From 2eff2a965d16ab7cac42745d74cb416b39150599 Mon Sep 17 00:00:00 2001
From: Lingjie Zhu <lingjie.zhu@nlpr.ia.ac.cn>
Date: Wed, 13 Jun 2018 15:28:06 +0800
Subject: [PATCH] deal with degeneracy in examples

---
 .../vsa_isotropic_metric_example.cpp                       | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Surface_mesh_approximation/examples/Surface_mesh_approximation/vsa_isotropic_metric_example.cpp b/Surface_mesh_approximation/examples/Surface_mesh_approximation/vsa_isotropic_metric_example.cpp
index ffc6647cb13..b6bacd90828 100644
--- a/Surface_mesh_approximation/examples/Surface_mesh_approximation/vsa_isotropic_metric_example.cpp
+++ b/Surface_mesh_approximation/examples/Surface_mesh_approximation/vsa_isotropic_metric_example.cpp
@@ -52,7 +52,12 @@ struct Compact_metric_point_proxy
       center = center + (center_pmap[f] - CGAL::ORIGIN) * area_pmap[f];
       sum_areas += area_pmap[f];
     }
-    center = center / sum_areas; // TODO: deal with case where sum = 0
+    // deal with case where sum = 0
+    if (center == CGAL::NULL_VECTOR || sum_areas <= FT(0.0)) {
+      std::cerr << "Error: degenerate geometry." << std::endl;
+      std::exit(EXIT_FAILURE);
+    }
+    center = center / sum_areas;
     return CGAL::ORIGIN + center;
   }