Fix angle function

src/animation/rotation.rs

@@ -35,12 +35,12 @@ mod test {
     fn sample() {
         let anim = RotationAnimation::new(Vector::new(30.0, 10.0));
 
-        let sample_1 = anim.sample(0.2, Vector::new(5.0, 16.0));
+        let sample_1 = anim.sample(0.3, Vector::new(16.0, 3.0));
         let sample_2 = anim.sample(0.7, Vector::new(22.0, 2.0));
         let sample_3 = anim.sample(0.5, Vector::new(4.0, 7.0));
 
-        assert!(2.4 < sample_1 && sample_1 < 2.5);
+        assert!(0.6 < sample_1 && sample_1 < 0.7);
-        assert!(0.7 < sample_2 && sample_2 < 0.8);
+        assert!(-3.1 < sample_2 && sample_2 < -3.0);
-        assert!(-2.3 < sample_3 && sample_3 < -2.2);
+        assert!(4.7 < sample_3 && sample_3 < 4.8);
     }
 }

src/vec.rs

@@ -24,7 +24,7 @@ impl Vector {
 
     /// Returns the angle.
     pub fn angle(self) -> f32 {
-        self.x.atan2(self.y)
+        self.y.atan2(self.x)
     }
 
     /// Returns the value of the smaller axis.
@@ -86,6 +86,13 @@ mod test {
         assert!(6.7 < vec.length() && vec.length() < 6.8);
     }
 
+    #[test]
+    fn angle() {
+        let vec = Vector::new(3.0, 6.0);
+
+        assert!(1.1 < vec.angle() && vec.angle() < 1.2);
+    }
+
     #[test]
     fn smaller() {
         assert_eq!(4.0, Vector::new(7.0, 4.0).smaller());