Struct hecs::View

pub struct View<'q, Q: Query> { /* private fields */ }

Provides random access to the results of a query

Implementations

impl<'q, Q: Query> View<'q, Q>

pub fn get<'m>(&'m self, entity: Entity) -> Option<QueryItem<'q, Q>> where
    Q: QueryShared, 

Retrieve the query results corresponding to entity

Will yield None if the entity does not exist or does not match the query.

Does not require exclusive access to the map, but is defined only for queries yielding only shared references.

pub fn get_mut<'m>(&'m mut self, entity: Entity) -> Option<QueryItem<'q, Q>>

Retrieve the query results corresponding to entity

Will yield None if the entity does not exist or does not match the query.

pub unsafe fn get_unchecked(&self, entity: Entity) -> Option<QueryItem<'q, Q>>

Like get_mut, but allows simultaneous access to multiple entities

Safety

Must not be invoked while any unique borrow of the fetched components of entity is live.

pub fn get_mut_n<const N: usize>(
    &mut self,
    entities: [Entity; N]
) -> [Option<QueryItem<'q, Q>>; N]

Like get_mut, but allows checked simultaneous access to multiple entities

For N > 3, the check for distinct entities will clone the array and take O(N log N) time.

Examples

let mut world = World::new();

let a = world.spawn((1, 1.0));
let b = world.spawn((2, 4.0));
let c = world.spawn((3, 9.0));

let mut query = world.query_mut::<&mut i32>();
let mut view = query.view();
let [a,b,c] = view.get_mut_n([a, b, c]);

assert_eq!(*a.unwrap(), 1);
assert_eq!(*b.unwrap(), 2);
assert_eq!(*c.unwrap(), 3);