Remove Edge::reverse

This simplifies some code, without any loss in functionality, as far as
I can tell.

Close #151

The issue this commit addresses is nominally blocked. However, given
that #173 exists, this mechanism doesn't have its desired effect anyway.

A proper fix will likely involve a deeper look at surface orientation,
and I don't think this hack will be part of that. Given that, and that
this removal simplifies some ongoing work, I feel good about doing this
now.

src/kernel/approximation.rs

@@ -33,10 +33,6 @@ impl Approximation {
  let mut points = Vec::new();
  edge.curve.approx(tolerance, &mut points);
 
- if edge.reverse {
- points.reverse()
- }
-
  // Insert the exact vertices of this edge into the approximation. This
  // means we don't rely on the curve approximation to deliver accurate
  // representations of these vertices, which they might not be able to
@@ -265,20 +261,6 @@ mod tests {
  segments: vec![Segment::from([b, c]), Segment::from([c, b])],
  }
  );
-
- let mut edge_reversed = Edge::new(curve.clone(), Some([v2, v1]));
- edge_reversed.reverse();
- assert_eq!(
- Approximation::for_edge(&edge_reversed, tolerance),
- Approximation {
- points: vec![d, c, b, a],
- segments: vec![
- Segment::from([d, c]),
- Segment::from([c, b]),
- Segment::from([b, a]),
- ],
- }
- );
  }
 
  #[test]

src/kernel/shapes/difference_2d.rs

@@ -75,7 +75,7 @@ impl Shape for fj::Difference2d {
  let mut a = self.a.edges();
  let mut b = self.b.edges();
 
- let (a, mut b) = if a.cycles.len() == 1 && b.cycles.len() == 1 {
+ let (a, b) = if a.cycles.len() == 1 && b.cycles.len() == 1 {
  (a.cycles.pop().unwrap(), b.cycles.pop().unwrap())
  } else {
  // See issue:
@@ -86,10 +86,6 @@ impl Shape for fj::Difference2d {
  );
  };
 
- for edge in &mut b.edges {
- edge.reverse();
- }
-
  Edges { cycles: vec![a, b] }
  }
 

src/kernel/topology/edges.rs

@@ -64,13 +64,6 @@ pub struct Edge {
  /// If there are no such vertices, that means the edge is connected to
  /// itself (like a full circle, for example).
  pub vertices: Option<[Vertex<1>; 2]>,
-
- /// Indicates whether the curve's direction is reversed
- ///
- /// Once this struct keeps track of the vertices that bound the edge, this
- /// field can probably be made redundant. The order of the bounding points
- /// will simply define the direction of the curve.
- pub reverse: bool,
 }
 
 impl Edge {
@@ -86,11 +79,7 @@ impl Edge {
  let vertices = vertices
  .map(|vertices| vertices.map(|vertex| vertex.to_1d(&curve)));
 
- Self {
- curve,
- vertices,
- reverse: false,
- }
+ Self { curve, vertices }
  }
 
  /// Create a circle
@@ -101,15 +90,9 @@ impl Edge {
  radius: Vector::from([radius, 0.]),
  }),
  vertices: None,
- reverse: false,
  }
  }
 
- /// Reverse the edge
- pub fn reverse(&mut self) {
- self.reverse = !self.reverse;
- }
-
  /// Create a transformed edge
  ///
  /// This method constructs new instances of [`Vertex`], by calling