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Felix Rath abceebebba
feat: Add World::get_reflect() and World::get_reflect_mut() (#14416)
# Objective

Sometimes one wants to retrieve a `&dyn Reflect` for an entity's
component, which so far required multiple, non-obvious steps and
`unsafe`-code.
The docs for
[`MutUntyped`](https://docs.rs/bevy/latest/bevy/ecs/change_detection/struct.MutUntyped.html#method.map_unchanged)
contain an example of the unsafe part.

## Solution

This PR adds the two methods:

```rust
// immutable variant
World::get_reflect(&self, entity: Entity, type_id: TypeId) -> Result<&dyn Reflect, GetComponentReflectError>

// mutable variant
World::get_reflect_mut(&mut self, entity: Entity, type_id: TypeId) -> Result<Mut<'_, dyn Reflect>, GetComponentReflectError>
```

which take care of the necessary steps, check required invariants etc.,
and contain the unsafety so the caller doesn't have to deal with it.

## Testing

- Did you test these changes? If so, how?
- Added tests and a doc test, also (successfully) ran `cargo run -p ci`.
- Are there any parts that need more testing?
- Could add tests for each individual error variant, but it's not
required imo.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Run `cargo test --doc --package bevy_ecs --all-features --
world::World::get_reflect --show-output` for the doctest
- Run `cargo test --package bevy_ecs --lib --all-features --
world::tests::reflect_tests --show-output` for the unittests
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
  - Don't think it's relevant, but tested on 64bit linux (only).

---

## Showcase

Copy of the doctest example which gives a good overview of what this
enables:

```rust
use bevy_ecs::prelude::*;
use bevy_reflect::Reflect;
use std::any::TypeId;

// define a `Component` and derive `Reflect` for it
#[derive(Component, Reflect)]
struct MyComponent;

// create a `World` for this example
let mut world = World::new();

// Note: This is usually handled by `App::register_type()`, but this example can not use `App`.
world.init_resource::<AppTypeRegistry>();
world.get_resource_mut::<AppTypeRegistry>().unwrap().write().register::<MyComponent>();

// spawn an entity with a `MyComponent`
let entity = world.spawn(MyComponent).id();

// retrieve a reflected reference to the entity's `MyComponent`
let comp_reflected: &dyn Reflect = world.get_reflect(entity, TypeId::of::<MyComponent>()).unwrap();

// make sure we got the expected type
assert!(comp_reflected.is::<MyComponent>());
```

## Migration Guide

No breaking changes, but users can use the new methods if they did it
manually before.

---------

Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2024-07-23 16:57:54 +00:00
.cargo Use rust-lld on windows rustdoc in config_fast_builds.toml (#13553) 2024-07-08 00:34:21 +00:00
.github Test for ambiguous system ordering in CI (#13950) 2024-07-17 21:05:48 +00:00
assets Allow volumetric fog to be localized to specific, optionally voxelized, regions. (#14099) 2024-07-16 03:14:12 +00:00
benches Recalibrated observe benchmark (#14381) 2024-07-18 18:25:33 +00:00
crates feat: Add World::get_reflect() and World::get_reflect_mut() (#14416) 2024-07-23 16:57:54 +00:00
docs bevy_reflect: Feature-gate function reflection (#14174) 2024-07-14 15:55:31 +00:00
docs-template Deduplicate Wasm optimization instructions (#14173) 2024-07-06 15:38:29 +00:00
errors Remove manual --cfg docsrs (#14376) 2024-07-22 18:58:04 +00:00
examples Don't ignore draw errors (#13240) 2024-07-22 19:22:30 +00:00
src Give alt text to Bevy logo (#13205) 2024-05-03 19:50:17 +00:00
tests Test for ambiguous system ordering in CI (#13950) 2024-07-17 21:05:48 +00:00
tools Remove manual --cfg docsrs (#14376) 2024-07-22 18:58:04 +00:00
.gitattributes Enforce linux-style line endings for .rs and .toml (#3197) 2021-11-26 21:05:35 +00:00
.gitignore Use folder for example showcase reports and add show logs flag (#13198) 2024-05-03 13:03:06 +00:00
Cargo.toml Remove manual --cfg docsrs (#14376) 2024-07-22 18:58:04 +00:00
CHANGELOG.md 0.13 changelog (#11918) 2024-02-17 07:22:02 +00:00
clippy.toml Fix beta lints (#12980) 2024-04-16 02:46:46 +00:00
CODE_OF_CONDUCT.md Update CODE_OF_CONDUCT.md 2020-08-19 20:25:58 +01:00
CONTRIBUTING.md Add a direct link in the docs to the Discord's #working-groups channel (#14321) 2024-07-15 01:06:42 +00:00
CREDITS.md Programmed soundtrack example (#12774) 2024-03-29 20:32:30 +00:00
deny.toml Fix duplicate dependencies on raw-window-handle (#12309) 2024-03-05 08:24:37 +00:00
LICENSE-APACHE Let the project page support GitHub's new ability to display open source licenses (#4966) 2022-06-08 17:55:57 +00:00
LICENSE-MIT Let the project page support GitHub's new ability to display open source licenses (#4966) 2022-06-08 17:55:57 +00:00
README.md Update funding link (#12425) 2024-03-11 21:46:04 +00:00
rustfmt.toml Cargo fmt with unstable features (#1903) 2021-04-21 23:19:34 +00:00
typos.toml Implement subpixel morphological antialiasing, or SMAA. (#13423) 2024-06-04 17:07:34 +00:00

Bevy

License Crates.io Downloads Docs CI Discord

What is Bevy?

Bevy is a refreshingly simple data-driven game engine built in Rust. It is free and open-source forever!

WARNING

Bevy is still in the early stages of development. Important features are missing. Documentation is sparse. A new version of Bevy containing breaking changes to the API is released approximately once every 3 months. We provide migration guides, but we can't guarantee migrations will always be easy. Use only if you are willing to work in this environment.

MSRV: Bevy relies heavily on improvements in the Rust language and compiler. As a result, the Minimum Supported Rust Version (MSRV) is generally close to "the latest stable release" of Rust.

Design Goals

  • Capable: Offer a complete 2D and 3D feature set
  • Simple: Easy for newbies to pick up, but infinitely flexible for power users
  • Data Focused: Data-oriented architecture using the Entity Component System paradigm
  • Modular: Use only what you need. Replace what you don't like
  • Fast: App logic should run quickly, and when possible, in parallel
  • Productive: Changes should compile quickly ... waiting isn't fun

About

  • Features: A quick overview of Bevy's features.
  • News: A development blog that covers our progress, plans and shiny new features.

Docs

Community

Before contributing or participating in discussions with the community, you should familiarize yourself with our Code of Conduct.

  • Discord: Bevy's official discord server.
  • Reddit: Bevy's official subreddit.
  • GitHub Discussions: The best place for questions about Bevy, answered right here!
  • Bevy Assets: A collection of awesome Bevy projects, tools, plugins and learning materials.

Contributing

If you'd like to help build Bevy, check out the Contributor's Guide. For simple problems, feel free to open an issue or PR and tackle it yourself!

For more complex architecture decisions and experimental mad science, please open an RFC (Request For Comments) so we can brainstorm together effectively!

Getting Started

We recommend checking out the Quick Start Guide for a brief introduction.

Follow the Setup guide to ensure your development environment is set up correctly. Once set up, you can quickly try out the examples by cloning this repo and running the following commands:

# Switch to the correct version (latest release, default is main development branch)
git checkout latest
# Runs the "breakout" example
cargo run --example breakout

To draw a window with standard functionality enabled, use:

use bevy::prelude::*;

fn main(){
  App::new()
    .add_plugins(DefaultPlugins)
    .run();
}

Fast Compiles

Bevy can be built just fine using default configuration on stable Rust. However for really fast iterative compiles, you should enable the "fast compiles" setup by following the instructions here.

Bevy Cargo Features

This list outlines the different cargo features supported by Bevy. These allow you to customize the Bevy feature set for your use-case.

Thanks

Bevy is the result of the hard work of many people. A huge thanks to all Bevy contributors, the many open source projects that have come before us, the Rust gamedev ecosystem, and the many libraries we build on.

A huge thanks to Bevy's generous sponsors. Bevy will always be free and open source, but it isn't free to make. Please consider sponsoring our work if you like what we're building.

This project is tested with BrowserStack.

License

Bevy is free, open source and permissively licensed! Except where noted (below and/or in individual files), all code in this repository is dual-licensed under either:

at your option. This means you can select the license you prefer! This dual-licensing approach is the de-facto standard in the Rust ecosystem and there are very good reasons to include both.

Some of the engine's code carries additional copyright notices and license terms due to their external origins. These are generally BSD-like, but exact details vary by crate: If the README of a crate contains a 'License' header (or similar), the additional copyright notices and license terms applicable to that crate will be listed. The above licensing requirement still applies to contributions to those crates, and sections of those crates will carry those license terms. The license field of each crate will also reflect this. For example, bevy_mikktspace has code under the Zlib license (as well as a copyright notice when choosing the MIT license).

The assets included in this repository (for our examples) typically fall under different open licenses. These will not be included in your game (unless copied in by you), and they are not distributed in the published bevy crates. See CREDITS.md for the details of the licenses of those files.

Your contributions

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.