refactor: scene deserialization organisation

src/main.rs

@@ -33,7 +33,7 @@ fn main() {
     return;
 
     // random spheres code; thought: make this available as cli flag?
-    let ground = Lambertian::rgb(0.5, 0.5, 0.5, 1.);
+    let ground = Lambertian::rgb(-2.5, 0.5, 0.5, 1.);
     let mut world: Vec<Arc<dyn Hittable>> = vec![Arc::new(Sphere::xyz(
         0.,
         -1000.,
@@ -112,6 +112,7 @@ fn main() {
     c.set_fov(20.);
     c.set_anti_alias_rate(23);
     c.set_max_depth(50);
+    c.set_vup(Vec3::new(0., 1., 0.));
     c.set_look_from(Vec3::new(13., 2., 3.));
     c.set_look_at(Vec3::new(0., 0., 0.));
     c.add_defocus_blur(0.6, 10.);