Pixel-Perfect Outline Shader for Bevy

A easy-use pixel-perfect outline shader for bevy using vertex extrusion method. Inspired by this wonderful tutorial.

Features

• Pixel perfect: the width of drawn outline is in pixel unit and the same as what we want.
• Eliminate foreshortening: the width of outline is uniform from near view to far view.
• Customizability. Width and color can be determined by user.

Usage

First, add bevy_outline as a dependency into your Cargo.toml:

[dependencies]
bevy_outline = "0.1.0"

Second, add OutlinePlugin into your app add set Msaa to a reasonable value:

App::new()
    .insert_resource(Msaa { samples: 4})
... ...
    .add_plugin(OutlinePlugin)
... ...

Third, use OutlineMaterial as a mesh material:

fn setup(
    ...
    mut outlines: ResMut<Assets<OutlineMaterial>>,
    ...
) {
    ...
    commands
        .spawn_bundle(PbrBundle {
            mesh: meshes.add(Mesh::from(shape::Cube { ..default() })),
            material: materials.add(Color::rgb(0.8, 0.7, 0.6).into()),
            transform: Transform::from_translation(translation),
            ..default()
        })
        .insert(outlines.add(OutlineMaterial {
            width: 5.,
            color: Color::rgba(0.2, 0.3, 0.4, 1.0),
        }));
    ...
}

Note that the unit of width attribute of OutlineMaterial is pixel.

Demos

See Example

Problems

• the width of outliner seems not to be uniform.
• outline of built-in torus seems weird (algorithm is wrong and will be fixed in 0.8)

Bevy Version Support

I intend to track the main branch of Bevy. PRs supporting this are welcome!

License

This project is licensed under the MIT License.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in bevy_outline by you, shall be licensed as MIT, without any additional terms or conditions.