Library for python containing an interpretation of ECS design pattern.
- Adding/removing entity's attributes causes dynamic addition/removal of the entity from the corresponding systems
- Systems with annotation-based syntax
- Asynchronous systems (yield skips a frame)
- Systems accept multiple arguments, preventing global mutable state issues
- Full compatibility with type hints
- Entity is a python object
- Component is entity's attribute
- System is an entity describing an interaction between cartesian product of entities
- Metasystem is a system that launches other systems
- MetasystemFacade encapsulates all general logic (add, remove, update)
pip install ecs-girvel
You can also see girvel/fallen, ecs is written for it.
from ecs import MetasystemFacade, System, Entity # TODO NEXT fix demo
import time
# 1. You create a metasystem
ms = MetasystemFacade()
dt = 0.04
# 2. You create systems and add them to metasystem
class VerticalSpeed:
vy: float
class GravityConstants:
g: float
@ms.add
@System
def gravity(target: VerticalSpeed, constants: GravityConstants):
target.vy += constants.g * dt
class Inert:
x: float
y: float
vx: float
vy: float
@ms.add
@System
def inertia(target: Inert):
target.x += target.vx * dt
target.y += target.vy * dt
class Displayable:
x: float
y: float
name: str
@ms.add
@System
def output(target: Displayable):
yield from range(int(1 / dt) - 1) # skips 24 out of 25 frames
print(f'{target.name}: {target.x:.2f}, {target.y:.2f}')
# 3. You create objects
class DynamicEntity(Entity):
def __init__(self, **attributes):
for key, value in attributes.items():
setattr(self, key, value)
ms.add(DynamicEntity(name='falling_guy1', x=0, y=0, vx=0, vy=0))
ms.add(DynamicEntity(name='falling_guy2', x=100, y=0, vx=0, vy=0))
ms.add(DynamicEntity(g=10))
# 4. Game loop
if __name__ == "__main__":
while True:
ms.update()
time.sleep(dt)