fix: Curve endpoint intersection (#10640)

* fix: Curve endpoint intersection Signed-off-by: Mark Tolmacs <mark@lazycat.hu> * fix debug --------- Signed-off-by: Mark Tolmacs <mark@lazycat.hu> Co-authored-by: dwelle <5153846+dwelle@users.noreply.github.com>
2026-01-12 15:02:56 +01:00
parent b9a255407f
commit da59205846
2 changed files with 24 additions and 6 deletions
@@ -1,6 +1,7 @@
 import { isPoint, pointDistance, pointFrom, pointFromVector } from "./point";
 import { vector, vectorNormal, vectorNormalize, vectorScale } from "./vector";
 import { LegendreGaussN24CValues, LegendreGaussN24TValues } from "./constants";
+import { lineSegment, lineSegmentIntersectionPoints } from "./segment";

 import type { Curve, GlobalPoint, LineSegment, LocalPoint } from "./types";

@@ -174,6 +175,23 @@ export function curveIntersectLineSegment<
    return [solution];
  }

+  // Fallback: approximate the curve with short segments to catch near-endpoint hits.
+  const startHit = lineSegmentIntersectionPoints(
+    lineSegment(bezierEquation(c, 0), bezierEquation(c, 1 / 20)),
+    l,
+  );
+  if (startHit) {
+    return [startHit];
+  }
+
+  const endHit = lineSegmentIntersectionPoints(
+    lineSegment(bezierEquation(c, 19 / 20), bezierEquation(c, 1)),
+    l,
+  );
+  if (endHit) {
+    return [endHit];
+  }
+
  return [];
 }