# bevy_particle_systems

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A native and WASM-compatible 2D particle system plugin for [bevy](https://bevyengine.org)

**Note: This crate is still under development and its API may change between releases.**

## Example

![](https://github.com/abnormalbrain/bevy_particle_systems/blob/main/assets/example.gif)
 
The above was captured running a release build of the `basic` example, `cargo run --example basic --release`, and ran at 190-200 FPS on a
2019 Intel i9 MacBook Pro, rendering about 10k particles.

```
INFO bevy diagnostic: frame_time                      :    5.125810ms (avg 5.211673ms)
INFO bevy diagnostic: fps                             :  206.027150   (avg 204.176718)
INFO bevy diagnostic: entity_count                    : 11358.713999   (avg 11341.450000)
```

## Usage

1. Add the [`ParticleSystemPlugin`] plugin.

```rust
use bevy::prelude::*;
use bevy_particle_systems::ParticleSystemPlugin;

fn main() {
    App::new()
        .add_plugins((DefaultPlugins, ParticleSystemPlugin)) // <-- Add the plugin
        // ...
        .add_systems(Startup, spawn_particle_system)
        .run();
}

fn spawn_particle_system() { /* ... */ }
```

2. Spawn a particle system whenever necessary.
```rust
use bevy::prelude::*;
use bevy_particle_systems::*;

fn spawn_particle_system(mut commands: Commands, asset_server: Res<AssetServer>) {
    commands
    // Add the bundle specifying the particle system itself.
    .spawn(ParticleSystemBundle {
        particle_system: ParticleSystem {
            max_particles: 10_000,
            texture: ParticleTexture::Sprite(asset_server.load("my_particle.png")),
            spawn_rate_per_second: 25.0.into(),
            initial_speed: JitteredValue::jittered(3.0, -1.0..1.0),
            lifetime: JitteredValue::jittered(8.0, -2.0..2.0),
            color: ColorOverTime::Gradient(Gradient::new(vec![
                ColorPoint::new(Color::WHITE, 0.0),
                ColorPoint::new(Color::srgba(0.0, 0.0, 1.0, 0.0), 1.0),
            ])),
            looping: true,
            system_duration_seconds: 10.0,
            ..ParticleSystem::default()
        },
        ..ParticleSystemBundle::default()
    })
    // Add the playing component so it starts playing. This can be added later as well.
    .insert(Playing);
}
```

## Bevy Versions

|`bevy_particle_systems`|`bevy`|
|:--|:--|
|0.13|0.14|
|0.12|0.13|
|0.11|0.12|
|0.10|0.11|
|0.9|0.10|
|0.6 - 0.8|0.9|
|0.5|0.8|
|0.4|0.7|