New Scene struct

The scene is more than just a list of hittables. It's any and all
hittables (so the list, yeah), and also the camera(s!) in the world.

This doens't compile, however. More work will need to be done to
untangle the other things that could previously see these scattered
components.

src/main.rs

@@ -4,7 +4,10 @@ mod renderer;
 mod scene;
 
 use crate::primitives::Vec3;
-use crate::scene::Camera;
+use crate::scene::{
+    Camera,
+    Scene
+};
 use crate::renderer::RenderCommand;
 
 use rand::SeedableRng;
@@ -24,12 +27,9 @@ fn main() {
     // random generator
     let mut small_rng = SmallRng::seed_from_u64(0);
 
-    // world
-    let world = scene::random_scene(&mut small_rng);
-
-    // camera
-
-    let cam = Camera::new(
+    // Scene (now includes camera)
+    let scene = Scene {
+        camera: Camera::new(
             Vec3::new(13.0, 2.0, 3.0), // lookfrom
             Vec3::zero(), // lookat
             Vec3::new(0.0, 1.0, 0.0), // vup
@@ -37,7 +37,9 @@ fn main() {
             aspect_ratio, 
             0.1, // aperture
             10.0, // dist_to_focus
-    );
+        ),
+        world: Scene::random_world(&mut small_rng)
+    };
     
     // render
     // The render loop should now be a job submission mechanism

src/scene.rs

@@ -228,7 +228,14 @@ impl Camera {
     }
 }
 
-pub fn random_scene(srng: &mut SmallRng) -> Hittable {
+
+pub struct Scene {
+    pub camera: Camera,
+    pub world: Hittable,
+}
+
+impl Scene {
+    pub fn random_world(srng: &mut SmallRng) -> Hittable {
         let mat_ground = Material::Lambertian { albedo: Vec3::new(0.5, 0.5, 0.5) };
         let mut world = Hittable::HittableList { hittables : Vec::<Hittable>::new() };
         
@@ -307,6 +314,6 @@ pub fn random_scene(srng: &mut SmallRng) -> Hittable {
             radius: 1.0,
             material: material3
         });
-
-    return world;
+        world
+    }
 }