Fix handling of duplicate points in approximation

This is the edge case being tracked in #138.

src/kernel/approximation.rs

@@ -5,9 +5,7 @@ use parry3d_f64::shape::Segment;
 
 use crate::math::Point;
 
-#[cfg(test)]
-use super::topology::edges::Cycle;
-use super::topology::edges::Edge;
+use super::topology::edges::{Cycle, Edge};
 
 /// An approximation of an edge, multiple edges, or a face
 #[derive(Debug, PartialEq)]
@@ -67,7 +65,6 @@ impl Approximation {
     ///
     /// `tolerance` defines how far the approximation is allowed to deviate from
     /// the actual cycle.
-    #[cfg(test)]
     pub fn for_cycle(cycle: &Cycle, tolerance: f64) -> Self {
         let mut points = Vec::new();
         let mut segments = Vec::new();

src/kernel/topology/edges.rs

@@ -70,7 +70,7 @@ impl Edges {
         let mut segments = Vec::new();
 
         for cycle in &self.cycles {
-            let approx = cycle.approx(tolerance);
+            let approx = Approximation::for_cycle(cycle, tolerance);
 
             points.extend(approx.points);
             segments.extend(approx.segments);
@@ -90,30 +90,6 @@ pub struct Cycle {
     pub edges: Vec<Edge>,
 }
 
-impl Cycle {
-    /// Compute an approximation of the cycle
-    ///
-    /// `tolerance` defines how far the approximation is allowed to deviate from
-    /// the actual cycle.
-    pub fn approx(&self, tolerance: f64) -> Approximation {
-        let mut points = Vec::new();
-        let mut segments = Vec::new();
-
-        for edge in &self.edges {
-            let approx = Approximation::for_edge(&edge, tolerance);
-
-            points.extend(approx.points);
-            segments.extend(approx.segments);
-        }
-
-        // As this is a cycle, the last vertex of an edge could be identical to
-        // the first vertex of the next. Let's remove those duplicates.
-        points.dedup();
-
-        Approximation { points, segments }
-    }
-}
-
 /// An edge of a shape
 #[derive(Clone, Debug)]
 pub struct Edge {