DeltaECS.Systems 0.0.35

DeltaECS.Systems

DeltaECS.Systems runs world-bound systems in deterministic dependency batches. Systems that only access different component ids can run together; structural and unknown world access forms an exclusive phase.

The package contains the runtime contract and scheduler. When a system is declared as a top-level partial class, the DeltaECS generator collects its generated API calls and supplies the Access property automatically. Keep an explicit Access property when the access set is dynamic or comes from an external source. Explicit ComponentId selectors and calls outside the generated API are treated as unknown access, so the scheduler keeps them in an exclusive phase.

using Delta.ECS;
using Delta.ECS.Systems;

using var world = new World();
world.Layouts.Register<Velocity>(new SchemaId(1));
world.Layouts.Register<Position>(new SchemaId(2));

Query movementQuery = world.WhereAll<Position, Velocity>();
Entity mover = world.Create<Position>();
world.Add(mover, new Velocity());

using var scheduler = new SystemScheduler(world);
var movement = new MovementSystem(movementQuery) { World = world };
scheduler.Add(movement);
scheduler.Tick();

public partial class MovementSystem : ISystem
{
    private readonly Query _query;

    public World World { get; init; } = null!;

    public MovementSystem(Query query) => _query = query;

    public void Tick()
    {
        World.ForEach(in _query,
            static (ref Position p, in Velocity v) => p.X += v.X);
    }
}

public struct Position { public float X; }
public struct Velocity { public float X; }

SystemAccess uses the ComponentId values registered in the system's world. Adds, Removes, entity creation/destruction, unknown access and nested use of the DeltaECS parallel executor are exclusive to keep immediate world mutation safe. The scheduler compiles its graph when systems are added or removed and reuses the resulting batches on subsequent ticks when dependency-aware scheduling is enabled.

To run every system sequentially in registration order, disable schedule optimization:

using var scheduler = new SystemScheduler(world, optimizeSchedule: false);

Linear mode does not inspect system access metadata or create scheduler worker threads. WorkerCount is 1 in this mode.