Make shapes Copy and Clone when possible

src/kdtree.rs

@@ -96,6 +96,7 @@ impl BoundingBox {
 /// [fogleman/pt](https://github.com/fogleman/pt/blob/master/pt/tree.go).
 /// Parts of the construction algorithm were also taken from PBRT, which helped
 /// optimize the code by a few orders of magnitude.
+#[derive(Clone)]
 pub struct KdTree<T> {
     root: Box<KdNode>,
     objects: Vec<T>,
@@ -222,6 +223,7 @@ impl<T: Bounded> KdTree<T> {
     }
 }
 
+#[derive(Clone)]
 enum KdNode {
     SplitX(f64, Box<KdNode>, Box<KdNode>),
     SplitY(f64, Box<KdNode>, Box<KdNode>),

src/shape.rs

@@ -72,8 +72,6 @@ impl Ray {
 }
 
 /// Record of when a hit occurs, and the corresponding normal
-///
-/// TODO: Look into adding more information, such as (u, v) texels
 pub struct HitRecord {
     /// The time at which the hit occurs (see `Ray`)
     pub time: f64,
@@ -99,6 +97,7 @@ impl HitRecord {
 }
 
 /// A shape that has been composed with a transformation
+#[derive(Copy, Clone)]
 pub struct Transformed<T> {
     shape: T,
     transform: glm::DMat4,

src/shape/cube.rs

@@ -4,6 +4,7 @@ use super::{HitRecord, Ray, Shape};
 use crate::kdtree::{Bounded, BoundingBox};
 
 /// A unit cube centered at the origin
+#[derive(Copy, Clone)]
 pub struct Cube;
 
 impl Bounded for Cube {

src/shape/mesh.rs

@@ -4,6 +4,7 @@ use super::{HitRecord, Ray, Shape};
 use crate::kdtree::{Bounded, BoundingBox, KdTree};
 
 /// A triangle with three vertices and three normals
+#[derive(Copy, Clone)]
 pub struct Triangle {
     /// The first vertex
     pub v1: glm::DVec3,

src/shape/monomial_surface.rs

@@ -9,6 +9,7 @@ use crate::kdtree::{Bounded, BoundingBox};
 /// Points satisfy the relation y = height * sqrt(x^2 + z^2)^exp, x^2 + z^2 <= 1.
 ///
 /// Normals and other things probably can't be generalized, so they work only for exp=4 for now
+#[derive(Copy, Clone)]
 pub struct MonomialSurface {
     /// The height of the surface
     pub height: f64,

src/shape/plane.rs

@@ -3,6 +3,7 @@ use rand::rngs::StdRng;
 use super::{HitRecord, Ray, Shape};
 
 /// A plane represented by the linear equation x • normal = value
+#[derive(Copy, Clone)]
 pub struct Plane {
     /// The normal vector
     pub normal: glm::DVec3,

src/shape/sphere.rs

@@ -5,6 +5,7 @@ use super::{HitRecord, Ray, Shape};
 use crate::kdtree::{Bounded, BoundingBox};
 
 /// A unit sphere centered at the origin
+#[derive(Copy, Clone)]
 pub struct Sphere;
 
 #[allow(clippy::many_single_char_names)]