Struct EntityQuery

Use an EntityQuery object to select entities with components that meet specific requirements.

Namespace: Unity.Entities
Assembly: Unity.Entities.dll
Syntax
public struct EntityQuery
Remarks

An entity query defines the set of component types that an archetype must contain in order for its chunks and entities to be selected and specifies whether the components accessed through the query are read-only or read-write.

For simple queries, you can create an EntityQuery based on an array of component types. The following example defines a EntityQuery that finds all entities with both Rotation and RotationSpeed components.

EntityQuery query = GetEntityQuery(typeof(ObjectRotation),
    ComponentType.ReadOnly<ObjectRotationSpeed>());

The query uses ComponentType.ReadOnly instead of the simpler typeof expression to designate that the system does not write to RotationSpeed. Always specify read-only when possible, since there are fewer constraints on read-only access to data, which can help the Job scheduler execute your Jobs more efficiently.

For more complex queries, you can use an EntityQueryDesc object to create the entity query. A query description provides a flexible query mechanism to specify which archetypes to select based on the following sets of components:

  • All = All component types in this array must exist in the archetype, and must be enabled on matching entities.
  • Any = At least one of the component types in this array must exist in the archetype, and must be enabled on matching entities.
  • None = None of the component types in this array can exist in the archetype, or they must be present and disabled on matching entities.
  • Disabled = All component types in this array must exist in the archetype, and must be disabled on matching entities.
  • Absent = None of the component types in this array can exist in the archetype
  • Present = All of the component types in this array must exist in the archetype, whether or not they are enabled.

For example, the following query includes archetypes containing Rotation and RotationSpeed components, but excludes any archetypes containing a Static component:

EntityQueryDesc description = new EntityQueryDesc
{
    None = new ComponentType[]
    {
        typeof(Static)
    },
    All = new ComponentType[]
    {
        typeof(ObjectRotation),
        ComponentType.ReadOnly<ObjectRotationSpeed>()
    }
};
EntityQuery query = GetEntityQuery(description);

Note: Do not include completely optional components in the query description. To handle optional components, use IJobChunk and the ArchetypeChunk.Has() method to determine whether a chunk contains the optional component or not. Since all entities within the same chunk have the same components, you only need to check whether an optional component exists once per chunk -- not once per entity.

Within a system class, use the ComponentSystemBase.GetEntityQuery() function to get a EntityQuery instance.

You can filter entities based on whether they have changed or whether they have a specific value for a shared component. Once you have created an EntityQuery object, you can reset and change the filter settings, but you cannot modify the base query.

Use an EntityQuery for the following purposes:

Note that Entities.ForEach defines an entity query implicitly based on the methods you call. You can access this implicit EntityQuery object using Entities.WithStoreEntityQueryInField. However, you cannot create an Entities.ForEach construction based on an existing EntityQuery object.

Properties

Name Description
IsEmpty

Reports whether this query would currently select zero entities.
IsEmptyIgnoreFilter

Reports whether this query would currently select zero entities. This will ignore any filters set on the EntityQuery.

Methods

Name Description
AddChangedVersionFilter(ComponentType)

Filters out entities in chunks for which the specified component has not changed. Additive with other filter functions.
AddDependency(JobHandle)

Adds another job handle to this EntityQuery's dependencies.
AddOrderVersionFilter()

Filters out entities in chunks for which no structural changes have occurred. Additive with other filter functions.
AddSharedComponentFilterManaged<SharedComponent>(SharedComponent)

Filters this EntityQuery so that it only selects entities with a shared component of type SharedComponent equal to sharedComponent. Additive with other filter functions.
AddSharedComponentFilter<SharedComponent>(SharedComponent)

Filters this EntityQuery so that it only selects entities with an unmanaged shared component of type SharedComponent equal to sharedComponent. Additive with other filter functions.
CalculateBaseEntityIndexArray(AllocatorHandle)

Generates an array containing the index of the first entity within each chunk, relative to the list of entities that match this query.
CalculateBaseEntityIndexArrayAsync(AllocatorHandle, JobHandle, out JobHandle)

Asynchronously generates an array containing the index of the first entity within each chunk, relative to the list of entities that match this query.
CalculateChunkCount()

Calculates the number of chunks that match this EntityQuery, taking into account all active query filters and enabled components.
CalculateChunkCountWithoutFiltering()

Calculates the number of chunks that match this EntityQuery, ignoring any set filters.
CalculateEntityCount()

Calculates the number of entities selected by this EntityQuery.
CalculateEntityCountWithoutFiltering()

Calculates the number of entities selected by this EntityQuery, ignoring any set filters.
CalculateFilteredChunkIndexArray(AllocatorHandle)

Generates an array which gives the index of each chunk relative to the set of chunks that currently match the query, after taking all active filtering into account.
CalculateFilteredChunkIndexArrayAsync(AllocatorHandle, JobHandle, out JobHandle)

Asynchronously generates an array which gives the index of each chunk relative to the set of chunks that currently match the query, after taking all active filtering into account.
CompareComponents(NativeArray<ComponentType>)

Obsolete. Use CompareQuery(in EntityQueryBuilder) instead.
CompareComponents(ComponentType[])

Obsolete. Use CompareQuery(in EntityQueryBuilder) instead.
CompareQuery(in EntityQueryBuilder)

Compares a query description to the description defining this EntityQuery.
CompleteDependency()

Ensures all jobs running on this EntityQuery complete.
CopyFromComponentDataArrayAsync<T>(NativeArray<T>, out JobHandle)

Obsolete. Use CopyFromComponentDataListAsync<T>(NativeList<T>, out JobHandle) instead.
CopyFromComponentDataArray<T>(NativeArray<T>)

Copies the values of component type T in a NativeArray into the entities matched by this query.
CopyFromComponentDataListAsync<T>(NativeList<T>, JobHandle, out JobHandle)

Asynchronously copies the values of component type T in a NativeList into the entities matched by this query.
CopyFromComponentDataListAsync<T>(NativeList<T>, out JobHandle)

Asynchronously copies the values of component type T in a NativeList into the entities matched by this query.
CreateArchetypeChunkArray(AllocatorHandle)

Obsolete. Use ToArchetypeChunkArray(AllocatorHandle) instead.
CreateArchetypeChunkArrayAsync(AllocatorHandle, out JobHandle)

Obsolete. Use ToArchetypeChunkListAsync(AllocatorHandle, out JobHandle) instead.
Dispose()

Disposes this EntityQuery instance.
Equals(object)

Compare a query to another object (assumed to be a boxed EntityQuery).
Equals(EntityQuery)

Compare two queries for equality.
GetCombinedComponentOrderVersion()

Gets the version for the combined components in this EntityQuery.
GetDependency()

Combines all dependencies in this EntityQuery into a single JobHandle.
GetEntityQueryDesc()

Returns an EntityQueryDesc, which can be used to re-create the EntityQuery.
GetEntityQueryMask()

Returns an EntityQueryMask, which can be used to quickly determine if an entity matches the query.
GetHashCode()

Compute the hash code for this query
GetSingletonBuffer<T>(bool)

Gets the value of a singleton buffer component. Note that if querying a singleton buffer component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
GetSingletonEntity()

Attempts to retrieve the single entity that this query matches.
GetSingletonRW<T>()

Gets the value of a singleton component. Note that if querying a singleton component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
GetSingleton<T>()

Gets the value of a singleton component. Note that if querying a singleton component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
HasFilter()

Reports whether this entity query has a filter applied to it.
HasSingleton<T>()

Checks whether a singelton component of the specified type exists. Note that if querying a singleton component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
Matches(Entity)

Returns true if the entity matches the query, false if it does not.
MatchesIgnoreFilter(Entity)

Returns true if the entity's archetype is matched by this query, ignoring all query filtering (including chunk filters and enableable components).
MatchesNoFilter(Entity)

Obsolete. Use MatchesIgnoreFilter(Entity) instead.
ResetFilter()

Resets this EntityQuery's chunk filter settings to the default (all filtering disabled).
SetChangedVersionFilter(ComponentType)

Filters out entities in chunks for which the specified component has not changed.
SetChangedVersionFilter(ComponentType[])

Filters out entities in chunks for which the specified component has not changed.
SetEnabledBitsOnAllChunks<T>(bool)

Obsolete. Use SetComponentEnabled<T>(EntityQuery, bool) instead.
SetOrderVersionFilter()

Filters out entities in chunks for which no structural changes have occurred.
SetSharedComponentFilterManaged<SharedComponent>(SharedComponent)

Filters this EntityQuery so that it only selects entities with a shared component of type SharedComponent equal to sharedComponent.
SetSharedComponentFilterManaged<SharedComponent1, SharedComponent2>(SharedComponent1, SharedComponent2)

Filters this EntityQuery based on the values of two separate shared components.
SetSharedComponentFilter<SharedComponent>(SharedComponent)

Filters this EntityQuery so that it only selects entities with shared component of type SharedComponent equal to sharedComponent.
SetSharedComponentFilter<SharedComponent1, SharedComponent2>(SharedComponent1, SharedComponent2)

Filters this EntityQuery based on the values of two separate unmanaged shared components.
SetSingleton<T>(T)

Sets the value of a singleton component. Note that if querying a singleton component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
ToArchetypeChunkArray(AllocatorHandle)

Synchronously creates an array of the chunks containing entities matching this EntityQuery.
ToArchetypeChunkList(NativeList<ArchetypeChunk>)

Synchronously fills a list with the chunks containing entities matching this EntityQuery.
ToArchetypeChunkListAsync(AllocatorHandle, JobHandle, out JobHandle)

Asynchronously creates a list of the chunks containing entities matching this EntityQuery.
ToArchetypeChunkListAsync(AllocatorHandle, out JobHandle)

Asynchronously creates a list of the chunks containing entities matching this EntityQuery.
ToComponentDataArrayAsync<T>(AllocatorHandle, out JobHandle)

Obsolete. Use ToComponentDataListAsync<T>(AllocatorHandle, out JobHandle) instead.
ToComponentDataArray<T>()

Creates a managed array containing the components of type T for the selected entities.
ToComponentDataArray<T>(AllocatorHandle)

Creates a NativeArray containing the components of type T for the selected entities.
ToComponentDataListAsync<T>(AllocatorHandle, JobHandle, out JobHandle)

Creates (and asynchronously populates) a NativeList containing the value of component T for the selected entities. Since the exact number of entities matching the query won't be known until the job runs, this method returns a Unity.Collections.NativeList<T>.
ToComponentDataListAsync<T>(AllocatorHandle, out JobHandle)

Creates (and asynchronously populates) a NativeList containing the value of component T for the selected entities. Since the exact number of entities matching the query won't be known until the job runs, this method returns a Unity.Collections.NativeList<T>.
ToEntityArray(AllocatorHandle)

Creates a NativeArray containing the selected entities.
ToEntityArrayAsync(AllocatorHandle, out JobHandle)

Obsolete. Use ToEntityListAsync(AllocatorHandle, out JobHandle) instead.
ToEntityListAsync(AllocatorHandle, JobHandle, out JobHandle)

Creates (and asynchronously populates) a NativeList containing the selected entities. Since the exact number of entities matching the query won't be known until the job runs, this method returns a Unity.Collections.NativeList<T>.
ToEntityListAsync(AllocatorHandle, out JobHandle)

Creates (and asynchronously populates) a NativeList containing the selected entities. Since the exact number of entities matching the query won't be known until the job runs, this method returns a Unity.Collections.NativeList<T>.
TryGetSingletonBuffer<T>(out DynamicBuffer<T>, bool)

Gets the value of a singleton buffer component, and returns whether or not a singleton buffer component of the specified type exists in the World. Note that if querying a singleton buffer component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
TryGetSingletonEntity<T>(out Entity)

Gets the singleton Entity, and returns whether or not a singleton Entity of the specified type exists in the World.
TryGetSingletonRW<T>(out RefRW<T>)

Gets a reference to the value of a singleton component, and returns whether or not a singleton component of the specified type matches inside the EntityQuery. Note that if querying a singleton component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.
TryGetSingleton<T>(out T)

Gets the value of a singleton component, and returns whether or not a singleton component of the specified type matches inside the EntityQuery. Note that if querying a singleton component from a system-associated entity, the query must include either EntityQueryOptions.IncludeSystems or the SystemInstance component.

Operators

Name Description
operator ==(EntityQuery, EntityQuery)

Test two queries for equality
operator !=(EntityQuery, EntityQuery)

Test two queries for inequality

Extension Methods