Aztecs v0.14.0 released - A modular game engine and ECS

Announcements
1

Hey endofriends! I’m really excited to share the latest version of Aztecs, a modular game engine and Entity Component System (ECS) built with Haskell :smiley:

The latest version now relies heavily on in-place mutation through a type-level Query API, that provides compile-time guarantees for read and write access. A System can then be implemented by taking some ECS access as input:

-- Components

newtype Position = Position Int
  deriving (Show, Eq)

instance (Monad m) => Component m Position where
  type ComponentStorage m Position = SparseStorage m

newtype Velocity = Velocity Int
  deriving (Show, Eq)

instance (Monad m) => Component m Velocity where
  type ComponentStorage m Velocity = SparseStorage m

-- System

data MoveSystem = MoveSystem

instance (PrimMonad m, MonadIO m) => System m MoveSystem where
  type SystemIn m MoveSystem = Query (W m Position, R Velocity)

  runSystem \_ = mapM\_ go
    where
      go (posRef, R (Velocity v)) = do
        modifyW posRef $ \\(Position p) -> Position (p + v)

        p <- readW posRef
        liftIO $ putStrLn $ "Moved to: " ++ show p

Systems can then be automatically scheduled with Before and After constraints, and in-parallel (if possible), at the type-level (also with compile-time errors):

app ::
  HSet
    '[ Run '[] MoveSystem,
       Run '[After MoveSystem] PhysicsSystem,
       Run '[After PhysicsSystem] CombatSystem,
       Run '[After CombatSystem] RenderSystem
     ]

I’m also really curious about how this generic ECS class might be used, I’ve been trying to get it as minimal as possible to potentially support a wide-range of ECS backends (like Apecs or maybe bindings to something like Bevy or Flecs):

-- | Entity Component System (ECS) implementation.

class ECS m where
  -- | Entity identifier.

  type Entity m :: Type

  -- | Task monad for running systems.

  type Task m :: Type -> Type

  -- | Spawn a new entity with a `Bundle` of components.

  spawn :: Bundle (Entity m) m -> m (Entity m)

  -- | Insert a `Bundle` of components into an existing entity

  -- (otherwise this will do nothing).

  insert :: Entity m -> Bundle (Entity m) m -> m ()

  -- | Remove an entity and its components.

  remove :: Entity m -> m ()

  -- | Run a `Task`.

  task :: (Task m) a -> m a
7 Likes
2

Cool. Does your engine support 3d rendering in some way?

1 Like
3

Thanks! Not yet but I’m just about to start adding more rendering support now that the core ECS is a little more nailed down.

The engine itself is split up into multiple repos (with a WIP 2D SDL2 renderer in aztecs-sdl) to be more modular, so some packages like aztecs-transform should be compatible with many different render backends.

I’d really like to get either GL or Vulkan going as a first implementation soon, and I’m really excited about using the Scheduler in Aztecs for render passes, where shaders can potentially be scheduled to run in-parallel on the GPU.

3 Likes
4

May i suggest you consider web-gpu instead of Open GL. Both are easier to use than vulkan but web-gpu is still active , often more performant and runs on the web ( in addition to desktop )

1 Like