wave6-ecb-set-component-enabled

ECB.SetComponentEnabled — Deferred Parallel Enable/Disable

Intent

Record a deferred enable/disable command for an IEnableableComponent from a parallel job using ECB.SetComponentEnabled() with a deterministic sort key.

Use When

• Parallel IJobEntity or IJobChunk must conditionally enable/disable based on computed per-entity logic
• The target entity is different from the entity being iterated (cross-entity enable/disable)
• EnabledRefRW is not available because the component is on a different entity

Avoid When

• Toggle can happen on main thread immediately — use EntityManager.SetComponentEnabled (no deferred overhead)
• EnabledRefRW can be used inline on the same entity — cheaper, no one-frame delay

Senior Pattern

[BurstCompile]
public partial struct ActivateInRangeJob : IJobEntity
{
    public EntityCommandBuffer.ParallelWriter Ecb;
    public float3 Origin;
    public float RadiusSq;

    [BurstCompile]
    public void Execute(
        [ChunkIndexInQuery] int chunkIndex,
        Entity entity,
        in LocalTransform transform)
    {
        bool inRange = math.distancesq(transform.Position, Origin) <= RadiusSq;
        Ecb.SetComponentEnabled<ActiveBehavior>(chunkIndex, entity, inRange);
    }
}

// Schedule and playback:
[UpdateInGroup(typeof(SimulationSystemGroup))]
[BurstCompile]
public partial struct ActivationSystem : ISystem
{
    [BurstCompile]
    public void OnUpdate(ref SystemState state)
    {
        var ecb = SystemAPI.GetSingleton<EndSimulationEntityCommandBufferSystem.Singleton>()
                           .CreateCommandBuffer(state.WorldUnmanaged);

        state.Dependency = new ActivateInRangeJob
        {
            Ecb = ecb.AsParallelWriter(),
            Origin = SystemAPI.GetSingleton<PlayerPosition>().Value,
            RadiusSq = activationRadius * activationRadius
        }.ScheduleParallel(state.Dependency);
    }
}

Anti-Patterns

• Missing [ChunkIndexInQuery] sort key — non-deterministic ECB playback order; enableable state flips are order-dependent when multiple commands target same entity.
• Recording ECB.SetComponentEnabled on an entity that does not have T — exception at playback.
• Using ECB.SetComponentEnabled when EnabledRefRW is available on the same entity — ECB adds one-frame delay and playback cost unnecessarily.
• Using ECB.AddComponent/RemoveComponent instead of SetComponentEnabled for frequent toggles — structural change; 10-100x more expensive at playback.