1 unstable release

0.1.0	Feb 20, 2024

#983 in Game dev

MIT license

4.5MB
346 lines

Bevoids

A WIP bevy plugin that aims to make boids easy to add to your game.

Gif showing 2d boids

How to use

I recommend to check out examples, to see how bevoids is used.

Adding the plugin, and configuring

For the plugin to work, you need to register it.

You also need to add the BoidsConfig resource, where you configure the space (2d or 3d), and enable/disable debugging:

fn main() {
    App::new()
        .add_plugins((DefaultPlugins, BoidsPlugin))
        .insert_resource(BoidsConfig {
            space: BoidSpace::TwoDimensional,
            debug: false,
        })
        .run();
}

Creating a Boid entity.

To create a boid entity, add the Boid component to your entity:

commands.spawn((
      MaterialMesh2dBundle {
          mesh: meshes
              .add(shape::RegularPolygon::new(10.0, 3).into())
              .into(),
          material: materials.add(ColorMaterial::from(Color::WHITE)),
          transform: Transform::from_xyz(x as f32 * spacer, y as f32 * spacer, 0.0),
          ..default()
      },
      Boid::new(
          BoidSpeed::new(BOID_MIN_SPEED, BOID_MAX_SPEED),
          BoidTurningStrength::new(
              BOID_COHESION,
              BOID_SEPARATION,
              BOID_ALIGNMENT,
              BOID_BORDER_TURN_STRENGTH,
          ),
          BoidViewConfig::new(BOID_FOV, BOID_PROTECTED_RANGE, BOID_VIEW_RANGE),
      )
  ));
}

Limiting the Boid's area of movement

If you want the boid to only move within a restricted area, add the BoidBorder component to it.

The component works like this:

It has 6 parameters; left, right, top, etc... Each of these parameters is an Option<(f32, f32)>, where the first f32 represents the position of the border, and the second represents a margin for when the boid should start turning.

Each side is optional, to give you the choice of where to restrict. You can for example only restrict the top and bottom, for birds that can roam the entire world!

commands.spawn((
        MaterialMesh2dBundle {
            mesh: meshes
                .add(shape::RegularPolygon::new(10.0, 3).into())
                .into(),
            material: materials.add(ColorMaterial::from(Color::WHITE)),
            transform: Transform::from_xyz(x as f32 * spacer, y as f32 * spacer, 0.0),
            ..default()
        },
        Boid::new(
            BoidSpeed::new(BOID_MIN_SPEED, BOID_MAX_SPEED),
            BoidTurningStrength::new(
                BOID_COHESION,
                BOID_SEPARATION,
                BOID_ALIGNMENT,
                BOID_BORDER_TURN_STRENGTH,
            ),
            BoidViewConfig::new(BOID_FOV, BOID_PROTECTED_RANGE, BOID_VIEW_RANGE),
        ),
        BoidBorder {
            left: Some((-BORDER_WIDTH / 2.0, BORDER_MARGIN)),
            right: Some((BORDER_WIDTH / 2.0, BORDER_MARGIN)),
            top: Some((BORDER_HEIGHT / 2.0, BORDER_MARGIN)),
            bottom: Some((-BORDER_HEIGHT / 2.0, BORDER_MARGIN)),
            front: None,
            back: None,
        },
    ));
}

Examples

Example name	Scene
simple2d	A simple 2d scene with 400 boids
simple3d	A simple 3d scene with 1000 boids

To run example, run cargo run --example <example-name>

License

This plugin is licensed under the MIT license:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Credits

I made this plugin completely alone, but here are some sites I used for reference:

Dependencies

~18–45MB
~736K SLoC