Struct QueryMut 

pub struct QueryMut<'w, T: Component> { /* private fields */ }

Exclusive write access to all entities with component T.

Implementations

impl<'w, T: Component> QueryMut<'w, T>

pub fn iter_mut( &mut self, ) -> impl Iterator<Item = (Entity, &mut Mut<'w, T>)> + '_

Iterate mutably over matching (Entity, &mut Mut<T>) pairs.

Reading through Mut<T> (via Deref) does not stamp the change tick. Only writing through DerefMut stamps it, so query_changed sees only entities that were actually mutated.

pub fn is_empty(&self) -> bool

Returns true if no entities matched.

pub fn len(&self) -> usize

Returns the number of matching entities.

Trait Implementations

impl<T: Component> SystemParam for QueryMut<'_, T>

type Item<'w> = QueryMut<'w, T>

The concrete type produced for a given world lifetime.

fn access() -> Vec<Access>

Declare what world data this parameter accesses.

unsafe fn fetch<'w>(world: UnsafeWorldCell) -> QueryMut<'w, T>

Extract the parameter from the world.