Function layer_setup 

pub unsafe extern "C" fn layer_setup(
    this: *mut layer,
    _altitude: f32,
    _xi0: f32,
    _wind_speed_: f32,
    _wind_direction: f32,
    W: f32,
    N_W: c_int,
    field_size: f32,
    OSF: c_int,
    duration: f32,
) -> c_int