Function raymarch_cloud 

pub fn raymarch_cloud(
    ray_origin: Vec3,
    ray_dir: Vec3,
    layers: &[CloudLayer],
    sun_dir: Vec3,
    n_steps: usize,
) -> Vec4

Raymarche through cloud layers and return Vec4(rgb_color, alpha).

ray_origin — world-space ray start ray_dir — normalised ray direction layers — cloud layer definitions sun_dir — direction toward the sun n_steps — number of marching steps