#148 Fix bug: vertex with no adjacent triangle when resolving intersections

Add regression test

Author: artem-ogre

CDT/extras/VerifyTopology.h

@@ -74,6 +74,17 @@ inline bool verifyTopology(const CDT::Triangulation<T, TNearPointLocator>& cdt)
     return true;
 }
 
+/// Check that each vertex has a neighbor triangle
+template <typename T, typename TNearPointLocator>
+inline bool eachVertexHasNeighborTriangle(
+    const CDT::Triangulation<T, TNearPointLocator>& cdt)
+{
+    for(const auto& vt : cdt.VertTrisInternal())
+        if(vt == noNeighbor)
+            return false;
+    return true;
+}
+
 } // namespace CDT
 
 #endif

CDT/include/Triangulation.h

@@ -355,6 +355,8 @@ class CDT_EXPORT Triangulation
 
     /// Access internal vertex adjacent triangles
     TriIndVec& VertTrisInternal();
+    /// Access internal vertex adjacent triangles
+    const TriIndVec& VertTrisInternal() const;
     /// @}
 
 private:
@@ -586,7 +588,6 @@ class CDT_EXPORT Triangulation
     bool hasEdge(VertInd a, VertInd b) const;
     void setAdjacentTriangle(const VertInd v, const TriInd t);
     void pivotVertexTriangleCW(VertInd v);
-    void removeAdjacentTriangle(VertInd v);
     /// Add vertex to nearest-point locator if locator is initialized
     void tryAddVertexToLocator(const VertInd v);
     /// Perform lazy initialization of nearest-point locator after the Kd-tree

CDT/include/Triangulation.hpp

@@ -208,12 +208,19 @@ void Triangulation<T, TNearPointLocator>::removeTriangles(
         }
     }
 }
+
 template <typename T, typename TNearPointLocator>
 TriIndVec& Triangulation<T, TNearPointLocator>::VertTrisInternal()
 {
     return m_vertTris;
 }
 
+template <typename T, typename TNearPointLocator>
+const TriIndVec& Triangulation<T, TNearPointLocator>::VertTrisInternal() const
+{
+    return m_vertTris;
+}
+
 template <typename T, typename TNearPointLocator>
 void Triangulation<T, TNearPointLocator>::finalizeTriangulation(
     const TriIndUSet& removedTriangles)
@@ -605,7 +612,6 @@ void Triangulation<T, TNearPointLocator>::insertEdgeIteration(
                 outerTrisL.push_back(edgeNeighbor(tOpo, polyL.back(), iVopo));
             }
             polyL.push_back(iVopo);
-            removeAdjacentTriangle(iVopo);
             iV = iVL;
             iVL = iVopo;
         }
@@ -627,7 +633,6 @@ void Triangulation<T, TNearPointLocator>::insertEdgeIteration(
                 outerTrisR.push_back(edgeNeighbor(tOpo, polyR.back(), iVopo));
             }
             polyR.push_back(iVopo);
-            removeAdjacentTriangle(iVopo);
             iV = iVR;
             iVR = iVopo;
         }
@@ -2005,13 +2010,6 @@ void Triangulation<T, TNearPointLocator>::pivotVertexTriangleCW(const VertInd v)
         triangles[m_vertTris[v]].vertices[2] == v);
 }
 
-template <typename T, typename TNearPointLocator>
-void Triangulation<T, TNearPointLocator>::removeAdjacentTriangle(
-    const VertInd v)
-{
-    m_vertTris[v] = noNeighbor;
-}
-
 template <typename T, typename TNearPointLocator>
 void Triangulation<T, TNearPointLocator>::tryAddVertexToLocator(const VertInd v)
 {

CDT/tests/cdt.test.cpp

@@ -556,6 +556,7 @@ TEMPLATE_LIST_TEST_CASE(
     cdt.insertVertices(vv);
     cdt.insertEdges(ee);
     REQUIRE(CDT::verifyTopology(cdt));
+    REQUIRE(CDT::eachVertexHasNeighborTriangle(cdt));
 
     // make true to update expected files (development purposes only)
     const auto outputFileBase = "expected/" +
@@ -671,7 +672,10 @@ TEMPLATE_LIST_TEST_CASE(
 
 TEMPLATE_LIST_TEST_CASE("Ground truth tests: crossing edges", "", CoordTypes)
 {
-    const auto inputFile = std::string("crossing-edges.txt");
+    const auto inputFile = GENERATE(
+        as<std::string>{},
+        "crossing-edges.txt",
+        "issue-148-crossing-edges.txt");
 
     const auto order = VertexInsertionOrder::Auto;
     const auto intersectingEdgesStrategy = IntersectingConstraintEdges::Resolve;
@@ -689,6 +693,7 @@ TEMPLATE_LIST_TEST_CASE("Ground truth tests: crossing edges", "", CoordTypes)
     cdt.insertVertices(vv);
     triangulationType == "" ? cdt.insertEdges(ee) : cdt.conformToEdges(ee);
     REQUIRE(CDT::verifyTopology(cdt));
+    REQUIRE(CDT::eachVertexHasNeighborTriangle(cdt));
     // make true to update expected files (development purposes only)
     const auto outputFileBase = "expected/" +
                                 inputFile.substr(0, inputFile.size() - 4) +

CDT/tests/expected/issue-148-crossing-edges__auto_resolve_all.txt

@@ -0,0 +1,38 @@
+15
+0 1 4   4294967295 5 2
+0 3 6   2 9 3
+0 4 3   0 7 1
+0 6 2   1 6 4294967295
+1 2 5   4294967295 6 5
+1 5 4   4 10 0
+2 6 5   3 13 4
+3 4 7   2 12 8
+3 7 9   7 12 9
+3 9 6   8 13 1
+4 5 8   5 14 11
+4 8 9   10 14 12
+4 9 7   11 8 7
+5 6 9   6 9 14
+5 9 8   13 11 10
+
+4
+3 9
+4 9
+5 9
+6 9
+
+0
+
+4
+3 9
+    1
+    3 5
+4 9
+    1
+    4 6
+5 9
+    1
+    3 5
+6 9
+    1
+    4 6

CDT/tests/expected/issue-148-crossing-edges__conforming_auto_resolve_all.txt

@@ -0,0 +1,50 @@
+19
+0 1 4   4294967295 5 2
+0 3 6   2 9 3
+0 4 3   0 7 1
+0 6 2   1 6 4294967295
+1 2 5   4294967295 6 5
+1 5 4   4 10 0
+2 6 5   3 13 4
+3 4 7   2 12 8
+3 7 10   7 16 9
+3 10 6   8 15 1
+4 5 8   5 14 11
+4 8 11   10 17 12
+4 11 7   11 16 7
+5 6 9   6 15 14
+5 9 8   13 17 10
+6 10 9   9 18 13
+7 11 10   12 18 8
+8 9 11   14 18 11
+9 10 11   15 16 17
+
+6
+3 10
+4 11
+5 9
+6 10
+9 10
+10 11
+
+0
+
+6
+3 10
+    1
+    3 5
+4 11
+    1
+    4 6
+5 9
+    1
+    3 5
+6 10
+    1
+    4 6
+9 10
+    1
+    3 5
+10 11
+    1
+    4 6

CDT/tests/inputs/issue-148-crossing-edges.txt

@@ -0,0 +1,9 @@
+6 2
+0 0.2
+1 0
+1 1
+0 1
+0.5 0.2
+0.8 0.5
+0 2
+1 3