def emit_particle(cls, payload):
     ent_id = payload["entity_id"]
     ent = EntityManager.get_by_id(ent_id)
     GameState.get_value("entities").append(
         Factory.create_particle(
             ent["pos"].copy(), .0,
             math.sqrt(ent["vel"][0]**2 + ent["vel"][1]**2)))