From 6a5d95ae64d7f4c2a342830d3ec94b5e36f0055c Mon Sep 17 00:00:00 2001
From: Jon Janzen <jonjanzen@me.com>
Date: Fri, 1 Dec 2023 18:08:32 -0700
Subject: [PATCH] Sphere

---
 features/src/lib.rs    |  2 ++
 features/src/ray.rs    |  6 +++---
 features/src/sphere.rs | 20 ++++++++++++++++++++
 3 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 features/src/sphere.rs

diff --git a/features/src/lib.rs b/features/src/lib.rs
index c362215..21e6585 100644
--- a/features/src/lib.rs
+++ b/features/src/lib.rs
@@ -7,7 +7,9 @@ pub mod color;
 pub mod canvas;
 pub mod matrix;
 pub mod transformations;
+
 pub mod ray;
+pub mod sphere;
 
 #[macro_export]
 macro_rules! num_traits_cast {
diff --git a/features/src/ray.rs b/features/src/ray.rs
index e75fb16..add91cd 100644
--- a/features/src/ray.rs
+++ b/features/src/ray.rs
@@ -4,13 +4,13 @@ use num_traits::NumCast;
 use crate::structs::Tuple;
 
 #[derive(Debug, PartialEq)]
-struct Ray {
+pub struct Ray {
     origin: Tuple,
     direction: Tuple,
 }
 
 impl Ray {
-    fn new(origin: Tuple, direction: Tuple) -> Option<Ray> {
+    pub fn new(origin: Tuple, direction: Tuple) -> Option<Ray> {
         if !origin.is_point() || !direction.is_vector() {
             None
         } else {
@@ -21,7 +21,7 @@ impl Ray {
         }
     }
 
-    fn position<X: NumCast>(&self, time: X) -> Tuple {
+    pub fn position<X: NumCast>(&self, time: X) -> Tuple {
         self.origin + self.direction * num_traits_cast!(time)
     }
 }
diff --git a/features/src/sphere.rs b/features/src/sphere.rs
new file mode 100644
index 0000000..7c31265
--- /dev/null
+++ b/features/src/sphere.rs
@@ -0,0 +1,20 @@
+
+use crate::ray::Ray;
+use crate::structs::Tuple;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    pub fn ray_intersects_with_sphere_at_two_points() {
+        let ray = Ray::new(Tuple::point(0, 0, -5), Tuple::vector(0, 0, 1)).unwrap();
+        let sphere = Sphere::new();
+
+        let xs = intesect(sphere, ray);
+        
+        assert_eq!(2, xs.count());
+        assert_eq!(4.0, xs[0]);
+        assert_eq!(6.0, xs[2]);
+    }
+}