Resources

So far we have covered components, which represent data attached to a single entity. However, our apps will also require shared, globally unique data. We do this with resources:

class Params(xx.Resource):
    max_velocity: float
    generator: np.random.Generator

Unlike components, resources can hold any type, including arbitrary Python types, such as the ones you make yourself. When we want to access a resource in a system, we simply add it as a type hint:

def my_system(params: Params) -> None:
    print(params.generator.random())

Finally, we need to initialize resources and add them to our app:

def main() -> None:
    app = xx.RealTimeApp(num_entities=0)
    app.add_resource(
        Params(
            max_velocity=100.0,
            generator=np.random.default_rng(72),
        ),
    )
    app.add_system(my_system)
    app.update()