Merge pull request #2110 from hannobraun/sweep

Extract `SweepCycle` from `SweepFace`

crates/fj-core/src/operations/sweep/cycle.rs

@@ -0,0 +1,105 @@
+use fj_interop::mesh::Color;
+use fj_math::Vector;
+
+use crate::{
+    objects::{Cycle, Face, Surface},
+    operations::{
+        build::BuildCycle, join::JoinCycle, sweep::half_edge::SweepHalfEdge,
+    },
+    services::Services,
+};
+
+use super::SweepCache;
+
+/// # Sweep a [`Cycle`]
+///
+/// See [module documentation] for more information.
+///
+/// [module documentation]: super
+pub trait SweepCycle {
+    /// # Sweep the [`Cycle`]
+    ///
+    /// Sweep the cycle into a set of connected faces. Each half-edge in the
+    /// cycle is swept into a face, meaning all resulting faces form a connected
+    /// set of side walls.
+    ///
+    /// Requires the surface that the half-edges of the cycle are defined in,
+    /// and optionally the color of the created faces.
+    ///
+    /// There is no face at the "top" (the end of the sweep path), as we don't
+    /// have enough information here to create that. We just have a single
+    /// cycle, and don't know whether that is supposed to be the only cycle
+    /// within a potential top face, or whether it's an exterior or interior
+    /// one.
+    ///
+    /// For the same reason, there also is no "bottom" face. Additionally,
+    /// whether a bottom face is even desirable depends on the context this
+    /// operation is called in, and therefore falls outside of its scope.
+    fn sweep_cycle(
+        &self,
+        surface: &Surface,
+        color: Option<Color>,
+        path: impl Into<Vector<3>>,
+        cache: &mut SweepCache,
+        services: &mut Services,
+    ) -> SweptCycle;
+}
+
+impl SweepCycle for Cycle {
+    fn sweep_cycle(
+        &self,
+        surface: &Surface,
+        color: Option<Color>,
+        path: impl Into<Vector<3>>,
+        cache: &mut SweepCache,
+        services: &mut Services,
+    ) -> SweptCycle {
+        let path = path.into();
+
+        let mut faces = Vec::new();
+        let mut top_edges = Vec::new();
+
+        for bottom_half_edge_pair in self.half_edges().pairs() {
+            let (bottom_half_edge, bottom_half_edge_next) =
+                bottom_half_edge_pair;
+
+            let (side_face, top_edge) = bottom_half_edge.sweep_half_edge(
+                bottom_half_edge_next.start_vertex().clone(),
+                surface,
+                color,
+                path,
+                cache,
+                services,
+            );
+
+            faces.push(side_face);
+
+            top_edges.push((
+                top_edge,
+                bottom_half_edge.path(),
+                bottom_half_edge.boundary(),
+            ));
+        }
+
+        let top_cycle = Cycle::empty().add_joined_edges(top_edges, services);
+
+        SweptCycle { faces, top_cycle }
+    }
+}
+
+/// The result of sweeping a cycle
+///
+/// See [`SweepCycle`].
+pub struct SweptCycle {
+    /// The faces created by sweeping each half-edge of the cycle
+    ///
+    /// See [`SweepCycle::sweep_cycle`] for more information.
+    pub faces: Vec<Face>,
+
+    /// A cycle mad up of the "top" half-edges of the resulting faces
+    ///
+    /// "Top" here refers to the place that the sweep path points to from the
+    /// original cycle. Essentially, this is a translated (along the sweep path)
+    /// and reversed version of the original cycle.
+    pub top_cycle: Cycle,
+}

crates/fj-core/src/operations/sweep/face.rs

@@ -1,18 +1,15 @@
-use std::ops::Deref;
-
 use fj_math::{Scalar, Vector};
 
 use crate::{
     algorithms::transform::TransformObject,
     geometry::GlobalPath,
     objects::{Cycle, Face, Region, Shell},
-    operations::{
-        build::BuildCycle, insert::Insert, join::JoinCycle, reverse::Reverse,
-    },
+    operations::{insert::Insert, reverse::Reverse},
     services::Services,
+    storage::Handle,
 };
 
-use super::{SweepCache, SweepHalfEdge};
+use super::{SweepCache, SweepCycle};
 
 /// # Sweep a [`Face`]
 ///
@@ -59,55 +56,32 @@ impl SweepFace for Face {
         let top_surface =
             bottom_face.surface().clone().translate(path, services);
 
-        let mut top_exterior = None;
+        let top_exterior = sweep_cycle(
+            bottom_face.region().exterior(),
+            &bottom_face,
+            &mut faces,
+            path,
+            cache,
+            services,
+        );
+
         let mut top_interiors = Vec::new();
 
-        // This might not be the cleanest way to do it, but here we're creating
-        // the side faces, and all the ingredients for the top face, in one big
-        // loop. Reason is, the side faces need to be connected to the top face,
-        // and this seems like the most straight-forward way to make sure of
-        // that.
-        for (i, bottom_cycle) in bottom_face.region().all_cycles().enumerate() {
-            let bottom_cycle = bottom_cycle.reverse(services);
-
-            let mut top_edges = Vec::new();
-            for bottom_half_edge_pair in bottom_cycle.half_edges().pairs() {
-                let (bottom_half_edge, bottom_half_edge_next) =
-                    bottom_half_edge_pair;
-
-                let (side_face, top_edge) = bottom_half_edge.sweep_half_edge(
-                    bottom_half_edge_next.start_vertex().clone(),
-                    bottom_face.surface().deref(),
-                    bottom_face.region().color(),
-                    path,
-                    cache,
-                    services,
-                );
-
-                let side_face = side_face.insert(services);
-
-                faces.push(side_face);
-
-                top_edges.push((
-                    top_edge,
-                    bottom_half_edge.path(),
-                    bottom_half_edge.boundary(),
-                ));
-            }
-
-            let top_cycle = Cycle::empty()
-                .add_joined_edges(top_edges, services)
-                .insert(services);
-
-            if i == 0 {
-                top_exterior = Some(top_cycle);
-            } else {
-                top_interiors.push(top_cycle);
-            };
+        for bottom_cycle in bottom_face.region().interiors() {
+            let top_cycle = sweep_cycle(
+                bottom_cycle,
+                &bottom_face,
+                &mut faces,
+                path,
+                cache,
+                services,
+            );
+
+            top_interiors.push(top_cycle);
         }
 
         let top_region = Region::new(
-            top_exterior.unwrap(),
+            top_exterior,
             top_interiors,
             bottom_face.region().color(),
         )
@@ -142,3 +116,29 @@ fn bottom_face(face: &Face, path: Vector<3>, services: &mut Services) -> Face {
         face.reverse(services)
     }
 }
+
+fn sweep_cycle(
+    bottom_cycle: &Cycle,
+    bottom_face: &Face,
+    faces: &mut Vec<Handle<Face>>,
+    path: Vector<3>,
+    cache: &mut SweepCache,
+    services: &mut Services,
+) -> Handle<Cycle> {
+    let swept_cycle = bottom_cycle.reverse(services).sweep_cycle(
+        bottom_face.surface(),
+        bottom_face.region().color(),
+        path,
+        cache,
+        services,
+    );
+
+    faces.extend(
+        swept_cycle
+            .faces
+            .into_iter()
+            .map(|side_face| side_face.insert(services)),
+    );
+
+    swept_cycle.top_cycle.insert(services)
+}

crates/fj-core/src/operations/sweep/mod.rs

@@ -3,15 +3,20 @@
 //! Sweeps 1D or 2D objects along a straight path, creating a 2D or 3D object,
 //! respectively.
 
+mod cycle;
 mod face;
 mod half_edge;
 mod path;
 mod sketch;
 mod vertex;
 
 pub use self::{
-    face::SweepFace, half_edge::SweepHalfEdge, path::SweepSurfacePath,
-    sketch::SweepSketch, vertex::SweepVertex,
+    cycle::{SweepCycle, SweptCycle},
+    face::SweepFace,
+    half_edge::SweepHalfEdge,
+    path::SweepSurfacePath,
+    sketch::SweepSketch,
+    vertex::SweepVertex,
 };
 
 use std::collections::BTreeMap;