ft (wip): random scene generation

src/objects/sphere.rs

@@ -29,6 +29,16 @@ impl Sphere {
             material: mat,
         }
     }
+
+    pub fn center(&self) -> &Vec3 {
+        &self.center
+    }
+
+    pub fn set_center(&mut self, center: Vec3) {
+        if self.center != center {
+            self.center = center;
+        }
+    }
 }
 
 impl Hittable for Sphere {
@@ -60,4 +70,12 @@ impl Hittable for Sphere {
     fn normal_at(&self, p: &Vec3) -> Vec3 {
         (*p - self.center).get_unit()
     }
+
+    fn inside(&self, p: &Vec3) -> bool {
+        (*p - self.center).length() < self.radius
+    }
+
+    fn closest_on_surface(&self, p: &Vec3) -> Vec3 {
+        self.normal_at(p) * self.radius
+    }
 }

src/objects/traits.rs

@@ -5,4 +5,7 @@ use crate::Vec3;
 pub trait Hittable {
     fn hit(&self, r: &Ray) -> Option<Hit>;
     fn normal_at(&self, p: &Vec3) -> Vec3;
+    // fn intersect<H: Hittable>(&self, o: &H) -> bool;
+    fn inside(&self, p: &Vec3) -> bool;
+    fn closest_on_surface(&self, p: &Vec3) -> Vec3;
 }