Struct bevy_ecs::change_detection::ResMut
source · Expand description
Unique mutable borrow of a Resource
.
See the Resource
documentation for usage.
If you need a shared borrow, use Res
instead.
Panics
Panics when used as a SystemParam
if the resource does not exist.
Use Option<ResMut<T>>
instead if the resource might not always exist.
Implementations§
source§impl<'a, T: ?Sized + Resource> ResMut<'a, T>
impl<'a, T: ?Sized + Resource> ResMut<'a, T>
sourcepub fn into_inner(self) -> &'a mut T
pub fn into_inner(self) -> &'a mut T
Consume self
and return a mutable reference to the
contained value while marking self
as “changed”.
sourcepub fn map_unchanged<U: ?Sized>(
self,
f: impl FnOnce(&mut T) -> &mut U
) -> Mut<'a, U>
pub fn map_unchanged<U: ?Sized>(
self,
f: impl FnOnce(&mut T) -> &mut U
) -> Mut<'a, U>
Maps to an inner value by applying a function to the contained reference, without flagging a change.
You should never modify the argument passed to the closure – if you want to modify the data
without flagging a change, consider using DetectChanges::bypass_change_detection
to make your intent explicit.
// When run, zeroes the translation of every entity.
fn reset_positions(mut transforms: Query<&mut Transform>) {
for transform in &mut transforms {
// We pinky promise not to modify `t` within the closure.
// Breaking this promise will result in logic errors, but will never cause undefined behavior.
let translation = transform.map_unchanged(|t| &mut t.translation);
// Only reset the translation if it isn't already zero;
my_utils::set_if_not_equal(translation, Vec2::ZERO);
}
}
Trait Implementations§
source§impl<'a, T: ?Sized + Resource> DetectChanges for ResMut<'a, T>
impl<'a, T: ?Sized + Resource> DetectChanges for ResMut<'a, T>
source§fn is_changed(&self) -> bool
fn is_changed(&self) -> bool
Returns
true
if this value was added or mutably dereferenced after the system last ran.source§fn set_changed(&mut self)
fn set_changed(&mut self)
Flags this value as having been changed. Read more
source§fn last_changed(&self) -> u32
fn last_changed(&self) -> u32
Returns the change tick recording the previous time this data was changed. Read more
source§fn set_last_changed(&mut self, last_change_tick: u32)
fn set_last_changed(&mut self, last_change_tick: u32)
Manually sets the change tick recording the previous time this data was mutated. Read more
source§fn bypass_change_detection(&mut self) -> &mut Self::Inner
fn bypass_change_detection(&mut self) -> &mut Self::Inner
Manually bypasses change detection, allowing you to mutate the underlying value without updating the change tick. Read more
source§impl<'w, 'a, T: Resource> IntoIterator for &'a ResMut<'w, T>where
&'a T: IntoIterator,
impl<'w, 'a, T: Resource> IntoIterator for &'a ResMut<'w, T>where
&'a T: IntoIterator,
source§impl<'w, 'a, T: Resource> IntoIterator for &'a mut ResMut<'w, T>where
&'a mut T: IntoIterator,
impl<'w, 'a, T: Resource> IntoIterator for &'a mut ResMut<'w, T>where
&'a mut T: IntoIterator,
Auto Trait Implementations§
impl<'a, T: ?Sized> RefUnwindSafe for ResMut<'a, T>where
T: RefUnwindSafe,
impl<'a, T: ?Sized> Send for ResMut<'a, T>
impl<'a, T: ?Sized> Sync for ResMut<'a, T>
impl<'a, T: ?Sized> Unpin for ResMut<'a, T>
impl<'a, T> !UnwindSafe for ResMut<'a, T>
Blanket Implementations§
source§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
T: Any,
source§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 moresource§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 moresource§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 moresource§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