Expand description
A system local SystemParam
.
A local may only be accessed by the system itself and is therefore not visible to other systems. If two or more systems specify the same local type each will have their own unique local.
Examples
fn write_to_local(mut local: Local<usize>) {
*local = 42;
}
fn read_from_local(local: Local<usize>) -> usize {
*local
}
let mut write_system = IntoSystem::into_system(write_to_local);
let mut read_system = IntoSystem::into_system(read_from_local);
write_system.initialize(world);
read_system.initialize(world);
assert_eq!(read_system.run((), world), 0);
write_system.run((), world);
// Note how the read local is still 0 due to the locals not being shared.
assert_eq!(read_system.run((), world), 0);
N.B. A Local
s value cannot be read or written to outside of the containing system.
To add configuration to a system, convert a capturing closure into the system instead:
struct Config(u32);
#[derive(Resource)]
struct Myu32Wrapper(u32);
fn reset_to_system(value: Config) -> impl FnMut(ResMut<Myu32Wrapper>) {
move |mut val| val.0 = value.0
}
// .add_system(reset_to_system(my_config))
Trait Implementations§
§impl<'w, 'a, T> IntoIterator for &'a Local<'w, T>where
T: 'static + FromWorld + Send,
&'a T: IntoIterator,
impl<'w, 'a, T> IntoIterator for &'a Local<'w, T>where
T: 'static + FromWorld + Send,
&'a T: IntoIterator,
§impl<'w, 'a, T> IntoIterator for &'a mut Local<'w, T>where
T: 'static + FromWorld + Send,
&'a mut T: IntoIterator,
impl<'w, 'a, T> IntoIterator for &'a mut Local<'w, T>where
T: 'static + FromWorld + Send,
&'a mut T: IntoIterator,
§type Item = <&'a mut T as IntoIterator>::Item
type Item = <&'a mut T as IntoIterator>::Item
The type of the elements being iterated over.
§type IntoIter = <&'a mut T as IntoIterator>::IntoIter
type IntoIter = <&'a mut T as IntoIterator>::IntoIter
Which kind of iterator are we turning this into?
Auto Trait Implementations§
impl<'a, T> RefUnwindSafe for Local<'a, T>where
T: RefUnwindSafe,
impl<'a, T> Send for Local<'a, T>
impl<'a, T> Sync for Local<'a, T>where
T: Sync,
impl<'a, T> Unpin for Local<'a, T>
impl<'a, T> !UnwindSafe for Local<'a, T>
Blanket Implementations§
§impl<T, U> AsBindGroupShaderType<U> for Twhere
U: ShaderType,
&'a T: for<'a> Into<U>,
impl<T, U> AsBindGroupShaderType<U> for Twhere
U: ShaderType,
&'a T: for<'a> Into<U>,
§fn as_bind_group_shader_type(&self, _images: &RenderAssets<Image>) -> U
fn as_bind_group_shader_type(&self, _images: &RenderAssets<Image>) -> 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§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
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