Struct rs_ecs::Query

pub struct Query<S> where
    S: QuerySpec,  { /* fields omitted */ }

Query to get an iterator over all entities with a certain combination of components.

Queries are provided as stand-alone structs to allow for prepared queries that can be re-used, as an optimzation. Hence, queries neet to borrow the World before their results can be iterated (see Query::borrow).

Examples

let mut world = World::new();

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

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

let mut query = Query::<(&i32, &mut bool)>::new();
for (i, b) in query.borrow(&world).iter() {
    *b = *i > 10;
}

Implementations

impl<S> Query<S> where
    S: QuerySpec, 

pub fn new() -> Self

Create a query.

Examples

let mut immutable_query = Query::<(&i32,)>::new();
let mut mutable_query = Query::<(&i32, &mut bool)>::new();
let mut query_with_entity = Query::<(&Entity, &i32, &mut bool)>::new();

pub fn borrow<'w>(&'w mut self, world: &'w World) -> QueryRef<'w, S>

Borrow the World to allow for iterating the query.

Examples

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

for (i, b) in borrow.iter() {
    println!("{}, {}", i, b);
}

pub fn with<C>(self) -> Query<With<S, C>> where
    C: 'static, 

Narrow down a query to entities that have a certain component, without borrowing that component.

For use with prepared queries, see With.

Examples

let query = Query::<(&i32,)>::new().with::<bool>();

pub fn without<C>(self) -> Query<Without<S, C>> where
    C: 'static, 

Narrow down a query to entities that do not have a certain component.

For use with prepared queries, see Without.

Examples

let query = Query::<(&i32,)>::new().without::<bool>();

Trait Implementations

impl<S> Default for Query<S> where
    S: QuerySpec, 

fn default() -> Self

Create a query.