pub struct Changed<T>(_);
Expand description
Filter that retrieves components of type T
that have been changed since the last
execution of this system.
This filter is useful for synchronizing components, and as a performance optimization as it means that the query contains fewer items for a system to iterate over.
Because the ordering of systems can change and this filter is only effective on changes before the query executes you need to use explicit dependency ordering or ordered stages to avoid frame delays.
If instead behavior is meant to change on whether the component changed or not
ChangeTrackers
may be used.
Examples
fn print_moving_objects_system(query: Query<&Name, Changed<Transform>>) {
for name in query.iter() {
println!("Entity Moved: {:?}", name);
}
}
Trait Implementations
sourceimpl<T: Component> WorldQuery for Changed<T>
impl<T: Component> WorldQuery for Changed<T>
Auto Trait Implementations
impl<T> RefUnwindSafe for Changed<T> where
T: RefUnwindSafe,
impl<T> Send for Changed<T> where
T: Send,
impl<T> Sync for Changed<T> where
T: Sync,
impl<T> Unpin for Changed<T> where
T: Unpin,
impl<T> UnwindSafe for Changed<T> where
T: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> Downcast for T where
T: Any,
impl<T> Downcast for T where
T: Any,
sourcepub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
pub 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
sourcepub fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
pub 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
sourcepub fn as_any(&self) -> &(dyn Any + 'static)
pub 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
sourcepub fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
pub 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<T> DowncastSync for T where
T: Any + Send + Sync,
impl<T> DowncastSync for T where
T: Any + Send + Sync,
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
sourcefn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
sourceimpl<T> WithSubscriber for T
impl<T> WithSubscriber for T
sourcefn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> where
S: Into<Dispatch>,
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
sourcefn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more