Add infrastructure for defining half-edge geometry

crates/fj-core/src/geometry/geometry.rs

@@ -56,6 +56,14 @@ impl Geometry {
         self_
     }
 
+    pub(crate) fn define_half_edge_inner(
+        &mut self,
+        half_edge: Handle<HalfEdge>,
+        geometry: HalfEdgeGeometry,
+    ) {
+        self.half_edge.insert(half_edge, geometry);
+    }
+
     pub(crate) fn define_surface_inner(
         &mut self,
         surface: Handle<Surface>,

crates/fj-core/src/layers/geometry.rs

@@ -1,14 +1,30 @@
 //! Layer infrastructure for [`Geometry`]
 
 use crate::{
-    geometry::{Geometry, SurfaceGeometry},
+    geometry::{Geometry, HalfEdgeGeometry, SurfaceGeometry},
-    objects::Surface,
+    objects::{HalfEdge, Surface},
     storage::Handle,
 };
 
 use super::{Command, Event, Layer};
 
 impl Layer<Geometry> {
+    /// Define the geometry of the provided half-edge
+    pub fn define_half_edge(
+        &mut self,
+        half_edge: Handle<HalfEdge>,
+        geometry: HalfEdgeGeometry,
+    ) {
+        let mut events = Vec::new();
+        self.process(
+            DefineHalfEdge {
+                half_edge,
+                geometry,
+            },
+            &mut events,
+        );
+    }
+
     /// Define the geometry of the provided surface
     pub fn define_surface(
         &mut self,
@@ -20,6 +36,31 @@ impl Layer<Geometry> {
     }
 }
 
+/// Define the geometry of a half-edge
+pub struct DefineHalfEdge {
+    half_edge: Handle<HalfEdge>,
+    geometry: HalfEdgeGeometry,
+}
+
+impl Command<Geometry> for DefineHalfEdge {
+    type Result = ();
+    type Event = Self;
+
+    fn decide(
+        self,
+        _: &Geometry,
+        events: &mut Vec<Self::Event>,
+    ) -> Self::Result {
+        events.push(self);
+    }
+}
+
+impl Event<Geometry> for DefineHalfEdge {
+    fn evolve(&self, state: &mut Geometry) {
+        state.define_half_edge_inner(self.half_edge.clone(), self.geometry);
+    }
+}
+
 /// Define the geometry of a surface
 pub struct DefineSurface {
     surface: Handle<Surface>,