Struct rs_ecs::QueryRef

pub struct QueryRef<'w, S> where
    S: QuerySpec,  { /* private fields */ }

Borrow of the World for a Query. Required to obtain an iterator.

Implementations

impl<S> QueryRef<'_, S> where
    S: QuerySpec, 

pub fn for_each<'q, F>(&'q mut self, f: F) where
    F: FnMut(<S::Fetch as Fetch<'q>>::Item), 

Visit all entities matching the query.

pub fn iter<'q>(&'q mut self) -> QueryIter<'q, S>

Create an iterator over the entities matching the query.

pub fn par_iter<'q>(&'q mut self) -> QueryParIter<'q, S> where
    <S::Fetch as Fetch<'q>>::Item: Send, 

Create a parallel iterator over the entities matching the query.

Examples

use rayon::join;

let mut world = World::new();

let entity1 = world.alloc();
world.insert(entity1, (42_i32, 23_u32, 1.0_f32));

let entity2 = world.alloc();
world.insert(entity2, (0_i32, true));

let mut query1 = Query::<&mut i32>::new();
let mut ref1 = query1.borrow(&world);
let mut iter1 = ref1.iter();

let mut query2 = Query::<(&u32, &mut f32)>::new();
let mut ref2 = query2.borrow(&world);
let mut iter2 = ref2.par_iter();

join(
    move || {
        for i in iter1 {
            *i -= 1;
        }
    },
    move || {
        iter2.for_each(|(u, f)| {
            *f += *u as f32;
        });
    },
);

pub fn map<'q>(&'q mut self) -> QueryMap<'q, S>

Create a map of the entities matching the query.

This is an alternative to get and get_mut for repeated calls, to amortize the set-up costs.

Examples

let mut world = World::new();

let entity = world.alloc();
world.insert(entity, (42_i32, 1.0_f32));

let mut query = Query::<(&i32, &f32)>::new();
let mut query = query.borrow(&world);
let mut query = query.map();

let (i, f) = query.get_mut(entity).unwrap();

assert_eq!(*i, 42);
assert_eq!(*f, 1.0);