION`.
- Fixed performance regression caused by the introduction of
transmission, by gating transmission shader logic behind the newly
introduced shader defs;
- Renamed ~~`STANDARDMATERIAL_NORMAL_MAP`~~ to
`STANDARD_MATERIAL_NORMAL_MAP` for consistency;
## Migration Guide
- If you were using `#ifdef STANDARDMATERIAL_NORMAL_MAP` on your shader
code, make sure to update the name to `STANDARD_MATERIAL_NORMAL_MAP`;
(with an underscore between `STANDARD` and `MATERIAL`)
# Objective
- `RayTest` vs `AabbCast` and `CircleCast` is inconsistent
## Solution
- Renaming the other two would only make the name more confusing, so we
rename `RayTest2d/3d` to `RayCast2d/3d`
# Objective
- `AssetTransformer` provides an input asset, and output an asset, but
provides no access to the `LabeledAsset`'s created by the `AssetLoader`.
Labeled sub assets are an extremely important piece of many assets, Gltf
in particular, and without them the amount of transformation on an asset
is limited. In order for `AssetTransformer`'s to be useful, they need to
have access to these sub assets.
- LabeledAsset's loaded by `AssetLoader`s are provided to `AssetSaver`s
in the `LoadAndSave` process, but the `LoadTransformAndSave` process
drops these values in the transform stage, and so `AssetSaver` is given
none.
- Fixes#11606
Ideally the AssetTransformer should not ignore labeled sub assets, and
they should be kept at least for the AssetSaver
## Solution
- I created a new struct similar to `SavedAsset` named
`TransformedAsset` which holds the input asset, and the HashMap of
`LabeledAsset`s. The transform function now takes as input a
`TransformedAsset`, and returns a `TransformedAsset::<AssetOutput>`.
This gives the transform function access to the labeled sub assets
created by the `AssetLoader`.
- I also created `TransformedSubAsset` which holds mutable references to
a sub asset and that sub assets HashMap of `LabeledAsset`s. This allows
you to travers the Tree of `LabeledAsset`s by reference relatively
easily.
- The `LoadTransformAndSave` processor was then reworked to use the new
structs, stopping the `LabeledAsset`s from being dropped.
---
## Changelog
- Created TransformedAsset struct and TransformedSubAsset struct.
- Changed `get_untyped_handle` to return a `UntypedHandle` directly
rather than a reference and added `get_handle` as a typed variant in
SavedAsset and TransformedAsset
- Added `SavedAsset::from_transformed` as a constructor from a
`TransformedAsset`
- Switched LoadTransformAndSave process code to work with new
`TransformedAsset` type
- Added a `ProcessError` for `AssetTransformer` in process.rs
- Switched `AssetTransformer::transform` to use `TransformedAsset` as
input and output.
- Switched `AssetTransformer` to use a `BoxedFuture` like `AssetLoader`
and `AssetSaver` to allow for async transformation code.
- Updated AssetTransformer example to use new structure.
# Objective
It's often necessary to rotate directions, but it currently has to be
done like this:
```rust
Direction3d::new_unchecked(quat * *direction)
```
It'd be nice if you could rotate `Direction3d` directly:
```rust
quat * direction
```
## Solution
Implement `Mul<Direction3d>` for `Quat` ~~and the other way around.~~
(Glam doesn't impl `Mul<Quat>` or `MulAssign<Quat>` for `Vec3`)
The quaternion must be a unit quaternion to keep the direction
normalized, so there is a `debug_assert!` to be sure. Almost all `Quat`
constructors produce unit quaternions, so there should only be issues if
doing something like `quat + quat` instead of `quat * quat`, using
`Quat::from_xyzw` directly, or when you have significant enough drift
caused by e.g. physics simulation that doesn't normalize rotation. In
general, these would probably cause unexpected results anyway.
I also moved tests around slightly to make `dim2` and `dim3` more
consistent (`dim3` had *two* separate `test` modules for some reason).
In the future, we'll probably want a `Rotation2d` type that would
support the same for `Direction2d`. I considered implementing
`Mul<Mat2>` for `Direction2d`, but that would probably be more
questionable since `Mat2` isn't as clearly associated with rotations as
`Quat` is.
# Objective
- The benchmarks for `bevy_ecs`' `iter_simple` group use `for` loops
instead of `World::spawn_batch`.
- There's a TODO comment that says to batch spawn them.
## Solution
- Replace the `for` loops with `World::spawn_batch`.
# Objective
- When running any of the stress tests, the refresh rate is currently
capped to 60hz because of the `ReactiveLowPower` default used when the
window is not in focus. Since stress tests should run as fast as
possible (and as such vsync is disabled for all of them), it makes sense
to always run them in `Continuous` mode. This is especially useful to
avoid capturing non-representative frame times when recording a Tracy
frame.
## Solution
- Always use the `Continuous` update mode in stress tests.
# Objective
I'm working on a developer console plugin, and I wanted to get a
field/index of a struct/list/tuple. My command parser already parses
member expressions and all that, so I wanted to construct a `ParsedPath`
manually, but it's all private.
## Solution
Make the internals of `ParsedPath` public and add documentation for
everything, and I changed the boxed slice inside `ParsedPath` to a
vector for more flexibility.
I also did a bunch of code cleanup. Improving documentation, error
messages, code, type names, etc.
---
## Changelog
- Added the ability to manually create `ParsedPath`s from their
elements, without the need of string parsing.
- Improved `ReflectPath` error handling.
## Migration Guide
- `bevy::reflect::AccessError` has been refactored.
That should be it I think, everything else that was changed was private
before this PR.
---------
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
- Deriving `Reflect` for some public ChangeDetection/Tick structs in
bevy_ecs
---------
Co-authored-by: Charles Bournhonesque <cbournhonesque@snapchat.com>
# Objective
- Finish PR #10322
## Solution
- Rebase changes in PR #10322 and format the changes.
Co-authored-by: Mauer-Oats <maueroats@users.noreply.github.com>
# Objective
- Add a basic form of shapecasting for bounding volumes
## Solution
- Implement AabbCast2d, AabbCast3d, BoundingCircleCast, and
BoundingSphereCast
- These are really just raycasts, but they modify the volumes the ray is
casting against
- The tests are slightly simpler, since they just use the raycast code
for the heavy lifting
# Objective
- Addresses **Support processing and loading files without extensions**
from #9714
- Addresses **More runtime loading configuration** from #9714
- Fixes#367
- Fixes#10703
## Solution
`AssetServer::load::<A>` and `AssetServer::load_with_settings::<A>` can
now use the `Asset` type parameter `A` to select a registered
`AssetLoader` without inspecting the provided `AssetPath`. This change
cascades onto `LoadContext::load` and `LoadContext::load_with_settings`.
This allows the loading of assets which have incorrect or ambiguous file
extensions.
```rust
// Allow the type to be inferred by context
let handle = asset_server.load("data/asset_no_extension");
// Hint the type through the handle
let handle: Handle<CustomAsset> = asset_server.load("data/asset_no_extension");
// Explicit through turbofish
let handle = asset_server.load::<CustomAsset>("data/asset_no_extension");
```
Since a single `AssetPath` no longer maps 1:1 with an `Asset`, I've also
modified how assets are loaded to permit multiple asset types to be
loaded from a single path. This allows for two different `AssetLoaders`
(which return different types of assets) to both load a single path (if
requested).
```rust
// Uses GltfLoader
let model = asset_server.load::<Gltf>("cube.gltf");
// Hypothetical Blob loader for data transmission (for example)
let blob = asset_server.load::<Blob>("cube.gltf");
```
As these changes are reflected in the `LoadContext` as well as the
`AssetServer`, custom `AssetLoaders` can also take advantage of this
behaviour to create more complex assets.
---
## Change Log
- Updated `custom_asset` example to demonstrate extension-less assets.
- Added `AssetServer::get_handles_untyped` and Added
`AssetServer::get_path_ids`
## Notes
As a part of that refactor, I chose to store `AssetLoader`s (within
`AssetLoaders`) using a `HashMap<TypeId, ...>` instead of a `Vec<...>`.
My reasoning for this was I needed to add a relationship between `Asset`
`TypeId`s and the `AssetLoader`, so instead of having a `Vec` and a
`HashMap`, I combined the two, removing the `usize` index from the
adjacent maps.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
The whole `Cow<'static, str>` naming for nodes and subgraphs in
`RenderGraph` is a mess.
## Solution
Replaces hardcoded and potentially overlapping strings for nodes and
subgraphs inside `RenderGraph` with bevy's labelsystem.
---
## Changelog
* Two new labels: `RenderLabel` and `RenderSubGraph`.
* Replaced all uses for hardcoded strings with those labels
* Moved `Taa` label from its own mod to all the other `Labels3d`
* `add_render_graph_edges` now needs a tuple of labels
* Moved `ScreenSpaceAmbientOcclusion` label from its own mod with the
`ShadowPass` label to `LabelsPbr`
* Removed `NodeId`
* Renamed `Edges.id()` to `Edges.label()`
* Removed `NodeLabel`
* Changed examples according to the new label system
* Introduced new `RenderLabel`s: `Labels2d`, `Labels3d`, `LabelsPbr`,
`LabelsUi`
* Introduced new `RenderSubGraph`s: `SubGraph2d`, `SubGraph3d`,
`SubGraphUi`
* Removed `Reflect` and `Default` derive from `CameraRenderGraph`
component struct
* Improved some error messages
## Migration Guide
For Nodes and SubGraphs, instead of using hardcoded strings, you now
pass labels, which can be derived with structs and enums.
```rs
// old
#[derive(Default)]
struct MyRenderNode;
impl MyRenderNode {
pub const NAME: &'static str = "my_render_node"
}
render_app
.add_render_graph_node::<ViewNodeRunner<MyRenderNode>>(
core_3d::graph::NAME,
MyRenderNode::NAME,
)
.add_render_graph_edges(
core_3d::graph::NAME,
&[
core_3d::graph::node::TONEMAPPING,
MyRenderNode::NAME,
core_3d::graph::node::END_MAIN_PASS_POST_PROCESSING,
],
);
// new
use bevy::core_pipeline::core_3d::graph::{Labels3d, SubGraph3d};
#[derive(Debug, Hash, PartialEq, Eq, Clone, RenderLabel)]
pub struct MyRenderLabel;
#[derive(Default)]
struct MyRenderNode;
render_app
.add_render_graph_node::<ViewNodeRunner<MyRenderNode>>(
SubGraph3d,
MyRenderLabel,
)
.add_render_graph_edges(
SubGraph3d,
(
Labels3d::Tonemapping,
MyRenderLabel,
Labels3d::EndMainPassPostProcessing,
),
);
```
### SubGraphs
#### in `bevy_core_pipeline::core_2d::graph`
| old string-based path | new label |
|-----------------------|-----------|
| `NAME` | `SubGraph2d` |
#### in `bevy_core_pipeline::core_3d::graph`
| old string-based path | new label |
|-----------------------|-----------|
| `NAME` | `SubGraph3d` |
#### in `bevy_ui::render`
| old string-based path | new label |
|-----------------------|-----------|
| `draw_ui_graph::NAME` | `graph::SubGraphUi` |
### Nodes
#### in `bevy_core_pipeline::core_2d::graph`
| old string-based path | new label |
|-----------------------|-----------|
| `node::MSAA_WRITEBACK` | `Labels2d::MsaaWriteback` |
| `node::MAIN_PASS` | `Labels2d::MainPass` |
| `node::BLOOM` | `Labels2d::Bloom` |
| `node::TONEMAPPING` | `Labels2d::Tonemapping` |
| `node::FXAA` | `Labels2d::Fxaa` |
| `node::UPSCALING` | `Labels2d::Upscaling` |
| `node::CONTRAST_ADAPTIVE_SHARPENING` |
`Labels2d::ConstrastAdaptiveSharpening` |
| `node::END_MAIN_PASS_POST_PROCESSING` |
`Labels2d::EndMainPassPostProcessing` |
#### in `bevy_core_pipeline::core_3d::graph`
| old string-based path | new label |
|-----------------------|-----------|
| `node::MSAA_WRITEBACK` | `Labels3d::MsaaWriteback` |
| `node::PREPASS` | `Labels3d::Prepass` |
| `node::DEFERRED_PREPASS` | `Labels3d::DeferredPrepass` |
| `node::COPY_DEFERRED_LIGHTING_ID` | `Labels3d::CopyDeferredLightingId`
|
| `node::END_PREPASSES` | `Labels3d::EndPrepasses` |
| `node::START_MAIN_PASS` | `Labels3d::StartMainPass` |
| `node::MAIN_OPAQUE_PASS` | `Labels3d::MainOpaquePass` |
| `node::MAIN_TRANSMISSIVE_PASS` | `Labels3d::MainTransmissivePass` |
| `node::MAIN_TRANSPARENT_PASS` | `Labels3d::MainTransparentPass` |
| `node::END_MAIN_PASS` | `Labels3d::EndMainPass` |
| `node::BLOOM` | `Labels3d::Bloom` |
| `node::TONEMAPPING` | `Labels3d::Tonemapping` |
| `node::FXAA` | `Labels3d::Fxaa` |
| `node::UPSCALING` | `Labels3d::Upscaling` |
| `node::CONTRAST_ADAPTIVE_SHARPENING` |
`Labels3d::ContrastAdaptiveSharpening` |
| `node::END_MAIN_PASS_POST_PROCESSING` |
`Labels3d::EndMainPassPostProcessing` |
#### in `bevy_core_pipeline`
| old string-based path | new label |
|-----------------------|-----------|
| `taa::draw_3d_graph::node::TAA` | `Labels3d::Taa` |
#### in `bevy_pbr`
| old string-based path | new label |
|-----------------------|-----------|
| `draw_3d_graph::node::SHADOW_PASS` | `LabelsPbr::ShadowPass` |
| `ssao::draw_3d_graph::node::SCREEN_SPACE_AMBIENT_OCCLUSION` |
`LabelsPbr::ScreenSpaceAmbientOcclusion` |
| `deferred::DEFFERED_LIGHTING_PASS` | `LabelsPbr::DeferredLightingPass`
|
#### in `bevy_render`
| old string-based path | new label |
|-----------------------|-----------|
| `main_graph::node::CAMERA_DRIVER` | `graph::CameraDriverLabel` |
#### in `bevy_ui::render`
| old string-based path | new label |
|-----------------------|-----------|
| `draw_ui_graph::node::UI_PASS` | `graph::LabelsUi::UiPass` |
---
## Future work
* Make `NodeSlot`s also use types. Ideally, we have an enum with unit
variants where every variant resembles one slot. Then to make sure you
are using the right slot enum and make rust-analyzer play nicely with
it, we should make an associated type in the `Node` trait. With today's
system, we can introduce 3rd party slots to a node, and i wasnt sure if
this was used, so I didn't do this in this PR.
## Unresolved Questions
When looking at the `post_processing` example, we have a struct for the
label and a struct for the node, this seems like boilerplate and on
discord, @IceSentry (sowy for the ping)
[asked](https://discord.com/channels/691052431525675048/743663924229963868/1175197016947699742)
if a node could automatically introduce a label (or i completely
misunderstood that). The problem with that is, that nodes like
`EmptyNode` exist multiple times *inside the same* (sub)graph, so there
we need extern labels to distinguish between those. Hopefully we can
find a way to reduce boilerplate and still have everything unique. For
EmptyNode, we could maybe make a macro which implements an "empty node"
for a type, but for nodes which contain code and need to be present
multiple times, this could get nasty...
# Objective
- [`thiserror`](https://docs.rs/thiserror/) is used to derive the error
type on `bevy_dynamic_plugin`'s
[`DynamicPluginLoadError`](https://docs.rs/bevy_dynamic_plugin/latest/bevy_dynamic_plugin/enum.DynamicPluginLoadError.html).
- It is an enum where each variant wraps a `libloading` error type.
- `thiserror` supports marking this internal error types as `#[source]`
so it can automatically fill out the
[`Error::source`](https://doc.rust-lang.org/std/error/trait.Error.html#method.source)
method.
- This allows other error handling libraries to get more information
about the error than what Bevy by default provides. It increases
interoperability between libraries.
## Solution
- Mark the internal `libloading::Error` of `DynamicPluginLoadError` with
`#[source]`.
---
## Changelog
- Implemented the
[`Error::source`](https://doc.rust-lang.org/std/error/trait.Error.html#method.source)
method for
[`DynamicPluginLoadError`](https://docs.rs/bevy_dynamic_plugin/latest/bevy_dynamic_plugin/enum.DynamicPluginLoadError.html).
---
Here is the output from `cargo-expand` before and after the change.
```rust
// Before
impl Error for DynamicPluginLoadError {}
```
```rust
// After
impl Error for DynamicPluginLoadError {
fn source(&self) -> Option<&(dyn Error + 'static)> {
use thiserror::__private::AsDynError as _;
match self {
DynamicPluginLoadError::Library { 0: source, .. } => {
Some(source.as_dyn_error())
}
DynamicPluginLoadError::Plugin { 0: source, .. } => {
Some(source.as_dyn_error())
}
}
}
}
```
# Objective
- SavedAsset's iter_labels returns ```&str```, however accessing
LabeledAssets requires ```CowArc<'static, str>```
- Although SavedAsset holds UntypedHandles in its hashmap of
LabeledAssets, they are inaccessible as LabeledAssets are casted to
SavedAsset or ErasedLoadedAsset, which don't contain their
UntypedHandles
- Adresses #11609
## Solution
- Used Trait bounds to allow for either ```CowArc<'static, str>``` or
```&str``` to be used as a label in get_labeled and get_erased_labeled.
- Added method get_untyped_handle to get UntypedHandle from the
LabeledAsset.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Example `send_and_receive_events` added in #11574 panics
```
thread 'Compute Task Pool (3)' panicked at bevy/crates/bevy_ecs/src/system/system_param.rs:570:17:
Resource requested by send_and_receive_events::read_and_write_different_event_types does not exist: bevy_ecs::event::Events<send_and_receive_events::A>
Encountered a panic in system `send_and_receive_events::read_and_write_different_event_types`!
Encountered a panic in system `bevy_app::main_schedule::Main::run_main`!
```
## Solution
- Register the events used in the system
- Don't use logger as it's not setup with `MinimalPlugins`, just print
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Kanabenki <lucien.menassol@gmail.com>
# Objective
- `impl_reflect_struct` doesn't cover tuple structs or enums.
- Problem brought up [on
Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1190623345817960463).
## Solution
- Replaces `impl_reflect_struct` with the new `impl_reflect` which works
for tuple structs and enums too.
---
## Changelog
- Internally in `bevy_reflect_derive`, we have a new `ReflectProvenance`
type which is composed of `ReflectTraitToImpl` and `ReflectSource`.
- `impl_reflect_struct` is gone and totally superseded by
`impl_reflect`.
---------
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
# Objective
- Allow `HashMap<Cow<'_, T>, _>` to use `&T` as key for `HashMap::get`
- Makes `CowArc` more like `Cow`
## Solution
Implements `Borrow<T>` and `AsRef<T>` for `CowArc<T>`.
# Objective
Right now, all assets in the main world get extracted and prepared in
the render world (if the asset's using the RenderAssetPlugin). This is
unfortunate for two cases:
1. **TextureAtlas** / **FontAtlas**: This one's huge. The individual
`Image` assets that make up the atlas are cloned and prepared
individually when there's no reason for them to be. The atlas textures
are built on the CPU in the main world. *There can be hundreds of images
that get prepared for rendering only not to be used.*
2. If one loads an Image and needs to transform it in a system before
rendering it, kind of like the [decompression
example](https://github.com/bevyengine/bevy/blob/main/examples/asset/asset_decompression.rs#L120),
there's a price paid for extracting & preparing the asset that's not
intended to be rendered yet.
------
* References #10520
* References #1782
## Solution
This changes the `RenderAssetPersistencePolicy` enum to bitflags. I felt
that the objective with the parameter is so similar in nature to wgpu's
[`TextureUsages`](https://docs.rs/wgpu/latest/wgpu/struct.TextureUsages.html)
and
[`BufferUsages`](https://docs.rs/wgpu/latest/wgpu/struct.BufferUsages.html),
that it may as well be just like that.
```rust
// This asset only needs to be in the main world. Don't extract and prepare it.
RenderAssetUsages::MAIN_WORLD
// Keep this asset in the main world and
RenderAssetUsages::MAIN_WORLD | RenderAssetUsages::RENDER_WORLD
// This asset is only needed in the render world. Remove it from the asset server once extracted.
RenderAssetUsages::RENDER_WORLD
```
### Alternate Solution
I considered introducing a third field to `RenderAssetPersistencePolicy`
enum:
```rust
enum RenderAssetPersistencePolicy {
/// Keep the asset in the main world after extracting to the render world.
Keep,
/// Remove the asset from the main world after extracting to the render world.
Unload,
/// This doesn't need to be in the render world at all.
NoExtract, // <-----
}
```
Functional, but this seemed like shoehorning. Another option is renaming
the enum to something like:
```rust
enum RenderAssetExtractionPolicy {
/// Extract the asset and keep it in the main world.
Extract,
/// Remove the asset from the main world after extracting to the render world.
ExtractAndUnload,
/// This doesn't need to be in the render world at all.
NoExtract,
}
```
I think this last one could be a good option if the bitflags are too
clunky.
## Migration Guide
* `RenderAssetPersistencePolicy::Keep` → `RenderAssetUsage::MAIN_WORLD |
RenderAssetUsage::RENDER_WORLD` (or `RenderAssetUsage::default()`)
* `RenderAssetPersistencePolicy::Unload` →
`RenderAssetUsage::RENDER_WORLD`
* For types implementing the `RenderAsset` trait, change `fn
persistence_policy(&self) -> RenderAssetPersistencePolicy` to `fn
asset_usage(&self) -> RenderAssetUsages`.
* Change any references to `cpu_persistent_access`
(`RenderAssetPersistencePolicy`) to `asset_usage` (`RenderAssetUsage`).
This applies to `Image`, `Mesh`, and a few other types.
# Objective
Improve compile times.
## Solution
The `-Z threads=0` option has been introduced into nightly rust somewhat
recently, and was showcased in this [rust-lang
article](https://blog.rust-lang.org/2023/11/09/parallel-rustc.html).
This option improves multithreading in rust and speeds up compilation. I
added this option to `config_fast_builds.toml` so others can also use
this option to improve compile times.
`-Z threads=0` automatically uses the same amount of threads as the
amount of threads in your system (See [rustc source
code](6b4f1c5e78/compiler/rustc_session/src/options.rs (L617))).
### Benchmarks
> **Disclaimer:** This section was written before I knew of `-Z
threads=0`, so it uses `-Z threads=8` instead.
I compiled bevy with/without the `-Z threads=8` and saw about a 7%
improvement in compliation times on my Kubuntu system with a 13th Gen
Intel® Core™ i5-13400.
Also the compile times go down over time, probably because I had other
things running in the background.
#### Without `-Z threads=8`
- 42.33s
- 40.90s
- 38.27s
- 38.07s
- 37.17s
- 37.67s
- 36.63s
- 37.24s
**Average**: 38.535
#### With `-Z threads=8`
- 36.77s
- 39.50s
- 38.86s
- 35.61s
- 34.37s
- 34.32s
- 34.44s
- 33.74s
**Average**: 35.95125
# Objective
- Address a `TODO` item in `bevy_animation`.
## Solution
- Replace the `cubic_spline_interpolation` macro with a function.
The function isn't marked as `#[inline(always)]` but from what I checked
with `cargo asm` it gets inlined (even in debug, unless I explicitly add
`#[inline(never)]`), so this should be identical to the macro. If needed
I can add the attribute.
Updates the requirements on
[erased-serde](https://github.com/dtolnay/erased-serde) to permit the
latest version.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/dtolnay/erased-serde/releases">erased-serde's
releases</a>.</em></p>
<blockquote>
<h2>0.4.2</h2>
<ul>
<li>Update proc-macro2 to fix caching issue when using a rustc-wrapper
such as sccache</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="8f555a2db2"><code>8f555a2</code></a>
Release 0.4.2</li>
<li><a
href="450a9108fc"><code>450a910</code></a>
Pull in proc-macro2 sccache fix</li>
<li><a
href="4726cdb49d"><code>4726cdb</code></a>
Release 0.4.1</li>
<li><a
href="4e04e70902"><code>4e04e70</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/erased-serde/issues/101">#101</a>
from dtolnay/sererror</li>
<li><a
href="c670c72da5"><code>c670c72</code></a>
Preserve error message of errors originated from Serialize impl</li>
<li><a
href="6893670cca"><code>6893670</code></a>
Ignore box_collection clippy lint</li>
<li><a
href="7ddf6aadd8"><code>7ddf6aa</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/erased-serde/issues/100">#100</a>
from KodrAus/fix/failing-serialize-impl</li>
<li><a
href="8227d20573"><code>8227d20</code></a>
handle the case where a Serialize fails without calling the
Serializer</li>
<li><a
href="160c15393e"><code>160c153</code></a>
Release 0.4.0</li>
<li><a
href="2e48977019"><code>2e48977</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/erased-serde/issues/99">#99</a>
from dtolnay/bench</li>
<li>Additional commits viewable in <a
href="https://github.com/dtolnay/erased-serde/compare/0.3.0...0.4.2">compare
view</a></li>
</ul>
</details>
<br />
Dependabot will resolve any conflicts with this PR as long as you don't
alter it yourself. You can also trigger a rebase manually by commenting
`@dependabot rebase`.
[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)
---
<details>
<summary>Dependabot commands and options</summary>
<br />
You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits
that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot squash and merge` will squash and merge this PR after
your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge
and block automerging
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot close` will close this PR and stop Dependabot recreating
it. You can achieve the same result by closing it manually
- `@dependabot show <dependency name> ignore conditions` will show all
of the ignore conditions of the specified dependency
- `@dependabot ignore this major version` will close this PR and stop
Dependabot creating any more for this major version (unless you reopen
the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop
Dependabot creating any more for this minor version (unless you reopen
the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop
Dependabot creating any more for this dependency (unless you reopen the
PR or upgrade to it yourself)
</details>
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
# Objective
Revert the changes to type parameter bounds introduced in #9046,
improves the `#[reflect(where)]` attribute (also from #9046), and adds
the ability to opt out of field bounds.
This is based on suggestions by @soqb and discussion on
[Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427).
## Solution
Reverts the changes to type parameter bounds when deriving `Reflect`,
introduced in #9046. This was originally done as a means of fixing a
recursion issue (#8965). However, as @soqb pointed out, we could achieve
the same result by simply making an opt-out attribute instead of messing
with the type parameter bounds.
This PR has four main changes:
1. Reverts the type parameter bounds from #9046
2. Includes `TypePath` as a default bound for active fields
3. Changes `#reflect(where)]` to be strictly additive
4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds
Change 1 means that, like before, type parameters only receive at most
the `TypePath` bound (if `#[reflect(type_path = false)]` is not present)
and active fields receive the `Reflect` or `FromReflect` bound. And with
Change 2, they will also receive `TypePath` (since it's indirectly
required by `Typed` to construct `NamedField` and `UnnamedField`
instances).
Change 3 was made to make room for Change 4. By splitting out the
responsibility of `#reflect(where)]`, we can use it with or without
`#reflect(no_field_bounds)]` for various use cases.
For example, if we hadn't done this, the following would have failed:
```rust
// Since we're not using `#reflect(no_field_bounds)]`,
// `T::Assoc` is automatically given the required bounds
// of `FromReflect + TypePath`
#[derive(Reflect)]
#[reflect(where T::Assoc: OtherTrait)]
struct Foo<T: MyTrait> {
value: T::Assoc,
}
```
This provides more flexibility to the user while still letting them add
or remove most trait bounds.
And to solve the original recursion issue, we can do:
```rust
#[derive(Reflect)]
#[reflect(no_field_bounds)] // <-- Added
struct Foo {
foo: Vec<Foo>
}
```
#### Bounds
All in all, we now have four sets of trait bounds:
- `Self` gets the bounds `Any + Send + Sync`
- Type parameters get the bound `TypePath`. This can be opted out of
with `#[reflect(type_path = false)]`
- Active fields get the bounds `TypePath` and `FromReflect`/`Reflect`
bounds. This can be opted out of with `#reflect(no_field_bounds)]`
- Custom bounds can be added with `#[reflect(where)]`
---
## Changelog
- Revert some changes #9046
- `#reflect(where)]` is now strictly additive
- Added `#reflect(no_field_bounds)]` attribute to opt out of automatic
field trait bounds when deriving `Reflect`
- Made the `TypePath` requirement on fields when deriving `Reflect` more
explicit
## Migration Guide
> [!important]
> This PR shouldn't be a breaking change relative to the current version
of Bevy (v0.12). And since it removes the breaking parts of #9046, that
PR also won't need a migration guide.
# Objective
Currently, the `Capsule` primitive is technically dimension-agnostic in
that it implements both `Primitive2d` and `Primitive3d`. This seems good
on paper, but it can often be useful to have separate 2D and 3D versions
of primitives.
For example, one might want a two-dimensional capsule mesh. We can't
really implement both 2D and 3D meshing for the same type using the
upcoming `Meshable` trait (see #11431). We also currently don't
implement `Bounded2d` for `Capsule`, see
https://github.com/bevyengine/bevy/pull/11336#issuecomment-1890797788.
Having 2D and 3D separate at a type level is more explicit, and also
more consistent with the existing primitives, as there are no other
types that implement both `Primitive2d` and `Primitive3d` at the same
time.
## Solution
Rename `Capsule` to `Capsule3d` and add `Capsule2d`. `Capsule2d`
implements `Bounded2d`.
For now, I went for `Capsule2d` for the sake of consistency and clarity.
Mathematically the more accurate term would be `Stadium` or `Pill` (see
[Wikipedia](https://en.wikipedia.org/wiki/Stadium_(geometry))), but
those might be less obvious to game devs. For reference, Godot has
[`CapsuleShape2D`](https://docs.godotengine.org/en/stable/classes/class_capsuleshape2d.html).
I can rename it if others think the geometrically correct name is better
though.
---
## Changelog
- Renamed `Capsule` to `Capsule3d`
- Added `Capsule2d` with `Bounded2d` implemented
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes#11479
## Solution
- Remove `collide_aabb.rs`
- Re-implement the example-specific collision code in the example,
taking advantage of the new `IntersectsVolume` trait.
## Changelog
- Removed `sprite::collide_aabb::collide` and
`sprite::collide_aabb::Collision`.
## Migration Guide
`sprite::collide_aabb::collide` and `sprite::collide_aabb::Collision`
were removed.
```rust
// Before
let collision = bevy::sprite::collide_aabb::collide(a_pos, a_size, b_pos, b_size);
if collision.is_some() {
// ...
}
// After
let collision = Aabb2d::new(a_pos.truncate(), a_size / 2.)
.intersects(&Aabb2d::new(b_pos.truncate(), b_size / 2.));
if collision {
// ...
}
```
If you were making use `collide_aabb::Collision`, see the new
`collide_with_side` function in the [`breakout`
example](https://bevyengine.org/examples/Games/breakout/).
## Discussion
As discussed in the linked issue, maybe we want to wait on `bevy_sprite`
generally making use of `Aabb2b` so users don't need to construct it
manually. But since they **do** need to construct the bounding circle
for the ball manually, this doesn't seem like a big deal to me.
---------
Co-authored-by: IQuick 143 <IQuick143cz@gmail.com>
# Objective
When developing my game I realized `extract_clusters` and
`prepare_clusters` systems are taking a lot of time despite me creating
very little lights. Reducing number of clusters from the default 4096 to
2048 or less greatly improved performance and stabilized FPS (~300 ->
1000+). I debugged it and found out that the main reason for this is
cloning `VisiblePointLights` in `extract_clusters` system. It contains
light entities grouped by clusters that they affect. The problem is that
we clone 4096 (assuming the default clusters configuration) vectors
every frame. If many of them happen to be non-empty it starts to be a
bottleneck because there is a lot of heap allocation. It wouldn't be a
problem if we reused those vectors in following frames but we don't.
## Solution
Avoid cloning multiple vectors and instead build a single vector
containing data for all clusters.
I've recorded a trace in `3d_scene` example with disabled v-sync before
and after the change.
Mean FPS went from 424 to 990. Mean time for `extract_clusters` system
was reduced from 210 us to 24 us and `prepare_clusters` from 189 us to
87 us.
---
## Changelog
- Improved performance of `extract_clusters` and `prepare_clusters`
systems for scenes where lights affect a big part of it.
# Objective
Fixes: https://github.com/bevyengine/bevy/issues/11549
Add a doctest example of what a custom implementation of an
`EntityMapper` would look like.
(need to wait until https://github.com/bevyengine/bevy/pull/11428 is
merged)
---------
Co-authored-by: Charles Bournhonesque <cbournhonesque@snapchat.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Hennadii Chernyshchyk <genaloner@gmail.com>
# Objective
The first part of #10569, split up from #11007.
The goal is to implement meshing support for Bevy's new geometric
primitives, starting with 2D primitives. 3D meshing will be added in a
follow-up, and we can consider removing the old mesh shapes completely.
## Solution
Add a `Meshable` trait that primitives need to implement to support
meshing, as suggested by the
[RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/12-primitive-shapes.md#meshing).
```rust
/// A trait for shapes that can be turned into a [`Mesh`].
pub trait Meshable {
/// The output of [`Self::mesh`]. This can either be a [`Mesh`]
/// or a builder used for creating a [`Mesh`].
type Output;
/// Creates a [`Mesh`] for a shape.
fn mesh(&self) -> Self::Output;
}
```
This PR implements it for the following primitives:
- `Circle`
- `Ellipse`
- `Rectangle`
- `RegularPolygon`
- `Triangle2d`
The `mesh` method typically returns a builder-like struct such as
`CircleMeshBuilder`. This is needed to support shape-specific
configuration for things like mesh resolution or UV configuration:
```rust
meshes.add(Circle { radius: 0.5 }.mesh().resolution(64));
```
Note that if no configuration is needed, you can even skip calling
`mesh` because `From<MyPrimitive>` is implemented for `Mesh`:
```rust
meshes.add(Circle { radius: 0.5 });
```
I also updated the `2d_shapes` example to use primitives, and tweaked
the colors to have better contrast against the dark background.
Before:
After:
Here you can see the UVs and different facing directions: (taken from
#11007, so excuse the 3D primitives at the bottom left)
---
## Changelog
- Added `bevy_render::mesh::primitives` module
- Added `Meshable` trait and implemented it for:
- `Circle`
- `Ellipse`
- `Rectangle`
- `RegularPolygon`
- `Triangle2d`
- Implemented `Default` and `Copy` for several 2D primitives
- Updated `2d_shapes` example to use primitives
- Tweaked colors in `2d_shapes` example to have better contrast against
the (new-ish) dark background
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Sending and receiving events of the same type in the same system is a
reasonably common need, generally due to event filtering.
- However, actually doing so is non-trivial, as the borrow checker
simultaneous hates mutable and immutable access.
## Solution
- Demonstrate two sensible patterns for doing so.
- Update the `ManualEventReader` docs to be more clear and link to this
example.
---------
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
Co-authored-by: ickk <git@ickk.io>
