Function tinyraytracer::jitter_along_normal

pub(crate) fn jitter_along_normal(
    pt: Vec3, 
    direction: Vec3, 
    normal: Vec3, 
    jitter: f32
) -> Vec3

This function jitters a point along a noraml vector. Why do we need that? @ssloy explains: “Why is that? It’s just that our point lies on the surface of the object, and (except for the question of numerical errors) any ray from this point will intersect the object itself.”