shapes: name space helper implementations in a sub module.

rtchallenge/src/shapes.rs

@@ -266,12 +266,19 @@ impl Shape {
 /// ```
 pub fn intersect<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
     match shape.geometry {
-        Geometry::Sphere => intersect_sphere(shape, ray),
+        Geometry::Sphere => sphere::intersect(shape, ray),
-        Geometry::Plane => intersect_plane(shape, ray),
+        Geometry::Plane => plane::intersect(shape, ray),
     }
 }
 
-fn intersect_sphere<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
+mod sphere {
+    use crate::{
+        intersections::{Intersection, Intersections},
+        rays::Ray,
+        shapes::Shape,
+        tuples::{dot, Tuple},
+    };
+    pub fn intersect<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
         let ray = ray.transform(shape.inverse_transform);
         let sphere_to_ray = ray.origin - Tuple::point(0., 0., 0.);
         let a = dot(ray.direction, ray.direction);
@@ -285,8 +292,17 @@ fn intersect_sphere<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
             Intersection::new((-b - discriminant.sqrt()) / (2. * a), &shape),
             Intersection::new((-b + discriminant.sqrt()) / (2. * a), &shape),
         ])
+    }
 }
-fn intersect_plane<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
+
+mod plane {
+    use crate::{
+        intersections::{Intersection, Intersections},
+        rays::Ray,
+        shapes::Shape,
+        EPSILON,
+    };
+    pub fn intersect<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
         if (ray.direction.y).abs() < EPSILON {
             return Intersections::default();
         }
@@ -294,4 +310,5 @@ fn intersect_plane<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
             -ray.origin.y / ray.direction.y,
             &shape,
         )])
+    }
 }