Fix multiple hanging edges and zero overlaps

.github/workflows/ci_builds.yml

@@ -18,11 +18,10 @@ jobs:
             name: "Ubuntu", 
             os: ubuntu-latest
           }
-        # Disable macOS untill https://github.com/conan-io/conan/issues/14835 is fixed in Conan 2.0.13
-        # - {
-        #     name: "macOS", 
-        #     os: macos-latest
-        #   }
+        - {
+            name: "macOS",
+            os: macos-latest
+          }
 
     steps:
     - uses: actions/checkout@v4

CDT/include/CDTUtils.h

@@ -425,6 +425,9 @@ CDT_EXPORT T distance(const V2d<T>& a, const V2d<T>& b);
 template <typename T>
 CDT_EXPORT T distanceSquared(const V2d<T>& a, const V2d<T>& b);
 
+/// Check if any of triangle's vertices belongs to a super-triangle
+CDT_EXPORT bool touchesSuperTriangle(const Triangle& t);
+
 } // namespace CDT
 
 #ifndef CDT_USE_AS_COMPILED_LIBRARY

CDT/include/CDTUtils.hpp

@@ -300,4 +300,9 @@ T distanceSquared(const V2d<T>& a, const V2d<T>& b)
     return distanceSquared(a.x, a.y, b.x, b.y);
 }
 
+bool touchesSuperTriangle(const Triangle& t)
+{
+    return t.vertices[0] < 3 || t.vertices[1] < 3 || t.vertices[2] < 3;
+}
+
 } // namespace CDT

CDT/include/Triangulation.h

@@ -509,9 +509,40 @@ class CDT_EXPORT Triangulation
      */
     void finalizeTriangulation(const TriIndUSet& removedTriangles);
     TriIndUSet growToBoundary(std::stack<TriInd> seeds) const;
-    void fixEdge(const Edge& edge, BoundaryOverlapCount overlaps);
     void fixEdge(const Edge& edge);
     void fixEdge(const Edge& edge, const Edge& originalEdge);
+    /**
+     *  Split existing constraint (fixed) edge
+     * @param edge fixed edge to split
+     * @param iSplitVert index of the vertex to be used as a split vertex
+     */
+    void splitFixedEdge(const Edge& edge, const VertInd iSplitVert);
+    /**
+     * Add a vertex that splits an edge into the triangulation
+     * @param splitVert position of split vertex
+     * @param iT index of a first triangle adjacent to the split edge
+     * @param iTopo index of a second triangle adjacent to the split edge
+     * (opposed to the first triangle)
+     * @return index of a newly added split vertex
+     */
+    VertInd addSplitEdgeVertex(
+        const V2d<T>& splitVert,
+        const TriInd iT,
+        const TriInd iTopo);
+    /**
+     * Split fixed edge and add a split vertex into the triangulation
+     * @param edge fixed edge to split
+     * @param splitVert position of split vertex
+     * @param iT index of a first triangle adjacent to the split edge
+     * @param iTopo index of a second triangle adjacent to the split edge
+     * (opposed to the first triangle)
+     * @return index of a newly added split vertex
+     */
+    VertInd splitFixedEdgeAt(
+        const Edge& edge,
+        const V2d<T>& splitVert,
+        const TriInd iT,
+        const TriInd iTopo);
     /**
      * Flag triangle as dummy
      * @note Advanced method for manually modifying the triangulation from
@@ -551,6 +582,7 @@ class CDT_EXPORT Triangulation
         VertInd superGeomVertCount,
         V2d<T> boxMin,
         V2d<T> boxMax);
+    std::pair<TriInd, TriInd> edgeTriangles(VertInd a, VertInd b) const;
     bool hasEdge(VertInd a, VertInd b) const;
     void setAdjacentTriangle(const VertInd v, const TriInd t);
     void pivotVertexTriangleCW(VertInd v);