From a5326b00b44bb15e6906074e53f554792b82e143 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hello@hannobraun.com>
Date: Mon, 28 Apr 2025 13:13:43 +0200
Subject: [PATCH] Add `geometry::Circle`

---
 experiments/2025-03-18/src/geometry/circle.rs | 18 ++++++++++++++++++
 experiments/2025-03-18/src/geometry/curve.rs  | 11 ++++++++---
 experiments/2025-03-18/src/geometry/mod.rs    |  5 +++--
 3 files changed, 29 insertions(+), 5 deletions(-)
 create mode 100644 experiments/2025-03-18/src/geometry/circle.rs

diff --git a/experiments/2025-03-18/src/geometry/circle.rs b/experiments/2025-03-18/src/geometry/circle.rs
new file mode 100644
index 000000000..005b4e894
--- /dev/null
+++ b/experiments/2025-03-18/src/geometry/circle.rs
@@ -0,0 +1,18 @@
+use fj_math::{Point, Vector};
+
+pub struct Circle {
+    pub a: Vector<3>,
+    pub b: Vector<3>,
+}
+
+impl Circle {
+    pub fn vector_from_local_point(
+        &self,
+        point: impl Into<Point<1>>,
+    ) -> Vector<3> {
+        let angle = point.into().t;
+        let (sin, cos) = angle.sin_cos();
+
+        self.a * cos + self.b * sin - self.a
+    }
+}
diff --git a/experiments/2025-03-18/src/geometry/curve.rs b/experiments/2025-03-18/src/geometry/curve.rs
index 551a4a281..cef7464a9 100644
--- a/experiments/2025-03-18/src/geometry/curve.rs
+++ b/experiments/2025-03-18/src/geometry/curve.rs
@@ -1,7 +1,7 @@
 use fj_interop::{CircleApproxParams, Tolerance};
 use fj_math::{Point, Transform, Vector};
 
-use super::Line;
+use super::{Circle, Line};
 
 /// # Curve geometry that has a fixed position (is _anchored_) in space
 ///
@@ -104,9 +104,14 @@ impl CurveGeometry for (Point<3>, fj_math::Circle<3>) {
     }
 
     fn point_from_local(&self, point: Point<1>) -> Point<3> {
-        let (_, circle) = *self;
+        let (offset, circle) = *self;
 
-        circle.point_from_circle_coords(point)
+        let circle = Circle {
+            a: circle.a(),
+            b: circle.b(),
+        };
+
+        offset + circle.vector_from_local_point(point)
     }
 
     fn project_point(&self, point: Point<3>) -> Point<1> {
diff --git a/experiments/2025-03-18/src/geometry/mod.rs b/experiments/2025-03-18/src/geometry/mod.rs
index 5b0c5f88e..c02d50b41 100644
--- a/experiments/2025-03-18/src/geometry/mod.rs
+++ b/experiments/2025-03-18/src/geometry/mod.rs
@@ -1,3 +1,4 @@
+mod circle;
 mod curve;
 mod line;
 mod sketch;
@@ -6,6 +7,6 @@ mod swept_curve;
 mod tri_mesh;
 
 pub use self::{
-    curve::AnchoredCurve, line::Line, sketch::Sketch, surface::SurfaceGeometry,
-    swept_curve::SweptCurve, tri_mesh::ToTriMesh,
+    circle::Circle, curve::AnchoredCurve, line::Line, sketch::Sketch,
+    surface::SurfaceGeometry, swept_curve::SweptCurve, tri_mesh::ToTriMesh,
 };