pub struct RemovedComponents<'w, 's, T>where
T: Component,{ /* private fields */ }
Expand description
A SystemParam
that yields entities that had their T
Component
removed or have been despawned with it.
This acts effectively the same as a MessageReader
.
Unlike hooks or observers (see the lifecycle module docs), this does not allow you to see which data existed before removal.
If you are using bevy_ecs
as a standalone crate,
note that the RemovedComponents
list will not be automatically cleared for you,
and will need to be manually flushed using World::clear_trackers
.
For users of bevy
and bevy_app
, World::clear_trackers
is
automatically called by bevy_app::App::update
and bevy_app::SubApp::update
.
For the main world, this is delayed until after all SubApp
s have run.
§Examples
Basic usage:
fn react_on_removal(mut removed: RemovedComponents<MyComponent>) {
removed.read().for_each(|removed_entity| println!("{}", removed_entity));
}
Implementations§
Source§impl<'w, 's, T> RemovedComponents<'w, 's, T>where
T: Component,
impl<'w, 's, T> RemovedComponents<'w, 's, T>where
T: Component,
Sourcepub fn reader(&self) -> &MessageCursor<RemovedComponentEntity>
pub fn reader(&self) -> &MessageCursor<RemovedComponentEntity>
Fetch underlying MessageCursor
.
Sourcepub fn reader_mut(&mut self) -> &mut MessageCursor<RemovedComponentEntity>
pub fn reader_mut(&mut self) -> &mut MessageCursor<RemovedComponentEntity>
Fetch underlying MessageCursor
mutably.
Sourcepub fn events(&self) -> Option<&Messages<RemovedComponentEntity>>
👎Deprecated since 0.17.0: Renamed to messages
.
pub fn events(&self) -> Option<&Messages<RemovedComponentEntity>>
messages
.Fetch underlying Messages
.
Sourcepub fn reader_mut_with_messages(
&mut self,
) -> Option<(&mut RemovedComponentReader<T>, &Messages<RemovedComponentEntity>)>
pub fn reader_mut_with_messages( &mut self, ) -> Option<(&mut RemovedComponentReader<T>, &Messages<RemovedComponentEntity>)>
Destructures to get a mutable reference to the MessageCursor
and a reference to Messages
.
This is necessary since Rust can’t detect destructuring through methods and most
usecases of the reader uses the Messages
as well.
Sourcepub fn reader_mut_with_events(
&mut self,
) -> Option<(&mut RemovedComponentReader<T>, &Messages<RemovedComponentEntity>)>
👎Deprecated since 0.17.0: Renamed to reader_mut_with_messages
.
pub fn reader_mut_with_events( &mut self, ) -> Option<(&mut RemovedComponentReader<T>, &Messages<RemovedComponentEntity>)>
reader_mut_with_messages
.Destructures to get a reference to the MessageCursor
and a reference to Messages
.
Sourcepub fn read(
&mut self,
) -> Map<Flatten<IntoIter<Cloned<MessageIterator<'_, RemovedComponentEntity>>>>, fn(RemovedComponentEntity) -> Entity> ⓘ
pub fn read( &mut self, ) -> Map<Flatten<IntoIter<Cloned<MessageIterator<'_, RemovedComponentEntity>>>>, fn(RemovedComponentEntity) -> Entity> ⓘ
Iterates over the messages this RemovedComponents
has not seen yet. This updates the
RemovedComponents
’s message counter, which means subsequent message reads will not include messages
that happened before now.
Sourcepub fn read_with_id(
&mut self,
) -> Map<Flatten<IntoIter<MessageIteratorWithId<'_, RemovedComponentEntity>>>, fn((&RemovedComponentEntity, MessageId<RemovedComponentEntity>)) -> (Entity, MessageId<RemovedComponentEntity>)> ⓘ
pub fn read_with_id( &mut self, ) -> Map<Flatten<IntoIter<MessageIteratorWithId<'_, RemovedComponentEntity>>>, fn((&RemovedComponentEntity, MessageId<RemovedComponentEntity>)) -> (Entity, MessageId<RemovedComponentEntity>)> ⓘ
Sourcepub fn len(&self) -> usize
pub fn len(&self) -> usize
Determines the number of removal messages available to be read from this RemovedComponents
without consuming any.
Sourcepub fn clear(&mut self)
pub fn clear(&mut self)
Consumes all available messages.
This means these messages will not appear in calls to RemovedComponents::read()
or
RemovedComponents::read_with_id()
and RemovedComponents::is_empty()
will return true
.
Trait Implementations§
Source§impl<T> SystemParam for RemovedComponents<'_, '_, T>where
T: Component,
impl<T> SystemParam for RemovedComponents<'_, '_, T>where
T: Component,
Source§type Item<'w, 's> = RemovedComponents<'w, 's, T>
type Item<'w, 's> = RemovedComponents<'w, 's, T>
Self
, instantiated with new lifetimes. Read moreSource§fn init_state(
world: &mut World,
) -> <RemovedComponents<'_, '_, T> as SystemParam>::State
fn init_state( world: &mut World, ) -> <RemovedComponents<'_, '_, T> as SystemParam>::State
State
.Source§fn init_access(
state: &<RemovedComponents<'_, '_, T> as SystemParam>::State,
system_meta: &mut SystemMeta,
component_access_set: &mut FilteredAccessSet,
world: &mut World,
)
fn init_access( state: &<RemovedComponents<'_, '_, T> as SystemParam>::State, system_meta: &mut SystemMeta, component_access_set: &mut FilteredAccessSet, world: &mut World, )
World
access used by this SystemParam
Source§fn apply(
state: &mut <RemovedComponents<'_, '_, T> as SystemParam>::State,
system_meta: &SystemMeta,
world: &mut World,
)
fn apply( state: &mut <RemovedComponents<'_, '_, T> as SystemParam>::State, system_meta: &SystemMeta, world: &mut World, )
SystemParam
’s state.
This is used to apply Commands
during ApplyDeferred
.Source§fn queue(
state: &mut <RemovedComponents<'_, '_, T> as SystemParam>::State,
system_meta: &SystemMeta,
world: DeferredWorld<'_>,
)
fn queue( state: &mut <RemovedComponents<'_, '_, T> as SystemParam>::State, system_meta: &SystemMeta, world: DeferredWorld<'_>, )
ApplyDeferred
.Source§unsafe fn validate_param<'w, 's>(
state: &'s mut <RemovedComponents<'_, '_, T> as SystemParam>::State,
_system_meta: &SystemMeta,
_world: UnsafeWorldCell<'w>,
) -> Result<(), SystemParamValidationError>
unsafe fn validate_param<'w, 's>( state: &'s mut <RemovedComponents<'_, '_, T> as SystemParam>::State, _system_meta: &SystemMeta, _world: UnsafeWorldCell<'w>, ) -> Result<(), SystemParamValidationError>
Source§unsafe fn get_param<'w, 's>(
state: &'s mut <RemovedComponents<'_, '_, T> as SystemParam>::State,
system_meta: &SystemMeta,
world: UnsafeWorldCell<'w>,
change_tick: Tick,
) -> <RemovedComponents<'_, '_, T> as SystemParam>::Item<'w, 's>
unsafe fn get_param<'w, 's>( state: &'s mut <RemovedComponents<'_, '_, T> as SystemParam>::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, change_tick: Tick, ) -> <RemovedComponents<'_, '_, T> as SystemParam>::Item<'w, 's>
SystemParamFunction
. Read moreimpl<'w, 's, T> ReadOnlySystemParam for RemovedComponents<'w, 's, T>where
T: Component,
ComponentIdFor<'s, T>: ReadOnlySystemParam,
Local<'s, RemovedComponentReader<T>>: ReadOnlySystemParam,
&'w RemovedComponentMessages: ReadOnlySystemParam,
Auto Trait Implementations§
impl<'w, 's, T> Freeze for RemovedComponents<'w, 's, T>
impl<'w, 's, T> RefUnwindSafe for RemovedComponents<'w, 's, T>where
T: RefUnwindSafe,
impl<'w, 's, T> Send for RemovedComponents<'w, 's, T>
impl<'w, 's, T> Sync for RemovedComponents<'w, 's, T>
impl<'w, 's, T> Unpin for RemovedComponents<'w, 's, T>
impl<'w, 's, T> !UnwindSafe for RemovedComponents<'w, 's, T>
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