Crate heron[−][src]

An ergonomic physics API for 2d and 3d bevy games. (powered by rapier)

Get started

Add the dependency

Add the library to Cargo.toml

heron = "0.1.1"

If you are creating a 2d game, change the default features:

heron = { version = "0.1.1", default-features = false, features = ["2d"] }

Note: when debugging you may consider enabling the debug feature, to render the collision shapes (works only for 2d, at the moment).

Install the plugin

To enable physics and collision detection, the PhysicsPlugin should be installed

use bevy::prelude::*;
use heron::prelude::*;

fn main() {
  App::build()
    .add_plugins(DefaultPlugins)
    .add_plugin(PhysicsPlugin::default())
    // ... Add your resources and systems
    .run();
}

Create rigid bodies

To create a rigid body, add the component Body to the entity, choosing a collision shape. It will turn the entity into a dynamic rigid body affected by physics.

The position, and rotation is defined by the bevy GlobalTransform component.

fn spawn(commands: &mut Commands) {
    commands

        // Spawn any bundle of your choice. Only make sure there is a `GlobalTransform`
        .spawn(SpriteBundle::default())

       // Make it a physics body, by attaching a collision shape
        .with(Body::Sphere { radius: 10.0 })

        // Optionally define a type (if absent, the body will be *dynamic*)
        .with(BodyType::Static)
         
        // Optionally define the velocity (works only with dynamic and kinematic bodies)
        .with(Velocity::from(Vec2::unit_x() * 2.0));
}

Control the position

When creating games, it is often useful to interact with the physics engine and move bodies programatically. For this, you have two options: Updating the Transform or applying a Velocity

Option 1: Update the Transform (teleport)

If the GlobalTransform is modified (generally as an effect of modifying the Transform component), then the rigid body will be teleported to the new position/rotation, ignoring physic rules.

Option 2: Use the Velocity component

For BodyType::Dynamic bodies only, one can add a Velocity component to the entity, that will move the body over time. Physics rules will be applied normally.

Modules

prelude	Re-exports of the most commons/useful types
rapier_plugin	Physics behavior powered by rapier
utils	Utility traits and extensions

Structs

AxisAngle	An axis-angle representation
Gravity	Resource that defines world's gravity.
PhysicsPlugin	Plugin to install in order to enable collision detection and physics behavior.
Restitution	Component that define the Coefficient of Restitution
Velocity	Component that defines the linear and angular velocity.

Enums

Body	Components that defines a body subject to physics and collision
BodyType	Component that defines the type of rigid body.
CollisionEvent	An event fired when the collision state between two entities changed