Interface IJobChunk

IJobChunk is a type of Job that iterates over a set of ArchetypeChunk instances.

Namespace: Unity.Entities

Syntax

[JobProducerType(typeof(JobChunkExtensions.JobChunkProducer<>))]
public interface IJobChunk

Remarks

Create and schedule an IJobChunk Job inside the OnUpdate() function of a SystemBase implementation. The Job component system calls the Execute function once for each ArchetypeChunk found by the EntityQuery used to schedule the Job.

To pass data to the Execute function beyond the parameters of the Execute() function, add public fields to the IJobChunk struct declaration and set those fields immediately before scheduling the Job. You must pass the component type information for any components that the Job reads or writes using a field of type, ArchetypeChunkComponentType<T>. Get this type information by calling the appropriate GetArchetypeChunkComponentType<T>(Boolean) function for the type of component.

For more information see Using IJobChunk.

    [GenerateAuthoringComponent]
public struct Target : IComponentData
{
   public Entity entity;
}

public class ChaserSystem : SystemBase
{
   private EntityQuery query; // Initialized in Oncreate()

   [BurstCompile]
   private struct ChaserSystemJob : IJobChunk
   {
       // Read-write data in the current chunk
       public ArchetypeChunkComponentType<Translation> PositionTypeAccessor;

       // Read-only data in the current chunk
       [ReadOnly]
       public ArchetypeChunkComponentType<Target> TargetTypeAccessor;

       // Read-only data stored (potentially) in other chunks
       [ReadOnly]
       //[NativeDisableParallelForRestriction]
       public ComponentDataFromEntity<LocalToWorld> EntityPositions;

       // Non-entity data
       public float deltaTime;

       public void Execute(ArchetypeChunk chunk, int chunkIndex, int firstEntityIndex)
       {
           NativeArray<Translation> positions = chunk.GetNativeArray<Translation>(PositionTypeAccessor);
           NativeArray<Target> targets = chunk.GetNativeArray<Target>(TargetTypeAccessor);

           for (int i = 0; i < positions.Length; i++)
           {
               Entity targetEntity = targets[i].entity;
               float3 targetPosition = EntityPositions[targetEntity].Position;
               float3 chaserPosition = positions[i].Value;

               float3 displacement = (targetPosition - chaserPosition);
               positions[i] = new Translation { Value = chaserPosition + displacement * deltaTime };
           }
       }
   }

   protected override void OnCreate()
   {
       query = this.GetEntityQuery(typeof(Translation), ComponentType.ReadOnly<Target>());
   }

   protected override void OnUpdate()
   {
       var job = new ChaserSystemJob();
       job.PositionTypeAccessor = this.GetArchetypeChunkComponentType<Translation>(false);
       job.TargetTypeAccessor = this.GetArchetypeChunkComponentType<Target>(true);

       job.EntityPositions = this.GetComponentDataFromEntity<LocalToWorld>(true);
       job.deltaTime = this.Time.DeltaTime;

       this.Dependency = job.Schedule(query, this.Dependency);
   }
}

Methods

Execute(ArchetypeChunk, Int32, Int32)

Implement the Execute() function to perform a unit of work on an ArchetypeChunk.

Declaration

void Execute(ArchetypeChunk chunk, int chunkIndex, int firstEntityIndex)

Parameters

Type	Name	Description
ArchetypeChunk	chunk	The current chunk.
Int32	chunkIndex	The index of the current chunk within the list of all chunks found by the Job's EntityQuery. Note that chunks are not processed in index order, except by chance.
Int32	firstEntityIndex	The index of the first entity in the current chunk within the list of all entities in all the chunks found by the Job's EntityQuery.

Remarks

The Job component system calls the Execute function once for each EntityArchetype found by the EntityQuery used to schedule the Job.