ft (wip): 10: dielectrics

src/objects/sphere.rs

@@ -4,6 +4,7 @@ use std::sync::Arc;
 use crate::objects::hit::Hit;
 use crate::objects::materials::traits::Material;
 use crate::objects::traits::Hittable;
+use crate::ray::Ray;
 use crate::Vec3;
 
 pub struct Sphere {
@@ -31,7 +32,7 @@ impl Sphere {
 }
 
 impl Hittable for Sphere {
-    fn hit(&self, r: &crate::ray::Ray) -> Option<Hit> {
+    fn hit(&self, r: &Ray) -> Option<Hit> {
         let oc = self.center - r.origin();
         let a = r.dir().length_squared();
         let h = r.dir().dot(&oc);
@@ -43,7 +44,14 @@ impl Hittable for Sphere {
         } else {
             let t = (h - sqrt(d)) / a;
             let p = r.at(t);
-            Some(Hit::new(t, p, self.normal_at(&p), self.material.clone()))
+            let out_n = (p - self.center) / self.radius;
+            Some(Hit::new(
+                t,
+                p,
+                self.normal_at(&p),
+                self.material.clone(),
+                out_n.dot(r.dir()) < 0.,
+            ))
         }
     }