Access dynamic buffers from jobs

If a job needs to lookup one or more buffers in its code, the job needs to use a BufferLookup lookup table. You create these in systems and then pass them to jobs that need them.

Modify the job

In the job that requires random access to a dynamic buffer:

1. Add a ReadOnly BufferLookup member variable.
2. In the IJobEntity.Execute method, index the BufferLookup lookup table by an entity. This provides access to the dynamic buffer attached to the entity.

public partial struct AccessDynamicBufferJob : IJobEntity
{
    [ReadOnly] public BufferLookup<ExampleBufferComponent> BufferLookup;
    public void Execute()
    {
        // ...
    }
}

Modify the systems

In systems that create instances of the job:

1. Add a BufferLookup member variable.
2. In OnCreate, use SystemState.GetBufferLookup to assign the BufferLookup variable.
3. At the beginning of OnUpdate, call Update on the BufferLookup variable. This updates the lookup table.
4. When you create an instance of the job, pass the lookup table to the job.

public partial struct AccessDynamicBufferFromJobSystem : ISystem
{
    private BufferLookup<ExampleBufferComponent> _bufferLookup;

    public void OnCreate(ref SystemState state)
    {
        _bufferLookup = state.GetBufferLookup<ExampleBufferComponent>(true);
    }

    public void OnUpdate(ref SystemState state)
    {
        _bufferLookup.Update(ref state);
        var exampleBufferAccessJob = new AccessDynamicBufferJob { BufferLookup = _bufferLookup };
        exampleBufferAccessJob.ScheduleParallel();
    }
}