From f74c9c50b7ea841b0c15757418b719706a4b405b Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Tue, 29 Sep 2015 15:40:39 -0700
Subject: [PATCH] Port fix for https://github.com/mapbox/earcut/issues/29

Refs https://github.com/mapbox/earcut.hpp/issues/6
---
 include/earcut.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/earcut.hpp b/include/earcut.hpp
index 87d4755..4f59792 100644
--- a/include/earcut.hpp
+++ b/include/earcut.hpp
@@ -668,7 +668,8 @@ Earcut<Coord, N>::getLeftmost(Node* start) {
 // check if a diagonal between two polygon nodes is valid (lies in polygon interior)
 template <typename Coord, typename N>
 bool Earcut<Coord, N>::isValidDiagonal(Node* a, Node* b) {
-    return !intersectsPolygon(a, a, b) &&
+    return a->next->i != b->i && a->prev->i != b->i &&
+           !intersectsPolygon(a, a, b) &&
            locallyInside(a, b) && locallyInside(b, a) &&
            middleInside(a, a->v, b->v);
 }