Struct double_dot_state::Ref

pub struct Ref<'a, T>
where
    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> Ref<'a, T>

where T: ?Sized,

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<(), Error>

Formats the value using the given formatter.

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

where T: ?Sized,

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &<Ref<'a, T> as Deref>::Target

Dereferences the value.

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

where T: ?Sized,

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> From<Mut<'a, T>> for Ref<'a, T>

where T: ?Sized,

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

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) -> <&'a Ref<'w, T> as IntoIterator>::IntoIter

Creates an iterator from a value.

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

where T: Component,

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

where 'wlong: 'wshort,

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, _: &ComponentId, last_change_tick: u32, change_tick: u32 ) -> RefFetch<'w, T>

Creates a new instance of this fetch.

unsafe fn clone_fetch<'w>( fetch: &<Ref<'__w, T> as WorldQuery>::Fetch<'w> ) -> <Ref<'__w, T> as WorldQuery>::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>, _: &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 <Ref<'__w, T> as WorldQuery>::Fetch<'w>, entity: Entity, table_row: TableRow ) -> <Ref<'__w, T> as WorldQuery>::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( _: &ComponentId, access: &mut FilteredAccess<ComponentId> )

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

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

fn matches_component_set( _: &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> ReadOnlyWorldQuery for Ref<'__w, T>

where T: Component,

SAFETY: access is read only