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Expressively define plugins using functions (#11080)
# Objective

Plugins are an incredible tool for encapsulating functionality. They are
low-key one of Bevy's best features. Combined with rust's module and
privacy system, it's a match made in heaven.

The one downside is that they can be a little too verbose to define. 90%
of all plugin definitions look something like this:

```rust
pub struct MyPlugin;

impl Plugin for MyPlugin {
    fn build(&self, app: &mut App) {
        app.init_resource::<CameraAssets>()
           .add_event::<SetCamera>()
           .add_systems(Update, (collect_set_camera_events, drive_camera).chain());
    }
}
```

Every so often it gets a little spicier:

```rust
pub struct MyGenericPlugin<T>(PhantomData<T>);

impl<T> Default for MyGenericPlugin<T> { 
    fn default() -> Self { ... }
 }

impl<T> Plugin for MyGenericPlugin<T> { ... }
```

This is an annoying amount of boilerplate. Ideally, plugins should be
focused and small in scope, which means any app is going to have a *lot*
of them. Writing a plugin should be as easy as possible, and the *only*
part of this process that carries any meaning is the body of `fn build`.

## Solution

Implement `Plugin` for functions that take `&mut App` as a parameter.

The two examples above now look like this:

```rust
pub fn my_plugin(app: &mut App) {
    app.init_resource::<CameraAssets>()
       .add_event::<SetCamera>()
       .add_systems(Update, (collect_set_camera_events, drive_camera).chain());
} 

pub fn my_generic_plugin<T>(app: &mut App) {
    // No need for PhantomData, it just works.
}
```

Almost all plugins can be written this way, which I believe will make
bevy code much more attractive. Less boilerplate and less meaningless
indentation. More plugins with smaller scopes.

---

## Changelog

The `Plugin` trait is now implemented for all functions that take `&mut
App` as their only parameter. This is an abbreviated way of defining
plugins with less boilerplate than manually implementing the trait.

---------

Co-authored-by: Federico Rinaldi <gisquerin@gmail.com>
2024-01-27 02:40:15 +00:00
.cargo Improve config_fast_builds.toml (#11529) 2024-01-25 19:07:51 +00:00
.github documentation in CI: remove lock file (#11507) 2024-01-24 17:28:29 +00:00
assets Fix scene example (#11289) 2024-01-22 15:14:41 +00:00
benches Add README to benches (#11508) 2024-01-24 17:11:28 +00:00
crates Expressively define plugins using functions (#11080) 2024-01-27 02:40:15 +00:00
docs Update to wgpu 0.19 and raw-window-handle 0.6 (#11280) 2024-01-26 18:14:21 +00:00
docs-template Update to wgpu 0.19 and raw-window-handle 0.6 (#11280) 2024-01-26 18:14:21 +00:00
errors fix B0003 example and update logs (#11162) 2024-01-10 21:40:24 +00:00
examples Expressively define plugins using functions (#11080) 2024-01-27 02:40:15 +00:00
src Schedule-First: the new and improved add_systems (#8079) 2023-03-18 01:45:34 +00:00
tests Use impl Into<A> for Assets::add (#10878) 2024-01-08 22:14:43 +00:00
tools Update to wgpu 0.19 and raw-window-handle 0.6 (#11280) 2024-01-26 18:14:21 +00:00
.gitattributes Enforce linux-style line endings for .rs and .toml (#3197) 2021-11-26 21:05:35 +00:00
.gitignore Fix example showcase (#10366) 2023-11-04 01:33:51 +00:00
Cargo.toml Update to wgpu 0.19 and raw-window-handle 0.6 (#11280) 2024-01-26 18:14:21 +00:00
CHANGELOG.md 0.12 Changelog (#10361) 2023-11-04 01:57:29 +00:00
clippy.toml Use clippy::doc_markdown more. (#10286) 2023-10-27 22:49:02 +00:00
CODE_OF_CONDUCT.md Update CODE_OF_CONDUCT.md 2020-08-19 20:25:58 +01:00
CONTRIBUTING.md [doc] Fix typo and formatting in CONTRIBUTING.md (#11381) 2024-01-17 17:07:53 +00:00
CREDITS.md Add morph targets (#8158) 2023-06-22 20:00:01 +00:00
deny.toml Standardize toml format with taplo (#10594) 2023-11-21 01:04:14 +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 Migrate third party plugins guidelines to the book (#11242) 2024-01-07 23:19:37 +00:00
rustfmt.toml Cargo fmt with unstable features (#1903) 2021-04-21 23:19:34 +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

  • The Bevy Book: Bevy's official documentation. The best place to start learning Bevy.
  • Bevy Rust API Docs: Bevy's Rust API docs, which are automatically generated from the doc comments in this repo.
  • Official Examples: Bevy's dedicated, runnable examples, which are great for digging into specific concepts.
  • Community-Made Learning Resources: More tutorials, documentation, and examples made by the Bevy community.

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 Bevy Book for a full tutorial.

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.