perpendicular vectors

pong/src/geom.rs

@@ -11,7 +11,9 @@ pub mod geom {
         }
 
         pub fn unit() -> Vector {
-            Vector { x: 1., y: 1. }
+            let mut vector = Vector { x: 1., y: 1. };
+            vector.normalize();
+            vector
         }
 
         pub fn new(x: f64, y: f64) -> Vector {
@@ -26,6 +28,18 @@ pub mod geom {
             self.y /= length;
         }
 
+        pub fn perpendicular_clockwise(&self) -> Vector {
+            let mut vector = Vector::new(self.y, -self.x);
+            vector.normalize();
+            vector
+        }
+
+        pub fn perpendicular_counter_clockwise(&self) -> Vector {
+            let mut vector = Vector::new(-self.y, self.x);
+            vector.normalize();
+            vector
+        }
+
         pub fn add(&mut self, other: &Vector) {
             self.x += other.x;
             self.y += other.y;

pong/tests/vector_tests.rs

@@ -41,3 +41,27 @@ pub fn should_calculate_angle_correctly(
     let res = vector_a.angle(&vector_b);
     assert_eq!(res, expected_angle);
 }
+
+#[rstest]
+#[case(Vector::new(1., 0.), Vector::new(0., -1.))]
+#[case(Vector::new(0., 1.), Vector::new(1., 0.))]
+#[case(Vector::new(7., 7.), Vector::new(0.7071067811865476, -0.7071067811865476))]
+pub fn should_get_perpendicular_clockwise(
+    #[case] vector: Vector,
+    #[case] expected: Vector
+) {
+    let res = vector.perpendicular_clockwise();
+    assert_eq!(res, expected);
+}
+
+#[rstest]
+#[case(Vector::new(0., -1.), Vector::new(1., 0.))]
+#[case(Vector::new(1., 0.), Vector::new(0., 1.))]
+#[case(Vector::new(7., 7.), Vector::new(-0.7071067811865476, 0.7071067811865476))]
+pub fn should_get_perpendicular_counter_clockwise(
+    #[case] vector: Vector,
+    #[case] expected: Vector
+) {
+    let res = vector.perpendicular_counter_clockwise();
+    assert_eq!(res, expected);
+}