Add Ray constructor that ensures direction vector is normalized

src/lib.rs

@@ -6,6 +6,15 @@ struct Ray<T: RealField> {
     direction: Vector3<T>,
 }
 
+impl<T: RealField> Ray<T> {
+    fn new(origin: Vector3<T>, direction: Vector3<T>) -> Ray<T> {
+        Ray {
+            origin,
+            direction: direction.normalize(),
+        }
+    }
+}
+
 impl<T: RealField> Ray<T> {
     fn point_at(&self, t: T) -> Vector3<T> {
         return self.origin + self.direction * t;