From 526f0a052a840c9468c0eeb99529c485bebeae8e Mon Sep 17 00:00:00 2001
From: artem-ogre <artem.ogre@gmail.com>
Date: Mon, 6 May 2024 13:52:05 +0200
Subject: [PATCH] #174 Temporary fix for the issue

---
 CDT/include/Triangulation.hpp | 12 +++++++++++-
 CDT/tests/cdt.test.cpp        | 30 ++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/CDT/include/Triangulation.hpp b/CDT/include/Triangulation.hpp
index 4b0a8a1..ebd62fe 100644
--- a/CDT/include/Triangulation.hpp
+++ b/CDT/include/Triangulation.hpp
@@ -1655,7 +1655,12 @@ void Triangulation<T, TNearPointLocator>::triangulatePseudoPolygonIteration(
     {
         const Edge outerEdge(b, c);
         const TriInd outerTri = outerTris.at(outerEdge);
-        if(outerTri != noNeighbor)
+        if(outerEdge.v2() <= m_nTargetVerts && outerTri == noNeighbor)
+        {
+            assert(outerTri != iT);
+            t.neighbors[1] = outerTri;
+        }
+        else if(outerTri != noNeighbor)
         {
             assert(outerTri != iT);
             t.neighbors[1] = outerTri;
@@ -1674,6 +1679,11 @@ void Triangulation<T, TNearPointLocator>::triangulatePseudoPolygonIteration(
     { // pseudo-poly is reduced to a single outer edge
         const Edge outerEdge(c, a);
         const TriInd outerTri = outerTris.at(outerEdge);
+        if(outerEdge.v2() <= m_nTargetVerts && outerTri == noNeighbor)
+        {
+            assert(outerTri != iT);
+            t.neighbors[2] = outerTri;
+        }
         if(outerTri != noNeighbor)
         {
             assert(outerTri != iT);
diff --git a/CDT/tests/cdt.test.cpp b/CDT/tests/cdt.test.cpp
index d073124..1d43eef 100644
--- a/CDT/tests/cdt.test.cpp
+++ b/CDT/tests/cdt.test.cpp
@@ -1,4 +1,5 @@
 #include <CDT.h>
+#include <InitializeWithGrid.h>
 #include <VerifyTopology.h>
 
 #include <catch2/benchmark/catch_benchmark.hpp>
@@ -958,4 +959,33 @@ TEST_CASE("Regression test #174: super-triangle of tiny bounding box", "")
     REQUIRE(CDT::verifyTopology(cdt));
     cdt.eraseSuperTriangle();
     REQUIRE(cdt.triangles.size() == std::size_t(1));
+}
+
+TEST_CASE("Regression test #175", "")
+{
+    CDT::Triangulation<double> cdt;
+    CDT::initializeWithRegularGrid(0., 3., 0., 4., 3, 4, cdt);
+    REQUIRE(CDT::verifyTopology(cdt));
+    saveToOff("/tmp/grid.off", cdt);
+
+    const std::vector<CDT::V2d<double> > vv = {
+        {0.5, 0.5},
+        {0.5, 3.5},
+        {2.5, 3.5},
+        {2.5, 0.5},
+    };
+    const std::vector<CDT::Edge> ee = {
+        CDT::Edge(0, 1),
+        CDT::Edge(1, 2),
+        CDT::Edge(2, 3),
+        CDT::Edge(0, 3),
+    };
+
+    cdt.insertVertices(vv);
+    REQUIRE(CDT::verifyTopology(cdt));
+    cdt.insertEdges(ee);
+    REQUIRE(CDT::verifyTopology(cdt));
+    cdt.eraseOuterTriangles();
+    REQUIRE(cdt.triangles.size() == std::size_t(14));
+    saveToOff("/tmp/after.off", cdt);
 }
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