DOTS Looping Best Practice Help

Hi, I have my code working as posted below. However it seems really inefficient. Still a noob at DOTS so appreciate all advice, thanks.

Goal:
1. Each mage casts revive spell when cooldown reached.
2. Revive checks mage distance to every dead body and revives those in range.

Problem:
1. Every update loop I am updating the list of dead bodies and their positions, ideally I would only update this list when the spell is due to be cast. Is that possible?
2. I've noticed large Garbage Collection spikes, am I disposing of the NativeArrays correctly?

Code (CSharp):

1. using Unity.Collections;
2. using Unity.Entities;
3. using Unity.Jobs;
4. using Unity.Mathematics;
5. using Unity.Transforms;
6. using UnityEngine;
7.  
8.  
9. public struct Mage : IComponentData
10. {
11.     public float Cooldown, Timer;
12. }
13.  
14. public class MageAuthoring : MonoBehaviour, IConvertGameObjectToEntity
15. {
16.     [Tooltip("The time before they can cast <revive> again.")]
17.     public float Cooldown, Timer;
18.     public void Convert(Entity entity, EntityManager dstManager, GameObjectConversionSystem conversionSystem)
19.     {
20.         dstManager.AddComponentData(entity,
21.             new Mage
22.             {
23.                 Cooldown = Cooldown,
24.                 Timer = Timer
25.             });
26.     }
27. }
28.  
29. public class MageSystem : SystemBase
30. {
31.     EntityCommandBufferSystem Barrier;
32.     protected override void OnCreate()
33.     {
34.         Barrier = World.GetOrCreateSystem<EndSimulationEntityCommandBufferSystem>();
35.     }
36.  
37.     protected unsafe override void OnUpdate()
38.     {
39.         float deltaTime = Time.DeltaTime;
40.         var commandBuffer = Barrier.CreateCommandBuffer().ToConcurrent();
41.  
42.         NativeArray<Translation> deadPositions = GetEntityQuery(ComponentType.ReadOnly<LifeTime>(), typeof(Translation)).ToComponentDataArray<Translation>(Allocator.TempJob);
43.         NativeArray<Entity> deadPeople = GetEntityQuery(ComponentType.ReadOnly<LifeTime>()).ToEntityArray(Allocator.TempJob);
44.  
45.         Entities.ForEach((Entity entity, int entityInQueryIndex, ref Mage mage, in Translation trans) =>
46.         {
47.             float distance = 0;
48.             int i = 0;
49.             if (mage.Timer < mage.Cooldown)
50.             {
51.                 mage.Timer += deltaTime;
52.             }
53.             else
54.             {
55.                 mage.Timer = 0;
56.  
57.                 while (i < deadPositions.Length)
58.                 {
59.                     distance = math.distance(trans.Value, deadPositions[i].Value);
60.                     if (distance < 20)
61.                     {
62.                         commandBuffer.AddComponent<Reviving>(entityInQueryIndex, deadPeople[i]);
63.                         commandBuffer.RemoveComponent<LifeTime>(entityInQueryIndex, deadPeople[i]);
64.                     }
65.                     i++;
66.                 }
67.             }
68.         }).WithDeallocateOnJobCompletion(deadPositions).WithDeallocateOnJobCompletion(deadPeople).ScheduleParallel();
69.     }
70. }

 

Just a small feedback for the moment: It's a good idea to cache entity queries (such as

GetEntityQuery(ComponentType.ReadOnly<LifeTime>(), typeof(Translation))

) in instance variables in the OnCreate method. Otherwise it'll perform many entity query cache lookups.

 

Hi Florian, thanks for the feedback. The problem is that the entity query results are constantly changing. So it needs to be up to date for when the mage casts 'revive'.

 

The query is a query, not the results. Look at it as a database query – the results change based on the data it queries. But the query itself can be remembered (a standard pattern). I hope that helps