From 4ee99de2fba55159b8a366b9544fb09dd4a4ca8b Mon Sep 17 00:00:00 2001
From: Mark Tolmacs <mark@lazycat.hu>
Date: Mon, 24 Mar 2025 15:24:06 +0100
Subject: [PATCH] Get three solutions for curve-line intersections to avoid
 issue with high inclination intersectors

---
 packages/math/src/curve.ts | 21 ++++++---------------
 packages/math/src/point.ts |  3 ++-
 packages/math/src/utils.ts |  2 +-
 3 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/packages/math/src/curve.ts b/packages/math/src/curve.ts
index a79fb43a19..a0b2e75c5c 100644
--- a/packages/math/src/curve.ts
+++ b/packages/math/src/curve.ts
@@ -157,22 +157,13 @@ export function curveIntersectLineSegment<
     return bezierEquation(c, t);
   };
 
-  let solution = calculate(initial_guesses[0]);
-  if (solution) {
-    return [solution];
-  }
+  const solutions = [
+    calculate(initial_guesses[0]),
+    calculate(initial_guesses[1]),
+    calculate(initial_guesses[2]),
+  ].filter((x, i, a): x is Point => x !== null && a.indexOf(x) === i);
 
-  solution = calculate(initial_guesses[1]);
-  if (solution) {
-    return [solution];
-  }
-
-  solution = calculate(initial_guesses[2]);
-  if (solution) {
-    return [solution];
-  }
-
-  return [];
+  return solutions;
 }
 
 /**
diff --git a/packages/math/src/point.ts b/packages/math/src/point.ts
index b6054a10a3..b760d020a7 100644
--- a/packages/math/src/point.ts
+++ b/packages/math/src/point.ts
@@ -91,9 +91,10 @@ export function isPoint(p: unknown): p is LocalPoint | GlobalPoint {
 export function pointsEqual<Point extends GlobalPoint | LocalPoint>(
   a: Point,
   b: Point,
+  precision: number = PRECISION,
 ): boolean {
   const abs = Math.abs;
-  return abs(a[0] - b[0]) < PRECISION && abs(a[1] - b[1]) < PRECISION;
+  return abs(a[0] - b[0]) < precision && abs(a[1] - b[1]) < precision;
 }
 
 /**
diff --git a/packages/math/src/utils.ts b/packages/math/src/utils.ts
index 8807c275e4..89765fa670 100644
--- a/packages/math/src/utils.ts
+++ b/packages/math/src/utils.ts
@@ -6,7 +6,7 @@ export const clamp = (value: number, min: number, max: number) => {
 
 export const round = (
   value: number,
-  precision: number,
+  precision: number = (Math.log(1 / PRECISION) * Math.LOG10E + 1) | 0,
   func: "round" | "floor" | "ceil" = "round",
 ) => {
   const multiplier = Math.pow(10, precision);