code

class Entity {
	virtual void update();
	virtual void render();
}

struct PhysicsData {
	int x, y, x_vel, y_vel;
}

void updatePhysics(PhysicsData& p) {...}

struct GeometryRenderData() {
	...
}

void renderGeometry(GeometryRenderData& d) {...}

class Box : Entity {
	PhysicsData physData;
	GeometryRenderData geoData;

	void update() {
		updatePhysics(physData);
	}

	void render() {
		renderGeometry(geoData);
	}
}