shapes: name space helper implementations in a sub module.

rtchallenge/src/shapes.rs

@@ -266,32 +266,49 @@ impl Shape {
 /// ```
 pub fn intersect<'s>(shape: &'s Shape, ray: &Ray) -> Intersections<'s> {
     match shape.geometry {
-        Geometry::Sphere => intersect_sphere(shape, ray),
-        Geometry::Plane => intersect_plane(shape, ray),
+        Geometry::Sphere => sphere::intersect(shape, ray),
+        Geometry::Plane => plane::intersect(shape, ray),
     }
 }
 
-fn intersect_sphere<'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);
-    let b = 2. * dot(ray.direction, sphere_to_ray);
-    let c = dot(sphere_to_ray, sphere_to_ray) - 1.;
-    let discriminant = b * b - 4. * a * c;
-    if discriminant < 0. {
-        return Intersections::default();
+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);
+        let b = 2. * dot(ray.direction, sphere_to_ray);
+        let c = dot(sphere_to_ray, sphere_to_ray) - 1.;
+        let discriminant = b * b - 4. * a * c;
+        if discriminant < 0. {
+            return Intersections::default();
+        }
+        Intersections::new(vec![
+            Intersection::new((-b - discriminant.sqrt()) / (2. * a), &shape),
+            Intersection::new((-b + discriminant.sqrt()) / (2. * a), &shape),
+        ])
     }
-    Intersections::new(vec![
-        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> {
-    if (ray.direction.y).abs() < EPSILON {
-        return Intersections::default();
+
+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();
+        }
+        Intersections::new(vec![Intersection::new(
+            -ray.origin.y / ray.direction.y,
+            &shape,
+        )])
     }
-    Intersections::new(vec![Intersection::new(
-        -ray.origin.y / ray.direction.y,
-        &shape,
-    )])
 }