Struct EntityWorldMut

pub struct EntityWorldMut<'w> { /* private fields */ }

A mutable reference to a particular Entity, and the entire world.

This is essentially a performance-optimized (Entity, &mut World) tuple, which caches the EntityLocation to reduce duplicate lookups.

Since this type provides mutable access to the entire world, only one EntityWorldMut can exist at a time for a given world.

See also EntityMut, which allows disjoint mutable access to multiple entities at once. Unlike EntityMut, this type allows adding and removing components, and despawning the entity.

Implementations

impl<'w> EntityWorldMut<'w>

pub fn id(&self) -> Entity

Returns the ID of the current entity.

pub fn location(&self) -> EntityLocation

Gets metadata indicating the location where the current entity is stored.

pub fn archetype(&self) -> &Archetype

Returns the archetype that the current entity belongs to.

pub fn contains<T: Component>(&self) -> bool

Returns true if the current entity has a component of type T. Otherwise, this returns false.

Notes

If you do not know the concrete type of a component, consider using Self::contains_id or Self::contains_type_id.

pub fn contains_id(&self, component_id: ComponentId) -> bool

Returns true if the current entity has a component identified by component_id. Otherwise, this returns false.

Notes

• If you know the concrete type of the component, you should prefer Self::contains.
• If you know the component’s TypeId but not its ComponentId, consider using Self::contains_type_id.

pub fn contains_type_id(&self, type_id: TypeId) -> bool

Returns true if the current entity has a component with the type identified by type_id. Otherwise, this returns false.

Notes

• If you know the concrete type of the component, you should prefer Self::contains.
• If you have a ComponentId instead of a TypeId, consider using Self::contains_id.

pub fn get<T: Component>(&self) -> Option<&T>

Gets access to the component of type T for the current entity. Returns None if the entity does not have a component of type T.

pub fn components<Q: ReadOnlyQueryData>(&self) -> Q::Item<'_>

Returns read-only components for the current entity that match the query Q.

Panics

If the entity does not have the components required by the query Q.

pub fn get_components<Q: ReadOnlyQueryData>(&self) -> Option<Q::Item<'_>>

Returns read-only components for the current entity that match the query Q, or None if the entity does not have the components required by the query Q.

pub fn into_borrow<T: Component>(self) -> Option<&'w T>

Consumes self and gets access to the component of type T with the world 'w lifetime for the current entity. Returns None if the entity does not have a component of type T.

pub fn get_ref<T: Component>(&self) -> Option<Ref<'_, T>>

Gets access to the component of type T for the current entity, including change detection information as a Ref.

Returns None if the entity does not have a component of type T.

pub fn into_ref<T: Component>(self) -> Option<Ref<'w, T>>

Consumes self and gets access to the component of type T with the world 'w lifetime for the current entity, including change detection information as a Ref.

Returns None if the entity does not have a component of type T.

pub fn get_mut<T: Component>(&mut self) -> Option<Mut<'_, T>>

Gets mutable access to the component of type T for the current entity. Returns None if the entity does not have a component of type T.

pub fn into_mut<T: Component>(self) -> Option<Mut<'w, T>>

Consumes self and gets mutable access to the component of type T with the world 'w lifetime for the current entity. Returns None if the entity does not have a component of type T.

pub fn get_change_ticks<T: Component>(&self) -> Option<ComponentTicks>

Retrieves the change ticks for the given component. This can be useful for implementing change detection in custom runtimes.

pub fn get_change_ticks_by_id( &self, component_id: ComponentId, ) -> Option<ComponentTicks>

Retrieves the change ticks for the given ComponentId. This can be useful for implementing change detection in custom runtimes.

You should prefer to use the typed API EntityWorldMut::get_change_ticks where possible and only use this in cases where the actual component types are not known at compile time.

pub fn get_by_id<F: DynamicComponentFetch>( &self, component_ids: F, ) -> Result<F::Ref<'_>, EntityComponentError>

Returns untyped read-only reference(s) to component(s) for the current entity, based on the given ComponentIds.

You should prefer to use the typed API EntityWorldMut::get where possible and only use this in cases where the actual component types are not known at compile time.

Unlike EntityWorldMut::get, this returns untyped reference(s) to component(s), and it’s the job of the caller to ensure the correct type(s) are dereferenced (if necessary).

Errors

Returns EntityComponentError::MissingComponent if the entity does not have a component.

Examples

For examples on how to use this method, see EntityRef::get_by_id.

pub fn into_borrow_by_id<F: DynamicComponentFetch>( self, component_ids: F, ) -> Result<F::Ref<'w>, EntityComponentError>

Consumes self and returns untyped read-only reference(s) to component(s) with lifetime 'w for the current entity, based on the given ComponentIds.

You should prefer to use the typed API EntityWorldMut::into_borrow where possible and only use this in cases where the actual component types are not known at compile time.

Unlike EntityWorldMut::into_borrow, this returns untyped reference(s) to component(s), and it’s the job of the caller to ensure the correct type(s) are dereferenced (if necessary).

Errors

Returns EntityComponentError::MissingComponent if the entity does not have a component.

Examples

For examples on how to use this method, see EntityRef::get_by_id.

pub fn get_mut_by_id<F: DynamicComponentFetch>( &mut self, component_ids: F, ) -> Result<F::Mut<'_>, EntityComponentError>

Returns untyped mutable reference(s) to component(s) for the current entity, based on the given ComponentIds.

You should prefer to use the typed API EntityWorldMut::get_mut where possible and only use this in cases where the actual component types are not known at compile time.

Unlike EntityWorldMut::get_mut, this returns untyped reference(s) to component(s), and it’s the job of the caller to ensure the correct type(s) are dereferenced (if necessary).

Errors

• Returns EntityComponentError::MissingComponent if the entity does not have a component.
• Returns EntityComponentError::AliasedMutability if a component is requested multiple times.

Examples

For examples on how to use this method, see EntityMut::get_mut_by_id.

pub fn into_mut_by_id<F: DynamicComponentFetch>( self, component_ids: F, ) -> Result<F::Mut<'w>, EntityComponentError>

Consumes self and returns untyped mutable reference(s) to component(s) with lifetime 'w for the current entity, based on the given ComponentIds.

You should prefer to use the typed API EntityWorldMut::into_mut where possible and only use this in cases where the actual component types are not known at compile time.

Unlike EntityWorldMut::into_mut, this returns untyped reference(s) to component(s), and it’s the job of the caller to ensure the correct type(s) are dereferenced (if necessary).

Errors

• Returns EntityComponentError::MissingComponent if the entity does not have a component.
• Returns EntityComponentError::AliasedMutability if a component is requested multiple times.

Examples

For examples on how to use this method, see EntityMut::get_mut_by_id.

pub fn insert<T: Bundle>(&mut self, bundle: T) -> &mut Self

Adds a Bundle of components to the entity.

This will overwrite any previous value(s) of the same component type.

pub fn insert_if_new<T: Bundle>(&mut self, bundle: T) -> &mut Self

Adds a Bundle of components to the entity without overwriting.

This will leave any previous value(s) of the same component type unchanged.

pub unsafe fn insert_by_id( &mut self, component_id: ComponentId, component: OwningPtr<'_>, ) -> &mut Self

Inserts a dynamic Component into the entity.

This will overwrite any previous value(s) of the same component type.

You should prefer to use the typed API EntityWorldMut::insert where possible.

Safety

• ComponentId must be from the same world as EntityWorldMut
• OwningPtr must be a valid reference to the type represented by ComponentId

pub unsafe fn insert_by_ids<'a, I: Iterator<Item = OwningPtr<'a>>>( &mut self, component_ids: &[ComponentId], iter_components: I, ) -> &mut Self

Inserts a dynamic Bundle into the entity.

This will overwrite any previous value(s) of the same component type.

You should prefer to use the typed API EntityWorldMut::insert where possible. If your Bundle only has one component, use the cached API EntityWorldMut::insert_by_id.

If possible, pass a sorted slice of ComponentId to maximize caching potential.

Safety

• Each ComponentId must be from the same world as EntityWorldMut
• Each OwningPtr must be a valid reference to the type represented by ComponentId

pub fn take<T: Bundle>(&mut self) -> Option<T>

Removes all components in the Bundle from the entity and returns their previous values.

Note: If the entity does not have every component in the bundle, this method will not remove any of them.

pub fn remove<T: Bundle>(&mut self) -> &mut Self

Removes any components in the Bundle from the entity.

See EntityCommands::remove for more details.

pub fn remove_with_requires<T: Bundle>(&mut self) -> &mut Self

Removes all components in the Bundle and remove all required components for each component in the bundle

pub fn retain<T: Bundle>(&mut self) -> &mut Self

Removes any components except those in the Bundle (and its Required Components) from the entity.

See EntityCommands::retain for more details.

pub fn remove_by_id(&mut self, component_id: ComponentId) -> &mut Self

Removes a dynamic Component from the entity if it exists.

You should prefer to use the typed API EntityWorldMut::remove where possible.

Panics

Panics if the provided ComponentId does not exist in the World.

pub fn clear(&mut self) -> &mut Self

Removes all components associated with the entity.

pub fn despawn(self)

Despawns the current entity.

See World::despawn for more details.

pub fn flush(self) -> Entity

Ensures any commands triggered by the actions of Self are applied, equivalent to World::flush

pub fn world(&self) -> &World

Gets read-only access to the world that the current entity belongs to.

pub unsafe fn world_mut(&mut self) -> &mut World

Returns this entity’s world.

See EntityWorldMut::world_scope or EntityWorldMut::into_world_mut for a safe alternative.

Safety

Caller must not modify the world in a way that changes the current entity’s location If the caller does do something that could change the location, self.update_location() must be called before using any other methods on this EntityWorldMut.

pub fn into_world_mut(self) -> &'w mut World

Returns this entity’s World, consuming itself.

pub fn world_scope<U>(&mut self, f: impl FnOnce(&mut World) -> U) -> U

Gives mutable access to this entity’s World in a temporary scope. This is a safe alternative to using EntityWorldMut::world_mut.

Examples

#[derive(Resource, Default, Clone, Copy)]
struct R(u32);

// This closure gives us temporary access to the world.
let new_r = entity.world_scope(|world: &mut World| {
    // Mutate the world while we have access to it.
    let mut r = world.resource_mut::<R>();
    r.0 += 1;

    // Return a value from the world before giving it back to the `EntityWorldMut`.
    *r
});

pub fn update_location(&mut self)

Updates the internal entity location to match the current location in the internal World.

This is only required when using the unsafe function EntityWorldMut::world_mut, which enables the location to change.

pub fn entry<'a, T: Component>(&'a mut self) -> Entry<'w, 'a, T>

Gets an Entry into the world for this entity and component for in-place manipulation.

The type parameter specifies which component to get.

Examples

#[derive(Component, Default, Clone, Copy, Debug, PartialEq)]
struct Comp(u32);

let mut entity = world.spawn_empty();
entity.entry().or_insert_with(|| Comp(4));
assert_eq!(world.query::<&Comp>().single(&world).0, 4);

entity.entry::<Comp>().and_modify(|mut c| c.0 += 1);
assert_eq!(world.query::<&Comp>().single(&world).0, 5);

pub fn trigger(&mut self, event: impl Event) -> &mut Self

Triggers the given event for this entity, which will run any observers watching for it.

pub fn observe<E: Event, B: Bundle, M>( &mut self, observer: impl IntoObserverSystem<E, B, M>, ) -> &mut Self

Creates an Observer listening for events of type E targeting this entity. In order to trigger the callback the entity must also match the query when the event is fired.

Trait Implementations

impl<'a> From<&'a EntityWorldMut<'_>> for EntityRef<'a>

fn from(value: &'a EntityWorldMut<'_>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a EntityWorldMut<'_>> for FilteredEntityRef<'a>

fn from(entity: &'a EntityWorldMut<'_>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a mut EntityWorldMut<'_>> for EntityMut<'a>

fn from(value: &'a mut EntityWorldMut<'_>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a mut EntityWorldMut<'_>> for FilteredEntityMut<'a>

fn from(entity: &'a mut EntityWorldMut<'_>) -> Self

Converts to this type from the input type.

impl<'a> From<EntityWorldMut<'a>> for FilteredEntityMut<'a>

fn from(entity: EntityWorldMut<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<EntityWorldMut<'a>> for FilteredEntityRef<'a>

fn from(entity: EntityWorldMut<'a>) -> Self

Converts to this type from the input type.

impl<'w> From<EntityWorldMut<'w>> for EntityMut<'w>

fn from(value: EntityWorldMut<'w>) -> Self

Converts to this type from the input type.

impl<'w> From<EntityWorldMut<'w>> for EntityRef<'w>

fn from(entity_mut: EntityWorldMut<'w>) -> EntityRef<'w>

Converts to this type from the input type.