Struct EntityArchetype

An EntityArchetype is a unique combination of component types. The EntityManager uses the archetype to group all entities that have the same sets of components.

Namespace: Unity.Entities

Assembly: Unity.Entities.dll

Syntax

public struct EntityArchetype

Remarks

An entity can change archetype fluidly over its lifespan. For example, when you add or remove components, the archetype of the affected entity changes.

An archetype object is not a container; rather it is an identifier to each unique combination of component types that an application has created at run time, either directly or implicitly.

You can create archetypes directly using CreateArchetype(params ComponentType[]). You also implicitly create archetypes whenever you add or remove a component from an entity. An EntityArchetype object is an immutable singleton; creating an archetype with the same set of components, either directly or implicitly, results in the same archetype for a given EntityManager.

The ECS framework uses archetypes to group entities that have the same structure together. The ECS framework stores component data in blocks of memory called chunks. A given chunk stores only entities having the same archetype. You can get the EntityArchetype object for a chunk from its Archetype property.

Instead of using new EntityArchetype(), use EntityManager.CreateArchetype() to create EntityArchetype values.

Properties

Name	Description
ChunkCapacity	The number of entities having this archetype that can fit into a single chunk of memory.
ChunkCount	The current number of chunks storing entities having this archetype.
Disabled	Reports whether this EntityArchetype instance contains disabled entities.
Prefab	Reports whether this EntityArchetype instance describes a Prefab.
StableHash	Retrieve the stable hash for this EntityArchetype.
TypesCount	The number of component types this archetype contains.
Valid	Reports whether this EntityArchetype instance references a non-null archetype.

Methods

Name	Description
CalculateDifference(EntityArchetype, EntityArchetype, TypeIndex*, out int, TypeIndex*, out int)	Calculates the difference between two archetypes. Reports what components need to be added to and removed from "before" in order to convert it to "after".
Equals(object)	Reports whether this EntityArchetype references the same archetype as another object.
Equals(EntityArchetype)	Compares archetypes for equality.
GetComponentTypes(Allocator)	Gets the types of the components making up this archetype.
GetComponentTypes(AllocatorHandle)	Gets the types of the components making up this archetype.
GetHashCode()	Returns the hash of the archetype.
ToString()	Construct a string representation of this archetype, for logging or debugging.

Operators

Name	Description
operator ==(EntityArchetype, EntityArchetype)	Compares the archetypes for equality.
operator !=(EntityArchetype, EntityArchetype)	Compares the archetypes for inequality.