koobas.hobune.stream
ECS/Dots: How do get combined data of component values/make this accessible to all entities?
I have lots of components that all have a float3 position property. I want the combined float3 of all of the components to be able to calculated, and I want the "combined positions" float3 to be accessible from all of the entities. How to do this?
Best Answer
Idea is to schedule jobs in such a way that you pass this data down the dependency stream:
public class CalculateAveragePositionSystem : SystemBase
{
EntityQuery _query;
NativeArray<float3> _averagePosition;
protected override void OnCreate ()
{
_query = EntityManager.CreateEntityQuery(
ComponentType.ReadOnly<AveragePositionSrc>()
, ComponentType.ReadOnly<LocalToWorld>()
);
_averagePosition = new NativeArray<float3>( 1 , Allocator.Persistent );
}
protected override void OnDestroy ()
{
_averagePosition.Dispose();
}
protected override void OnUpdate ()
{
NativeArray<LocalToWorld> ltrArray = _query.ToComponentDataArray<LocalToWorld>( Allocator.TempJob );
var averagePosition = _averagePosition;// alias
Job
.WithName("calculate_sum_job")
.WithDisposeOnCompletion( ltrArray )
.WithCode( ()=>
{
float3 vec = default(float3);
for( int i=0 ; i<ltrArray.Length ; i++ )
vec += ltrArray[i].Position;
vec /= (float)ltrArray.Length;
averagePosition[0] = vec;
} )
.WithBurst().Schedule();
Entities
.WithName("do_something_with_that_data_job")
.WithReadOnly( averagePosition )
.ForEach( ( ref AveragePositionDst averagePositionMarker ) =>
{
averagePositionMarker.Value = averagePosition[0];
} )
.WithBurst().ScheduleParallel();
}
}
public struct AveragePositionSrc : IComponentData {}
public struct AveragePositionDst : IComponentData { public float3 Value; }
Hello @emerz210, to combine multiple queries, you can pass an array of EntityQueryDesc. Check the below code example. The following example selects any archetypes that contain a RotationQuaternion component or a RotationSpeed component (or both):
var desc1 = new EntityQueryDesc
{
All = new ComponentType[] { typeof(RotationQuaternion) }
};
var desc2 = new EntityQueryDesc
{
All = new ComponentType[] { typeof(RotationSpeed) }
};
EntityQuery query
= GetEntityQuery(new EntityQueryDesc[] { desc1, desc2 });
This is a good answer for some very different question.
He wants to sum float3 values. Not merge EntityQuery instances.
