0645429df9
The root dir of our repository has grown quite a lot the past few months.
I'd like to make it more clear where the bulk of the engine lives (`src/`) and
also make it more clear which Mach libraries are consumable as standalone projects.
As for the name of this directory, `libs` was my first choice but there's a bit of
a convention of that being external libraries in Zig projects _today_, while these
are libraries maintained as part of Mach in this repository - not external ones.
We will name this directory `libs`, and if we have a need for external libraries
we will use `external` or `deps` for that directory name. I considered other names
such as `components`, `systems`, `modules` (which are bad as they overlap with
major ECS / engine concepts), and it seems likely the official Zig package manager
will break the convention of using a `libs` dir anyway.
Performed via:
```sh
mkdir libs/
git mv freetype libs/
git mv basisu libs/
git mv gamemode libs/
git mv glfw libs/
git mv gpu libs/
git mv gpu-dawn libs/
git mv sysaudio libs/
git mv sysjs libs/
git mv ecs libs/
```
git-subtree-dir: glfw
git-subtree-mainline:
|
||
|---|---|---|
| .. | ||
| .github | ||
| src | ||
| .gitattributes | ||
| .gitignore | ||
| build.zig | ||
| LICENSE | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| README.md | ||
mach/ecs, an Entity Component System for Zig 
mach/ecs is an Entity Component System for Zig built from first-principles.
Design principles:
- Clean-room implementation (author has not read any other ECS implementation code.)
- Solve the problems ECS solves, in a way that is natural to Zig and leverages Zig comptime.
- Avoid patent infringement upon Unity ECS patent claims.
- Fast. Optimal for CPU caches, multi-threaded, leverage comptime as much as is reasonable.
- Simple. Small API footprint, should be natural and fun - not like you're writing boilerplate.
- Enable other libraries to provide tracing, editors, visualizers, profilers, etc.
⚠️ in-development ⚠️
Under heavy development, not ready for use!
As development continues, we're publishing a blog series "Let's build an Entity Component System from scatch".
Join us in developing it, give us advice, etc. on Matrix chat or follow updates on Twitter.
Known issues
There are plenty of known issues, and things that just aren't implemented yet. And certainly many unknown issues, too.
- Missing multi-threading!
- Currently only handles entity management, no world management or scheduling. No global data, etc.
- Lack of API documentation (see "example" test)
- Missing hooks that would enable visualizing memory usage, # of entities, components, etc. and otherwise enable integration of editors/visualizers/profilers/etc.
- We have dense and sparse data, but no shared data yet.
- If many entities are deleted, iteration becomes slower due to needing to skip over entities in the free_slots set, we should add a .compact() method that allows for remediating this.
- If tons of entities are deleted, even with .compact(), memory would not be free'd / returned to the OS by the underlying components arrays. We could add a .compactAndFree() method to correct this.
- It would be nicer if there were configuration options for performing .compactAndFree() automatically, e.g. if the number of free entity slots is particularly high or something.
- Currently we do not expose an API for pre-allocating entities (i.e. allocating capacity up front) but that's very important for perf and memory usage in the real world.
- When entity is deleted, maybe via systems / an event/callback, need a way to be notified of destruction. Same with updated maybe.
See also the numerous TODOs in main.zig.
Copyright & patent mitigation
The initial implementation was a clean-room implementation by Stephen Gutekanst without having read other ECS implementations' code, but with speaking to people familiar with other ECS implementations. Contributions past the initial implementation may be made by individuals in non-clean-room settings (familiar with open source implementations only.)
Critically, this entity component system stores components for a classified archetype using independent arrays allocated per component as well as hashmaps for sparse component data as an optimization. This is a novel and fundamentally different process than what is described in Unity Software Inc's patent US 10,599,560. This is not legal advice.