Trait bevy::hierarchy::HierarchyQueryExt

pub trait HierarchyQueryExt<'w, 's, D, F>
where D: QueryData, F: QueryFilter,
{ // Required methods fn iter_descendants( &'w self, entity: Entity, ) -> DescendantIter<'w, 's, D, F> where <D as QueryData>::ReadOnly: WorldQuery<Item<'w> = &'w Children>; fn iter_ancestors(&'w self, entity: Entity) -> AncestorIter<'w, 's, D, F> where <D as QueryData>::ReadOnly: WorldQuery<Item<'w> = &'w Parent>; }
Expand description

An extension trait for Query that adds hierarchy related methods.

Required Methods§

fn iter_descendants(&'w self, entity: Entity) -> DescendantIter<'w, 's, D, F>
where <D as QueryData>::ReadOnly: WorldQuery<Item<'w> = &'w Children>,

Returns an Iterator of Entitys over all of entitys descendants.

Can only be called on a Query of Children (i.e. Query<&Children>).

Traverses the hierarchy breadth-first.

§Examples
fn system(query: Query<Entity, With<Marker>>, children_query: Query<&Children>) {
    let entity = query.single();
    for descendant in children_query.iter_descendants(entity) {
        // Do something!
    }
}

fn iter_ancestors(&'w self, entity: Entity) -> AncestorIter<'w, 's, D, F>
where <D as QueryData>::ReadOnly: WorldQuery<Item<'w> = &'w Parent>,

Returns an Iterator of Entitys over all of entitys ancestors.

Can only be called on a Query of Parent (i.e. Query<&Parent>).

§Examples
fn system(query: Query<Entity, With<Marker>>, parent_query: Query<&Parent>) {
    let entity = query.single();
    for ancestor in parent_query.iter_ancestors(entity) {
        // Do something!
    }
}

Implementors§

§

impl<'w, 's, D, F> HierarchyQueryExt<'w, 's, D, F> for Query<'w, 's, D, F>
where D: QueryData, F: QueryFilter,