enforce point and vector for origin and direction

features/src/ray.rs

@@ -1,15 +1,20 @@
 use crate::structs::Tuple;
 
+#[derive(Debug, PartialEq)]
 struct Ray {
     origin: Tuple,
     direction: Tuple,
 }
 
 impl Ray {
-    fn new(origin: Tuple, direction: Tuple) -> Ray {
-        Ray {
-            origin,
-            direction,
+    fn new(origin: Tuple, direction: Tuple) -> Option<Ray> {
+        if !origin.is_point() || !direction.is_vector() {
+            None
+        } else {
+            Some(Ray {
+                origin,
+                direction,
+            })
         }
     }
 }
@@ -24,8 +29,24 @@ mod tests {
         let origin = Tuple::point(1, 2, 3);
         let direction = Tuple::vector(4, 5, 6);
 
-        let ray = Ray::new(origin, direction);
+        let ray = Ray::new(origin, direction).unwrap();
         assert_eq!(ray.origin, origin);
         assert_eq!(ray.direction, direction);
     }
+
+    #[test]
+    pub fn origin_must_be_point() {
+        let direction = Tuple::vector::<i32, i32, i32>(4, 5, 6);
+
+        let ray = Ray::new(direction, direction);
+        assert_eq!(ray, None);
+    }
+
+    #[test]
+    pub fn direction_must_be_vector() {
+        let point = Tuple::point::<i32, i32, i32>(4, 5, 6);
+        let ray = Ray::new(point, point);
+        assert_eq!(ray, None);
+    }
+
 }