Clean up HalfEdgeBuilder, make it more flexible

crates/fj-kernel/src/algorithms/intersect/curve_edge.rs

@@ -88,7 +88,8 @@ mod tests {
         let surface = Surface::xy_plane();
         let curve = Curve::builder(&stores, surface).build_u_axis();
         let half_edge = HalfEdge::builder(&stores, surface)
-            .build_line_segment_from_points([[1., -1.], [1., 1.]]);
+            .as_line_segment_from_points([[1., -1.], [1., 1.]])
+            .build();
 
         let intersection = CurveEdgeIntersection::compute(&curve, &half_edge);
 
@@ -107,7 +108,8 @@ mod tests {
         let surface = Surface::xy_plane();
         let curve = Curve::builder(&stores, surface).build_u_axis();
         let half_edge = HalfEdge::builder(&stores, surface)
-            .build_line_segment_from_points([[-1., -1.], [-1., 1.]]);
+            .as_line_segment_from_points([[-1., -1.], [-1., 1.]])
+            .build();
 
         let intersection = CurveEdgeIntersection::compute(&curve, &half_edge);
 
@@ -126,7 +128,8 @@ mod tests {
         let surface = Surface::xy_plane();
         let curve = Curve::builder(&stores, surface).build_u_axis();
         let half_edge = HalfEdge::builder(&stores, surface)
-            .build_line_segment_from_points([[-1., -1.], [1., -1.]]);
+            .as_line_segment_from_points([[-1., -1.], [1., -1.]])
+            .build();
 
         let intersection = CurveEdgeIntersection::compute(&curve, &half_edge);
 
@@ -140,7 +143,8 @@ mod tests {
         let surface = Surface::xy_plane();
         let curve = Curve::builder(&stores, surface).build_u_axis();
         let half_edge = HalfEdge::builder(&stores, surface)
-            .build_line_segment_from_points([[-1., 0.], [1., 0.]]);
+            .as_line_segment_from_points([[-1., 0.], [1., 0.]])
+            .build();
 
         let intersection = CurveEdgeIntersection::compute(&curve, &half_edge);
 

crates/fj-kernel/src/algorithms/sweep/edge.rs

@@ -192,23 +192,28 @@ mod tests {
         let stores = Stores::new();
 
         let half_edge = HalfEdge::builder(&stores, Surface::xy_plane())
-            .build_line_segment_from_points([[0., 0.], [1., 0.]]);
+            .as_line_segment_from_points([[0., 0.], [1., 0.]])
+            .build();
 
         let face = (half_edge, Color::default()).sweep([0., 0., 1.], &stores);
 
         let expected_face = {
             let surface = Surface::xz_plane();
 
             let bottom = HalfEdge::builder(&stores, surface)
-                .build_line_segment_from_points([[0., 0.], [1., 0.]]);
+                .as_line_segment_from_points([[0., 0.], [1., 0.]])
+                .build();
             let top = HalfEdge::builder(&stores, surface)
-                .build_line_segment_from_points([[0., 1.], [1., 1.]])
+                .as_line_segment_from_points([[0., 1.], [1., 1.]])
+                .build()
                 .reverse();
             let left = HalfEdge::builder(&stores, surface)
-                .build_line_segment_from_points([[0., 0.], [0., 1.]])
+                .as_line_segment_from_points([[0., 0.], [0., 1.]])
+                .build()
                 .reverse();
             let right = HalfEdge::builder(&stores, surface)
-                .build_line_segment_from_points([[1., 0.], [1., 1.]]);
+                .as_line_segment_from_points([[1., 0.], [1., 1.]])
+                .build();
 
             let cycle = Cycle::new(surface, [bottom, right, top, left]);
 

crates/fj-kernel/src/algorithms/sweep/face.rs

@@ -113,7 +113,8 @@ mod tests {
             let [a, b] = [window[0], window[1]];
 
             let half_edge = HalfEdge::builder(&stores, Surface::xy_plane())
-                .build_line_segment_from_points([a, b]);
+                .as_line_segment_from_points([a, b])
+                .build();
             (half_edge, Color::default()).sweep(UP, &stores)
         });
 
@@ -148,7 +149,8 @@ mod tests {
             let [a, b] = [window[0], window[1]];
 
             let half_edge = HalfEdge::builder(&stores, Surface::xy_plane())
-                .build_line_segment_from_points([a, b])
+                .as_line_segment_from_points([a, b])
+                .build()
                 .reverse();
             (half_edge, Color::default()).sweep(DOWN, &stores)
         });

crates/fj-kernel/src/algorithms/sweep/vertex.rs

@@ -166,7 +166,8 @@ mod tests {
         let half_edge = (vertex, surface).sweep([0., 0., 1.], &stores);
 
         let expected_half_edge = HalfEdge::builder(&stores, surface)
-            .build_line_segment_from_points([[0., 0.], [0., 1.]]);
+            .as_line_segment_from_points([[0., 0.], [0., 1.]])
+            .build();
         assert_eq!(half_edge, expected_half_edge);
     }
 

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

@@ -53,7 +53,8 @@ impl<'a> CycleBuilder<'a> {
 
             self.half_edges.push(
                 HalfEdge::builder(self.stores, self.surface)
-                    .build_line_segment_from_points(points),
+                    .as_line_segment_from_points(points)
+                    .build(),
             );
         }
 
@@ -74,7 +75,8 @@ impl<'a> CycleBuilder<'a> {
                 [last, first].map(|vertex| vertex.surface_form().position());
             self.half_edges.push(
                 HalfEdge::builder(self.stores, self.surface)
-                    .build_line_segment_from_points(vertices),
+                    .as_line_segment_from_points(vertices)
+                    .build(),
             );
         }
 

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

@@ -9,23 +9,50 @@ use crate::{
     stores::Stores,
 };
 
-/// API for building an [`HalfEdge`]
+/// API for building a [`HalfEdge`]
 ///
 /// Also see [`HalfEdge::builder`].
 pub struct HalfEdgeBuilder<'a> {
     /// The stores that the created objects are put in
     pub stores: &'a Stores,
 
-    /// The surface that the [`HalfEdge`] is defined in
+    /// The surface that the [`HalfEdge`]'s [`Curve`] is defined in
     pub surface: Surface,
+
+    /// The curve that the [`HalfEdge`] is defined in
+    pub curve: Option<Curve>,
+
+    /// The vertices that bound this [`HalfEdge`] in the [`Curve`]
+    pub vertices: Option<[Vertex; 2]>,
+
+    /// The global form of the [`HalfEdge`]
+    ///
+    /// Can be provided to the builder, if available, or computed by one of the
+    /// build methods.
+    pub global_form: Option<GlobalEdge>,
 }
 
 impl<'a> HalfEdgeBuilder<'a> {
-    /// Build a circle from the given radius
-    pub fn build_circle_from_radius(
-        self,
-        radius: impl Into<Scalar>,
-    ) -> HalfEdge {
+    /// Build the [`HalfEdge`] with the given curve
+    pub fn with_curve(mut self, curve: Curve) -> Self {
+        self.curve = Some(curve);
+        self
+    }
+
+    /// Build the [`HalfEdge`] with the given vertices
+    pub fn with_vertices(mut self, vertices: [Vertex; 2]) -> Self {
+        self.vertices = Some(vertices);
+        self
+    }
+
+    /// Build the [`HalfEdge`] with the provided global form
+    pub fn with_global_form(mut self, global_form: GlobalEdge) -> Self {
+        self.global_form = Some(global_form);
+        self
+    }
+
+    /// Build the [`HalfEdge`] as a circle from the given radius
+    pub fn as_circle_from_radius(mut self, radius: impl Into<Scalar>) -> Self {
         let curve = Curve::builder(self.stores, self.surface)
             .build_circle_from_radius(radius);
 
@@ -57,17 +84,17 @@ impl<'a> HalfEdgeBuilder<'a> {
             )
         };
 
-        let global_form = GlobalEdge::builder()
-            .build_from_curve_and_vertices(&curve, &vertices);
+        self.curve = Some(curve);
+        self.vertices = Some(vertices);
 
-        HalfEdge::new(curve, vertices, global_form)
+        self
     }
 
-    /// Build a line segment from two points
-    pub fn build_line_segment_from_points(
-        self,
+    /// Build the [`HalfEdge`] as a line segment from the given points
+    pub fn as_line_segment_from_points(
+        mut self,
         points: [impl Into<Point<2>>; 2],
-    ) -> HalfEdge {
+    ) -> Self {
         let points = points.map(Into::into);
 
         let global_vertices = points.map(|position| {
@@ -124,8 +151,23 @@ impl<'a> HalfEdgeBuilder<'a> {
             ]
         };
 
-        let global_form = GlobalEdge::builder()
-            .build_from_curve_and_vertices(&curve, &vertices);
+        self.curve = Some(curve);
+        self.vertices = Some(vertices);
+
+        self
+    }
+
+    /// Finish building the [`HalfEdge`]
+    pub fn build(self) -> HalfEdge {
+        let curve = self.curve.expect("Can't build `HalfEdge` without curve");
+        let vertices = self
+            .vertices
+            .expect("Can't build `HalfEdge` without vertices");
+
+        let global_form = self.global_form.unwrap_or_else(|| {
+            GlobalEdge::builder()
+                .build_from_curve_and_vertices(&curve, &vertices)
+        });
 
         HalfEdge::new(curve, vertices, global_form)
     }

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

@@ -38,7 +38,7 @@ impl VertexBuilder {
         self
     }
 
-    /// Build a vertex from a curve position
+    /// Finish building the [`Vertex`]
     pub fn build(self) -> Vertex {
         let surface_form = self.surface_form.unwrap_or_else(|| {
             SurfaceVertexBuilder {

crates/fj-kernel/src/iter.rs

@@ -462,7 +462,8 @@ mod tests {
         let stores = Stores::new();
 
         let object = HalfEdge::builder(&stores, Surface::xy_plane())
-            .build_line_segment_from_points([[0., 0.], [1., 0.]]);
+            .as_line_segment_from_points([[0., 0.], [1., 0.]])
+            .build();
 
         assert_eq!(1, object.curve_iter().count());
         assert_eq!(0, object.cycle_iter().count());

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

@@ -18,7 +18,13 @@ pub struct HalfEdge {
 impl HalfEdge {
     /// Build a `HalfEdge` using [`HalfEdgeBuilder`]
     pub fn builder(stores: &Stores, surface: Surface) -> HalfEdgeBuilder {
-        HalfEdgeBuilder { stores, surface }
+        HalfEdgeBuilder {
+            stores,
+            surface,
+            curve: None,
+            vertices: None,
+            global_form: None,
+        }
     }
 
     /// Create a new instance of `HalfEdge`

crates/fj-operations/src/sketch.rs

@@ -27,7 +27,8 @@ impl Shape for fj::Sketch {
                 // none need to be added here.
 
                 let half_edge = HalfEdge::builder(stores, surface)
-                    .build_circle_from_radius(circle.radius());
+                    .as_circle_from_radius(circle.radius())
+                    .build();
                 let cycle = Cycle::new(surface, [half_edge]);
 
                 Face::from_exterior(cycle).with_color(Color(self.color()))