Requested revisions.

src/aabb/aabb_impl.rs

@@ -238,6 +238,7 @@ impl<T: BHValue, const D: usize> Aabb<T, D> {
     ///
     /// [`Aabb`]: struct.Aabb.html
     pub fn intersects_aabb(&self, aabb: &Aabb<T, D>) -> bool {
+        // TODO: Try adding a SIMD specialization.
         for i in 0..D {
             if self.max[i] < aabb.min[i] || aabb.max[i] < self.min[i] {
                 return false;

src/ball.rs

@@ -6,13 +6,13 @@ use crate::{
 };
 use nalgebra::Point;
 
-/// A 2d circle.
+/// A circle, which can be used for traversing 2D BVHs.
 pub type Circle<T> = Ball<T, 2>;
 
-/// A 3d sphere.
+/// A sphere, which can be used for traversing 3D BVHs.
 pub type Sphere<T> = Ball<T, 3>;
 
-/// In 2D, a circle. In 3D, a sphere. This can be used for traversing BVH's.
+/// In 2D, a circle. In 3D, a sphere. This can be used for traversing BVHs.
 #[derive(Debug, Clone, Copy)]
 pub struct Ball<T: BHValue, const D: usize> {
     /// The center of the ball.
@@ -62,6 +62,7 @@ impl<T: BHValue, const D: usize> Ball<T, D> {
         for i in 0..D {
             distance_squared += (point[i] - self.center[i]).powi(2);
         }
+        // Squaring the RHS is faster than computing the square root of the LHS.
         distance_squared <= self.radius.powi(2)
     }
 
@@ -81,17 +82,18 @@ impl<T: BHValue, const D: usize> Ball<T, D> {
     /// [`Aabb`]: struct.Aabb.html
     /// [`Ball`]: struct.Ball.html
     pub fn intersects_aabb(&self, aabb: &Aabb<T, D>) -> bool {
-        // https://gamemath.com/book/geomtests.html A.14
+        // https://gamemath.com/book/geomtests.html#intersection_sphere_aabb
         // Finding the point in/on the AABB that is closest to the ball's center or,
-        // more specifically, find the squared distance betwen that point and the
+        // more specifically, find the squared distance between that point and the
         // ball's center.
         let mut distance_squared = T::zero();
         for i in 0..D {
             let closest_on_aabb = self.center[i].clamp(aabb.min[i], aabb.max[i]);
             distance_squared += (closest_on_aabb - self.center[i]).powi(2);
         }
 
-        // Then test if that point is in/on the ball.
+        // Then test if that point is in/on the ball. Squaring the RHS is faster than computing
+        // the square root of the LHS.
         distance_squared <= self.radius.powi(2)
     }
 }