Added Triangle 1 to 4 split

src/OpenMesh/Core/Mesh/TriMeshT.hh

@@ -337,6 +337,64 @@ public:
   inline VertexHandle split_copy(FaceHandle _fh, const Point& _p)
   { const VertexHandle vh = this->add_vertex(_p);  PolyMesh::split_copy(_fh, vh); return vh; }
 
+
+  /** \brief Face split (= 1-to-4) split, splits edges at midpoints and adds 4 new faces in the interior).
+   *
+   * @param _fh Face handle that should be splitted
+   */
+  inline void split(FaceHandle _fh)
+  {
+    // Collect halfedges of face
+    HalfedgeHandle he0 = this->halfedge_handle(_fh);
+    HalfedgeHandle he1 = this->next_halfedge_handle(he0);
+    HalfedgeHandle he2 = this->next_halfedge_handle(he1);
+
+    EdgeHandle eh0 = this->edge_handle(he0);
+    EdgeHandle eh1 = this->edge_handle(he1);
+    EdgeHandle eh2 = this->edge_handle(he2);
+
+    // Collect points of face
+    VertexHandle p0 = this->to_vertex_handle(he0);
+    VertexHandle p1 = this->to_vertex_handle(he1);
+    VertexHandle p2 = this->to_vertex_handle(he2);
+
+    // Calculate midpoint coordinates
+    const Point new0 = (this->point(p0) + this->point(p2)) * static_cast< typename Point::value_type >(0.5);
+    const Point new1 = (this->point(p0) + this->point(p1)) * static_cast< typename Point::value_type >(0.5);
+    const Point new2 = (this->point(p1) + this->point(p2)) * static_cast< typename Point::value_type >(0.5);
+
+    // Add vertices at midpoint coordinates
+    VertexHandle v0 = this->add_vertex(new0);
+    VertexHandle v1 = this->add_vertex(new1);
+    VertexHandle v2 = this->add_vertex(new2);
+
+    const bool split0 = !this->is_boundary(he0);
+    const bool split1 = !this->is_boundary(he1);
+    const bool split2 = !this->is_boundary(he2);
+
+    // delete original face
+    this->delete_face(_fh);
+
+    // split boundary edges of deleted face ( if not boundary )
+    if ( split0 ) {
+      this->split(eh0,v0);
+    }
+
+    if ( split1 ) {
+      this->split(eh1,v1);
+    }
+
+    if ( split2 ) {
+      this->split(eh2,v2);
+    }
+
+    // Retriangulate
+    this->add_face(v0 , p0, v1);
+    this->add_face(p2, v0 , v2);
+    this->add_face(v2,v1,p1);
+    this->add_face(v2 , v0, v1);
+  }
+
   /** \brief Face split (= 1-to-3 split, calls corresponding PolyMeshT function).
    *
    * The properties of the new faces will be undefined!

src/Unittests/unittests_trimesh_split.cc

+
+#include <gtest/gtest.h>
+#include <Unittests/unittests_common.hh>
+#include <iostream>
+
+namespace {
+
+class OpenMeshSplitTriangleMesh : public OpenMeshBase {
+
+    protected:
+
+        // This function is called before each test is run
+        virtual void SetUp() {
+
+            // Do some initial stuff with the member data here...
+        }
+
+        // This function is called after all tests are through
+        virtual void TearDown() {
+
+            // Do some final stuff with the member data here...
+        }
+
+    // Member already defined in OpenMeshBase
+    //Mesh mesh_;
+};
+
+/*
+ * ====================================================================
+ * Define tests below
+ * ====================================================================
+ */
+
+/* splits a face that has a property in a triangle mesh with split_copy
+ * the property should be copied to the new faces
+ */
+TEST_F(OpenMeshSplitTriangleMesh, Split_Triangle_Mesh_1_4) {
+
+  mesh_.clear();
+
+  mesh_.request_vertex_status();
+  mesh_.request_edge_status();
+  mesh_.request_face_status();
+
+  // Add some vertices
+  Mesh::VertexHandle vhandle[6];
+
+  vhandle[0] = mesh_.add_vertex(Mesh::Point(0, 1, 0));
+  vhandle[1] = mesh_.add_vertex(Mesh::Point(1, 0, 0));
+  vhandle[2] = mesh_.add_vertex(Mesh::Point(2, 1, 0));
+  vhandle[3] = mesh_.add_vertex(Mesh::Point(3, 0, 0));
+  vhandle[4] = mesh_.add_vertex(Mesh::Point(4, 1, 0));
+  vhandle[5] = mesh_.add_vertex(Mesh::Point(2,-1, 0));
+
+  // Add three faces
+  std::vector<Mesh::VertexHandle> face_vhandles;
+
+  face_vhandles.push_back(vhandle[0]);
+  face_vhandles.push_back(vhandle[1]);
+  face_vhandles.push_back(vhandle[2]);
+  mesh_.add_face(face_vhandles);
+
+  face_vhandles.clear();
+
+  face_vhandles.push_back(vhandle[2]);
+  face_vhandles.push_back(vhandle[1]);
+  face_vhandles.push_back(vhandle[3]);
+  Mesh::FaceHandle to_split = mesh_.add_face(face_vhandles);
+
+  face_vhandles.clear();
+
+  face_vhandles.push_back(vhandle[2]);
+  face_vhandles.push_back(vhandle[3]);
+  face_vhandles.push_back(vhandle[4]);
+  mesh_.add_face(face_vhandles);
+
+  face_vhandles.clear();
+
+  face_vhandles.push_back(vhandle[1]);
+  face_vhandles.push_back(vhandle[5]);
+  face_vhandles.push_back(vhandle[3]);
+  mesh_.add_face(face_vhandles);
+
+  /* Test setup:
+   *
+   * edge x => halfedge x/x+1
+   * i.e. edge 0 => halfedge 0/1
+   *
+   * 0 --4--- 2 ------ 4
+   *  \      / \      /
+   *   0  0 2   6  2 /
+   *    \  /  1  \  /
+   *     1 ---8--- 3
+   *      \       /
+   *       \  3  /
+   *        \   /
+   *         \ /
+   *          5
+   */
+
+  EXPECT_EQ(4u, mesh_.n_faces());
+
+  // split face with new vertex
+  mesh_.split(to_split);
+
+  mesh_.garbage_collection();
+
+  EXPECT_EQ(10u, mesh_.n_faces());
+
+
+
+}
+
+}
+
+
+