added metals and dielectrics

src/sphere.rs

@@ -9,20 +9,22 @@ pub struct Sphere<'a> {
 }
 
 impl Sphere<'_> {
-    pub fn new<T: Material>(center: Point3, radius: f64, mat_ptr: &T) -> Self {
+    pub fn new<T: Material>(center: Point3, radius: f64, mat_ptr: &'static T) -> Self {
         Sphere {center, radius, mat_ptr}
     }
 }
 
 impl Hittable for Sphere<'_> {
-    fn hit(&mut self, r: &crate::ray::Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool {
+    fn hit(&mut self, r: &crate::ray::Ray, t_min: f64, t_max: f64) -> Option<HitRecord> {
         let oc = r.origin() - self.center;
         let a = r.direction().length_squared();
         let half_b = oc.dot(&r.direction());
-        let c = oc.length_squared() - self.radius*self.radius;
+        let c = oc.length_squared() - self.radius * self.radius;
 
-        let discriminant = half_b*half_b - a*c;
-        if discriminant < 0.0 { return false; }
+        let discriminant = half_b * half_b - a * c;
+        if discriminant < 0.0 {
+            return None;
+        }
         let sqrtd = discriminant.sqrt();
 
         // Find the nearest root that lies in the acceptable range
@@ -30,16 +32,26 @@ impl Hittable for Sphere<'_> {
         if root < t_min || t_max < root {
             root = (-half_b + sqrtd) / a;
             if root < t_min || t_max < root {
-                return false;
+                return None;
             }
         }
 
-        rec.t = root;
-        rec.p = r.at(rec.t);
-        let outward_normal = (rec.p - self.center) / self.radius;
-        rec.set_face_normal(r, &outward_normal);
-        rec.mat_ptr = self.mat_ptr;
+        let p = r.at(root);
+        let outward_normal = (p - self.center) / self.radius;
+        let front_face = r.direction().dot(&outward_normal) < 0.0;
 
-        return true;
+        let outward_normal = if front_face {
+            outward_normal
+        } else {
+            outward_normal * -1.0
+        };
+
+        Some(HitRecord {
+            t: root,
+            p: p,
+            normal: outward_normal,
+            front_face,
+            mat_ptr: self.mat_ptr,
+        })
     }
 }