diff -r c1ff4f107569 -r 24590af32ad6 src/geometry.cpp
--- a/src/geometry.cpp	Sat Mar 05 15:40:43 2022 +0200
+++ b/src/geometry.cpp	Sat Mar 05 16:57:28 2022 +0200
@@ -217,3 +217,21 @@
 			return glm::dot(crosses[0], vector) < 1e-6;
 		});
 }
+
+/**
+ * @brief Determines the winding of a 2d polygon
+ * @param polygon
+ * @return winding
+ */
+Winding geom::winding(const QPolygonF &polygon)
+{
+	// based on https://stackoverflow.com/a/1165943
+	double sum = 0.0;
+	for (int i = 0; i < polygon.size(); i += 1)
+	{
+		const QPointF& p1 = polygon[i];
+		const QPointF& p2 = polygon[(i + 1) % polygon.size()];
+		sum += (p2.x() - p1.x()) * (p2.y() + p1.y());
+	}
+	return (sum < 0) ? Winding::Anticlockwise : Winding::Clockwise;
+}