A [NativeContainer] that provides access to all instances of components of type T, indexed by Entity.
ComponentLookup is a native container that provides array-like access to components of a specific
type. You can use ComponentLookup to look up data associated with one entity while iterating over a
different set of entities. For example, Unity.Transforms stores the Entity object of parent entities
in a Parent component and looks up the parent's LocalToWorld matrix using
ComponentLookup<LocalToWorld> when calculating the world positions of child entities.
To get a ComponentLookup, call ComponentSystemBase.GetComponentLookup.
Pass a ComponentLookup container to a job by defining a public field of the appropriate type
in your IJob implementation. You can safely read from ComponentLookup in any job, but by
default, you cannot write to components in the container in parallel jobs (including
IJobEntity, Entities.Foreach and IJobChunk). If you know that two instances of a parallel
job can never write to the same index in the container, you can disable the restriction on parallel writing
by adding [NativeDisableParallelForRestrictionAttribute] to the ComponentLookup field definition in the job struct.
If you would like to access an entity's components outside of a job, consider using the EntityManager methods
EntityManager.GetComponentData and EntityManager.SetComponentData
instead, to avoid the overhead of creating a ComponentLookup object.
[NativeContainer]: https://docs.unity3d.com/ScriptReference/Unity.Collections.LowLevel.Unsafe.NativeContainerAttribute
[NativeDisableParallelForRestrictionAttribute]: https://docs.unity3d.com/ScriptReference/Unity.Collections.NativeDisableParallelForRestrictionAttribute.html
| Property | Description |
|---|---|
| this[Entity] | Gets the IComponentData instance of type T for the specified entity. |
| Method | Description |
|---|---|
| DidChange | Reports whether any of IComponentData components of the type T, in the chunk containing the specified Entity, could have changed. |
| EntityExists | Reports whether the specified entity exists. Does not consider whether this component exists on the given entity. |
| GetEnabledRefRO | Gets a safe reference to the component enabled state. |
| GetEnabledRefROOptional | Gets a safe reference to the component enabled state. |
| GetEnabledRefRW | Gets a safe reference to the component enabled state. |
| GetEnabledRefRWOptional | Gets a safe reference to the component enabled state. |
| GetRefRO | Gets a safe reference to the component data. |
| GetRefRW | Gets a safe reference to the component data. |
| HasComponent | Reports whether the specified Entity instance still refers to a valid entity and that it has a component of type T. |
| IsComponentEnabled | Checks whether the IComponentData of type T is enabled on the specified Entity. For the purposes of EntityQuery matching, an entity with a disabled component will behave as if it does not have that component. The type T must implement the IEnableableComponent interface. |
| SetComponentEnabled | Enable or disable the IComponentData of type T on the specified system using a SystemHandle. This operation does not cause a structural change (even if it occurs on a worker thread), or affect the value of the component. For the purposes of EntityQuery matching, a system with a disabled component will behave as if it does not have that component. The type T must implement the IEnableableComponent interface. |
| TryGetComponent | Retrieves the component associated with the specified Entity, if it exists. Then reports if the instance still refers to a valid entity and that it has a component of type T. |
| TryGetRefRO | Attempts to get a safe reference to the component data, failing gracefully if the component isn't present. |
| TryGetRefRW | Attempts to get a safe reference to the component data, failing gracefully if the component isn't present. |
| Update | When a ComponentLookup is cached by a system across multiple system updates, calling this function inside the system's OnUpdate() method performs the minimal incremental updates necessary to make the type handle safe to use. |