# Bevy Silk
[](https://github.com/ManevilleF/bevy_silk/actions/workflows/rust.yml)
[](./LICENSE)
[](https://github.com/rust-secure-code/safety-dance/)
[](https://crates.io/crates/bevy_silk)
[](https://docs.rs/bevy_silk)
[](https://deps.rs/crate/bevy_silk)
CPU driven Cloth engine for Bevy using Verlet integration.
by [Félix Lescaudey de Maneville](https://linktree.com/ManevilleF)
## Get started
### Dependency
Add `bevy_silk` as a dependency in the `Cargo.toml`
`bevy_silk = "0.1"`
Or follow the main git branch
`bevy_silk = { git = "https://github.com/ManevilleF/bevy_silk" }`
### Plugin
Add the `ClothPlugin` to your bevy app
```rust no_run
use bevy::prelude::*;
use bevy_silk::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_plugin(ClothPlugin)
// ... Add your resources and systems
.run();
}
```
### Add cloth to a mesh
For a mesh to be used as cloth, add the `ClothBuilder` component to any entity with a `Handle<Mesh>` component.
> Note: `Transform` and `GlobalTransform` are also required
cloth data which will be populated automatically from the associated `Handle<Mesh>`.
```rust
use bevy::prelude::*;
use bevy_silk::prelude::*;
fn spawn(mut commands: Commands) {
commands.spawn_bundle(PbrBundle {
// Add your mesh, material and your custom PBR data
..Default::default()
}).insert(ClothBuilder::new()
// Define fixed vertices using an Iterator
.with_fixed_points(0..9)
// Define the stick generation mode
.with_stick_generation(StickGeneration::Quads)
// Defines the sticks target length option
.with_stick_length(StickLen::Auto)
// The cloth will compute flat mesh normals
.with_flat_normal_computation()
// ...
);
}
```
### Configuration
You can customize the global cloth physics by inserting the `ClothConfig` resource to your app:
```rust no_run
use bevy::prelude::*;
use bevy_silk::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.insert_resource(ClothConfig {
gravity: Vec3::new(0.0, -9.81, 0.0),
friction: 0.02,
sticks_computation_depth: 5
})
.add_plugin(ClothPlugin)
// ... Add your resources and systems
.run();
}
```
`ClothConfig` can also be used as a *component* to override the global configuration.
## Wind
You may add wind forces to the simulation for a more dynamic clothing effect, for each force you may choose from:
- `Wind::Constant` for constant wind force
- `Wind::SinWave` for a sinwave following wind intensity with custom force and frequency.
`Wind` forces can be added as a resource to your app through the `Winds` container:
```rust no_run
use bevy::prelude::*;
use bevy_silk::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.insert_resource(Winds {
wind_forces: vec![Wind::SinWave {
max_velocity: Vec3::new(10.0, 15.0, -5.0),
frequency: 3.0,
normalize: false,
abs: false
}]
})
.add_plugin(ClothPlugin)
// ... Add your resources and systems
.run();
}
```
> Check the flag example for simple wind effect.
## Mesh utils
`bevy_silk` provides a plane mesh generation function `rectangle_mesh` useful for classic cloth uses like flags or capes
## Q&A
- `My mesh falls immediately and infinitely when I add a Cloth component, how to fix it?`
You probably didn't specify any *fixed points*, meaning there are no vertices anchored to your entity's `GlobalTransform`.
## TODO list
- [x] Wind
- [x] Custom stick target length options
- [ ] Different stick behaviors (spring, stick, etc)
- [x] dynamic flat normal mapping
- [x] dynamic smooth normal mapping
- [ ] Collision support
- [ ] Cloth cutting maybe?
## Examples
1. Flag example
run `cargo run --example flag_example --features debug`
2. Balloon example
run `cargo run --example balloon_example --features debug`
3. Moving example
run `cargo run --example moving_example --features debug`