Struct bevy_ecs::change_detection::Ref

pub struct Ref<'a, T: ?Sized> { /* private fields */ }

Shared borrow of an entity’s component with access to change detection. Similar to Mut but is immutable and so doesn’t require unique access.

Implementations

impl<'a, T: ?Sized> Ref<'a, T>

pub fn into_inner(self) -> &'a T

Trait Implementations

impl<'a, T> AsRef<T> for Ref<'a, T>

fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.

impl<'a, T> Debug for Ref<'a, T>where T: Debug + ?Sized,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a, T: ?Sized> Deref for Ref<'a, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'a, T: ?Sized> DetectChanges for Ref<'a, T>

fn is_added(&self) -> bool

Returns true if this value was added after the system last ran.

fn is_changed(&self) -> bool

Returns true if this value was added or mutably dereferenced after the system last ran.

fn last_changed(&self) -> u32

Returns the change tick recording the time this data was most recently changed.

impl<'a, T: ?Sized> From<Mut<'a, T>> for Ref<'a, T>

fn from(mut_ref: Mut<'a, T>) -> Self

Converts to this type from the input type.

impl<'w, 'a, T> IntoIterator for &'a Ref<'w, T>where &'a T: IntoIterator,

type Item = <&'a T as IntoIterator>::Item

The type of the elements being iterated over.

type IntoIter = <&'a T as IntoIterator>::IntoIter

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'__w, T: Component> WorldQuery for Ref<'__w, T>

SAFETY: Self is the same as Self::ReadOnly

type Fetch<'w> = RefFetch<'w, T>

Per archetype/table state used by this WorldQuery to fetch Self::Item

type Item<'w> = Ref<'w, T>

The item returned by this WorldQuery

type ReadOnly = Ref<'__w, T>

The read-only variant of this WorldQuery, which satisfies the ReadOnlyWorldQuery trait.

type State = ComponentId

State used to construct a Self::Fetch. This will be cached inside QueryState, so it is best to move as much data / computation here as possible to reduce the cost of constructing Self::Fetch.

fn shrink<'wlong: 'wshort, 'wshort>(item: Ref<'wlong, T>) -> Ref<'wshort, T>

This function manually implements subtyping for the query items.

const IS_DENSE: bool = _

Returns true if (and only if) every table of every archetype matched by this fetch contains all of the matched components. This is used to select a more efficient “table iterator” for “dense” queries. If this returns true, WorldQuery::set_table must be used before WorldQuery::fetch can be called for iterators. If this returns false, WorldQuery::set_archetype must be used before WorldQuery::fetch can be called for iterators.

const IS_ARCHETYPAL: bool = true

Returns true if (and only if) this Fetch relies strictly on archetypes to limit which components are accessed by the Query.

unsafe fn init_fetch<'w>( world: &'w World, component_id: &ComponentId, last_change_tick: u32, change_tick: u32 ) -> RefFetch<'w, T>

Creates a new instance of this fetch.

unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w>

While this function can be called for any query, it is always safe to call if Self: ReadOnlyWorldQuery holds.

unsafe fn set_archetype<'w>( fetch: &mut RefFetch<'w, T>, component_id: &ComponentId, _archetype: &'w Archetype, table: &'w Table )

Adjusts internal state to account for the next Archetype. This will always be called on archetypes that match this WorldQuery.

unsafe fn set_table<'w>( fetch: &mut RefFetch<'w, T>, component_id: &ComponentId, table: &'w Table )

Adjusts internal state to account for the next Table. This will always be called on tables that match this WorldQuery.

unsafe fn fetch<'w>( fetch: &mut Self::Fetch<'w>, entity: Entity, table_row: TableRow ) -> Self::Item<'w>

Fetch Self::Item for either the given entity in the current Table, or for the given entity in the current Archetype. This must always be called after WorldQuery::set_table with a table_row in the range of the current Table or after WorldQuery::set_archetype with a entity in the current archetype.

fn update_component_access( component_id: &ComponentId, access: &mut FilteredAccess<ComponentId> )

fn update_archetype_component_access( component_id: &ComponentId, archetype: &Archetype, access: &mut Access<ArchetypeComponentId> )

fn init_state(world: &mut World) -> ComponentId

fn matches_component_set( state: &ComponentId, set_contains_id: &impl Fn(ComponentId) -> bool ) -> bool

unsafe fn filter_fetch( fetch: &mut Self::Fetch<'_>, entity: Entity, table_row: TableRow ) -> bool

Safety

impl<'__w, T: Component> ReadOnlyWorldQuery for Ref<'__w, T>

SAFETY: access is read only