Function pbrt::integrators::bdpt::random_walk

pub fn random_walk<'a>(
    scene: &'a Scene, 
    ray: &Ray, 
    sampler: &mut dyn Sampler, 
    beta: &mut Spectrum, 
    pdf: Float, 
    max_depth: u32, 
    mode: TransportMode, 
    path: &mut Vec<Vertex<'a, 'a, 'a>>
) -> usize