wave8-ijobchunk-use-enabled-mask-guard

IJobChunk useEnabledMask Guard

Intent

Correctly handle the enableable component bitmask in IJobChunk to avoid processing disabled entities or skipping enabled ones.

Use When

• An IJobChunk implementation iterates over chunks that contain one or more IEnableableComponent types
• The query includes any component that implements IEnableableComponent

Avoid When

• The job uses IJobEntity — IJobEntity handles the enableable mask automatically; this guard is only needed in IJobChunk
• No IEnableableComponent types are in the query — useEnabledMask will always be false; the fast path handles all entities

Senior Pattern

[BurstCompile]
public struct ProcessActiveEntitiesJob : IJobChunk
{
    public ComponentTypeHandle<Velocity> VelocityHandle;
    [ReadOnly] public ComponentTypeHandle<ActiveTag> ActiveTagHandle;  // IEnableableComponent
    [ReadOnly] public EntityTypeHandle EntityHandle;

    [BurstCompile]
    public void Execute(in ArchetypeChunk chunk, int unfilteredChunkIndex,
        bool useEnabledMask, in v128 chunkEnabledMask)
    {
        var velocities = chunk.GetNativeArray(ref VelocityHandle);

        if (useEnabledMask)
        {
            // Some entities in chunk may be disabled — iterate only enabled ones:
            var enumerator = new ChunkEntityEnumerator(useEnabledMask, chunkEnabledMask, chunk.Count);
            while (enumerator.NextEntityIndex(out int i))
            {
                velocities[i] = new Velocity { Value = velocities[i].Value * 0.9f };
            }
        }
        else
        {
            // All entities in chunk are enabled — iterate all without mask overhead:
            for (int i = 0; i < chunk.Count; i++)
            {
                velocities[i] = new Velocity { Value = velocities[i].Value * 0.9f };
            }
        }
    }
}

// Schedule — query includes IEnableableComponent type:
EntityQuery query = state.GetEntityQuery(
    ComponentType.ReadWrite<Velocity>(),
    ComponentType.ReadOnly<ActiveTag>());

state.Dependency = new ProcessActiveEntitiesJob
{
    VelocityHandle  = state.GetComponentTypeHandle<Velocity>(),
    ActiveTagHandle = state.GetComponentTypeHandle<ActiveTag>(isReadOnly: true),
    EntityHandle    = state.GetEntityTypeHandle()
}.ScheduleParallel(query, state.Dependency);