# Objective
- Fixes#17960
## Solution
- Followed the [edition upgrade
guide](https://doc.rust-lang.org/edition-guide/editions/transitioning-an-existing-project-to-a-new-edition.html)
## Testing
- CI
---
## Summary of Changes
### Documentation Indentation
When using lists in documentation, proper indentation is now linted for.
This means subsequent lines within the same list item must start at the
same indentation level as the item.
```rust
/* Valid */
/// - Item 1
/// Run-on sentence.
/// - Item 2
struct Foo;
/* Invalid */
/// - Item 1
/// Run-on sentence.
/// - Item 2
struct Foo;
```
### Implicit `!` to `()` Conversion
`!` (the never return type, returned by `panic!`, etc.) no longer
implicitly converts to `()`. This is particularly painful for systems
with `todo!` or `panic!` statements, as they will no longer be functions
returning `()` (or `Result<()>`), making them invalid systems for
functions like `add_systems`. The ideal fix would be to accept functions
returning `!` (or rather, _not_ returning), but this is blocked on the
[stabilisation of the `!` type
itself](https://doc.rust-lang.org/std/primitive.never.html), which is
not done.
The "simple" fix would be to add an explicit `-> ()` to system
signatures (e.g., `|| { todo!() }` becomes `|| -> () { todo!() }`).
However, this is _also_ banned, as there is an existing lint which (IMO,
incorrectly) marks this as an unnecessary annotation.
So, the "fix" (read: workaround) is to put these kinds of `|| -> ! { ...
}` closuers into variables and give the variable an explicit type (e.g.,
`fn()`).
```rust
// Valid
let system: fn() = || todo!("Not implemented yet!");
app.add_systems(..., system);
// Invalid
app.add_systems(..., || todo!("Not implemented yet!"));
```
### Temporary Variable Lifetimes
The order in which temporary variables are dropped has changed. The
simple fix here is _usually_ to just assign temporaries to a named
variable before use.
### `gen` is a keyword
We can no longer use the name `gen` as it is reserved for a future
generator syntax. This involved replacing uses of the name `gen` with
`r#gen` (the raw-identifier syntax).
### Formatting has changed
Use statements have had the order of imports changed, causing a
substantial +/-3,000 diff when applied. For now, I have opted-out of
this change by amending `rustfmt.toml`
```toml
style_edition = "2021"
```
This preserves the original formatting for now, reducing the size of
this PR. It would be a simple followup to update this to 2024 and run
`cargo fmt`.
### New `use<>` Opt-Out Syntax
Lifetimes are now implicitly included in RPIT types. There was a handful
of instances where it needed to be added to satisfy the borrow checker,
but there may be more cases where it _should_ be added to avoid
breakages in user code.
### `MyUnitStruct { .. }` is an invalid pattern
Previously, you could match against unit structs (and unit enum
variants) with a `{ .. }` destructuring. This is no longer valid.
### Pretty much every use of `ref` and `mut` are gone
Pattern binding has changed to the point where these terms are largely
unused now. They still serve a purpose, but it is far more niche now.
### `iter::repeat(...).take(...)` is bad
New lint recommends using the more explicit `iter::repeat_n(..., ...)`
instead.
## Migration Guide
The lifetimes of functions using return-position impl-trait (RPIT) are
likely _more_ conservative than they had been previously. If you
encounter lifetime issues with such a function, please create an issue
to investigate the addition of `+ use<...>`.
## Notes
- Check the individual commits for a clearer breakdown for what
_actually_ changed.
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
-
[`nonstandard_macro_braces`](https://rust-lang.github.io/rust-clippy/master/index.html#nonstandard_macro_braces)
is a Clippy lint that enforces what braces certain known macros are
allowed to use.
- For instance, requiring `println!()` instead of `println!{}`.
- I started working on this after seeing
https://github.com/TheBevyFlock/bevy_cli/issues/277.
## Solution
- Enable `nonstandard_macro_braces` in the workspace.
- Configure Clippy so it enforces `[]` braces for `children!`.
## Testing
1. Create `examples/clippy_test.rs`.
2. Paste the following code:
```rust
//! Some docs woooooooo
use bevy::prelude::*;
fn main() {
let _ = children!(Name::new("Foo"));
}
```
3. Run `cargo clippy --example clippy_test`.
4. Ensure the following warning is emitted:
```sh
warning: use of irregular braces for `children!` macro
--> examples/clippy_test.rs:6:13
|
6 | let _ = children!(Name::new("Foo"));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `children![Name::new("Foo")]`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonstandard_macro_braces
= note: requested on the command line with `-W clippy::nonstandard-macro-braces`
warning: `bevy` (example "clippy_test") generated 1 warning (run `cargo clippy --fix --example "clippy_test"` to apply 1 suggestion)
```
## Objective
Get rid of a redundant Cargo feature flag.
## Solution
Use the built-in `target_abi = "sim"` instead of a custom Cargo feature
flag, which is set for the iOS (and visionOS and tvOS) simulator. This
has been stable since Rust 1.78.
In the future, some of this may become redundant if Wgpu implements
proper supper for the iOS Simulator:
https://github.com/gfx-rs/wgpu/issues/7057
CC @mockersf who implemented [the original
fix](https://github.com/bevyengine/bevy/pull/10178).
## Testing
- Open mobile example in Xcode.
- Launch the simulator.
- See that no errors are emitted.
- Remove the code cfg-guarded behind `target_abi = "sim"`.
- See that an error now happens.
(I haven't actually performed these steps on the latest `main`, because
I'm hitting an unrelated error (EDIT: It was
https://github.com/bevyengine/bevy/pull/17637). But tested it on
0.15.0).
---
## Migration Guide
> If you're using a project that builds upon the mobile example, remove
the `ios_simulator` feature from your `Cargo.toml` (Bevy now handles
this internally).
This commit builds on top of the work done in #16589 and #17051, by
adding support for fallible observer systems.
As with the previous work, the actual results of the observer system are
suppressed for now, but the intention is to provide a way to handle
errors in a global way.
Until then, you can use a `PipeSystem` to manually handle results.
---------
Signed-off-by: Jean Mertz <git@jeanmertz.com>
# Objective
Bevy's ECS provides several core traits such as `Component`,
`SystemParam`, etc that determine where a type can be used. When reading
the docs, this currently requires scrolling down to and scanning the
"Trait Implementations" section. Make these core traits more visible.
## Solution
Add a color-coded labels below the type heading denoting the following
types:
- `Component`
- immutable components are labeled as such
- `Resource`
- `Asset`
- `Event`
- `Plugin` & `PluginGroup`
- `ScheduleLabel` & `SystemSet`
- `SystemParam`
As docs.rs does not provide an option for post-processing the html,
these are added via JS with traits implementations being detected by
scanning the DOM. Rustdoc's html output is unstable, which could
potentially lead to this detection (or the adding of the labels) to
break, however it only needs to work when a new release is deployed and
falls back to the status quo of not displaying these labels.
Idea by JMS55, implementation by Jondolf (see
https://github.com/Jondolf/bevy_docs_extension_demo/).
## Testing
Run this in Bevy's root folder:
```bash
RUSTDOCFLAGS="--html-after-content docs-rs/trait-tags.html --cfg docsrs_dep" RUSTFLAGS="--cfg docsrs_dep" cargo doc --no-deps -p <some_bevy_package>
```
---
## Showcase
Check it out on
[docs.rs](https://docs.rs/bevy_docs_extension_demo/0.1.1/bevy_docs_extension_demo/struct.TestAllTraits.html)
## Release Notes
On docs.rs, Bevy now displays labels indicating which core traits a type
implements:
If you want to add these to your own crate, check out [these
instructions](https://github.com/bevyengine/bevy/blob/main/docs-rs#3rd-party-crates).
---------
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
Co-authored-by: Carter Weinberg <weinbergcarter@gmail.com>
# Objective
- It's currently very hard for beginners and advanced users to get a
full understanding of a complete render phase.
## Solution
- Implement a full custom render phase
- The render phase in the example is intended to show a custom stencil
phase that renders the stencil in red directly on the screen
---
## Showcase
<img width="1277" alt="image"
src="https://github.com/user-attachments/assets/e9dc0105-4fb6-463f-ad53-0529b575fd28"
/>
## Notes
More docs to explain what is going on is still needed but the example
works and can already help some people.
We might want to consider using a batched phase and cold specialization
in the future, but the example is already complex enough as it is.
---------
Co-authored-by: Christopher Biscardi <chris@christopherbiscardi.com>
# Objective
- I was getting familiar with the many_components example to test some
recent pr's for executor changes and saw some things to improve.
## Solution
- Use `insert_by_ids` instead of `insert_by_id`. This reduces the number
of archetype moves and improves startup times substantially.
- Add a tracing span to `base_system`. I'm not sure why, but tracing
spans weren't showing for this system. I think it's something to do with
how pipe system works, but need to investigate more. The approach in
this pr is a little better than the default span too, since it allows
adding the number of entities queried to the span which is not possible
with the default system span.
- println the number of archetype component id's that are created. This
is useful since part of the purpose of this stress test is to test how
well the use of FixedBitSet scales in the executor.
## Testing
- Ran the example with `cargo run --example many_components -F
trace_tracy 1000000` and connected with tracy
- Timed the time it took to spawn 1 million entities on main (240 s) vs
this pr (15 s)
---
## Showcase
## Future Work
- Currently systems are created with a random set of components and
entities are created with a random set of components without any
correlation between the randomness. This means that some systems won't
match any entities and some entities could not match any systems. It
might be better to spawn the entities from the pool of components that
match the queries that the systems are using.
This pr uses the `extern crate self as` trick to make proc macros behave
the same way inside and outside bevy.
# Objective
- Removes noise introduced by `crate as` in the whole bevy repo.
- Fixes#17004.
- Hardens proc macro path resolution.
## TODO
- [x] `BevyManifest` needs cleanup.
- [x] Cleanup remaining `crate as`.
- [x] Add proper integration tests to the ci.
## Notes
- `cargo-manifest-proc-macros` is written by me and based/inspired by
the old `BevyManifest` implementation and
[`bkchr/proc-macro-crate`](https://github.com/bkchr/proc-macro-crate).
- What do you think about the new integration test machinery I added to
the `ci`?
More and better integration tests can be added at a later stage.
The goal of these integration tests is to simulate an actual separate
crate that uses bevy. Ideally they would lightly touch all bevy crates.
## Testing
- Needs RA test
- Needs testing from other users
- Others need to run at least `cargo run -p ci integration-test` and
verify that they work.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Didn't remove WgpuWrapper. Not sure if it's needed or not still.
## Testing
- Did you test these changes? If so, how? Example runner
- Are there any parts that need more testing? Web (portable atomics
thingy?), DXC.
## Migration Guide
- Bevy has upgraded to [wgpu
v24](https://github.com/gfx-rs/wgpu/blob/trunk/CHANGELOG.md#v2400-2025-01-15).
- When using the DirectX 12 rendering backend, the new priority system
for choosing a shader compiler is as follows:
- If the `WGPU_DX12_COMPILER` environment variable is set at runtime, it
is used
- Else if the new `statically-linked-dxc` feature is enabled, a custom
version of DXC will be statically linked into your app at compile time.
- Else Bevy will look in the app's working directory for
`dxcompiler.dll` and `dxil.dll` at runtime.
- Else if they are missing, Bevy will fall back to FXC (not recommended)
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: IceSentry <c.giguere42@gmail.com>
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
The entity disabling / default query filter work added in #17514 and
#13120 is neat, but we don't teach users how it works!
We should fix that before 0.16.
## Solution
Write a simple example to teach the basics of entity disabling!
## Testing
`cargo run --example entity_disabling`
## Showcase
---------
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
The bounding_2d example was originally placed in 2d_rendering because
there was no folder for bounding or math, but now that this folder exist
it makes no sense for it to be here.
## Solution
Move the example
## Testing
I ran the example
*Occlusion culling* allows the GPU to skip the vertex and fragment
shading overhead for objects that can be quickly proved to be invisible
because they're behind other geometry. A depth prepass already
eliminates most fragment shading overhead for occluded objects, but the
vertex shading overhead, as well as the cost of testing and rejecting
fragments against the Z-buffer, is presently unavoidable for standard
meshes. We currently perform occlusion culling only for meshlets. But
other meshes, such as skinned meshes, can benefit from occlusion culling
too in order to avoid the transform and skinning overhead for unseen
meshes.
This commit adapts the same [*two-phase occlusion culling*] technique
that meshlets use to Bevy's standard 3D mesh pipeline when the new
`OcclusionCulling` component, as well as the `DepthPrepass` component,
are present on the camera. It has these steps:
1. *Early depth prepass*: We use the hierarchical Z-buffer from the
previous frame to cull meshes for the initial depth prepass, effectively
rendering only the meshes that were visible in the last frame.
2. *Early depth downsample*: We downsample the depth buffer to create
another hierarchical Z-buffer, this time with the current view
transform.
3. *Late depth prepass*: We use the new hierarchical Z-buffer to test
all meshes that weren't rendered in the early depth prepass. Any meshes
that pass this check are rendered.
4. *Late depth downsample*: Again, we downsample the depth buffer to
create a hierarchical Z-buffer in preparation for the early depth
prepass of the next frame. This step is done after all the rendering, in
order to account for custom phase items that might write to the depth
buffer.
Note that this patch has no effect on the per-mesh CPU overhead for
occluded objects, which remains high for a GPU-driven renderer due to
the lack of `cold-specialization` and retained bins. If
`cold-specialization` and retained bins weren't on the horizon, then a
more traditional approach like potentially visible sets (PVS) or low-res
CPU rendering would probably be more efficient than the GPU-driven
approach that this patch implements for most scenes. However, at this
point the amount of effort required to implement a PVS baking tool or a
low-res CPU renderer would probably be greater than landing
`cold-specialization` and retained bins, and the GPU driven approach is
the more modern one anyway. It does mean that the performance
improvements from occlusion culling as implemented in this patch *today*
are likely to be limited, because of the high CPU overhead for occluded
meshes.
Note also that this patch currently doesn't implement occlusion culling
for 2D objects or shadow maps. Those can be addressed in a follow-up.
Additionally, note that the techniques in this patch require compute
shaders, which excludes support for WebGL 2.
This PR is marked experimental because of known precision issues with
the downsampling approach when applied to non-power-of-two framebuffer
sizes (i.e. most of them). These precision issues can, in rare cases,
cause objects to be judged occluded that in fact are not. (I've never
seen this in practice, but I know it's possible; it tends to be likelier
to happen with small meshes.) As a follow-up to this patch, we desire to
switch to the [SPD-based hi-Z buffer shader from the Granite engine],
which doesn't suffer from these problems, at which point we should be
able to graduate this feature from experimental status. I opted not to
include that rewrite in this patch for two reasons: (1) @JMS55 is
planning on doing the rewrite to coincide with the new availability of
image atomic operations in Naga; (2) to reduce the scope of this patch.
A new example, `occlusion_culling`, has been added. It demonstrates
objects becoming quickly occluded and disoccluded by dynamic geometry
and shows the number of objects that are actually being rendered. Also,
a new `--occlusion-culling` switch has been added to `scene_viewer`, in
order to make it easy to test this patch with large scenes like Bistro.
[*two-phase occlusion culling*]:
https://medium.com/@mil_kru/two-pass-occlusion-culling-4100edcad501
[Aaltonen SIGGRAPH 2015]:
https://www.advances.realtimerendering.com/s2015/aaltonenhaar_siggraph2015_combined_final_footer_220dpi.pdf
[Some literature]:
https://gist.github.com/reduz/c5769d0e705d8ab7ac187d63be0099b5?permalink_comment_id=5040452#gistcomment-5040452
[SPD-based hi-Z buffer shader from the Granite engine]:
https://github.com/Themaister/Granite/blob/master/assets/shaders/post/hiz.comp
## Migration guide
* When enqueuing a custom mesh pipeline, work item buffers are now
created with
`bevy::render::batching::gpu_preprocessing::get_or_create_work_item_buffer`,
not `PreprocessWorkItemBuffers::new`. See the
`specialized_mesh_pipeline` example.
## Showcase
Occlusion culling example:
Bistro zoomed out, before occlusion culling:
Bistro zoomed out, after occlusion culling:
In this scene, occlusion culling reduces the number of meshes Bevy has
to render from 1591 to 585.
This commit allows specular highlights to be tinted with a color and for
the reflectance and color tint values to vary across a model via a pair
of maps. The implementation follows the [`KHR_materials_specular`] glTF
extension. In order to reduce the number of samplers and textures in the
default `StandardMaterial` configuration, the maps are gated behind the
`pbr_specular_textures` Cargo feature.
Specular tinting is currently unsupported in the deferred renderer,
because I didn't want to bloat the deferred G-buffers. A possible fix
for this in the future would be to make the G-buffer layout more
configurable, so that specular tints could be supported on an opt-in
basis. As an alternative, Bevy could force meshes with specular tints to
render in forward mode. Both of these solutions require some more
design, so I consider them out of scope for now.
Note that the map is a *specular* map, not a *reflectance* map. In Bevy
and Filament terms, the reflectance values in the specular map range
from [0.0, 0.5], rather than [0.0, 1.0]. This is an unfortunate
[`KHR_materials_specular`] specification requirement that stems from the
fact that glTF is specified in terms of a specular strength model, not
the reflectance model that Filament and Bevy use. A workaround, which is
noted in the `StandardMaterial` documentation, is to set the
`reflectance` value to 2.0, which spreads the specular map range from
[0.0, 1.0] as normal.
The glTF loader has been updated to parse the [`KHR_materials_specular`]
extension. Note that, unless the non-default `pbr_specular_textures` is
supplied, the maps are ignored. The `specularFactor` value is applied as
usual. Note that, as with the specular map, the glTF `specularFactor` is
twice Bevy's `reflectance` value.
This PR adds a new example, `specular_tint`, which demonstrates the
specular tint and map features. Note that this example requires the
[`KHR_materials_specular`] Cargo feature.
[`KHR_materials_specular`]:
https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_specular
## Changelog
### Added
* Specular highlights can now be tinted with the `specular_tint` field
in `StandardMaterial`.
* Specular maps are now available in `StandardMaterial`, gated behind
the `pbr_specular_textures` Cargo feature.
* The `KHR_materials_specular` glTF extension is now supported, allowing
for customization of specular reflectance and specular maps. Note that
the latter are gated behind the `pbr_specular_textures` Cargo feature.
This commit adds support for *decal projectors* to Bevy, allowing for
textures to be projected on top of geometry. Decal projectors are
clusterable objects, just as punctual lights and light probes are. This
means that decals are only evaluated for objects within the conservative
bounds of the projector, and they don't require a second pass.
These clustered decals require support for bindless textures and as such
currently don't work on WebGL 2, WebGPU, macOS, or iOS. For an
alternative that doesn't require bindless, see PR #16600. I believe that
both contact projective decals in #16600 and clustered decals are
desirable to have in Bevy. Contact projective decals offer broader
hardware and driver support, while clustered decals don't require the
creation of bounding geometry.
A new example, `decal_projectors`, has been added, which demonstrates
multiple decals on a rotating object. The decal projectors can be scaled
and rotated with the mouse.
There are several limitations of this initial patch that can be
addressed in follow-ups:
1. There's no way to specify the Z-index of decals. That is, the order
in which multiple decals are blended on top of one another is arbitrary.
A follow-up could introduce some sort of Z-index field so that artists
can specify that some decals should be blended on top of others.
2. Decals don't take the normal of the surface they're projected onto
into account. Most decal implementations in other engines have a feature
whereby the angle between the decal projector and the normal of the
surface must be within some threshold for the decal to appear. Often,
artists can specify a fade-off range for a smooth transition between
oblique surfaces and aligned surfaces.
3. There's no distance-based fadeoff toward the end of the projector
range. Many decal implementations have this.
This addresses #2401.
## Showcase
# Objective
Bevy sprite image mode lacks proportional scaling for the underlying
texture. In many cases, it's required. For example, if it is desired to
support a wide variety of screens with a single texture, it's okay to
cut off some portion of the original texture.
## Solution
I added scaling of the texture during the preparation step. To fill the
sprite with the original texture, I scaled UV coordinates accordingly to
the sprite size aspect ratio and texture size aspect ratio. To fit
texture in a sprite the original `quad` is scaled and then the
additional translation is applied to place the scaled quad properly.
## Testing
For testing purposes could be used `2d/sprite_scale.rs`. Also, I am
thinking that it would be nice to have some tests for a
`crates/bevy_sprite/src/render/mod.rs:sprite_scale`.
---
## Showcase
<img width="1392" alt="image"
src="https://github.com/user-attachments/assets/c2c37b96-2493-4717-825f-7810d921b4bc"
/>
# Objective
- This PR adds a new stress test called `many_materials` to benchmark
the rendering performance of many animated materials.
- Fixes#11588
- This PR continues the work started in the previous PR #11592, which
was closed due to inactivity.
## Solution
- Created a new example (`examples/stress_tests/many_materials.rs`) that
renders a grid of cubes with animated materials.
- The size of the grid can be configured using the `-n` command-line
argument (or `--grid-size`). The default grid size is 10x10.
- The materials animate by cycling through colors in the HSL color
space.
## Testing
- I have tested these changes locally on my Linux machine.
- Reviewers can test the changes by running the example with different
grid sizes and observing the performance (FPS, frame time).
- I have not tested on other platforms (macOS, Windows, wasm), but I
expect it to work as the code uses standard Bevy features.
---
## Showcase
<details>
<summary>Click to view showcase</summary>
</details>
Implement procedural atmospheric scattering from [Sebastien Hillaire's
2020 paper](https://sebh.github.io/publications/egsr2020.pdf). This
approach should scale well even down to mobile hardware, and is
physically accurate.
## Co-author: @mate-h
He helped massively with getting this over the finish line, ensuring
everything was physically correct, correcting several places where I had
misunderstood or misapplied the paper, and improving the performance in
several places as well. Thanks!
## Credits
@aevyrie: helped find numerous bugs and improve the example to best show
off this feature :)
Built off of @mtsr's original branch, which handled the transmittance
lut (arguably the most important part)
## Showcase:
## For followup
- Integrate with pcwalton's volumetrics code
- refactor/reorganize for better integration with other effects
- have atmosphere transmittance affect directional lights
- add support for generating skybox/environment map
---------
Co-authored-by: Emerson Coskey <56370779+EmersonCoskey@users.noreply.github.com>
Co-authored-by: atlv <email@atlasdostal.com>
Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
Co-authored-by: Emerson Coskey <coskey@emerlabs.net>
Co-authored-by: Máté Homolya <mate.homolya@gmail.com>
# Objective
After #17398, Bevy now has relations! We don't teach users how to make /
work with these in the examples yet though, but we definitely should.
## Solution
- Add a simple abstract example that goes over defining, spawning,
traversing and removing a custom relations.
- ~~Add `Relationship` and `RelationshipTarget` to the prelude: the
trait methods are really helpful here.~~
- this causes subtle ambiguities with method names and weird compiler
errors. Not doing it here!
- Clean up related documentation that I referenced when writing this
example.
## Testing
`cargo run --example relationships`
## Notes to reviewers
1. Yes, I know that the cycle detection code could be more efficient. I
decided to reduce the caching to avoid distracting from the broader
point of "here's how you traverse relationships".
2. Instead of using an `App`, I've decide to use
`World::run_system_once` + system functions defined inside of `main` to
do something closer to literate programming.
---------
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
Co-authored-by: MinerSebas <66798382+MinerSebas@users.noreply.github.com>
Co-authored-by: Kristoffer Søholm <k.soeholm@gmail.com>
Added an external assets section to .gitignore. This prevents
contributors from accidentally adding or committing them.
I believe currently the only externel asset is the meshlet bunny.
# Objective
Fixes https://github.com/bevyengine/bevy/issues/17111
## Solution
Move `#![warn(clippy::allow_attributes,
clippy::allow_attributes_without_reason)]` to the workspace `Cargo.toml`
## Testing
Lots of CI testing, and local testing too.
---------
Co-authored-by: Benjamin Brienen <benjamin.brienen@outlook.com>
# Objective
- Bevy 0.15 added support for custom cursor images in
https://github.com/bevyengine/bevy/pull/14284.
- However, to do animated cursors using the initial support shipped in
0.15 means you'd have to animate the `Handle<Image>`: You can't use a
`TextureAtlas` like you can with sprites and UI images.
- For my use case, my cursors are spritesheets. To animate them, I'd
have to break them down into multiple `Image` assets, but that seems
less than ideal.
## Solution
- Allow users to specify a `TextureAtlas` field when creating a custom
cursor image.
- To create parity with Bevy's `TextureAtlas` support on `Sprite`s and
`ImageNode`s, this also allows users to specify `rect`, `flip_x` and
`flip_y`. In fact, for my own use case, I need to `flip_y`.
## Testing
- I added unit tests for `calculate_effective_rect` and
`extract_and_transform_rgba_pixels`.
- I added a brand new example for custom cursor images. It has controls
to toggle fields on and off. I opted to add a new example because the
existing cursor example (`window_settings`) would be far too messy for
showcasing these custom cursor features (I did start down that path but
decided to stop and make a brand new example).
- The new example uses a [Kenny cursor icon] sprite sheet. I included
the licence even though it's not required (and it's CC0).
- I decided to make the example just loop through all cursor icons for
its animation even though it's not a _realistic_ in-game animation
sequence.
- I ran the PNG through https://tinypng.com. Looks like it's about 35KB.
- I'm open to adjusting the example spritesheet if required, but if it's
fine as is, great.
[Kenny cursor icon]: https://kenney-assets.itch.io/crosshair-pack
---
## Showcase
https://github.com/user-attachments/assets/8f6be8d7-d1d4-42f9-b769-ef8532367749
## Migration Guide
The `CustomCursor::Image` enum variant has some new fields. Update your
code to set them.
Before:
```rust
CustomCursor::Image {
handle: asset_server.load("branding/icon.png"),
hotspot: (128, 128),
}
```
After:
```rust
CustomCursor::Image {
handle: asset_server.load("branding/icon.png"),
texture_atlas: None,
flip_x: false,
flip_y: false,
rect: None,
hotspot: (128, 128),
}
```
## References
- Feature request [originally raised in Discord].
[originally raised in Discord]:
https://discord.com/channels/691052431525675048/692572690833473578/1319836362219847681
# Objective
Building upon https://github.com/bevyengine/bevy/pull/17191, improve the
`animated_mesh` example by removing code, adding comments, and making
the example more c&p'able.
## Solution
- Split the setup function in two to clarify what the example is
demonstrating.
- `setup_mesh_and_animation` is the demonstration.
- `setup_camera_and_environment` just sets up the example app.
- Changed the animation playing to use `AnimationPlayer` directly
instead of creating `AnimationTransitions`.
- This appears sufficient when only playing a single animation.
- Added a comment pointing users to an example of multiple animations.
- Changed the animation to be the run cycle.
- I think it got accidentally changed to the idle in
[#17191](https://github.com/bevyengine/bevy/pull/17191), so this is
reverting back to the original.
- Note that we can improve it to select the animation by name if
[#16529](https://github.com/bevyengine/bevy/pull/16529) lands.
- Renamed `FOX_PATH` to a more neutral `GLTF_PATH`.
- Updated the example descriptions to mention the fox.
- This adds a little character and hints that the example involves
character animation.
- Removed a seemingly redundant `AnimationGraphHandle` component.
- Removed an unnecessary `clone()`.
- Added various comments.
## Notes
- A draft of this PR was discussed on Discord:
https://discord.com/channels/691052431525675048/1326910663972618302/1326920498663133348
- There was discord discussion on whether a component is "inserted
onto", "inserted into" or "added to" an entity.
- "Added to" is most common in code and docs, and seems best to me. But
it awkwardly differs from the name of `EntityCommands::insert`.
- This PR prefers "added to".
- I plan to follow up this PR with similar changes to the
`animated_mesh_control` and `animated_mesh_events` examples.
- But I could roll them into this PR if requested.
## Testing
`cargo run --example animated_mesh`
---------
Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
Gamepad / directional navigation needs an example, for both teaching and
testing purposes.
## Solution
- Add a simple grid-based example.
- Fix an intermittent panic caused by a race condition with bevy_a11y
- Clean up small issues noticed in bevy_input_focus
## To do: this PR
- [x] figure out why "enter" isn't doing anything
- [x] change button color on interaction rather than printing
- [x] add on-screen directions
- [x] move to an asymmetric grid to catch bugs
- [x] ~~fix colors not resetting on button press~~ lol this is mostly
just a problem with hacking `Interaction` for this
- [x] swap to using observers + bubbling, rather than `Interaction`
## To do: future work
- when I increase the button size, such that there is no line break, the
text on the buttons is no longer centered :( EDIT: this is
https://github.com/bevyengine/bevy/issues/16783
- add gamepad stick navigation
- add tools to find the nearest populated quadrant to make diagonal
inputs work
- add a `add_edges` method to `DirectionalNavigationMap`
- add a `add_grid` method to `DirectionalNavigationMap`
- make the example's layout more complex and realistic
- add tools to automatically generate this list
- add button shake on failed navigation rather than printing an error
- make Pressed events easier to mock: default fields, PointerId::Focus
## Testing
`cargo run --example directional_navigation`
---------
Co-authored-by: Rob Parrett <robparrett@gmail.com>
# Objective
Many instances of `clippy::too_many_arguments` linting happen to be on
systems - functions which we don't call manually, and thus there's not
much reason to worry about the argument count.
## Solution
Allow `clippy::too_many_arguments` globally, and remove all lint
attributes related to it.
Fixes#17192.
Replaces "animated_fox" with "animated_mesh".
I considered a few different names - should it say "skinned_mesh" to be
precise? Should it mention gltf? But "animated_mesh" seems intuitive and
keeps it short.
## Testing
- Ran all three examples (Windows 10).
# Objective
The debug features (`DebugPickingPlugin`) from `bevy_mod_picking` were
not upstreamed with the rest of the core changes, this PR reintroduces
it for usage inside `bevy_dev_tools`
## Solution
Vast majority of this code is taken as-is from `bevy_mod_picking` aside
from changes to ensure compilation and code style, as such @aevyrie was
added as the co-author for this change.
### Main changes
* `multiselection` support - the relevant code was explicitly not
included in the process of upstreaming the rest of the package, so it
also has been omitted here.
* `bevy_egui` support - the old package had a preference for using
`bevy_egui` instead of `bevy_ui` if possible, I couldn't see a way to
support this in a core crate, so this has been removed.
Relevant code has been added to the `bevy_dev_tools` crate instead of
`bevy_picking` as it is a better fit and requires a dependency on
`bevy_ui` for drawing debug elements.
### Minor changes
* Changed the debug text size from `60` to `12` as the former was so
large as to be unreadable in the new example.
## Testing
* `cargo run -p ci`
* Added a new example in `dev_tools/picking_debug` and visually verified
the in-window results and the console messages
---------
Co-authored-by: Aevyrie <aevyrie@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Our `animated_fox` example used to be a bare-bones example of how to
spawn an animated gltf and play a single animation.
I think that's a valuable example, and the current `animated_fox`
example is doing way too much. Users who are trying to understand how
our animation system are presented with an enormous amount of
information that may not be immediately relevant.
Over the past few releases, I've been migrating a simple app of mine
where the only animation I need is a single gltf that starts playing a
single animation when it is loaded. It has been a slight struggle to
wade through changes to the animation system to figure out the minimal
amount of things required to accomplish this.
Somewhat motivated by this [recent reddit
thread](https://www.reddit.com/r/rust/comments/1ht93vl/comment/m5c0nc9/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1)
where Bevy and animation got a mention.
## Solution
- Split `animated_fox` into three separate examples
- `animated_fox` - Loads and immediately plays a single animation
- `animated_fox_control` - Shows how to control animations
- `animated_fox_events` - Shows fancy particles when the fox's feet hit
the ground
- Some minor drive-by tidying of these examples
I have created this PR after playing around with the idea and liking how
it turned out, but the duplication isn't totally ideal and there's some
slight overlap with other examples and inconsistencies:
- `animation_events` is simplified and not specific to "loaded animated
scenes" and seems valuable on its own
- `animation_graph` also uses a fox
I am happy to close this if there's no consensus that it's a good idea /
step forward for these examples.
## Testing
`cargo run --example animated_fox`
`cargo run --example animated_fox_control`
`cargo run --example animated_fox_events`
Bump version after release
This PR has been auto-generated
---------
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
RIght now it's not possible to opt out of sprite or ui picking at the
feature level without jumping through some hoops.
If you add the `bevy_sprite` feature, you get
`bevy_sprite_picking_backend`.
If you add the `bevy_ui` feature, you get `bevy_ui_picking_backend`
To get `bevy_sprite` without picking, I think you would have to do
something like this, which seems **very** annoying.
```toml
[dependencies]
bevy = { version = "0.15", default-features = false, features = [
# ... omitted
# "bevy_sprite",
# "bevy_ui", # this also brings in bevy_sprite
# "bevy_text", # this also brings in bevy_sprite
"bevy_render",
"bevy_core_pipeline",
"bevy_color",
] }
bevy_internal = { version = "0.15", default-features = false, features = [
"bevy_sprite",
"bevy_ui",
"bevy_text"
] }
```
## Solution
- Remove `bevy_sprite_picking_backend` from the `bevy_sprite` feature.
- Remove `bevy_ui_picking_backend` from the `bevy_ui` feature.
These are still in Bevy's `default-plugins`.
## Testing
I did some basic testing in a minimal project based on the
`sprite_picking` example to verify that "picking stuff" didn't get
included with `bevy_sprite`.
I would appreciate help testing. I am just unraveling these features and
think that this is correct, but I am not 100% sure.
## Migration Guide
`bevy_sprite_picking_backend` is no longer included by default when
using the `bevy_sprite` feature. If you are using Bevy without default
features and relied on sprite picking, add this feature to your
`Cargo.toml`.
`bevy_ui_picking_backend` is no longer included by default when using
the `bevy_ui` feature. If you are using Bevy without default features
and relied on sprite picking, add this feature to your `Cargo.toml`.
## Additional info
It looks like we attempted to fix this earlier in #16469, but the fix
was incomplete?
# Objective
Improve DAG building for virtual geometry
## Solution
- Use METIS to group triangles into meshlets which lets us minimize
locked vertices which improves simplification, instead of using meshopt
which prioritizes culling efficiency. Also some other minor tweaks.
- Currently most meshlets have 126 triangles, and not 128. Fixing this
might involve calling METIS recursively ourselves to manually bisect the
graph, not sure. Not going to attempt to fix this in this PR.
## Testing
- Did you test these changes? If so, how?
- Tested on bunny.glb and cliff.glb
- Are there any parts that need more testing?
- No
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Download the new bunny asset, run the meshlet example.
---
## Showcase
New
Old
---------
Co-authored-by: IceSentry <IceSentry@users.noreply.github.com>
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/16556
- Closes https://github.com/bevyengine/bevy/issues/11807
## Solution
- Simplify custom projections by using a single source of truth -
`Projection`, removing all existing generic systems and types.
- Existing perspective and orthographic structs are no longer components
- I could dissolve these to simplify further, but keeping them around
was the fast way to implement this.
- Instead of generics, introduce a third variant, with a trait object.
- Do an object safety dance with an intermediate trait to allow cloning
boxed camera projections. This is a normal rust polymorphism papercut.
You can do this with a crate but a manual impl is short and sweet.
## Testing
- Added a custom projection example
---
## Showcase
- Custom projections and projection handling has been simplified.
- Projection systems are no longer generic, with the potential for many
different projection components on the same camera.
- Instead `Projection` is now the single source of truth for camera
projections, and is the only projection component.
- Custom projections are still supported, and can be constructed with
`Projection::custom()`.
## Migration Guide
- `PerspectiveProjection` and `OrthographicProjection` are no longer
components. Use `Projection` instead.
- Custom projections should no longer be inserted as a component.
Instead, simply set the custom projection as a value of `Projection`
with `Projection::custom()`.
# Objective
- As stated in the related issue, this PR is to better align the feature
flag name with what it actually does and the plans for the future.
- Fixes#16852
## Solution
- Simple find / replace
## Testing
- Local run of `cargo run -p ci`
## Migration Guide
The `track_change_detection` feature flag has been renamed to
`track_location` to better reflect its extended capabilities.
# Objective
Make it easier to test for `Text2d` performance regressions.
Related to #16972
## Solution
Add a new `stress_test`, based on `many_sprites` and other existing
stress tests.
The `many-glyphs` option is inspired by
https://github.com/bevyengine/bevy/issues/16901#issuecomment-2558572382.
## Testing
```bash
cargo run --release --example many_text2d -- --help
cargo run --release --example many_text2d
cargo run --release --example many_text2d -- --many_glyphs
```
etc
# Objective
- Fixes#16563
- Make sure bevy_image is available when needed
## Solution
- Add a new feature for `bevy_image`
- Also enable the `bevy_image` feature in `bevy_internal` for all
features that use `bevy_image` themselves
# Objective
- Our benchmarks and `compile_fail` tests lag behind the rest of the
engine because they are not in the Cargo workspace, so not checked by
CI.
- Fixes#16801, please see it for further context!
## Solution
- Add benchmarks and `compile_fail` tests to the Cargo workspace.
- Fix any leftover formatting issues and documentation.
## Testing
- I think CI should catch most things!
## Questions
<details>
<summary>Outdated issue I was having with function reflection being
optional</summary>
The `reflection_types` example is failing in Rust-Analyzer for me, but
not a normal check.
```rust
error[E0004]: non-exhaustive patterns: `ReflectRef::Function(_)` not covered
--> examples/reflection/reflection_types.rs:81:11
|
81 | match value.reflect_ref() {
| ^^^^^^^^^^^^^^^^^^^ pattern `ReflectRef::Function(_)` not covered
|
note: `ReflectRef<'_>` defined here
--> /Users/bdeep/dev/bevy/bevy/crates/bevy_reflect/src/kind.rs:178:1
|
178 | pub enum ReflectRef<'a> {
| ^^^^^^^^^^^^^^^^^^^^^^^
...
188 | Function(&'a dyn Function),
| -------- not covered
= note: the matched value is of type `ReflectRef<'_>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
126 ~ ReflectRef::Opaque(_) => {},
127 + ReflectRef::Function(_) => todo!()
|
```
I think it is because the following line is feature-gated:
cc0f6a8db4/examples/reflection/reflection_types.rs (L117-L122)
My theory for why this is happening is because the benchmarks enabled
`bevy_reflect`'s `function` feature, which gets merged with the rest of
the features when RA checks the workspace, but the `#[cfg(...)]` gate in
the example isn't detecting it:
cc0f6a8db4/benches/Cargo.toml (L19)
Any thoughts on how to fix this? It's not blocking, since the example
still compiles as normal, but it's just RA and the command `cargo check
--workspace --all-targets` appears to fail.
</summary>
# Objective
Expand `track_change_detection` feature to also track entity spawns and
despawns. Use this to create better error messages.
# Solution
Adds `Entities::entity_get_spawned_or_despawned_by` as well as `{all
entity reference types}::spawned_by`.
This also removes the deprecated `get_many_entities_mut` & co (and
therefore can't land in 0.15) because we don't yet have no Polonius.
## Testing
Added a test that checks that the locations get updated and these
updates are ordered correctly vs hooks & observers.
---
## Showcase
Access location:
```rust
let mut world = World::new();
let entity = world.spawn_empty().id();
println!("spawned by: {}", world.entity(entity).spawned_by());
```
```
spawned by: src/main.rs:5:24
```
Error message (with `track_change_detection`):
```rust
world.despawn(entity);
world.entity(entity);
```
```
thread 'main' panicked at src/main.rs:11:11:
Entity 0v1#4294967296 was despawned by src/main.rs:10:11
```
and without:
```
thread 'main' panicked at src/main.rs:11:11:
Entity 0v1#4294967296 does not exist (enable `track_change_detection` feature for more details)
```
Similar error messages now also exists for `Query::get`,
`World::entity_mut`, `EntityCommands` creation and everything that
causes `B0003`, e.g.
```
error[B0003]: Could not insert a bundle (of type `MaterialMeshBundle<StandardMaterial>`) for entity Entity { index: 7, generation: 1 }, which was despawned by src/main.rs:10:11. See: https://bevyengine.org/learn/errors/#b0003
```
---------
Co-authored-by: kurk070ff <108901106+kurk070ff@users.noreply.github.com>
Co-authored-by: Freya Pines <freya@MacBookAir.lan>
Co-authored-by: Freya Pines <freya@Freyas-MacBook-Air.local>
Co-authored-by: Matty Weatherley <weatherleymatthew@gmail.com>
# Objective
This PR continues the work of `bevy_input_focus` by adding a pluggable
tab navigation framework.
As part of this work, `FocusKeyboardEvent` now propagates to the window
after exhausting all ancestors.
## Testing
Unit tests and manual tests.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
This PR adds support for *mixed lighting* to Bevy, whereby some parts of
the scene are lightmapped, while others take part in real-time lighting.
(Here *real-time lighting* means lighting at runtime via the PBR shader,
as opposed to precomputed light using lightmaps.) It does so by adding a
new field, `affects_lightmapped_meshes` to `IrradianceVolume` and
`AmbientLight`, and a corresponding field
`affects_lightmapped_mesh_diffuse` to `DirectionalLight`, `PointLight`,
`SpotLight`, and `EnvironmentMapLight`. By default, this value is set to
true; when set to false, the light contributes nothing to the diffuse
irradiance component to meshes with lightmaps.
Note that specular light is unaffected. This is because the correct way
to bake specular lighting is *directional lightmaps*, which we have no
support for yet.
There are two general ways I expect this field to be used:
1. When diffuse indirect light is baked into lightmaps, irradiance
volumes and reflection probes shouldn't contribute any diffuse light to
the static geometry that has a lightmap. That's because the baking tool
should have already accounted for it, and in a higher-quality fashion,
as lightmaps typically offer a higher effective texture resolution than
the light probe does.
2. When direct diffuse light is baked into a lightmap, punctual lights
shouldn't contribute any diffuse light to static geometry with a
lightmap, to avoid double-counting. It may seem odd to bake *direct*
light into a lightmap, as opposed to indirect light. But there is a use
case: in a scene with many lights, avoiding light leaks requires shadow
mapping, which quickly becomes prohibitive when many lights are
involved. Baking lightmaps allows light leaks to be eliminated on static
geometry.
A new example, `mixed_lighting`, has been added. It demonstrates a sofa
(model from the [glTF Sample Assets]) that has been lightmapped offline
using [Bakery]. It has four modes:
1. In *baked* mode, all objects are locked in place, and all the diffuse
direct and indirect light has been calculated ahead of time. Note that
the bottom of the sphere has a red tint from the sofa, illustrating that
the baking tool captured indirect light for it.
2. In *mixed direct* mode, lightmaps capturing diffuse direct and
indirect light have been pre-calculated for the static objects, but the
dynamic sphere has real-time lighting. Note that, because the diffuse
lighting has been entirely pre-calculated for the scenery, the dynamic
sphere casts no shadow. In a real app, you would typically use real-time
lighting for the most important light so that dynamic objects can shadow
the scenery and relegate baked lighting to the less important lights for
which shadows aren't as important. Also note that there is no red tint
on the sphere, because there is no global illumination applied to it. In
an actual game, you could fix this problem by supplementing the
lightmapped objects with an irradiance volume.
3. In *mixed indirect* mode, all direct light is calculated in
real-time, and the static objects have pre-calculated indirect lighting.
This corresponds to the mode that most applications are expected to use.
Because direct light on the scenery is computed dynamically, shadows are
fully supported. As in mixed direct mode, there is no global
illumination on the sphere; in a real application, irradiance volumes
could be used to supplement the lightmaps.
4. In *real-time* mode, no lightmaps are used at all, and all punctual
lights are rendered in real-time. No global illumination exists.
In the example, you can click around to move the sphere, unless you're
in baked mode, in which case the sphere must be locked in place to be
lit correctly.
## Showcase
Baked mode:
Mixed direct mode:
Mixed indirect mode (default):
Real-time mode:
## Migration guide
* The `AmbientLight` resource, the `IrradianceVolume` component, and the
`EnvironmentMapLight` component now have `affects_lightmapped_meshes`
fields. If you don't need to use that field (for example, if you aren't
using lightmaps), you can safely set the field to true.
* `DirectionalLight`, `PointLight`, and `SpotLight` now have
`affects_lightmapped_mesh_diffuse` fields. If you don't need to use that
field (for example, if you aren't using lightmaps), you can safely set
the field to true.
[glTF Sample Assets]:
https://github.com/KhronosGroup/glTF-Sample-Assets/tree/main
[Bakery]:
https://geom.io/bakery/wiki/index.php?title=Bakery_-_GPU_Lightmapper
# Objective
We were waiting for 1.83 to address most of these, due to a bug with
`missing_docs` and `expect`. Relates to, but does not entirely complete,
#15059.
## Solution
- Upgrade to 1.83
- Switch `allow(missing_docs)` to `expect(missing_docs)`
- Remove a few now-unused `allow`s along the way, or convert to `expect`
# Objective
Draw the UI debug overlay using the UI renderer.
Significantly simpler and easier to use than
`bevy_dev_tools::ui_debug_overlay` which uses `bevy_gizmos`.
* Supports multiple windows and UI rendered to texture.
* Draws rounded debug rects for rounded UI nodes.
Fixes#16666
## Solution
Removed the `ui_debug_overlay` module from `bevy_dev_tools`.
Added a `bevy_ui_debug` feature gate.
Draw the UI debug overlay using the UI renderer.
Adds a new module `bevy_ui::render::debug_overlay`.
The debug overlay extraction function queries for the existing UI layout
and then adds a border around each UI node with `u32::MAX / 2` added to
each stack index so it's drawn on top.
There is a `UiDebugOptions` resource that can be used to enable or
disable the debug overlay and set the line width.
## Testing
The `testbed_ui` example has been changed to use the new debug overlay:
```
cargo run --example testbed_ui --features bevy_ui_debug
```
Press Space to toggle the debug overlay on and off.
---
## Showcase
<img width="961" alt="testbed-ui-new-debug"
src="https://github.com/user-attachments/assets/e9523d18-39ae-46a8-adbe-7d3f3ab8e951">
## Migration Guide
The `ui_debug_overlay` module has been removed from `bevy_dev_tools`.
There is a new debug overlay implemented using the `bevy_ui` renderer.
To use it, enable the `bevy_ui_debug` feature and set the `enable` field
of the `UiDebugOptions` resource to `true`.
# Objective
We currently have no benchmarks for large worlds with many entities,
components and systems.
Having a benchmark for a world with many components is especially useful
for the performance improvements needed for relations. This is also a
response to this [comment from
cart](https://github.com/bevyengine/bevy/pull/14385#issuecomment-2311292546).
> I'd like both a small bevy_ecs-scoped executor benchmark that
generates thousands of components used by hundreds of systems.
## Solution
I use dynamic components and components to construct a benchmark with
2000 components, 4000 systems, and 10000 entities.
## Some notes
- ~I use a lot of random entities, which creates unpredictable
performance, I should use a seeded PRNG.~
- Not entirely sure if everything is ran concurrently currently. And
there are many conflicts, meaning there's probably a lot of
first-come-first-serve going on. Not entirely sure if these benchmarks
are very reproducible.
- Maybe add some more safety comments
- Also component_reads_and_writes() is about to be deprecated #16339,
but there's no other way to currently do what I'm trying to do.
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
Co-authored-by: BD103 <59022059+BD103@users.noreply.github.com>
Updates the requirements on
[thiserror](https://github.com/dtolnay/thiserror) to permit the latest
version.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/dtolnay/thiserror/releases">thiserror's
releases</a>.</em></p>
<blockquote>
<h2>2.0.3</h2>
<ul>
<li>Support the same Path field being repeated in both Debug and Display
representation in error message (<a
href="https://redirect.github.com/dtolnay/thiserror/issues/383">#383</a>)</li>
<li>Improve error message when a format trait used in error message is
not implemented by some field (<a
href="https://redirect.github.com/dtolnay/thiserror/issues/384">#384</a>)</li>
</ul>
</blockquote>
</details>
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<summary>Commits</summary>
<ul>
<li><a
href="15fd26e476"><code>15fd26e</code></a>
Release 2.0.3</li>
<li><a
href="7046023130"><code>7046023</code></a>
Simplify how has_bonus_display is accumulated</li>
<li><a
href="9cc1d0b251"><code>9cc1d0b</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/thiserror/issues/384">#384</a>
from dtolnay/nowrap</li>
<li><a
href="1d040f358a"><code>1d040f3</code></a>
Use Var wrapper only for Pointer formatting</li>
<li><a
href="6a6132d79b"><code>6a6132d</code></a>
Extend no-display ui test to cover another fmt trait</li>
<li><a
href="a061beb9dc"><code>a061beb</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/thiserror/issues/383">#383</a>
from dtolnay/both</li>
<li><a
href="63882935be"><code>6388293</code></a>
Support Display and Debug of same path in error message</li>
<li><a
href="dc0359eeec"><code>dc0359e</code></a>
Defer binding_value construction</li>
<li><a
href="520343e37d"><code>520343e</code></a>
Add test of Debug and Display of paths</li>
<li><a
href="49be39dee1"><code>49be39d</code></a>
Release 2.0.2</li>
<li>Additional commits viewable in <a
href="https://github.com/dtolnay/thiserror/compare/1.0.0...2.0.3">compare
view</a></li>
</ul>
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# Objective
Error handling in bevy is hard. See for reference
https://github.com/bevyengine/bevy/issues/11562,
https://github.com/bevyengine/bevy/issues/10874 and
https://github.com/bevyengine/bevy/issues/12660. The goal of this PR is
to make it better, by allowing users to optionally return `Result` from
systems as outlined by Cart in
<https://github.com/bevyengine/bevy/issues/14275#issuecomment-2223708314>.
## Solution
This PR introduces a new `ScheuleSystem` type to represent systems that
can be added to schedules. Instances of this type contain either an
infallible `BoxedSystem<(), ()>` or a fallible `BoxedSystem<(),
Result>`. `ScheuleSystem` implements `System<In = (), Out = Result>` and
replaces all uses of `BoxedSystem` in schedules. The async executor now
receives a result after executing a system, which for infallible systems
is always `Ok(())`. Currently it ignores this result, but more useful
error handling could also be implemented.
Aliases for `Error` and `Result` have been added to the `bevy_ecs`
prelude, as well as const `OK` which new users may find more friendly
than `Ok(())`.
## Testing
- Currently there are not actual semantics changes that really require
new tests, but I added a basic one just to make sure we don't break
stuff in the future.
- The behavior of existing systems is totally unchanged, including
logging.
- All of the existing systems tests pass, and I have not noticed
anything strange while playing with the examples
## Showcase
The following minimal example prints "hello world" once, then completes.
```rust
use bevy::prelude::*;
fn main() {
App::new().add_systems(Update, hello_world_system).run();
}
fn hello_world_system() -> Result {
println!("hello world");
Err("string")?;
println!("goodbye world");
OK
}
```
## Migration Guide
This change should be pretty much non-breaking, except for users who
have implemented their own custom executors. Those users should use
`ScheduleSystem` in place of `BoxedSystem<(), ()>` and import the
`System` trait where needed. They can choose to do whatever they wish
with the result.
## Current Work
+ [x] Fix tests & doc comments
+ [x] Write more tests
+ [x] Add examples
+ [X] Draft release notes
## Draft Release Notes
As of this release, systems can now return results.
First a bit of background: Bevy has hisotrically expected systems to
return the empty type `()`. While this makes sense in the context of the
ecs, it's at odds with how error handling is typically done in rust:
returning `Result::Error` to indicate failure, and using the
short-circuiting `?` operator to propagate that error up the call stack
to where it can be properly handled. Users of functional languages will
tell you this is called "monadic error handling".
Not being able to return `Results` from systems left bevy users with a
quandry. They could add custom error handling logic to every system, or
manually pipe every system into an error handler, or perhaps sidestep
the issue with some combination of fallible assignents, logging, macros,
and early returns. Often, users would just litter their systems with
unwraps and possible panics.
While any one of these approaches might be fine for a particular user,
each of them has their own drawbacks, and none makes good use of the
language. Serious issues could also arrise when two different crates
used by the same project made different choices about error handling.
Now, by returning results, systems can defer error handling to the
application itself. It looks like this:
```rust
// Previous, handling internally
app.add_systems(my_system)
fn my_system(window: Query<&Window>) {
let Ok(window) = query.get_single() else {
return;
};
// ... do something to the window here
}
// Previous, handling externally
app.add_systems(my_system.pipe(my_error_handler))
fn my_system(window: Query<&Window>) -> Result<(), impl Error> {
let window = query.get_single()?;
// ... do something to the window here
Ok(())
}
// Previous, panicking
app.add_systems(my_system)
fn my_system(window: Query<&Window>) {
let window = query.single();
// ... do something to the window here
}
// Now
app.add_systems(my_system)
fn my_system(window: Query<&Window>) -> Result {
let window = query.get_single()?;
// ... do something to the window here
Ok(())
}
```
There are currently some limitations. Systems must either return `()` or
`Result<(), Box<dyn Error + Send + Sync + 'static>>`, with no
in-between. Results are also ignored by default, and though implementing
a custom handler is possible, it involves writing your own custom ecs
executor (which is *not* recomended).
Systems should return errors when they cannot perform their normal
behavior. In turn, errors returned to the executor while running the
schedule will (eventually) be treated as unexpected. Users and library
authors should prefer to return errors for anything that disrupts the
normal expected behavior of a system, and should only handle expected
cases internally.
We have big plans for improving error handling further:
+ Allowing users to change the error handling logic of the default
executors.
+ Adding source tracking and optional backtraces to errors.
+ Possibly adding tracing-levels (Error/Warn/Info/Debug/Trace) to
errors.
+ Generally making the default error logging more helpful and
inteligent.
+ Adding monadic system combininators for fallible systems.
+ Possibly removing all panicking variants from our api.
---------
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
- Required by #16622 due to differing implementations of `System` by
`FunctionSystem` and `ExclusiveFunctionSystem`.
- Optimize the memory usage of instances of `apply_deferred` in system
schedules.
## Solution
By changing `apply_deferred` from being an ordinary system that ends up
as an `ExclusiveFunctionSystem`, and instead into a ZST struct that
implements `System` manually, we save ~320 bytes per instance of
`apply_deferred` in any schedule.
## Testing
- All current tests pass.
---
## Migration Guide
- If you were previously calling the special `apply_deferred` system via
`apply_deferred(world)`, don't.
