pub struct Single<'w, 's, D, F = ()>where
D: QueryData,
F: QueryFilter,{ /* private fields */ }
Expand description
System parameter that provides access to single entity’s components, much like Query::single
/Query::single_mut
.
This SystemParam
fails validation if zero or more than one matching entity exists.
This will cause the system to be skipped, according to the rules laid out in SystemParamValidationError
.
Use Option<Single<D, F>>
instead if zero or one matching entities can exist.
See Query
for more details.
§Example
#[derive(Component)]
struct Boss {
health: f32
};
fn hurt_boss(mut boss: Single<&mut Boss>) {
boss.health -= 4.0;
}
Note that because Single
implements Deref
and DerefMut
, methods and fields like health
can be accessed directly.
You can also access the underlying data manually, by calling .deref
/.deref_mut
, or by using the *
operator.
Implementations§
Source§impl<'w, 's, D, F> Single<'w, 's, D, F>where
D: QueryData,
F: QueryFilter,
impl<'w, 's, D, F> Single<'w, 's, D, F>where
D: QueryData,
F: QueryFilter,
Sourcepub fn into_inner(self) -> <D as QueryData>::Item<'w, 's>
pub fn into_inner(self) -> <D as QueryData>::Item<'w, 's>
Returns the inner item with ownership.
Trait Implementations§
Source§impl<'a, 'b, D, F> SystemParam for Single<'a, 'b, D, F>where
D: QueryData + 'static,
F: QueryFilter + 'static,
impl<'a, 'b, D, F> SystemParam for Single<'a, 'b, D, F>where
D: QueryData + 'static,
F: QueryFilter + 'static,
Source§type State = QueryState<D, F>
type State = QueryState<D, F>
Used to store data which persists across invocations of a system.
Source§type Item<'w, 's> = Single<'w, 's, D, F>
type Item<'w, 's> = Single<'w, 's, D, F>
The item type returned when constructing this system param.
The value of this associated type should be
Self
, instantiated with new lifetimes. Read moreSource§fn init_state(world: &mut World) -> <Single<'a, 'b, D, F> as SystemParam>::State
fn init_state(world: &mut World) -> <Single<'a, 'b, D, F> as SystemParam>::State
Creates a new instance of this param’s
State
.Source§fn init_access(
state: &<Single<'a, 'b, D, F> as SystemParam>::State,
system_meta: &mut SystemMeta,
component_access_set: &mut FilteredAccessSet,
world: &mut World,
)
fn init_access( state: &<Single<'a, 'b, D, F> as SystemParam>::State, system_meta: &mut SystemMeta, component_access_set: &mut FilteredAccessSet, world: &mut World, )
Registers any
World
access used by this SystemParam
Source§unsafe fn get_param<'w, 's>(
state: &'s mut <Single<'a, 'b, D, F> as SystemParam>::State,
system_meta: &SystemMeta,
world: UnsafeWorldCell<'w>,
change_tick: Tick,
) -> <Single<'a, 'b, D, F> as SystemParam>::Item<'w, 's>
unsafe fn get_param<'w, 's>( state: &'s mut <Single<'a, 'b, D, F> as SystemParam>::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, change_tick: Tick, ) -> <Single<'a, 'b, D, F> as SystemParam>::Item<'w, 's>
Creates a parameter to be passed into a
SystemParamFunction
. Read moreSource§unsafe fn validate_param(
state: &mut <Single<'a, 'b, D, F> as SystemParam>::State,
system_meta: &SystemMeta,
world: UnsafeWorldCell<'_>,
) -> Result<(), SystemParamValidationError>
unsafe fn validate_param( state: &mut <Single<'a, 'b, D, F> as SystemParam>::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'_>, ) -> Result<(), SystemParamValidationError>
Source§fn apply(state: &mut Self::State, system_meta: &SystemMeta, world: &mut World)
fn apply(state: &mut Self::State, system_meta: &SystemMeta, world: &mut World)
Applies any deferred mutations stored in this
SystemParam
’s state.
This is used to apply Commands
during ApplyDeferred
.Source§fn queue(
state: &mut Self::State,
system_meta: &SystemMeta,
world: DeferredWorld<'_>,
)
fn queue( state: &mut Self::State, system_meta: &SystemMeta, world: DeferredWorld<'_>, )
Queues any deferred mutations to be applied at the next
ApplyDeferred
.impl<'a, 'b, D, F> ReadOnlySystemParam for Single<'a, 'b, D, F>where
D: ReadOnlyQueryData + 'static,
F: QueryFilter + 'static,
Auto Trait Implementations§
impl<'w, 's, D, F> Freeze for Single<'w, 's, D, F>
impl<'w, 's, D, F> RefUnwindSafe for Single<'w, 's, D, F>
impl<'w, 's, D, F> Send for Single<'w, 's, D, F>
impl<'w, 's, D, F> Sync for Single<'w, 's, D, F>
impl<'w, 's, D, F> Unpin for Single<'w, 's, D, F>
impl<'w, 's, D, F> UnwindSafe for Single<'w, 's, D, F>
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Source§impl<T, C, D> Curve<T> for D
impl<T, C, D> Curve<T> for D
Source§fn sample_unchecked(&self, t: f32) -> T
fn sample_unchecked(&self, t: f32) -> T
Sample a point on this curve at the parameter value
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, extracting the associated value.
This is the unchecked version of sampling, which should only be used if the sample time t
is already known to lie within the curve’s domain. Read moreSource§fn sample(&self, t: f32) -> Option<T>
fn sample(&self, t: f32) -> Option<T>
Sample a point on this curve at the parameter value
t
, returning None
if the point is
outside of the curve’s domain.Source§fn sample_clamped(&self, t: f32) -> T
fn sample_clamped(&self, t: f32) -> T
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&self,
iter: impl IntoIterator<Item = f32>,
) -> impl Iterator<Item = Option<T>>
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&self,
iter: impl IntoIterator<Item = f32>,
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fn sample_iter_unchecked( &self, iter: impl IntoIterator<Item = f32>, ) -> impl Iterator<Item = T>
Sample a collection of
n >= 0
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,
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&self,
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fn sample_iter_clamped( &self, iter: impl IntoIterator<Item = f32>, ) -> impl Iterator<Item = T>
Sample a collection of
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,
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fn map<S, F>(self, f: F) -> MapCurve<T, S, Self, F>where
F: Fn(T) -> S,
Create a new curve by mapping the values of this curve via a function
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; i.e., if the
sample at time t
for this curve is x
, the value at time t
on the new curve will be
f(x)
.Source§fn reparametrize<F>(self, domain: Interval, f: F) -> ReparamCurve<T, Self, F>
fn reparametrize<F>(self, domain: Interval, f: F) -> ReparamCurve<T, Self, F>
Create a new
Curve
whose parameter space is related to the parameter space of this curve
by f
. For each time t
, the sample from the new curve at time t
is the sample from
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. The given domain
will be the domain of the new curve. The
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self,
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) -> Result<LinearReparamCurve<T, Self>, LinearReparamError>
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&self,
samples: usize,
) -> Result<impl Iterator<Item = T>, ResamplingError>
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Extract an iterator over evenly-spaced samples from this curve. Read more
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&self,
segments: usize,
interpolation: I,
) -> Result<SampleCurve<T, I>, ResamplingError>
fn resample<I>( &self, segments: usize, interpolation: I, ) -> Result<SampleCurve<T, I>, ResamplingError>
Resample this
Curve
to produce a new one that is defined by interpolation over equally
spaced sample values, using the provided interpolation
to interpolate between adjacent samples.
The curve is interpolated on segments
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&self,
segments: usize,
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&self,
segments: usize,
) -> Result<SampleAutoCurve<T>, ResamplingError>where
T: StableInterpolate,
Resample this
Curve
to produce a new one that is defined by interpolation over equally
spaced sample values, using automatic interpolation to interpolate between adjacent samples.
The curve is interpolated on segments
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only the start and end points of the curve are used as samples; if segments
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&self,
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interpolation: I,
) -> Result<UnevenSampleCurve<T, I>, ResamplingError>
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&self,
sample_times: impl IntoIterator<Item = f32>,
) -> Result<UnevenSampleAutoCurve<T>, ResamplingError>where
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Resample this
Curve
to produce a new one that is defined by automatic interpolation over
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This curve, but with its first derivative included in sampling. Read more
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Sample this curve at the parameter value
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