Struct Or

pub struct Or<T>(/* private fields */);

A filter that tests if any of the given filters apply.

This is useful for example if a system with multiple components in a query only wants to run when one or more of the components have changed.

The And equivalent to this filter is a tuple testing that all the contained filters apply instead.

Examples

fn print_cool_entity_system(query: Query<Entity, Or<(Changed<Color>, Changed<Node>)>>) {
    for entity in &query {
        println!("Entity {:?} got a new style or color", entity);
    }
}

Trait Implementations

impl QueryFilter for Or<()>

const IS_ARCHETYPAL: bool = true

Returns true if (and only if) this Filter relies strictly on archetypes to limit which components are accessed by the Query.

unsafe fn filter_fetch( fetch: &mut Self::Fetch<'_>, entity: Entity, table_row: TableRow, ) -> bool

Returns true if the provided Entity and TableRow should be included in the query results. If false, the entity will be skipped.

impl<F: QueryFilter> QueryFilter for Or<(F₁, F₂, …, Fₙ)>

This trait is implemented for tuples up to 16 items long.

const IS_ARCHETYPAL: bool = _

Returns true if (and only if) this Filter relies strictly on archetypes to limit which components are accessed by the Query.

unsafe fn filter_fetch( fetch: &mut Self::Fetch<'_>, entity: Entity, table_row: TableRow, ) -> bool

Returns true if the provided Entity and TableRow should be included in the query results. If false, the entity will be skipped.

impl WorldQuery for Or<()>

SAFETY: fetch accesses are a subset of the subqueries’ accesses This is sound because update_component_access adds accesses according to the implementations of all the subqueries. update_component_access replace the filters with a disjunction where every element is a conjunction of the previous filters and the filters of one of the subqueries. This is sound because matches_component_set returns a disjunction of the results of the subqueries’ implementations.

const IS_DENSE: bool = true

Returns true if (and only if) every table of every archetype matched by this fetch contains all of the matched components. This is used to select a more efficient “table iterator” for “dense” queries. If this returns true, WorldQuery::set_table must be used before WorldQuery::fetch can be called for iterators. If this returns false, WorldQuery::set_archetype must be used before WorldQuery::fetch can be called for iterators.

type Fetch<'w> = ()

Per archetype/table state used by this WorldQuery to fetch Self::Item

type Item<'w> = bool

The item returned by this WorldQuery For QueryData this will be the item returned by the query. For QueryFilter this will be either (), or a bool indicating whether the entity should be included or a tuple of such things.

type State = ()

State used to construct a Self::Fetch. This will be cached inside QueryState, so it is best to move as much data / computation here as possible to reduce the cost of constructing Self::Fetch.

fn shrink<'wlong: 'wshort, 'wshort>( item: Self::Item<'wlong>, ) -> Self::Item<'wshort>

This function manually implements subtyping for the query items.

fn shrink_fetch<'wlong: 'wshort, 'wshort>( fetch: Self::Fetch<'wlong>, ) -> Self::Fetch<'wshort>

This function manually implements subtyping for the query fetches.

unsafe fn init_fetch<'w>( world: UnsafeWorldCell<'w>, state: &Self::State, last_run: Tick, this_run: Tick, ) -> Self::Fetch<'w>

Creates a new instance of this fetch.

unsafe fn set_table<'w>( fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table, )

Adjusts internal state to account for the next Table. This will always be called on tables that match this WorldQuery.

unsafe fn set_archetype<'w>( fetch: &mut Self::Fetch<'w>, state: &Self::State, archetype: &'w Archetype, table: &'w Table, )

Adjusts internal state to account for the next Archetype. This will always be called on archetypes that match this WorldQuery.

unsafe fn fetch<'w>( fetch: &mut Self::Fetch<'w>, _entity: Entity, _table_row: TableRow, ) -> Self::Item<'w>

Fetch Self::Item for either the given entity in the current Table, or for the given entity in the current Archetype. This must always be called after WorldQuery::set_table with a table_row in the range of the current Table or after WorldQuery::set_archetype with a entity in the current archetype.

fn update_component_access( state: &Self::State, access: &mut FilteredAccess<ComponentId>, )

Adds any component accesses used by this WorldQuery to access.

fn init_state(world: &mut World) -> Self::State

Creates and initializes a State for this WorldQuery type.

fn get_state(components: &Components) -> Option<Self::State>

Attempts to initialize a State for this WorldQuery type using read-only access to Components.

fn matches_component_set( _state: &Self::State, _set_contains_id: &impl Fn(ComponentId) -> bool, ) -> bool

Returns true if this query matches a set of components. Otherwise, returns false.

fn set_access(_state: &mut Self::State, _access: &FilteredAccess<ComponentId>)

Sets available accesses for implementors with dynamic access such as FilteredEntityRef or FilteredEntityMut.

impl<F: QueryFilter> WorldQuery for Or<(F₁, F₂, …, Fₙ)>

This trait is implemented for tuples up to 16 items long. SAFETY: fetch accesses are a subset of the subqueries’ accesses This is sound because update_component_access adds accesses according to the implementations of all the subqueries. update_component_access replace the filters with a disjunction where every element is a conjunction of the previous filters and the filters of one of the subqueries. This is sound because matches_component_set returns a disjunction of the results of the subqueries’ implementations.

const IS_DENSE: bool = _

Returns true if (and only if) every table of every archetype matched by this fetch contains all of the matched components. This is used to select a more efficient “table iterator” for “dense” queries. If this returns true, WorldQuery::set_table must be used before WorldQuery::fetch can be called for iterators. If this returns false, WorldQuery::set_archetype must be used before WorldQuery::fetch can be called for iterators.

type Fetch<'w> = (OrFetch<'w, F>,)

Per archetype/table state used by this WorldQuery to fetch Self::Item

type Item<'w> = bool

The item returned by this WorldQuery For QueryData this will be the item returned by the query. For QueryFilter this will be either (), or a bool indicating whether the entity should be included or a tuple of such things.

type State = (<F as WorldQuery>::State,)

State used to construct a Self::Fetch. This will be cached inside QueryState, so it is best to move as much data / computation here as possible to reduce the cost of constructing Self::Fetch.

fn shrink<'wlong: 'wshort, 'wshort>( item: Self::Item<'wlong>, ) -> Self::Item<'wshort>

This function manually implements subtyping for the query items.

fn shrink_fetch<'wlong: 'wshort, 'wshort>( fetch: Self::Fetch<'wlong>, ) -> Self::Fetch<'wshort>

This function manually implements subtyping for the query fetches.

unsafe fn init_fetch<'w>( world: UnsafeWorldCell<'w>, state: &Self::State, last_run: Tick, this_run: Tick, ) -> Self::Fetch<'w>

Creates a new instance of this fetch.

unsafe fn set_table<'w>( fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table, )

Adjusts internal state to account for the next Table. This will always be called on tables that match this WorldQuery.

unsafe fn set_archetype<'w>( fetch: &mut Self::Fetch<'w>, state: &Self::State, archetype: &'w Archetype, table: &'w Table, )

Adjusts internal state to account for the next Archetype. This will always be called on archetypes that match this WorldQuery.

unsafe fn fetch<'w>( fetch: &mut Self::Fetch<'w>, _entity: Entity, _table_row: TableRow, ) -> Self::Item<'w>

Fetch Self::Item for either the given entity in the current Table, or for the given entity in the current Archetype. This must always be called after WorldQuery::set_table with a table_row in the range of the current Table or after WorldQuery::set_archetype with a entity in the current archetype.

fn update_component_access( state: &Self::State, access: &mut FilteredAccess<ComponentId>, )

Adds any component accesses used by this WorldQuery to access.

fn init_state(world: &mut World) -> Self::State

Creates and initializes a State for this WorldQuery type.

fn get_state(components: &Components) -> Option<Self::State>

Attempts to initialize a State for this WorldQuery type using read-only access to Components.

fn matches_component_set( _state: &Self::State, _set_contains_id: &impl Fn(ComponentId) -> bool, ) -> bool

Returns true if this query matches a set of components. Otherwise, returns false.

fn set_access(_state: &mut Self::State, _access: &FilteredAccess<ComponentId>)

Sets available accesses for implementors with dynamic access such as FilteredEntityRef or FilteredEntityMut.

impl ArchetypeFilter for Or<()>

impl<F: ArchetypeFilter> ArchetypeFilter for Or<(F₁, F₂, …, Fₙ)>

This trait is implemented for tuples up to 16 items long.