pub struct Entity { /* private fields */ }
Expand description
Lightweight identifier of an entity.
The identifier is implemented using a generational index: a combination of an ID and a generation. This allows fast insertion after data removal in an array while minimizing loss of spatial locality.
Usage
This data type is returned by iterating a Query
that has Entity
as part of its query fetch type parameter (learn more).
It can also be obtained by calling EntityCommands::id
or EntityMut::id
.
fn setup(mut commands: Commands) {
// Calling `spawn` returns `EntityCommands`.
let entity = commands.spawn().id();
}
fn exclusive_system(world: &mut World) {
// Calling `spawn` returns `EntityMut`.
let entity = world.spawn().id();
}
It can be used to refer to a specific entity to apply EntityCommands
, or to call Query::get
(or similar methods) to access its components.
fn dispose_expired_food(mut commands: Commands, query: Query<Entity, With<Expired>>) {
for food_entity in &query {
commands.entity(food_entity).despawn();
}
}
Implementations
impl Entity
impl Entity
pub fn from_raw(id: u32) -> Entity
pub fn from_raw(id: u32) -> Entity
Creates a new entity reference with the specified id
and a generation of 0.
Note
Spawning a specific entity
value is rarely the right choice. Most apps should favor
Commands::spawn
. This method should generally
only be used for sharing entities across apps, and only when they have a scheme
worked out to share an ID space (which doesn’t happen by default).
In general, one should not try to synchronize the ECS by attempting to ensure that
Entity
lines up between instances, but instead insert a secondary identifier as
a component.
There are still some use cases where it might be appropriate to use this function externally.
Examples
Initializing a collection (e.g. array
or Vec
) with a known size:
// Create a new array of size 10 and initialize it with (invalid) entities.
let mut entities: [Entity; 10] = [Entity::from_raw(0); 10];
// ... replace the entities with valid ones.
Deriving Reflect
for a component that has an Entity
field:
#[derive(Reflect, Component)]
#[reflect(Component)]
pub struct MyStruct {
pub entity: Entity,
}
impl FromWorld for MyStruct {
fn from_world(_world: &mut World) -> Self {
Self {
entity: Entity::from_raw(u32::MAX),
}
}
}
pub fn to_bits(self) -> u64
pub fn to_bits(self) -> u64
Convert to a form convenient for passing outside of rust.
Only useful for identifying entities within the same instance of an application. Do not use for serialization between runs.
No particular structure is guaranteed for the returned bits.
pub fn from_bits(bits: u64) -> Entity
pub fn from_bits(bits: u64) -> Entity
Reconstruct an Entity
previously destructured with Entity::to_bits
.
Only useful when applied to results from to_bits
in the same instance of an application.
pub fn id(self) -> u32
pub fn id(self) -> u32
Return a transiently unique identifier.
No two simultaneously-live entities share the same ID, but dead entities’ IDs may collide with both live and dead entities. Useful for compactly representing entities within a specific snapshot of the world, such as when serializing.
pub fn generation(self) -> u32
pub fn generation(self) -> u32
Returns the generation of this Entity’s id. The generation is incremented each time an entity with a given id is despawned. This serves as a “count” of the number of times a given id has been reused (id, generation) pairs uniquely identify a given Entity.
Trait Implementations
impl<'de> Deserialize<'de> for Entity
impl<'de> Deserialize<'de> for Entity
fn deserialize<D>(
deserializer: D
) -> Result<Entity, <D as Deserializer<'de>>::Error> where
D: Deserializer<'de>,
fn deserialize<D>(
deserializer: D
) -> Result<Entity, <D as Deserializer<'de>>::Error> where
D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
impl FromReflect for Entity
impl FromReflect for Entity
fn from_reflect(reflect: &(dyn Reflect + 'static)) -> Option<Entity>
fn from_reflect(reflect: &(dyn Reflect + 'static)) -> Option<Entity>
Constructs a concrete instance of Self
from a reflected value.
impl GetTypeRegistration for Entity
impl GetTypeRegistration for Entity
impl Ord for Entity
impl Ord for Entity
1.21.0 · sourcefn max(self, other: Self) -> Self
fn max(self, other: Self) -> Self
Compares and returns the maximum of two values. Read more
1.21.0 · sourcefn min(self, other: Self) -> Self
fn min(self, other: Self) -> Self
Compares and returns the minimum of two values. Read more
1.50.0 · sourcefn clamp(self, min: Self, max: Self) -> Self where
Self: PartialOrd<Self>,
fn clamp(self, min: Self, max: Self) -> Self where
Self: PartialOrd<Self>,
Restrict a value to a certain interval. Read more
impl PartialEq<Entity> for Entity
impl PartialEq<Entity> for Entity
impl PartialOrd<Entity> for Entity
impl PartialOrd<Entity> for Entity
fn partial_cmp(&self, other: &Entity) -> Option<Ordering>
fn partial_cmp(&self, other: &Entity) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
1.0.0 · sourcefn lt(&self, other: &Rhs) -> bool
fn lt(&self, other: &Rhs) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
1.0.0 · sourcefn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
impl Reflect for Entity
impl Reflect for Entity
fn get_type_info(&self) -> &'static TypeInfo
fn get_type_info(&self) -> &'static TypeInfo
fn into_any(self: Box<Entity, Global>) -> Box<dyn Any + 'static, Global>
fn into_any(self: Box<Entity, Global>) -> Box<dyn Any + 'static, Global>
Returns the value as a Box<dyn Any>
.
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
Returns the value as a &mut dyn Any
.
fn as_reflect(&self) -> &(dyn Reflect + 'static)
fn as_reflect(&self) -> &(dyn Reflect + 'static)
Casts this type to a reflected value
fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)
fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)
Casts this type to a mutable reflected value
fn clone_value(&self) -> Box<dyn Reflect + 'static, Global>
fn clone_value(&self) -> Box<dyn Reflect + 'static, Global>
Clones the value as a Reflect
trait object. Read more
fn apply(&mut self, value: &(dyn Reflect + 'static))
fn apply(&mut self, value: &(dyn Reflect + 'static))
Applies a reflected value to this value. Read more
fn set(
&mut self,
value: Box<dyn Reflect + 'static, Global>
) -> Result<(), Box<dyn Reflect + 'static, Global>>
fn set(
&mut self,
value: Box<dyn Reflect + 'static, Global>
) -> Result<(), Box<dyn Reflect + 'static, Global>>
Performs a type-checked assignment of a reflected value to this value. Read more
fn reflect_ref(&self) -> ReflectRef<'_>
fn reflect_ref(&self) -> ReflectRef<'_>
Returns an enumeration of “kinds” of type. Read more
fn reflect_mut(&mut self) -> ReflectMut<'_>
fn reflect_mut(&mut self) -> ReflectMut<'_>
Returns a mutable enumeration of “kinds” of type. Read more
fn reflect_hash(&self) -> Option<u64>
fn reflect_hash(&self) -> Option<u64>
Returns a hash of the value (which includes the type). Read more
fn reflect_partial_eq(&self, value: &(dyn Reflect + 'static)) -> Option<bool>
fn reflect_partial_eq(&self, value: &(dyn Reflect + 'static)) -> Option<bool>
Returns a “partial equality” comparison result. Read more
fn serializable(&self) -> Option<Serializable<'_>>
fn serializable(&self) -> Option<Serializable<'_>>
Returns a serializable version of the value. Read more
impl Serialize for Entity
impl Serialize for Entity
fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
S: Serializer,
fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
S: Serializer,
Serialize this value into the given Serde serializer. Read more
impl SparseSetIndex for Entity
impl SparseSetIndex for Entity
fn sparse_set_index(&self) -> usize
fn get_sparse_set_index(value: usize) -> Entity
impl WorldQuery for Entity
impl WorldQuery for Entity
SAFETY: no component or archetype access
impl<'w> WorldQueryGats<'w> for Entity
impl<'w> WorldQueryGats<'w> for Entity
impl Copy for Entity
impl Eq for Entity
impl ReadOnlyWorldQuery for Entity
SAFETY: access is read only
impl StructuralEq for Entity
impl StructuralPartialEq for Entity
Auto Trait Implementations
impl RefUnwindSafe for Entity
impl Send for Entity
impl Sync for Entity
impl Unpin for Entity
impl UnwindSafe for Entity
Blanket Implementations
impl<T, U> AsBindGroupShaderType<U> for T where
U: ShaderType,
&'a T: for<'a> Into<U>,
impl<T, U> AsBindGroupShaderType<U> for T where
U: ShaderType,
&'a T: for<'a> Into<U>,
fn as_bind_group_shader_type(
&self,
_images: &HashMap<Handle<Image>, <Image as RenderAsset>::PreparedAsset, RandomState, Global>
) -> U
fn as_bind_group_shader_type(
&self,
_images: &HashMap<Handle<Image>, <Image as RenderAsset>::PreparedAsset, RandomState, Global>
) -> U
Return the T
ShaderType
for self
. When used in AsBindGroup
derives, it is safe to assume that all images in self
exist. Read more
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
impl<T> Downcast for T where
T: Any,
impl<T> Downcast for T where
T: Any,
fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
Convert Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
. Box<dyn Any>
can
then be further downcast
into Box<ConcreteType>
where ConcreteType
implements Trait
. Read more
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
Convert Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
. Read more
fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
Convert &Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s. Read more
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
Convert &mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s. Read more
sourceimpl<Q, K> Equivalent<K> for Q where
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Q where
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
sourcefn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Compare self to key
and return true
if they are equal.
impl<T> GetPath for T where
T: Reflect,
impl<T> GetPath for T where
T: Reflect,
fn path(
&'r self,
path: &'p str
) -> Result<&'r (dyn Reflect + 'static), ReflectPathError<'p>>
fn path(
&'r self,
path: &'p str
) -> Result<&'r (dyn Reflect + 'static), ReflectPathError<'p>>
Returns a reference to the value specified by path
. Read more
fn path_mut(
&'r mut self,
path: &'p str
) -> Result<&'r mut (dyn Reflect + 'static), ReflectPathError<'p>>
fn path_mut(
&'r mut self,
path: &'p str
) -> Result<&'r mut (dyn Reflect + 'static), ReflectPathError<'p>>
Returns a mutable reference to the value specified by path
. Read more
fn get_path<T>(&'r self, path: &'p str) -> Result<&'r T, ReflectPathError<'p>> where
T: Reflect,
fn get_path<T>(&'r self, path: &'p str) -> Result<&'r T, ReflectPathError<'p>> where
T: Reflect,
Returns a statically typed reference to the value specified by path
.
fn get_path_mut<T>(
&'r mut self,
path: &'p str
) -> Result<&'r mut T, ReflectPathError<'p>> where
T: Reflect,
fn get_path_mut<T>(
&'r mut self,
path: &'p str
) -> Result<&'r mut T, ReflectPathError<'p>> where
T: Reflect,
Returns a statically typed mutable reference to the value specified by
path
. Read more
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
T: Future, type Output = <T as Future>::Output;
sourcefn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
T: Future, type Output = <T as Future>::Output;
sourceimpl<T> Serialize for T where
T: Serialize + ?Sized,
impl<T> Serialize for T where
T: Serialize + ?Sized,
fn erased_serialize(&self, serializer: &mut dyn Serializer) -> Result<Ok, Error>
impl<T> TypeData for T where
T: 'static + Send + Sync + Clone,
impl<T> TypeData for T where
T: 'static + Send + Sync + Clone,
fn clone_type_data(&self) -> Box<dyn TypeData + 'static, Global>
sourceimpl<T> WithSubscriber for T
impl<T> WithSubscriber for T
sourcefn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
T: Future, type Output = <T as Future>::Output;
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
sourcefn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
T: Future, type Output = <T as Future>::Output;
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more