From 92ad22f65614a87cf8ccfab1d16ff682b9957c02 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Mon, 19 Sep 2022 23:35:03 +0300
Subject: [PATCH] Add cg::fill_missing_faces that creates faces for edge loops
 without a connected face

---
 libs/cg/include/psemek/cg/dcel.hpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/libs/cg/include/psemek/cg/dcel.hpp b/libs/cg/include/psemek/cg/dcel.hpp
index 8d87016d..a7ec1b95 100644
--- a/libs/cg/include/psemek/cg/dcel.hpp
+++ b/libs/cg/include/psemek/cg/dcel.hpp
@@ -587,6 +587,23 @@ namespace psemek::cg
 		return result;
 	}
 
+	template <typename Point, typename Edge, typename Face, typename Index>
+	void fill_missing_faces(dcel<Point, Edge, Face, Index> & dcel)
+	{
+		for (Index i = 0; i < dcel.edges.size(); ++i)
+		{
+			if (dcel.edges[i].face != dcel.null) continue;
+
+			auto e = dcel.edge(i);
+			auto f = dcel.push_face();
+			f.edge(e);
+			e.face(f);
+
+			for (e = e.next(); e.index() != i; e = e.next())
+				e.face(f);
+		}
+	}
+
 	template <typename Index = std::size_t, typename Iterator>
 	auto polygon_dcel(Iterator begin, Iterator end)
 	{