1 files changed, 25 insertions, 0 deletions
diff --git a/src/scene/mod.rs b/src/scene/mod.rs
index 7c77412..f8c1e09 100644
--- a/src/scene/mod.rs
+++ b/src/scene/mod.rs
@@ -5,3 +5,28 @@ pub mod shapes;
 
 mod scene;
 pub use scene::*;
+
+use crate::core::{Ray, Vector3f};
+use crate::Float;
+
+/// Returns the context of a intersection
+pub struct Intersection {
+    /// Normal vector at intersection
+    pub n: Vector3f,
+    pub p: Vector3f,
+}
+
+impl Intersection {
+    pub fn norm_against_ray(&self, r: &Ray) -> Vector3f {
+        if self.n.dot(&r.direction) < 0.0 {
+            self.n
+        } else {
+            -self.n
+        }
+    }
+}
+
+/// Defines a common trait for objects in the scene
+pub trait Hittable {
+    fn intersect(&self, ray: &Ray) -> Option<Intersection>;
+}