Spurious crashes - Switching to enums

Segfaults and stack overflows. I get overflows when running in either
debug or release. Segmentation faults when hooked up to GDB. I think it
may be related to the copying of uninitialized trait objects, but I
don't know.

I've decided the trait-based interface just isn't worth this. I'll
rearrange the materials into an Enum and a big match block.

src/hittable.rs

@@ -2,16 +2,17 @@
 use crate::vec3::Vec3;
 use crate::ray::Ray;
 use crate::material::Material;
+use std::rc::Rc;
 
-pub struct HitRecord<'a>{
+pub struct HitRecord{
     pub p: Vec3,
     pub normal: Vec3,
-    pub material: Option<&'a Material>,
+    pub material: Option<Rc<dyn Material>>,
     pub t: f32,
     pub front_face: bool,
 }
 
-impl<'a> HitRecord<'a>{
+impl HitRecord{
     pub fn set_face_normal(&mut self, r: Ray, outward_normal: Vec3) -> (){
         self.front_face = Vec3::dot(r.dir, outward_normal) < 0.0;
         self.normal = if self.front_face { outward_normal } else { -outward_normal };

src/main.rs

@@ -28,7 +28,7 @@ fn main() {
         (400.0 / aspect_ratio) as i32
     );
     let samples_per_pixel = 100;
-    let max_depth = 50;
+    let max_depth = 100;
     
     // world
 
@@ -37,7 +37,7 @@ fn main() {
         Box::new(
             Sphere{
                 center: Vec3{ x: 0.0, y: 0.0, z: -1.0},
-                radius: 0.5
+                radius: 0.5,
                 material: None,
             }
         )
@@ -75,7 +75,7 @@ fn main() {
     eprintln!("Done!");
 }
 
-fn ray_color(r: Ray, world: &HittableList, depth: u32, srng: &mut SmallRng, distrib: Uniform<f32> ) -> Vec3 {
+fn ray_color(r: Ray, world: &dyn Hittable, depth: u32, srng: &mut SmallRng, distrib: Uniform<f32> ) -> Vec3 {
     // recursion depth guard
     if depth == 0 {
         return Vec3::new(0.0, 0.0, 0.0);

src/material.rs

@@ -3,11 +3,9 @@ use crate::ray::Ray;
 use crate::hittable::HitRecord;
 use crate::Vec3;
 
-pub struct Material;
-
-pub Scatter {
+pub trait Material {
     fn scatter(
-        ray_in: Ray, rec: HitRecord, attenuation: Vec3, scattered: Ray
+        &self, ray_in: Ray, rec: HitRecord, attenuation: Vec3, scattered: Ray
     ) -> bool;
 }
 

src/sphere.rs

@@ -5,16 +5,17 @@ use crate::hittable::{
     HitRecord,
 };
 use crate::material::Material;
-
 use crate::ray::Ray;
 
-pub struct Sphere<'a>{
+use std::rc::Rc;
+
+pub struct Sphere{
     pub center: Vec3,
     pub radius: f32,
-    pub material: &'a Material,
+    pub material: Option<Rc<dyn Material>>,
 }
 
-impl<'a> Hittable for Sphere<'a> {
+impl Hittable for Sphere {
     fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord>{
         let oc = r.orig - self.center;
         let a = r.dir.length_squared();
@@ -26,7 +27,7 @@ impl<'a> Hittable for Sphere<'a> {
             return None;
         }
         let sqrtd = discriminant.sqrt();
-
+        
         // nearest root that lies within tolerance
         let root = (-half_b - sqrtd) / a;
         if root < t_min || root > t_max {
@@ -35,11 +36,10 @@ impl<'a> Hittable for Sphere<'a> {
                 return None;
             }
         }
-        
         let mut record = HitRecord{
             p: r.at(root),
             normal: (r.at(root) - self.center) / self.radius,
-            material: Some(self.material),
+            material: self.material.clone(),
             t: root,
             front_face: false,
         };