oflecs provides native Flecs bindings for the Odin programming language.

This is a personal project, I have not extensively testing the entire Flecs API. I just make changes when I need to for my personal projects. I also implemented the Flecs Quickstart demos and made sure they work.

• Flecs is built as a static library
• Bindings are generated using odin-c-bindgen
• Wrapper designed for usage similar to other bindings for Flecs
• The workflow is currently only scripted for Windows

This repository exists primarily for my own use, but is published publicly in case it’s useful to others.

This project consists of two layers:

1. Low-level generated bindings
   Generated directly from flecs.h using odin-c-bindgen.

2. A handwritten wrapper layer
   I wrote a wrapper on top of the generated bindings to make Flecs usage feel more similar to other language bindings without using an object-oriented API.

The wrapper aims to:

• Reduce boilerplate
• Replace common C macros with Odin procedures
• Provide a more Odin-style API
• Keep everything explicit and data-oriented (no classes, no hidden state)

This wrapper is opinionated and reflects how I like to use Flecs.

• Not object-oriented
• Thin abstractions over Flecs concepts
• Explicit world ownership
• Struct-based handles (Entity, Query, System, etc.)
• Minimal magic, no fluent OO chains

ECS_COMPONENT(world, Position);
ECS_COMPONENT(world, Velocity);

ecs_entity_t e = ecs_new(world);

// Add a component. This creates the component in the ECS storage, but does not
// assign it with a value.
ecs_add(world, e, Velocity);

// Set the value for the Position & Velocity components. A component will be
// added if the entity doesn't have it yet.
ecs_set(world, e, Position, {10, 20});
ecs_set(world, e, Velocity, {1, 2});

// Get a component
const Position *p = ecs_get(world, e, Position);

// Remove component
ecs_remove(world, e, Position);

Position :: struct {
    x, y: f32,
}

Velocity :: struct {
    x, y: f32,
}

world := ecs.init()

e := ecs.entity(world)
defer ecs.delete(e)

// Add component (no value yet)
ecs.add(e, Velocity)

// Set component values
ecs.set(e, Position{10, 20})
ecs.set(e, Velocity{1, 2})

// Get component
p := ecs.get(e, Position)
fmt.println(p)

// Remove component
ecs.remove(e, Position)

Notes:

• Components are registered lazily on first use
• ecs.set automatically adds the component if missing
• The API stays explicit and procedural

Below is a condensed example showing the wrapper style:

world := ecs.init()

e := ecs.entity(world, "Bob")
defer ecs.delete(e)

ecs.add(e, Position)
ecs.set(e, Position{10, 20})

pos := ecs.get(e, Position)
fmt.println(pos)

Query example:

q := ecs.query_builder(world)
ecs.with(&q, Position)
ecs.build(&q)
defer ecs.finished(q)

ecs.each(q, proc(e: ecs.Entity, ce: ecs.Entity) {
    fmt.println(ecs.get_name(e))
})

System example:

q := ecs.query_builder(world)
ecs.with(&q, Position)

move_system := ecs.system(q, proc "c" (iter: ^ecs.iter_t) {
    pos := ecs.field(iter, Position)
    pos.x += 1
})
defer ecs.delete(move_system)

ecs.run(move_system)

The full example used for testing lives in the examples/ directory.

• ✅ Works for my personal projects and updated for my personal use cases
• ✅ Works for Flecs quickstart examples
• ❌ Not exhaustively tested across Flecs
• ❌ Not all Flecs APIs are wrapped but everthing should be exposed
• ❌ Wrapper API may change without notice

If you need fully validated bindings, you should audit and extend these yourself.

• Windows
• Odin (must be available in PATH)
• Visual Studio 2022 (MSVC toolchain)

• libclang 20.1.8

Download LLVM/Clang from:

https://github.com/llvm/llvm-project/releases/tag/llvmorg-20.1.8

After extracting the Windows archive, copy:

• lib/libclang.lib → llvm/libclang.lib
• bin/libclang.dll → llvm/libclang.dll

Directory layout:

llvm/
  libclang.lib
  libclang.dll

Make sure you have the requirements installed. Including libclang.lib and libclang.dll in the llvm directory.

From the repository root:

init.bat

This will:

1. Build Flecs as a static library
2. Ensure libclang is installed where the bindgen expects it
3. Build the bindgen executable

Then generate the bindings:

generate_flecs_bindings.bat

Final outputs:

distr/oflecs/
├─ flecs.odin
└─ flecs.lib

You can now copy the oflecs folder for use in your Odin projects.