--- a/src/triangulate.cpp	Sun Apr 09 17:05:40 2023 +0300
+++ b/src/triangulate.cpp	Mon Apr 10 12:40:49 2023 +0300
@@ -96,7 +96,7 @@
 			*(polyBegin + shared_boundary.second),
 			*(polyBegin + earcut_triangle_1.third_vertex),
 		};
-		if (isConvex(quad)) {
+		if (quadrilateral_convexity(quad) == convexity_e::convex) {
 			result.quadrilaterals.push_back(quad);
 			result.cutTriangles.insert(earcut_triangle_1.triangleid);
 			result.cutTriangles.insert(earcut_triangle_2.triangleid);