Struct ResourceEntities 

pub struct ResourceEntities(/* private fields */);

A cache that links each ComponentId from a resource to the corresponding entity.

Implementations

impl ResourceEntities

pub fn iter(&self) -> impl Iterator<Item = (ComponentId, Entity)>

Returns an iterator over all registered resource components and their corresponding entity.

This must scan the entire array of components to find non-empty values, which may be slow even if there are few resources.

pub fn get(&self, id: ComponentId) -> Option<Entity>

Returns the entity for the given resource component, or None if there is no entity.

Trait Implementations

impl Default for ResourceEntities

fn default() -> ResourceEntities

Returns the “default value” for a type.

impl<'a> ReadOnlySystemParam for &'a ResourceEntities

impl<'a> SystemParam for &'a ResourceEntities

type State = ()

Used to store data which persists across invocations of a system.

type Item<'w, 's> = &'w ResourceEntities

The item type returned when constructing this system param. The value of this associated type should be Self, instantiated with new lifetimes.

fn init_state(_world: &mut World) -> Self::State

Creates a new instance of this param’s State.

fn init_access( _state: &Self::State, system_meta: &mut SystemMeta, system_access: &mut SystemAccess, _world: &mut World, )

Registers any World access used by this SystemParam.

unsafe fn get_param<'w, 's>( _state: &'s mut Self::State, _system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, _change_tick: Tick, ) -> Result<Self::Item<'w, 's>, SystemParamValidationError>

Creates a parameter to be passed into a SystemParamFunction.

fn apply(state: &mut Self::State, system_meta: &SystemMeta, world: &mut World)

Applies any deferred mutations stored in this SystemParam’s state. This is used to apply Commands during ApplyDeferred.

fn queue( state: &mut Self::State, system_meta: &SystemMeta, world: DeferredWorld<'_>, )

Queues any deferred mutations to be applied at the next ApplyDeferred.