Show HN: Evolved.lua – An Evolved Entity Component System for Lua

cmovq · 2025-05-21T16:52:42 1747846362

> Components are stored in contiguous arrays in a SoA (Structure of Arrays) manner, which allows for fast iteration and processing

Does this actually matter in Lua? Aren’t all array elements going to be pointers to heap allocated objects anyways?

The point of SoA is your likely to be accessed values are adjacent in memory, but if you’re chasing a pointer to get that value then you’re not getting anything out of it.

blackmat · 2025-05-21T21:40:10 1747863610

Yes, organizing components as SoA can provide a significant performance boost in Lua, especially with LuaJIT. Both iteration and element access become faster, and it also reduces memory allocations and GC pressure when creating entities. And yes, Lua tables can be contiguous in memory if you use them carefully.

dicytea · 2025-05-22T05:42:52 1747892572

Do you have any published benchmarks?

blackmat · 2025-05-22T08:21:00 1747902060

Comparative benchmarks are a big task on their own, and usually the author's library wins in them. I have internal benchmarks in the repository, but they are not designed for comparison or for evaluation by outsiders. Maybe I'll get to that someday.

As for the SoA approach, here you can find a small and exaggerated example: https://luajit.org/ext_ffi.html

PhilipRoman · 2025-05-21T17:08:50 1747847330

Lua uses tagged unions so that primitives are stored inline within a table. Some time ago I benchmarked this and the perf gains from SOA were significant. Besides, even if you had to chase pointers, SOA still means you can reduce the number of allocations.

binary132 · 2025-05-22T12:20:29 1747916429

It always makes me happy to see people publishing Lua libraries in $YEAR. I am also working on Lua stuff. Thank you for posting!

euvin · 2025-05-21T16:46:54 1747846014

Cool to see a new ECS project! I've been learning and using JECS (https://github.com/Ukendio/jecs) for a project of mine, and some of the core ideas (like Chunks) felt familiar. This project definitely seems to have a more in-depth documentation though and a lot more features especially by having its own scheduler stuff. Would love to try it out on a new project someday

blackmat · 2025-05-21T21:49:57 1747864197

Hmm! I haven't heard of JECS before. I need to check it out :-) Thanks for the kind words!

sali0 · 2025-05-22T04:57:55 1747889875

Will give this a try. I was using claude code to make a small game in love2d, and really hoped for a nice lua ecs lib to help manage the game objects (its my first time playing around with game dev).

je42 · 2025-05-21T19:21:32 1747855292

One alternatives I like is https://bakpakin.github.io/tiny-ecs/doc/

blackmat · 2025-05-21T21:53:44 1747864424

Yeah, tiny-ecs is good, but it doesn't quite fit my needs. With these thoughts in mind, I started this project.

dogprez · 2025-05-21T17:45:35 1747849535

What makes it an "envolved" ecs?

blackmat · 2025-05-21T22:06:51 1747865211

Honestly, it's just a fancy way of saying I learned a few things from earlier attempts and made some tweaks. I just think "evolved" sounds cool!

poly2it · 2025-05-21T18:32:41 1747852361

Any examples of projects using this?

blackmat · 2025-05-21T21:58:03 1747864683

Not yet, but I wrote this library to use in a project of mine. When I finish it, I will add a link to the README. As for a small demo project, I have one in mind, but I haven't started it yet.