Struct bevy::math::bounding::BoundingCircle

pub struct BoundingCircle {
    pub center: Vec2,
    pub circle: Circle,
}

Expand description

A bounding circle

Fields§

§center: Vec2

The center of the bounding circle

§circle: Circle

The circle

Implementations§

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impl BoundingCircle

pub fn new(center: Vec2, radius: f32) -> BoundingCircle

Constructs a bounding circle from its center and radius.

Examples found in repository ?

examples/2d/bounding_2d.rs (line 375)

fn bounding_circle_cast_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let ray_cast = get_and_draw_ray(&mut gizmos, &time);
    let circle_cast = BoundingCircleCast {
        circle: BoundingCircle::new(Vec2::ZERO, 15.),
        ray: ray_cast,
    };

    for (volume, mut intersects) in volumes.iter_mut() {
        let toi = match *volume {
            CurrentVolume::Aabb(_) => None,
            CurrentVolume::Circle(c) => circle_cast.circle_collision_at(c),
        };

        **intersects = toi.is_some();
        if let Some(toi) = toi {
            gizmos.circle_2d(
                circle_cast.ray.ray.origin + *circle_cast.ray.ray.direction * toi,
                circle_cast.circle.radius(),
                LIME,
            );
        }
    }
}

fn get_intersection_position(time: &Time) -> Vec2 {
    let x = (0.8 * time.elapsed_seconds()).cos() * 250.;
    let y = (0.4 * time.elapsed_seconds()).sin() * 100.;
    Vec2::new(x, y)
}

fn aabb_intersection_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let center = get_intersection_position(&time);
    let aabb = Aabb2d::new(center, Vec2::splat(50.));
    gizmos.rect_2d(center, 0., aabb.half_size() * 2., YELLOW);

    for (volume, mut intersects) in volumes.iter_mut() {
        let hit = match volume {
            CurrentVolume::Aabb(a) => aabb.intersects(a),
            CurrentVolume::Circle(c) => aabb.intersects(c),
        };

        **intersects = hit;
    }
}

fn circle_intersection_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let center = get_intersection_position(&time);
    let circle = BoundingCircle::new(center, 50.);
    gizmos.circle_2d(center, circle.radius(), YELLOW);

    for (volume, mut intersects) in volumes.iter_mut() {
        let hit = match volume {
            CurrentVolume::Aabb(a) => circle.intersects(a),
            CurrentVolume::Circle(c) => circle.intersects(c),
        };

        **intersects = hit;
    }
}

More examples

Hide additional examples

examples/games/breakout.rs (line 371)

fn check_for_collisions(
    mut commands: Commands,
    mut score: ResMut<Score>,
    mut ball_query: Query<(&mut Velocity, &Transform), With<Ball>>,
    collider_query: Query<(Entity, &Transform, Option<&Brick>), With<Collider>>,
    mut collision_events: EventWriter<CollisionEvent>,
) {
    let (mut ball_velocity, ball_transform) = ball_query.single_mut();

    for (collider_entity, collider_transform, maybe_brick) in &collider_query {
        let collision = ball_collision(
            BoundingCircle::new(ball_transform.translation.truncate(), BALL_DIAMETER / 2.),
            Aabb2d::new(
                collider_transform.translation.truncate(),
                collider_transform.scale.truncate() / 2.,
            ),
        );

        if let Some(collision) = collision {
            // Sends a collision event so that other systems can react to the collision
            collision_events.send_default();

            // Bricks should be despawned and increment the scoreboard on collision
            if maybe_brick.is_some() {
                commands.entity(collider_entity).despawn();
                **score += 1;
            }

            // Reflect the ball's velocity when it collides
            let mut reflect_x = false;
            let mut reflect_y = false;

            // Reflect only if the velocity is in the opposite direction of the collision
            // This prevents the ball from getting stuck inside the bar
            match collision {
                Collision::Left => reflect_x = ball_velocity.x > 0.0,
                Collision::Right => reflect_x = ball_velocity.x < 0.0,
                Collision::Top => reflect_y = ball_velocity.y < 0.0,
                Collision::Bottom => reflect_y = ball_velocity.y > 0.0,
            }

            // Reflect velocity on the x-axis if we hit something on the x-axis
            if reflect_x {
                ball_velocity.x = -ball_velocity.x;
            }

            // Reflect velocity on the y-axis if we hit something on the y-axis
            if reflect_y {
                ball_velocity.y = -ball_velocity.y;
            }
        }
    }
}

pub fn from_point_cloud( translation: Vec2, rotation: impl Into<Rotation2d>, points: &[Vec2] ) -> BoundingCircle

Computes a BoundingCircle containing the given set of points, transformed by translation and rotation.

The bounding circle is not guaranteed to be the smallest possible.

pub fn radius(&self) -> f32

Get the radius of the bounding circle

Examples found in repository ?

examples/2d/bounding_2d.rs (line 186)

fn render_volumes(mut gizmos: Gizmos, query: Query<(&CurrentVolume, &Intersects)>) {
    for (volume, intersects) in query.iter() {
        let color = if **intersects { AQUA } else { ORANGE_RED };
        match volume {
            CurrentVolume::Aabb(a) => {
                gizmos.rect_2d(a.center(), 0., a.half_size() * 2., color);
            }
            CurrentVolume::Circle(c) => {
                gizmos.circle_2d(c.center(), c.radius(), color);
            }
        }
    }
}

#[derive(Component, Deref, DerefMut, Default)]
struct Intersects(bool);

const OFFSET_X: f32 = 125.;
const OFFSET_Y: f32 = 75.;

fn setup(mut commands: Commands, loader: Res<AssetServer>) {
    commands.spawn(Camera2dBundle::default());
    commands.spawn((
        SpatialBundle {
            transform: Transform::from_xyz(-OFFSET_X, OFFSET_Y, 0.),
            ..default()
        },
        Shape::Circle(Circle::new(45.)),
        DesiredVolume::Aabb,
        Intersects::default(),
    ));

    commands.spawn((
        SpatialBundle {
            transform: Transform::from_xyz(0., OFFSET_Y, 0.),
            ..default()
        },
        Shape::Rectangle(Rectangle::new(80., 80.)),
        Spin,
        DesiredVolume::Circle,
        Intersects::default(),
    ));

    commands.spawn((
        SpatialBundle {
            transform: Transform::from_xyz(OFFSET_X, OFFSET_Y, 0.),
            ..default()
        },
        Shape::Triangle(Triangle2d::new(
            Vec2::new(-40., -40.),
            Vec2::new(-20., 40.),
            Vec2::new(40., 50.),
        )),
        Spin,
        DesiredVolume::Aabb,
        Intersects::default(),
    ));

    commands.spawn((
        SpatialBundle {
            transform: Transform::from_xyz(-OFFSET_X, -OFFSET_Y, 0.),
            ..default()
        },
        Shape::Line(Segment2d::new(Dir2::from_xy(1., 0.3).unwrap(), 90.)),
        Spin,
        DesiredVolume::Circle,
        Intersects::default(),
    ));

    commands.spawn((
        SpatialBundle {
            transform: Transform::from_xyz(0., -OFFSET_Y, 0.),
            ..default()
        },
        Shape::Capsule(Capsule2d::new(25., 50.)),
        Spin,
        DesiredVolume::Aabb,
        Intersects::default(),
    ));

    commands.spawn((
        SpatialBundle {
            transform: Transform::from_xyz(OFFSET_X, -OFFSET_Y, 0.),
            ..default()
        },
        Shape::Polygon(RegularPolygon::new(50., 6)),
        Spin,
        DesiredVolume::Circle,
        Intersects::default(),
    ));

    commands.spawn(
        TextBundle::from_section(
            "",
            TextStyle {
                font: loader.load("fonts/FiraMono-Medium.ttf"),
                font_size: 26.0,
                ..default()
            },
        )
        .with_style(Style {
            position_type: PositionType::Absolute,
            bottom: Val::Px(10.0),
            left: Val::Px(10.0),
            ..default()
        }),
    );
}

fn draw_filled_circle(gizmos: &mut Gizmos, position: Vec2, color: Srgba) {
    for r in [1., 2., 3.] {
        gizmos.circle_2d(position, r, color);
    }
}

fn draw_ray(gizmos: &mut Gizmos, ray: &RayCast2d) {
    gizmos.line_2d(
        ray.ray.origin,
        ray.ray.origin + *ray.ray.direction * ray.max,
        WHITE,
    );
    draw_filled_circle(gizmos, ray.ray.origin, FUCHSIA);
}

fn get_and_draw_ray(gizmos: &mut Gizmos, time: &Time) -> RayCast2d {
    let ray = Vec2::new(time.elapsed_seconds().cos(), time.elapsed_seconds().sin());
    let dist = 150. + (0.5 * time.elapsed_seconds()).sin().abs() * 500.;

    let aabb_ray = Ray2d {
        origin: ray * 250.,
        direction: Dir2::new_unchecked(-ray),
    };
    let ray_cast = RayCast2d::from_ray(aabb_ray, dist - 20.);

    draw_ray(gizmos, &ray_cast);
    ray_cast
}

fn ray_cast_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let ray_cast = get_and_draw_ray(&mut gizmos, &time);

    for (volume, mut intersects) in volumes.iter_mut() {
        let toi = match volume {
            CurrentVolume::Aabb(a) => ray_cast.aabb_intersection_at(a),
            CurrentVolume::Circle(c) => ray_cast.circle_intersection_at(c),
        };
        **intersects = toi.is_some();
        if let Some(toi) = toi {
            draw_filled_circle(
                &mut gizmos,
                ray_cast.ray.origin + *ray_cast.ray.direction * toi,
                LIME,
            );
        }
    }
}

fn aabb_cast_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let ray_cast = get_and_draw_ray(&mut gizmos, &time);
    let aabb_cast = AabbCast2d {
        aabb: Aabb2d::new(Vec2::ZERO, Vec2::splat(15.)),
        ray: ray_cast,
    };

    for (volume, mut intersects) in volumes.iter_mut() {
        let toi = match *volume {
            CurrentVolume::Aabb(a) => aabb_cast.aabb_collision_at(a),
            CurrentVolume::Circle(_) => None,
        };

        **intersects = toi.is_some();
        if let Some(toi) = toi {
            gizmos.rect_2d(
                aabb_cast.ray.ray.origin + *aabb_cast.ray.ray.direction * toi,
                0.,
                aabb_cast.aabb.half_size() * 2.,
                LIME,
            );
        }
    }
}

fn bounding_circle_cast_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let ray_cast = get_and_draw_ray(&mut gizmos, &time);
    let circle_cast = BoundingCircleCast {
        circle: BoundingCircle::new(Vec2::ZERO, 15.),
        ray: ray_cast,
    };

    for (volume, mut intersects) in volumes.iter_mut() {
        let toi = match *volume {
            CurrentVolume::Aabb(_) => None,
            CurrentVolume::Circle(c) => circle_cast.circle_collision_at(c),
        };

        **intersects = toi.is_some();
        if let Some(toi) = toi {
            gizmos.circle_2d(
                circle_cast.ray.ray.origin + *circle_cast.ray.ray.direction * toi,
                circle_cast.circle.radius(),
                LIME,
            );
        }
    }
}

fn get_intersection_position(time: &Time) -> Vec2 {
    let x = (0.8 * time.elapsed_seconds()).cos() * 250.;
    let y = (0.4 * time.elapsed_seconds()).sin() * 100.;
    Vec2::new(x, y)
}

fn aabb_intersection_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let center = get_intersection_position(&time);
    let aabb = Aabb2d::new(center, Vec2::splat(50.));
    gizmos.rect_2d(center, 0., aabb.half_size() * 2., YELLOW);

    for (volume, mut intersects) in volumes.iter_mut() {
        let hit = match volume {
            CurrentVolume::Aabb(a) => aabb.intersects(a),
            CurrentVolume::Circle(c) => aabb.intersects(c),
        };

        **intersects = hit;
    }
}

fn circle_intersection_system(
    mut gizmos: Gizmos,
    time: Res<Time>,
    mut volumes: Query<(&CurrentVolume, &mut Intersects)>,
) {
    let center = get_intersection_position(&time);
    let circle = BoundingCircle::new(center, 50.);
    gizmos.circle_2d(center, circle.radius(), YELLOW);

    for (volume, mut intersects) in volumes.iter_mut() {
        let hit = match volume {
            CurrentVolume::Aabb(a) => circle.intersects(a),
            CurrentVolume::Circle(c) => circle.intersects(c),
        };

        **intersects = hit;
    }
}

pub fn aabb_2d(&self) -> Aabb2d

Computes the smallest Aabb2d containing this BoundingCircle.

pub fn closest_point(&self, point: Vec2) -> Vec2

Finds the point on the bounding circle that is closest to the given point.

If the point is outside the circle, the returned point will be on the perimeter of the circle. Otherwise, it will be inside the circle and returned as is.

Trait Implementations§

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impl BoundingVolume for BoundingCircle

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type Translation = Vec2

The position type used for the volume. This should be Vec2 for 2D and Vec3 for 3D.

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type Rotation = Rotation2d

The rotation type used for the volume. This should be f32 for 2D and Quat for 3D.

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type HalfSize = f32

The type used for the size of the bounding volume. Usually a half size. For example an f32 radius for a circle, or a Vec3 with half sizes for x, y and z for a 3D axis-aligned bounding box

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fn center(&self) -> <BoundingCircle as BoundingVolume>::Translation

Returns the center of the bounding volume.

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fn half_size(&self) -> <BoundingCircle as BoundingVolume>::HalfSize

Returns the half size of the bounding volume.

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fn visible_area(&self) -> f32

Computes the visible surface area of the bounding volume. This method can be useful to make decisions about merging bounding volumes, using a Surface Area Heuristic. Read more

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