good

GOOD — Game Overdrive On Dart — is an ECS game engine for Flutter.

Your game is data in columns and systems that walk them. The simulation runs on its own isolate at a fixed timestep, keeps every component in shared native memory, and allocates nothing on the per-frame path, so neither a Flutter rebuild nor the garbage collector can stall it.

The good ecosystem includes goo2d for 2D games and goo3d for 3D games, both built on the good kernel.

flutter pub add goo2d

That is the only dependency a 2D game needs, because goo2d re-exports the kernel. Physics and networking are separate packages you add when you want them, and each one needs its system declared before it does anything.

Read the documentation for installing, starting a project, building a game and shipping it.

Packages

Package	What it is
goo2d	The 2D engine, and the only thing a 2D game depends on
goo3d	The 3D engine: transforms, hierarchy and the camera
good	The kernel: ECS, memory pool, ring buffers, scenes, the tick loop, input, assets, coroutines, GameView
good_cli	The good command: scaffolding, codegen, the asset pipeline, packaging
goo2d_physics_box2d	Box2D v3 physics. Opt-in
goo2d_ffi_box2d	Vendored Box2D and the C shim under it
good_net	Network messages, sessions, and the transport contract. Opt-in
good_net_p2p	A peer-to-peer backend for good_net, with no server to run

The packages explains why the split falls where it does.

Status

The documentation describes the finished engine, and parts of it are still being written. docs/reference/roadmap.md lists what is implemented, what is deferred, and the rough edges. It is updated before anything else, so where a package README disagrees with it, it is the package README that is behind.

Working on the engine

pip install -r docs/requirements.txt
mkdocs serve

packages/ is the engine. docs/ is the site, published by .github/workflows/docs.yml on every push to the default branch.