Fine-tune `Radians::to_distance`

An angle of 0 radians will "point" to the top-center of a `Rectangle` and
then increase clockwise.

1 files changed, 8 insertions, 7 deletions

diff --git a/core/src/angle.rs b/core/src/angle.rs
index 91fc2ba7..c8f3f013 100644
--- a/core/src/angle.rs
+++ b/core/src/angle.rs
@@ -1,6 +1,6 @@
 use crate::{Point, Rectangle, Vector};
 
-use std::f32::consts::PI;
+use std::f32::consts::{FRAC_PI_2, PI};
 use std::ops::RangeInclusive;
 
 /// Degrees
@@ -57,15 +57,16 @@ impl num_traits::FromPrimitive for Radians {
 impl Radians {
     /// Calculates the line in which the [`Angle`] intercepts the `bounds`.
     pub fn to_distance(&self, bounds: &Rectangle) -> (Point, Point) {
-        let v1 = Vector::new(f32::cos(self.0), f32::sin(self.0));
+        let angle = self.0 - FRAC_PI_2;
+        let r = Vector::new(f32::cos(angle), f32::sin(angle));
 
-        let distance_to_rect = f32::min(
-            f32::abs((bounds.y - bounds.center().y) / v1.y),
-            f32::abs(((bounds.x + bounds.width) - bounds.center().x) / v1.x),
+        let distance_to_rect = f32::max(
+            f32::abs(r.x * bounds.width / 2.0),
+            f32::abs(r.y * bounds.height / 2.0),
         );
 
-        let start = bounds.center() + v1 * distance_to_rect;
-        let end = bounds.center() - v1 * distance_to_rect;
+        let start = bounds.center() - r * distance_to_rect;
+        let end = bounds.center() + r * distance_to_rect;
 
         (start, end)
     }