From 2e78643d26833b1a9cd41d724e192fa3dd7a30b0 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Fri, 21 Apr 2023 11:24:16 +0200
Subject: [PATCH 1/3] Convert `Triangle` into `Polygon`

---
 crates/fj-kernel/src/operations/build/face.rs  | 10 +++++-----
 crates/fj-kernel/src/operations/build/mod.rs   |  2 +-
 crates/fj-kernel/src/operations/build/shell.rs | 10 +++++-----
 crates/fj-kernel/src/operations/mod.rs         |  2 +-
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/crates/fj-kernel/src/operations/build/face.rs b/crates/fj-kernel/src/operations/build/face.rs
index 127777444..8f6cabe55 100644
--- a/crates/fj-kernel/src/operations/build/face.rs
+++ b/crates/fj-kernel/src/operations/build/face.rs
@@ -16,7 +16,7 @@ pub trait BuildFace {
     fn triangle(
         points: [impl Into<Point<3>>; 3],
         objects: &mut Service<Objects>,
-    ) -> Triangle {
+    ) -> Polygon<3> {
         let [a, b, c] = points.map(Into::into);
 
         let surface = Surface::plane_from_points([a, b, c]).insert(objects);
@@ -39,7 +39,7 @@ pub trait BuildFace {
 
         let face = Face::new(surface, exterior, [], None);
 
-        Triangle {
+        Polygon {
             face,
             edges,
             vertices,
@@ -52,13 +52,13 @@ impl BuildFace for Face {}
 /// A triangle
 ///
 /// Returned by [`BuildFace::triangle`].
-pub struct Triangle {
+pub struct Polygon<const D: usize> {
     /// The face that forms the triangle
     pub face: Face,
 
     /// The edges of the triangle
-    pub edges: [Handle<HalfEdge>; 3],
+    pub edges: [Handle<HalfEdge>; D],
 
     /// The vertices of the triangle
-    pub vertices: [Handle<Vertex>; 3],
+    pub vertices: [Handle<Vertex>; D],
 }
diff --git a/crates/fj-kernel/src/operations/build/mod.rs b/crates/fj-kernel/src/operations/build/mod.rs
index 2cc47ed35..7f2e1a85a 100644
--- a/crates/fj-kernel/src/operations/build/mod.rs
+++ b/crates/fj-kernel/src/operations/build/mod.rs
@@ -7,7 +7,7 @@ mod surface;
 pub use self::{
     cycle::BuildCycle,
     edge::BuildHalfEdge,
-    face::{BuildFace, Triangle},
+    face::{BuildFace, Polygon},
     shell::{BuildShell, Tetrahedron},
     surface::BuildSurface,
 };
diff --git a/crates/fj-kernel/src/operations/build/shell.rs b/crates/fj-kernel/src/operations/build/shell.rs
index a8f0f3376..a61298f0d 100644
--- a/crates/fj-kernel/src/operations/build/shell.rs
+++ b/crates/fj-kernel/src/operations/build/shell.rs
@@ -7,7 +7,7 @@ use crate::{
     storage::Handle,
 };
 
-use super::{BuildFace, Triangle};
+use super::{BuildFace, Polygon};
 
 /// Build a [`Shell`]
 pub trait BuildShell {
@@ -35,19 +35,19 @@ pub trait BuildShell {
     ) -> Tetrahedron {
         let [a, b, c, d] = points.map(Into::into);
 
-        let [Triangle {
+        let [Polygon {
             face: face_abc,
             edges: [ab, bc, ca],
             vertices: [a, b, c],
-        }, Triangle {
+        }, Polygon {
             face: face_bad,
             edges: [ba, ad, db],
             vertices: [_, _, d],
-        }, Triangle {
+        }, Polygon {
             face: face_dac,
             edges: [da, ac, cd],
             ..
-        }, Triangle {
+        }, Polygon {
             face: face_cbd,
             edges: [cb, bd, dc],
             ..
diff --git a/crates/fj-kernel/src/operations/mod.rs b/crates/fj-kernel/src/operations/mod.rs
index 7b05c5335..4d9185e0f 100644
--- a/crates/fj-kernel/src/operations/mod.rs
+++ b/crates/fj-kernel/src/operations/mod.rs
@@ -7,7 +7,7 @@ mod update;
 pub use self::{
     build::{
         BuildCycle, BuildFace, BuildHalfEdge, BuildShell, BuildSurface,
-        Tetrahedron, Triangle,
+        Polygon, Tetrahedron,
     },
     insert::Insert,
     update::{UpdateCycle, UpdateFace, UpdateHalfEdge, UpdateShell},

From d906a0d486ebc51b14a0ca70420276f1d3a369b6 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Fri, 21 Apr 2023 11:25:12 +0200
Subject: [PATCH 2/3] Update documentation of `Polygon`

---
 crates/fj-kernel/src/operations/build/face.rs | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/crates/fj-kernel/src/operations/build/face.rs b/crates/fj-kernel/src/operations/build/face.rs
index 8f6cabe55..5be614c85 100644
--- a/crates/fj-kernel/src/operations/build/face.rs
+++ b/crates/fj-kernel/src/operations/build/face.rs
@@ -49,16 +49,14 @@ pub trait BuildFace {
 
 impl BuildFace for Face {}
 
-/// A triangle
-///
-/// Returned by [`BuildFace::triangle`].
+/// A polygon
 pub struct Polygon<const D: usize> {
-    /// The face that forms the triangle
+    /// The face that forms the polygon
     pub face: Face,
 
-    /// The edges of the triangle
+    /// The edges of the polygon
     pub edges: [Handle<HalfEdge>; D],
 
-    /// The vertices of the triangle
+    /// The vertices of the polygon
     pub vertices: [Handle<Vertex>; D],
 }

From 8d389c882dae9b7713095a2bc77d002aa4a92c9a Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Fri, 21 Apr 2023 11:26:51 +0200
Subject: [PATCH 3/3] Add implementation note

---
 crates/fj-kernel/src/operations/build/face.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crates/fj-kernel/src/operations/build/face.rs b/crates/fj-kernel/src/operations/build/face.rs
index 5be614c85..d83536c88 100644
--- a/crates/fj-kernel/src/operations/build/face.rs
+++ b/crates/fj-kernel/src/operations/build/face.rs
@@ -50,6 +50,12 @@ pub trait BuildFace {
 impl BuildFace for Face {}
 
 /// A polygon
+///
+/// # Implementation Note
+///
+/// Currently code that deals with `Polygon` might assume that the polygon has
+/// no holes. Unless you create a `Polygon` yourself, or modify a `Polygon`'s
+/// `face` field to have interior cycles, this should not affect you.
 pub struct Polygon<const D: usize> {
     /// The face that forms the polygon
     pub face: Face,