Respect existing boundary when updating HalfEdge as line segment

crates/fj-kernel/src/builder/curve.rs

@@ -38,6 +38,14 @@ pub trait CurveBuilder {
  &mut self,
  points: [impl Into<Point<2>>; 2],
  ) -> SurfacePath;
+
+ /// Update partial curve to be a line, from provided points and line coords
+ ///
+ /// Returns the updated path.
+ fn update_as_line_from_points_with_line_coords(
+ &mut self,
+ points: [(impl Into<Point<1>>, impl Into<Point<2>>); 2],
+ ) -> SurfacePath;
 }
 
 impl CurveBuilder for PartialCurve {
@@ -82,4 +90,13 @@ impl CurveBuilder for PartialCurve {
  self.path = Some(path.into());
  path
  }
+
+ fn update_as_line_from_points_with_line_coords(
+ &mut self,
+ points: [(impl Into<Point<1>>, impl Into<Point<2>>); 2],
+ ) -> SurfacePath {
+ let path = SurfacePath::from_points_with_line_coords(points);
+ self.path = Some(path.into());
+ path
+ }
 }

crates/fj-kernel/src/builder/edge.rs

@@ -150,6 +150,7 @@ impl HalfEdgeBuilder for PartialHalfEdge {
  }
 
  fn update_as_line_segment(&mut self) {
+ let boundary = self.vertices.each_ref_ext().map(|vertex| vertex.0);
  let points_surface = self.vertices.each_ref_ext().map(|vertex| {
  vertex
  .1
@@ -158,13 +159,23 @@ impl HalfEdgeBuilder for PartialHalfEdge {
  .expect("Can't infer line segment without surface position")
  });
 
- self.curve
- .write()
- .update_as_line_from_points(points_surface);
-
- for (vertex, position) in self.vertices.each_mut_ext().zip_ext([0., 1.])
- {
- vertex.0 = Some([position].into());
+ if let [Some(start), Some(end)] = boundary {
+ let boundary = [start, end];
+ self.curve
+ .write()
+ .update_as_line_from_points_with_line_coords(
+ boundary.zip_ext(points_surface),
+ );
+ } else {
+ self.curve
+ .write()
+ .update_as_line_from_points(points_surface);
+
+ for (vertex, position) in
+ self.vertices.each_mut_ext().zip_ext([0., 1.])
+ {
+ vertex.0 = Some([position].into());
+ }
  }
 
  self.infer_global_form();

crates/fj-kernel/src/geometry/path.rs

@@ -58,6 +58,13 @@ impl SurfacePath {
  (Self::Line(line), coords)
  }
 
+ /// Create a line from two points that include line coordinates
+ pub fn from_points_with_line_coords(
+ points: [(impl Into<Point<1>>, impl Into<Point<2>>); 2],
+ ) -> Self {
+ Self::Line(Line::from_points_with_line_coords(points))
+ }
+
  /// Convert a point on the path into surface coordinates
  pub fn point_from_path_coords(
  &self,

crates/fj-math/src/line.rs

@@ -181,6 +181,30 @@ mod tests {
 
  use super::Line;
 
+ #[test]
+ fn from_points_with_line_coords() {
+ let line = Line::from_points_with_line_coords([
+ ([0.], [0., 0.]),
+ ([1.], [1., 0.]),
+ ]);
+ assert_eq!(line.origin(), Point::from([0., 0.]));
+ assert_eq!(line.direction(), Vector::from([1., 0.]));
+
+ let line = Line::from_points_with_line_coords([
+ ([1.], [0., 1.]),
+ ([0.], [1., 1.]),
+ ]);
+ assert_eq!(line.origin(), Point::from([1., 1.]));
+ assert_eq!(line.direction(), Vector::from([-1., 0.]));
+
+ let line = Line::from_points_with_line_coords([
+ ([-1.], [0., 2.]),
+ ([0.], [1., 2.]),
+ ]);
+ assert_eq!(line.origin(), Point::from([1., 2.]));
+ assert_eq!(line.direction(), Vector::from([1., 0.]));
+ }
+
  #[test]
  fn is_coincident_with() {
  let (line, _) = Line::from_points([[0., 0.], [1., 0.]]);