void inputActions(SDL_Event e, int step) {
  switch (e.key.keysym.sym) {
    case SDLK_1:
      setSample(1, step);
      break;
    case SDLK_2:
      setSample(2, step);
      break;
    case SDLK_3:
      setSample(3, step);
      break;
    case SDLK_4:
      setSample(4, step);
      break;
    default:
      break;
  }
}