mach/libs/ecs

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, just working from first-principles)
• Solve the problems ECS solves, in a way that is natural to Zig and leverages Zig comptime.
• 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 Discord 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.