Struct OptionRead 

pub struct OptionRead<T: Component>(/* private fields */);

Fetch marker: yields Option<&'w T> (entity need not have T).

Trait Implementations

impl<T: Component> WorldQuery for OptionRead<T>

type Item<'w> = Option<&'w T>

The type yielded per entity.

fn required_types() -> Vec<TypeId>

Required component TypeIds (must all be present in the archetype).

fn matches(_: &Archetype) -> bool

true if arch satisfies this query.

unsafe fn fetch<'w>(a: &'w Archetype, row: usize) -> Option<&'w T>

Fetches the item for row in arch.