apecs
Fast ECS framework for game programming
https://github.com/jonascarpay/apecs#readme
Version on this page: | 0.6.0.0 |
LTS Haskell 22.17: | 0.9.6 |
Stackage Nightly 2024-04-19: | 0.9.6 |
Latest on Hackage: | 0.9.6 |
BSD-3-Clause licensed by Jonas Carpay
Maintained by [email protected]
This version can be pinned in stack with:
apecs-0.6.0.0@sha256:71d875f725886089ecc7498b6547d417a34714ab4d2469f890dbfc7f387e68eb,1938
Module documentation for 0.6.0.0
Depends on 5 packages(full list with versions):
apecs
apecs is an Entity Component System (ECS) framework inspired by specs and Entitas. ECS presents a data-driven approach to game development, that elegantly tackles many of the unique issues of game programming. The apecs front-end DSL exposes a small number of combinators that allow game logic to be expressive and extremely fast.
Links
Performance
ecs-bench shows that apecs is competitive with the fastest Rust ECS frameworks.
Example
{-# LANGUAGE DataKinds, ScopedTypeVariables, TypeFamilies, MultiParamTypeClasses, TemplateHaskell #-}
import Apecs
import Linear (V2 (..))
newtype Position = Position (V2 Double) deriving Show
-- To declare a component, we need to specify how to store it
instance Component Position where
type Storage Position = Map Position -- The simplest store is a Map
newtype Velocity = Velocity (V2 Double) deriving Show
instance Component Velocity where
type Storage Velocity = Cache 100 (Map Velocity) -- Caching adds fast reads/writes
data Flying = Flying
instance Component Flying where
type Storage Flying = Map Flying
makeWorld "World" [''Position, ''Velocity, ''Flying] -- Generate World and instances
game :: System World ()
game = do
newEntity (Position 0, Velocity 1)
newEntity (Position 2, Velocity 1)
newEntity (Position 1, Velocity 2, Flying)
-- Add velocity to position
cmap $ \(Position p, Velocity v) -> Position (v+p)
-- Apply gravity to non-flying entities
cmap $ \(Velocity v, _ :: Not Flying) -> Velocity (v - (V2 0 1))
-- Print a list of entities and their positions
cmapM_ $ \(Position p, Entity e) -> liftIO . print $ (e, p)
main :: IO ()
main = initWorld >>= runSystem game
Changes
[0.6.0.0]
Changed
- Nothing, but since 0.5.1 was API-breaking I’ve decided to bump to 0.6
[0.5.1.1]
Changed
Register
needs UndecidableInstances in GHC 8.6.2, I’m looking for a way around this. I’ve removed it for now.
[0.5.1.0]
Added
- The
Register
store, which allows reverse lookups for bounded enums. For example, ifBool
has storageRegister (Map Bool)
,regLookup True
will yield a list of all entities with aTrue
component. Can also be used to emulate a hash table, wherefromEnum
is the hashing function. This allows us to make simple spatial hashes. I’m open to suggestions for better names than Register. cmapIf
, cmap with a conditional test
Changed
ExplInit
now too takes a monad argument.- Started rewrite of the test suite
- Caches now internally use -2 to denote absence, to avoid possible conflict with -1 as a global entity
Removed
- The STM instances have been removed, to be moved to their own package
[0.5.0.0]
Changed
System w a
is now a synonym forSystemT w IO a
. A variable monad argument allows apecs to be run in monads like ST or STM. Most of the library has been rewritten to be as permissive as possible in its monad argument.
Added
- STM stores. These will be moved to a separate package soon.
[0.4.1.2]
Changed
- Either can now be deleted, deleting
Either a b
is the same as deleting(a,b)
. - Some were missing their inline pragma’s, now they don’t
[0.4.1.1]
Changed
- Export
Get
,Set
,Destroy
,Members
by default - Export
cfold
,cfoldM
,cfoldM_
by default - Fix () instance
[0.4.1.0]
Added
cfold
,cfoldM
,cfoldM_
Either
instances andEitherStore
Changed
- Changed MaybeStore implementation to no longer use -1 for missing entities.
- Fixed some outdated documentation.
- Change the
global
void entity to -2, just to be sure it won’t conflict if accidentally used in a cache.
[0.4.0.0]
Added
- A changelog
Changed
Store
is now split into 5 separate type classes;ExplInit
,ExplGet
,ExplSet
,ExplDestroy
, andExplMembers
. This makes it illegal to e.g. iterate over aNot
.- phantom arguments are now given as
Proxy
values, re-exported fromData.Proxy
. This makes phantom arguments explicit and avoids undefined values.