Struct SystemState

Contains raw entity system state. Used by unmanaged systems (ISystemBase) as well as managed systems behind the scenes.

Namespace: Unity.Entities

Syntax

public struct SystemState

Properties

DebugName

Return a debug name for unmanaged systems.

Declaration

public FixedString64 DebugName { get; }

Property Value

Type	Description
FixedString64

Dependency

The ECS-related data dependencies of the system.

Declaration

public JobHandle Dependency { get; set; }

Property Value

Type	Description
JobHandle

Remarks

Before , the Dependency property represents the combined job handles of any job that writes to the same components that the current system reads -- or reads the same components that the current system writes to. When you use Entities.ForEach or Job.WithCode, the system uses the Dependency property to specify a job’s dependencies when scheduling it. The system also combines the new job's JobHandle with Dependency so that any subsequent job scheduled in the system depends on the earlier jobs (in sequence).

You can opt out of this default dependency management by explicitly passing a JobHandle to Entities.ForEach or Job.WithCode. When you pass in a JobHandle, these constructions also return a JobHandle representing the input dependencies combined with the new job. The JobHandle objects of any jobs scheduled with explicit dependencies are not combined with the system’s Dependency property. You must set the Dependency property manually to make sure that later systems receive the correct job dependencies.

You can combine implicit and explicit dependency management (by using JobHandle.CombineDependencies); however, doing so can be error prone. When you set the Dependency property, the assigned JobHandle replaces any existing dependency, it is not combined with them.

Note that the default, implicit dependency management does not include IJobChunk jobs. You must manage the dependencies for IJobChunk explicitly.

Enabled

Controls whether this system executes when its OnUpdate function is called.

Declaration

public bool Enabled { get; set; }

Property Value

Type	Description
Boolean	True, if the system is enabled.

Remarks

The Enabled property is intended for debugging so that you can easily turn on and off systems from the Entity Debugger window. A system with Enabled set to false will not update, even if its Unity.Entities.SystemState.ShouldRunSystem function returns true.

EntityManager

The EntityManager object of the World in which this system exists.

Declaration

public EntityManager EntityManager { get; }

Property Value

Type	Description
EntityManager	The EntityManager for this system.

GlobalSystemVersion

The current change version number in this World.

Declaration

public uint GlobalSystemVersion { get; }

Property Value

Type	Description
UInt32

Remarks

The system updates the component version numbers inside any ArchetypeChunk instances that this system accesses with write permissions to this value.

LastSystemVersion

The current version of this system.

Declaration

public uint LastSystemVersion { get; }

Property Value

Type	Description
UInt32	The GlobalSystemVersion the last time this system ran.

Remarks

LastSystemVersion is updated to match the GlobalSystemVersion whenever a system runs.

When you use SetChangedVersionFilter(ComponentType) or DidChange(DynamicComponentTypeHandle, UInt32), LastSystemVersion provides the basis for determining whether a component could have changed since the last time the system ran.

When a system accesses a component and has write permission, it updates the change version of that component type to the current value of LastSystemVersion. The system updates the component type's version whether or not it actually modifies data in any instances of the component type -- this is one reason why you should specify read-only access to components whenever possible.

For efficiency, ECS tracks the change version of component types by chunks, not by individual entities. If a system updates the component of a given type for any entity in a chunk, then ECS assumes that the components of all entities in that chunk could have been changed. Change filtering allows you to save processing time by skipping all entities in an unchanged chunk, but does not support skipping individual entities in a chunk that does contain changes.

Time

The current Time data for this system's world.

Declaration

public TimeData Time { get; }

Property Value

Type	Description
TimeData

UnmanagedMetaIndex

Return the unmanaged type index of the system (>= 0 for ISystemBase-type systems), or -1 for managed systems.

Declaration

public int UnmanagedMetaIndex { get; }

Property Value

Type	Description
Int32

World

The World in which this system exists.

Declaration

public World World { get; }

Property Value

Type	Description
World	The World of this system.

WorldUnmanaged

The unmanaged portion of the world in which this system exists.

Declaration

public WorldUnmanaged WorldUnmanaged { get; }

Property Value

Type	Description
WorldUnmanaged	The unmanaged world of this system.

Methods

CompleteDependency()

Declaration

public void CompleteDependency()

GetBufferTypeHandle<T>(Boolean)

Gets the run-time type information required to access an array of buffer components in a chunk.

Declaration

public BufferTypeHandle<T> GetBufferTypeHandle<T>(bool isReadOnly = false)
    where T : struct, IBufferElementData

Parameters

Type	Name	Description
Boolean	isReadOnly	Whether the data is only read, not written. Access data as read-only whenever possible.

Returns

Type	Description
BufferTypeHandle<T>	An object representing the type information required to safely access buffer components stored in a chunk.

Type Parameters

Name	Description
T	A struct that implements IBufferElementData.

Remarks

Pass a BufferTypeHandle instance to a job that has access to chunk data, such as an IJobChunk job, to access that type of buffer component inside the job.

GetComponentTypeHandle<T>(Boolean)

Gets the run-time type information required to access an array of component data in a chunk.

Declaration

public ComponentTypeHandle<T> GetComponentTypeHandle<T>(bool isReadOnly = false)
    where T : struct, IComponentData

Parameters

Type	Name	Description
Boolean	isReadOnly	Whether the component data is only read, not written. Access components as read-only whenever possible.

Returns

Type	Description
ComponentTypeHandle<T>	An object representing the type information required to safely access component data stored in a chunk.

Type Parameters

Name	Description
T	A struct that implements IComponentData.

Remarks

Pass an ComponentTypeHandle<T> instance to a job that has access to chunk data, such as an IJobChunk job, to access that type of component inside the job.

GetDynamicComponentTypeHandle(ComponentType)

Gets the run-time type information required to access an array of component data in a chunk.

Declaration

public DynamicComponentTypeHandle GetDynamicComponentTypeHandle(ComponentType componentType)

Parameters

Type	Name	Description
ComponentType	componentType	Type of the component

Returns

Type	Description
DynamicComponentTypeHandle	An object representing the type information required to safely access component data stored in a chunk.

Remarks

Pass an DynamicComponentTypeHandle instance to a job that has access to chunk data, such as an IJobChunk job, to access that type of component inside the job.

GetEntityQuery(NativeArray<ComponentType>)

Gets the cached query for the specified component types, if one exists; otherwise, creates a new query instance and caches it.

Declaration

public EntityQuery GetEntityQuery(NativeArray<ComponentType> componentTypes)

Parameters

Type	Name	Description
NativeArray<ComponentType>	componentTypes	An array of component types.

Returns

Type	Description
EntityQuery	The new or cached query.

GetEntityQuery(ComponentType[])

Gets the cached query for the specified component types, if one exists; otherwise, creates a new query instance and caches it.

Declaration

public EntityQuery GetEntityQuery(params ComponentType[] componentTypes)

Parameters

Type	Name	Description
ComponentType[]	componentTypes	An array or comma-separated list of component types.

Returns

Type	Description
EntityQuery	The new or cached query.

GetEntityQuery(EntityQueryDesc[])

Combines an array of query description objects into a single query.

Declaration

public EntityQuery GetEntityQuery(params EntityQueryDesc[] queryDesc)

Parameters

Type	Name	Description
EntityQueryDesc[]	queryDesc	An array of query description objects to be combined to define the query.

Returns

Type	Description
EntityQuery	The new or cached query.

Remarks

This function looks for a cached query matching the combined query descriptions, and returns it if one exists; otherwise, the function creates a new query instance and caches it.

GetEntityTypeHandle()

Gets the run-time type information required to access the array of Entity objects in a chunk.

Declaration

public EntityTypeHandle GetEntityTypeHandle()

Returns

Type	Description
EntityTypeHandle	An object representing the type information required to safely access Entity instances stored in a chunk.

GetSharedComponentTypeHandle<T>()

Gets the run-time type information required to access a shared component data in a chunk.

Declaration

public SharedComponentTypeHandle<T> GetSharedComponentTypeHandle<T>()
    where T : struct, ISharedComponentData

Returns

Type	Description
SharedComponentTypeHandle<T>	An object representing the type information required to safely access shared component data stored in a chunk.

Type Parameters

Name	Description
T	A struct that implements ISharedComponentData.