Struct HierarchySystem

pub struct HierarchySystem<P> { /* private fields */ }

System for maintaining a Hierarchy resource.

Type parameters:

• P: Component type that provides Parent links for the maintained Hierarchy

Implementations

impl<P> HierarchySystem<P>

where P: Component + Parent + Send + Sync + 'static, P::Storage: Tracked,

pub fn new(world: &mut World) -> Self

Examples found in repository

examples/sort.rs (line 25)

fn main() {
    let mut world = World::new();
    let mut dispatcher = DispatcherBuilder::new()
        .with(
            HierarchySystem::<Parent>::new(&mut world),
            "hierarchy_system",
            &[],
        )
        .build();
    dispatcher.setup(&mut world);

    let _e0 = world.create_entity().build();
    let e1 = world.create_entity().build();
    let e2 = world.create_entity().build();
    let e3 = world.create_entity().build();
    let e4 = world.create_entity().build();
    let e5 = world.create_entity().build();
    let _e6 = world.create_entity().build();
    let _e7 = world.create_entity().build();
    let _e8 = world.create_entity().build();
    let _e9 = world.create_entity().build();

    {
        let mut parents = world.write_storage::<Parent>();
        parents.insert(e1, Parent { entity: e5 }).unwrap();
        parents.insert(e3, Parent { entity: e1 }).unwrap();
        parents.insert(e4, Parent { entity: e5 }).unwrap();
        parents.insert(e5, Parent { entity: e2 }).unwrap();
    }

    dispatcher.dispatch(&mut world);

    {
        let parents = world.read_storage::<Parent>();
        for entity in world.read_resource::<Hierarchy<Parent>>().all() {
            let formatted = parents
                .get(*entity)
                .map(|parent| format!("{:?}", parent.entity))
                .unwrap_or(format!("None"));
            println!("{:?}: {}", entity, formatted);
        }
    }
}

Trait Implementations

impl<'a, P> System<'a> for HierarchySystem<P>

where P: Component + Parent + Send + Sync + 'static, P::Storage: Tracked,

type SystemData = (ParentData<'a, P>, Write<'a, Hierarchy<P>, PanicHandler>)

The resource bundle required to execute this system.

fn run(&mut self, (data, hierarchy): Self::SystemData)

Executes the system with the required system data.

fn running_time(&self) -> RunningTime

Returns a hint how long the system needs for running. This is used to optimize the way they’re executed (might allow more parallelization).

fn accessor<'b>(&'b self) -> AccessorCow<'a, 'b, Self>

Return the accessor from the SystemData.

fn setup(&mut self, world: &mut World)

Sets up the World using Self::SystemData::setup.

fn dispose(self, world: &mut World)

where Self: Sized,

Performs clean up that requires resources from the World. This commonly removes components from world which depend on external resources.