GitHub - Meehai/microecs: Minimal Entity Component System (ECS) in python and numpy. Uses raylib for examples. Docs: https://meehai.gitlab.io/microecs

Minimal (~600 LoC, cloc microecs/) Entity Component System in python and numpy. Examples also use raylib for rendering.

Usage:

Via pip: pip install microecs
From source code:

git clone https://gitlab.com/meehai/microecs      # clone the source code
cd microecs                                       # go in the cloned directory
python -m venv .venv && source .venv/bin/activate # make a virtual env, optional but useful
python -m pip install -e .                        # install micro ecs in this virtual env
python -m pytest test/                            # run the unit & integration tests to verify installation
python examples/01-hello-world.py                 # run the basic hello world example (others in that dir)

Docs: meehai.gitlab.io/microecs — built by docs/build_docs.sh (pdoc; no sphinx/config). Build locally with bash docs/build_docs.sh and open the printed file:// link.

Simple example

from dataclasses import field
import numpy as np
from microecs import World, Component

class HasPosition(Component):
    position: np.ndarray = field(metadata={"shape": (2, ), "dtype": "float32", "default": np.float32([0, 0])})
class HasVelocity(Component):
    velocity: np.ndarray = field(metadata={"shape": (2, ), "dtype": "float32", "default": np.float32([0, 0])})

world = World(components=[HasPosition, HasVelocity])
# both velocity and position (data) are optional since they have a default
eid1 = world.add_entity(components=[HasPosition, HasVelocity])
# data is passed as kwargs to add_entity
eid2 = world.add_entity(components=[HasPosition, HasVelocity],
                        velocity=np.float32([1, 1]))
world.update() # add_entity uses a command buffer internally until this is called
print(f"Added 2 entities. Id1={eid1}, Id2={eid2}")

# Querying: batch operate on all entities at once.
qr = world.query(HasVelocity) # qr is a QueryResult object, a numpy-based Structure of Arrays (SoA).
qr.velocity += np.float32([0.1, 0.5])

Documentation

Primitives — the five building blocks (Component, Entity, Pool, QueryResult, World), mutation timing, and how numpy-like the query views really are.
Systems & Per-Entity Iteration — writing systems, the three ways to touch data (vectorized, zip-rows, the Entity API), and when each is right.
Hello World (raylib) — a complete runnable program, walked through part by part.
Benchmarks — microecs vs OOP, and microecs vs six other Python ECS libraries (including the C++ EnTT and C flecs bindings) across seven workloads and an N-sweep to 1M.