Make Curve generic over its dimensionality

crates/fj-kernel/src/algorithms/approx/curves.rs

@@ -21,9 +21,9 @@ use super::Tolerance;
 /// The `approximate_between` methods of the curves then need to make sure to
 /// only return points in between those vertices, not the vertices themselves.
 pub fn approx_curve(
-    curve: &Curve,
+    curve: &Curve<3>,
     tolerance: Tolerance,
-    out: &mut Vec<geometry::Point<1>>,
+    out: &mut Vec<geometry::Point<1, 3>>,
 ) {
     match curve {
         Curve::Circle(curve) => approx_circle(curve, tolerance, out),
@@ -38,7 +38,7 @@ pub fn approx_curve(
 pub fn approx_circle(
     circle: &Circle<3>,
     tolerance: Tolerance,
-    out: &mut Vec<geometry::Point<1>>,
+    out: &mut Vec<geometry::Point<1, 3>>,
 ) {
     let radius = circle.a.magnitude();
 

crates/fj-kernel/src/algorithms/approx/cycles.rs

@@ -8,7 +8,7 @@ use super::{curves::approx_curve, edges::approximate_edge, Tolerance};
 #[derive(Debug, Eq, PartialEq, Hash)]
 pub struct CycleApprox {
     /// The points that approximate the cycle
-    pub points: Vec<geometry::Point<3>>,
+    pub points: Vec<geometry::Point<3, 3>>,
 }
 
 impl CycleApprox {

crates/fj-kernel/src/algorithms/approx/edges.rs

@@ -2,8 +2,8 @@ use crate::{geometry, topology::EdgeVertex};
 
 pub fn approximate_edge(
     vertices: Option<[EdgeVertex; 2]>,
-    mut points: Vec<geometry::Point<1>>,
-) -> Vec<geometry::Point<1>> {
+    mut points: Vec<geometry::Point<1, 3>>,
+) -> Vec<geometry::Point<1, 3>> {
     // Insert the exact vertices of this edge into the approximation. This means
     // we don't rely on the curve approximation to deliver accurate
     // representations of these vertices, which they might not be able to do.

crates/fj-kernel/src/algorithms/approx/faces.rs

@@ -11,7 +11,7 @@ pub struct FaceApprox {
     ///
     /// These could be actual vertices from the model, points that approximate
     /// an edge, or points that approximate a face.
-    pub points: HashSet<geometry::Point<3>>,
+    pub points: HashSet<geometry::Point<3, 3>>,
 
     /// Approximation of the exterior cycle
     pub exterior: CycleApprox,

crates/fj-kernel/src/algorithms/intersection/surface_surface.rs

@@ -3,7 +3,7 @@ use fj_math::{Line, Point, Scalar, Vector};
 use crate::geometry::{Curve, Surface};
 
 /// Test intersection between two surfaces
-pub fn surface_surface(a: &Surface, b: &Surface) -> Option<Curve> {
+pub fn surface_surface(a: &Surface, b: &Surface) -> Option<Curve<3>> {
     // Algorithm from Real-Time Collision Detection by Christer Ericson. See
     // section 5.4.4, Intersection of Two Planes.
 

crates/fj-kernel/src/algorithms/triangulation/delaunay.rs

@@ -5,8 +5,8 @@ use crate::geometry;
 
 /// Create a Delaunay triangulation of all points
 pub fn triangulate(
-    points: Vec<geometry::Point<2>>,
-) -> Vec<[geometry::Point<2>; 3]> {
+    points: Vec<geometry::Point<2, 3>>,
+) -> Vec<[geometry::Point<2, 3>; 3]> {
     use spade::Triangulation as _;
 
     let triangulation = spade::DelaunayTriangulation::<_>::bulk_load(points)
@@ -31,7 +31,7 @@ pub fn triangulate(
 }
 
 // Enables the use of `geometry::Point` in the triangulation.
-impl HasPosition for geometry::Point<2> {
+impl HasPosition for geometry::Point<2, 3> {
     type Scalar = Scalar;
 
     fn position(&self) -> spade::Point2<Self::Scalar> {

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

@@ -11,16 +11,20 @@ use crate::geometry;
 /// The nomenclature is inspired by Boundary Representation Modelling Techniques
 /// by Ian Stroud. "Curve" refers to unbounded one-dimensional geometry, while
 /// while edges are bounded portions of curves.
+///
+/// The `D` parameter defines the dimensions in which the curve is defined.
+/// Typically, only `2` or `3` make sense, which means the curve is defined on
+/// a surface or in a space, respectively.
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
-pub enum Curve {
+pub enum Curve<const D: usize> {
     /// A circle
-    Circle(Circle<3>),
+    Circle(Circle<D>),
 
     /// A line
-    Line(Line<3>),
+    Line(Line<D>),
 }
 
-impl Curve {
+impl Curve<3> {
     /// Construct a `Curve` that represents the x-axis
     pub fn x_axis() -> Self {
         Self::Line(Line {
@@ -45,8 +49,21 @@ impl Curve {
         })
     }
 
+    /// Create a new instance that is transformed by `transform`
+    #[must_use]
+    pub fn transform(self, transform: &Transform) -> Self {
+        match self {
+            Self::Circle(curve) => {
+                Self::Circle(transform.transform_circle(&curve))
+            }
+            Self::Line(curve) => Self::Line(transform.transform_line(&curve)),
+        }
+    }
+}
+
+impl<const D: usize> Curve<D> {
     /// Access the origin of the curve's coordinate system
-    pub fn origin(&self) -> Point<3> {
+    pub fn origin(&self) -> Point<D> {
         match self {
             Self::Circle(curve) => curve.center,
             Self::Line(curve) => curve.origin,
@@ -62,17 +79,6 @@ impl Curve {
         }
     }
 
-    /// Create a new instance that is transformed by `transform`
-    #[must_use]
-    pub fn transform(self, transform: &Transform) -> Self {
-        match self {
-            Self::Circle(curve) => {
-                Self::Circle(transform.transform_circle(&curve))
-            }
-            Self::Line(curve) => Self::Line(transform.transform_line(&curve)),
-        }
-    }
-
     /// Convert a point in model coordinates to curve coordinates
     ///
     /// Projects the point onto the curve before computing curve coordinate.
@@ -84,23 +90,25 @@ impl Curve {
     /// an error.
     pub fn point_to_curve_coords(
         &self,
-        point: impl Into<Point<3>>,
-    ) -> geometry::Point<1> {
-        let point_3d = point.into();
+        point: impl Into<Point<D>>,
+    ) -> geometry::Point<1, D> {
+        let point_canonical = point.into();
 
-        let point_1d = match self {
-            Self::Circle(curve) => curve.point_to_circle_coords(point_3d),
-            Self::Line(curve) => curve.point_to_line_coords(point_3d),
+        let point_native = match self {
+            Self::Circle(curve) => {
+                curve.point_to_circle_coords(point_canonical)
+            }
+            Self::Line(curve) => curve.point_to_line_coords(point_canonical),
         };
 
-        geometry::Point::new(point_1d, point_3d)
+        geometry::Point::new(point_native, point_canonical)
     }
 
     /// Convert a point on the curve into model coordinates
     pub fn point_from_curve_coords(
         &self,
         point: impl Into<Point<1>>,
-    ) -> Point<3> {
+    ) -> Point<D> {
         match self {
             Self::Circle(curve) => curve.point_from_circle_coords(point),
             Self::Line(curve) => curve.point_from_line_coords(point),
@@ -111,7 +119,7 @@ impl Curve {
     pub fn vector_from_curve_coords(
         &self,
         point: impl Into<Vector<1>>,
-    ) -> Vector<3> {
+    ) -> Vector<D> {
         match self {
             Self::Circle(curve) => curve.vector_from_circle_coords(point),
             Self::Line(curve) => curve.vector_from_line_coords(point),

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

@@ -1,33 +1,36 @@
-/// A point that can be losslessly converted into its canonical form
+/// A point that stores a native and a canonical form
 ///
-/// The canonical form is always the 3D representation. It needs to be provided
-/// when constructing the point, along with the point's native form.
+/// The native form of a point is whatever representation is most appropriate in
+/// the current context. The canonical form is the representation that the
+/// native form was created from.
+///
+/// Typically, the canonical form is more general and has higher dimensionality
+/// (for example, a point in a 3D space), while the native form is more specific
+/// and has lower dimensionality (for example, the point in 2D surface
+/// coordinates, on surface within that 3D space).
+///
+/// The purpose of storing both forms is to be able to losslessly convert the
+/// point back to its canonical form. Even if this conversion can be computed on
+/// the fly, such a conversion might not result in the original canonical form,
+/// due to floating point accuracy issues. Hence, such a conversion would not be
+/// lossless, which could result in bugs.
+///
+/// The `N` parameter defines the dimensionality of the native form, while the
+/// `C` parameter defines the dimensionality of the canonical form.
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
-pub struct Point<const D: usize> {
-    /// This point's native form
-    ///
-    /// The native form of the point is its representation in its native
-    /// coordinate system. This could be a 1-dimensional curve, 2-dimensional
-    /// surface, or 3-dimensional model coordinate system.
-    native: fj_math::Point<D>,
-
-    /// The canonical form of the point
-    ///
-    /// This is always the 3D representation of the point. Since this is always
-    /// kept here, unchanged, as the point is converted into other coordinate
-    /// systems, it allows for a lossless conversion back into 3D coordinates,
-    /// unaffected by floating point accuracy issues.
-    canonical: fj_math::Point<3>,
+pub struct Point<const N: usize, const C: usize> {
+    native: fj_math::Point<N>,
+    canonical: fj_math::Point<C>,
 }
 
-impl<const D: usize> Point<D> {
+impl<const N: usize, const C: usize> Point<N, C> {
     /// Construct a new instance
     ///
-    /// Both the native and the canonical form must be provide. The caller must
-    /// guarantee that both of them match.
+    /// Both the native and the canonical form must be provided. The caller must
+    /// guarantee that both of them match, i.e. define the same point.
     pub fn new(
-        native: impl Into<fj_math::Point<D>>,
-        canonical: impl Into<fj_math::Point<3>>,
+        native: impl Into<fj_math::Point<N>>,
+        canonical: impl Into<fj_math::Point<C>>,
     ) -> Self {
         Self {
             native: native.into(),
@@ -36,12 +39,12 @@ impl<const D: usize> Point<D> {
     }
 
     /// Access the point's native form
-    pub fn native(&self) -> fj_math::Point<D> {
+    pub fn native(&self) -> fj_math::Point<N> {
         self.native
     }
 
     /// Access the point's canonical form
-    pub fn canonical(&self) -> fj_math::Point<3> {
+    pub fn canonical(&self) -> fj_math::Point<C> {
         self.canonical
     }
 }

crates/fj-kernel/src/geometry/surfaces/mod.rs

@@ -62,7 +62,7 @@ impl Surface {
     pub fn point_to_surface_coords(
         &self,
         point_3d: impl Into<Point<3>>,
-    ) -> geometry::Point<2> {
+    ) -> geometry::Point<2, 3> {
         let point_3d = point_3d.into();
 
         let point_2d = match self {

crates/fj-kernel/src/geometry/surfaces/swept.rs

@@ -6,7 +6,7 @@ use crate::geometry::Curve;
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub struct SweptCurve {
     /// The curve that this surface was swept from
-    pub curve: Curve,
+    pub curve: Curve<3>,
 
     /// The path that the curve was swept along
     pub path: Vector<3>,

crates/fj-kernel/src/shape/api.rs

@@ -147,7 +147,7 @@ impl Shape {
     /// Access an iterator over all curves
     ///
     /// The caller must not make any assumptions about the order of curves.
-    pub fn curves(&self) -> Iter<Curve> {
+    pub fn curves(&self) -> Iter<Curve<3>> {
         self.stores.curves.iter()
     }
 
@@ -385,7 +385,7 @@ mod tests {
             }
         }
 
-        fn add_curve(&mut self) -> Handle<Curve> {
+        fn add_curve(&mut self) -> Handle<Curve<3>> {
             self.insert(Curve::x_axis()).unwrap()
         }
 

crates/fj-kernel/src/shape/object.rs

@@ -14,7 +14,7 @@ pub trait Object:
 }
 
 impl private::Sealed for Point<3> {}
-impl private::Sealed for Curve {}
+impl private::Sealed for Curve<3> {}
 impl private::Sealed for Surface {}
 
 impl private::Sealed for Vertex {}
@@ -23,7 +23,7 @@ impl private::Sealed for Cycle {}
 impl private::Sealed for Face {}
 
 impl Object for Point<3> {}
-impl Object for Curve {}
+impl Object for Curve<3> {}
 impl Object for Surface {}
 
 impl Object for Vertex {}

crates/fj-kernel/src/shape/stores.rs

@@ -52,7 +52,7 @@ impl Stores {
 }
 
 pub type Points = Store<Point<3>>;
-pub type Curves = Store<Curve>;
+pub type Curves = Store<Curve<3>>;
 pub type Surfaces = Store<Surface>;
 
 pub type Vertices = Store<Vertex>;

crates/fj-kernel/src/shape/validate.rs

@@ -23,7 +23,7 @@ impl Validate for Point<3> {
     }
 }
 
-impl Validate for Curve {
+impl Validate for Curve<3> {
     fn validate(&self, _: Scalar, _: &Stores) -> Result<(), ValidationError> {
         Ok(())
     }
@@ -202,7 +202,7 @@ pub enum ValidationError {
 impl ValidationError {
     /// Indicate whether validation found a missing curve
     #[cfg(test)]
-    pub fn missing_curve(&self, curve: &Handle<Curve>) -> bool {
+    pub fn missing_curve(&self, curve: &Handle<Curve<3>>) -> bool {
         if let Self::Structural(StructuralIssues { missing_curve, .. }) = self {
             return missing_curve.as_ref() == Some(curve);
         }
@@ -270,7 +270,7 @@ impl From<StructuralIssues> for ValidationError {
 #[derive(Debug, Default)]
 pub struct StructuralIssues {
     /// Missing curve found in edge validation
-    pub missing_curve: Option<Handle<Curve>>,
+    pub missing_curve: Option<Handle<Curve<3>>>,
 
     /// Missing vertices found in edge validation
     pub missing_vertices: HashSet<Handle<Vertex>>,

crates/fj-kernel/src/topology/edges.rs

@@ -26,7 +26,7 @@ pub struct Edge {
     /// The edge can be a segment of the curve that is bounded by two vertices,
     /// or if the curve is continuous (i.e. connects to itself), the edge could
     /// be defined by the whole curve, and have no bounding vertices.
-    pub curve: Handle<Curve>,
+    pub curve: Handle<Curve<3>>,
 
     /// Access the vertices that bound the edge on the curve
     ///
@@ -38,7 +38,7 @@ pub struct Edge {
 impl Edge {
     /// Construct an instance of `Edge`
     pub fn new(
-        curve: Handle<Curve>,
+        curve: Handle<Curve<3>>,
         vertices: Option<[Handle<Vertex>; 2]>,
     ) -> Self {
         let vertices = vertices.map(|vertices| {
@@ -61,7 +61,7 @@ impl Edge {
     ///
     /// This is a convenience method that saves the caller from dealing with the
     /// [`Handle`].
-    pub fn curve(&self) -> Curve {
+    pub fn curve(&self) -> Curve<3> {
         self.curve.get()
     }
 
@@ -98,5 +98,5 @@ pub struct EdgeVertex {
     /// The local representation of the vertex
     ///
     /// Represents the vertex in terms of the coordinates of the edge's curve.
-    pub local: geometry::Point<1>,
+    pub local: geometry::Point<1, 3>,
 }