pub struct QueryParIter<'w, 's, D: QueryData, F: QueryFilter> { /* private fields */ }
Expand description
A parallel iterator over query results of a Query
.
This struct is created by the Query::par_iter
and
Query::par_iter_mut
methods.
Implementations§
Source§impl<'w, 's, D: QueryData, F: QueryFilter> QueryParIter<'w, 's, D, F>
impl<'w, 's, D: QueryData, F: QueryFilter> QueryParIter<'w, 's, D, F>
Sourcepub fn batching_strategy(self, strategy: BatchingStrategy) -> Self
pub fn batching_strategy(self, strategy: BatchingStrategy) -> Self
Changes the batching strategy used when iterating.
For more information on how this affects the resultant iteration, see
BatchingStrategy
.
Sourcepub fn for_each<FN: Fn(QueryItem<'w, D>) + Send + Sync + Clone>(self, func: FN)
pub fn for_each<FN: Fn(QueryItem<'w, D>) + Send + Sync + Clone>(self, func: FN)
Runs func
on each query result in parallel.
§Panics
If the ComputeTaskPool
is not initialized. If using this from a query that is being
initialized and run from the ECS scheduler, this should never panic.
Sourcepub fn for_each_init<FN, INIT, T>(self, init: INIT, func: FN)
pub fn for_each_init<FN, INIT, T>(self, init: INIT, func: FN)
Runs func
on each query result in parallel on a value returned by init
.
init
may be called multiple times per thread, and the values returned may be discarded between tasks on any given thread.
Callers should avoid using this function as if it were a parallel version
of Iterator::fold
.
§Example
use bevy_utils::Parallel;
use crate::{bevy_ecs::prelude::Component, bevy_ecs::system::Query};
#[derive(Component)]
struct T;
fn system(query: Query<&T>){
let mut queue: Parallel<usize> = Parallel::default();
// queue.borrow_local_mut() will get or create a thread_local queue for each task/thread;
query.par_iter().for_each_init(|| queue.borrow_local_mut(),|local_queue,item| {
**local_queue += 1;
});
// collect value from every thread
let entity_count: usize = queue.iter_mut().map(|v| *v).sum();
}
§Panics
If the ComputeTaskPool
is not initialized. If using this from a query that is being
initialized and run from the ECS scheduler, this should never panic.