DOTS ForEach in ForEach

Questions & Answers
,
1

I am looking for something like this

Entities.ForEach((Component1 c1, Translation t1) =>
{
	Entities.ForEach((Component2 c2, Translation t2) =>
	{
		// create job to calculate c1/c2 stuff and apply result to translations
	}).Schedule();    
}).Schedule();

of course, i want it with burst but right now i am interested just in having this working with jobs to start somewhere
if anybody can help with some example or tutorial I’d be glad

2

Make sure it won’t approach O(n²) or will scale badly² otherwise.

public struct Component1 : IComponentData{ public int Value; }
public struct Component2 : IComponentData{ public int Value; }
public class MySystem : SystemBase
{
    EndSimulationEntityCommandBufferSystem _endSimulationEcbSystem;
    EntityQuery _query2;
    protected override void OnCreate ()
    {
        _endSimulationEcbSystem = World.GetOrCreateSystem<EndSimulationEntityCommandBufferSystem>();
        _query2 = EntityManager.CreateEntityQuery(
                ComponentType.ReadWrite<Translation>()
            ,	ComponentType.ReadOnly<Component2>()
        );
    }
    protected override void OnUpdate ()
    {
        var command = _endSimulationEcbSystem.CreateCommandBuffer().AsParallelWriter();
        var translationData = GetComponentDataFromEntity<Translation>( isReadOnly:true );
        var component2Data = GetComponentDataFromEntity<Component2>( isReadOnly:true );
        NativeArray<Entity> entities2 = _query2.ToEntityArray( Allocator.TempJob );

        Entities
            .WithName("my_job")
            .WithReadOnly(translationData)
            .WithReadOnly(component2Data)
            .WithReadOnly(entities2).WithDisposeOnCompletion(entities2)
            .ForEach( ( in int entityInQueryIndex , in Translation translation , in Component1 component1 , in Entity entity )=>
            {
                float3 newPos = translation.Value;
                for( int i=0 ; i<entities2.Length ; i++ )
                {
                    Entity otherEntity = entities2*;*
                float3 otherPos = translationData[otherEntity].Value;*
                Component2 component2 = component2Data[otherEntity];*
                /* calculations */
            }
            command.SetComponent<Translation>( entityInQueryIndex , entity , new Translation{
                Value = newPos
            } );
        } )
        .WithBurst().ScheduleParallel();

        _endSimulationEcbSystem.AddJobHandleForProducer( Dependency );
    }
}