Merge pull request #1950 from hannobraun/curve

Add `Curve` object

crates/fj-core/src/algorithms/transform/curve.rs

@@ -0,0 +1,19 @@
+use fj_math::Transform;
+
+use crate::{objects::Curve, services::Services};
+
+use super::{TransformCache, TransformObject};
+
+impl TransformObject for Curve {
+    fn transform_with_cache(
+        self,
+        _: &Transform,
+        _: &mut Services,
+        _: &mut TransformCache,
+    ) -> Self {
+        // There's nothing to actually transform here, as `Curve` holds no data.
+        // We still need this implementation though, as a new `Curve` object
+        // must be created to represent the new and transformed curve.
+        Self::new()
+    }
+}

crates/fj-core/src/algorithms/transform/edge.rs

@@ -18,6 +18,10 @@ impl TransformObject for HalfEdge {
         // coordinates.
         let path = self.path();
         let boundary = self.boundary();
+        let curve = self
+            .curve()
+            .clone()
+            .transform_with_cache(transform, services, cache);
         let start_vertex = self
             .start_vertex()
             .clone()
@@ -27,7 +31,7 @@ impl TransformObject for HalfEdge {
             .clone()
             .transform_with_cache(transform, services, cache);
 
-        Self::new(path, boundary, start_vertex, global_form)
+        Self::new(path, boundary, curve, start_vertex, global_form)
     }
 }
 

crates/fj-core/src/algorithms/transform/mod.rs

@@ -1,5 +1,6 @@
 //! API for transforming objects
 
+mod curve;
 mod cycle;
 mod edge;
 mod face;

crates/fj-core/src/objects/kinds/curve.rs

@@ -0,0 +1,32 @@
+/// A curve
+///
+/// `Curve` represents a curve in space, but holds no data to define that curve.
+/// It is referenced by [`HalfEdge`], which defines the curve in the coordinates
+/// of its surface.
+///
+/// `Curve` exists to allow identifying which [`HalfEdge`]s are supposed to be
+/// coincident in global space.
+///
+/// # Equality
+///
+/// `Curve` contains no data and exists purely to be used within a `Handle`,
+/// where `Handle::id` can be used to compare different instances of `Curve`.
+///
+/// If `Curve` had `Eq`/`PartialEq` implementations, it containing no data would
+/// mean that all instances of `Curve` would be considered equal. This would be
+/// very error-prone.
+///
+/// If you need to reference a `Curve` from a struct that needs to derive
+/// `Eq`/`Ord`/..., you can use `HandleWrapper<Curve>` to do that. It will use
+/// `Handle::id` to provide those `Eq`/`Ord`/... implementations.
+///
+/// [`HalfEdge`]: crate::objects::HalfEdge
+#[derive(Clone, Debug, Default, Hash)]
+pub struct Curve {}
+
+impl Curve {
+    /// Create a new instance
+    pub fn new() -> Self {
+        Self::default()
+    }
+}

crates/fj-core/src/objects/kinds/edge.rs

@@ -2,7 +2,7 @@ use fj_math::Point;
 
 use crate::{
     geometry::{BoundaryOnCurve, SurfacePath},
-    objects::Vertex,
+    objects::{Curve, Vertex},
     storage::{Handle, HandleWrapper},
 };
 
@@ -42,6 +42,7 @@ use crate::{
 pub struct HalfEdge {
     path: SurfacePath,
     boundary: BoundaryOnCurve,
+    curve: HandleWrapper<Curve>,
     start_vertex: HandleWrapper<Vertex>,
     global_form: HandleWrapper<GlobalEdge>,
 }
@@ -51,12 +52,14 @@ impl HalfEdge {
     pub fn new(
         path: SurfacePath,
         boundary: impl Into<BoundaryOnCurve>,
+        curve: Handle<Curve>,
         start_vertex: Handle<Vertex>,
         global_form: Handle<GlobalEdge>,
     ) -> Self {
         Self {
             path,
             boundary: boundary.into(),
+            curve: curve.into(),
             start_vertex: start_vertex.into(),
             global_form: global_form.into(),
         }
@@ -82,6 +85,11 @@ impl HalfEdge {
         self.path.point_from_path_coords(start)
     }
 
+    /// Access the curve of the half-edge
+    pub fn curve(&self) -> &Handle<Curve> {
+        &self.curve
+    }
+
     /// Access the vertex from where this half-edge starts
     pub fn start_vertex(&self) -> &Handle<Vertex> {
         &self.start_vertex

crates/fj-core/src/objects/kinds/mod.rs

@@ -1,3 +1,4 @@
+pub mod curve;
 pub mod cycle;
 pub mod edge;
 pub mod face;

crates/fj-core/src/objects/mod.rs

@@ -46,6 +46,7 @@ mod stores;
 
 pub use self::{
     kinds::{
+        curve::Curve,
         cycle::{Cycle, HalfEdgesOfCycle},
         edge::{GlobalEdge, HalfEdge},
         face::{Face, FaceSet, Handedness},

crates/fj-core/src/objects/object.rs

@@ -1,7 +1,7 @@
 use crate::{
     objects::{
-        Cycle, Face, GlobalEdge, HalfEdge, Objects, Region, Shell, Sketch,
+        Curve, Cycle, Face, GlobalEdge, HalfEdge, Objects, Region, Shell,
-        Solid, Surface, Vertex,
+        Sketch, Solid, Surface, Vertex,
     },
     storage::{Handle, HandleWrapper, ObjectId},
     validate::{Validate, ValidationError},
@@ -91,6 +91,7 @@ macro_rules! object {
 }
 
 object!(
+    Curve, "curve", curves;
     Cycle, "cycle", cycles;
     Face, "face", faces;
     GlobalEdge, "global edge", global_edges;

crates/fj-core/src/objects/stores.rs

@@ -6,13 +6,16 @@ use crate::{
 };
 
 use super::{
-    Cycle, Face, GlobalEdge, HalfEdge, Region, Shell, Sketch, Solid, Surface,
+    Curve, Cycle, Face, GlobalEdge, HalfEdge, Region, Shell, Sketch, Solid,
-    Vertex,
+    Surface, Vertex,
 };
 
 /// The available object stores
 #[derive(Debug, Default)]
 pub struct Objects {
+    /// Store for [`Curve`]s
+    pub curves: Store<Curve>,
+
     /// Store for [`Cycle`]s
     pub cycles: Store<Cycle>,
 

crates/fj-core/src/operations/build/edge.rs

@@ -3,7 +3,7 @@ use fj_math::{Arc, Point, Scalar};
 
 use crate::{
     geometry::{BoundaryOnCurve, SurfacePath},
-    objects::{GlobalEdge, HalfEdge, Vertex},
+    objects::{Curve, GlobalEdge, HalfEdge, Vertex},
     operations::Insert,
     services::Services,
 };
@@ -16,10 +16,11 @@ pub trait BuildHalfEdge {
         boundary: impl Into<BoundaryOnCurve>,
         services: &mut Services,
     ) -> HalfEdge {
+        let curve = Curve::new().insert(services);
         let start_vertex = Vertex::new().insert(services);
         let global_form = GlobalEdge::new().insert(services);
 
-        HalfEdge::new(path, boundary, start_vertex, global_form)
+        HalfEdge::new(path, boundary, curve, start_vertex, global_form)
     }
 
     /// Create an arc

crates/fj-core/src/operations/insert.rs

@@ -1,6 +1,6 @@
 use crate::{
     objects::{
-        Cycle, Face, GlobalEdge, HalfEdge, Region, Shell, Sketch, Solid,
+        Curve, Cycle, Face, GlobalEdge, HalfEdge, Region, Shell, Sketch, Solid,
         Surface, Vertex,
     },
     services::Services,
@@ -43,6 +43,7 @@ macro_rules! impl_insert {
 }
 
 impl_insert!(
+    Curve, curves;
     Cycle, cycles;
     Face, faces;
     GlobalEdge, global_edges;

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

@@ -14,6 +14,7 @@ impl Reverse for Cycle {
                 HalfEdge::new(
                     current.path(),
                     current.boundary().reverse(),
+                    current.curve().clone(),
                     next.start_vertex().clone(),
                     current.global_form().clone(),
                 )

crates/fj-core/src/operations/update/edge.rs

@@ -19,6 +19,7 @@ impl UpdateHalfEdge for HalfEdge {
         HalfEdge::new(
             self.path(),
             self.boundary(),
+            self.curve().clone(),
             start_vertex,
             self.global_form().clone(),
         )
@@ -28,6 +29,7 @@ impl UpdateHalfEdge for HalfEdge {
         HalfEdge::new(
             self.path(),
             self.boundary(),
+            self.curve().clone(),
             self.start_vertex().clone(),
             global_form,
         )

crates/fj-core/src/validate/curve.rs

@@ -0,0 +1,12 @@
+use crate::objects::Curve;
+
+use super::{Validate, ValidationConfig, ValidationError};
+
+impl Validate for Curve {
+    fn validate_with_config(
+        &self,
+        _: &ValidationConfig,
+        _: &mut Vec<ValidationError>,
+    ) {
+    }
+}

crates/fj-core/src/validate/edge.rs

@@ -95,6 +95,7 @@ mod tests {
             HalfEdge::new(
                 valid.path(),
                 boundary,
+                valid.curve().clone(),
                 valid.start_vertex().clone(),
                 valid.global_form().clone(),
             )

crates/fj-core/src/validate/mod.rs

@@ -1,5 +1,6 @@
 //! Infrastructure for validating objects
 
+mod curve;
 mod cycle;
 mod edge;
 mod face;