Ensure direction is normalized.

src/sound/footstep.rs

@@ -127,7 +127,7 @@ pub struct FootstepPlugin;
 impl Plugin for FootstepPlugin {
     fn build(&self, app: &mut App) {
         app.add_systems(PreUpdate, added).add_systems(
-            PostUpdate,
+            FixedPostUpdate,
             update.after(TransformSystem::TransformPropagate),
         );
     }

src/visibility.rs

@@ -86,7 +86,7 @@ impl Viewshed {
                         } else {
                             let should_push = std::cell::RefCell::new(true);
                             let coord = Vec2::new(coord.x as f32 + 0.5, coord.y as f32 + 0.5);
-                            let dir = Dir2::new_unchecked((coord - *start).normalize());
+                            let dir = Dir2::new_unchecked((coord - *start).normalize_or_zero());
                             // println!("Casting from {coord} to {dir:?}");
                             spatial_query.cast_ray_predicate(
                                 *start,