WIP t3_item

Polyhedron/demo/Polyhedron/CMakeLists.txt

@@ -334,6 +334,7 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
                                 scene_points_with_normal_item)
 
   add_item(scene_lcc_item Scene_lcc_item.cpp)
+  add_item(scene_triangulation_3_item Scene_triangulation_3_item.cpp)
 
   foreach(lib demo_framework scene_basic_objects scene_color_ramp
               scene_polygon_soup_item scene_nef_polyhedron_item)

Polyhedron/demo/Polyhedron/Plugins/IO/CMakeLists.txt

@@ -51,8 +51,7 @@ set_package_properties(
   PURPOSE "Can be used for I/O (DICOM, VTU, VTP.")
 
 polyhedron_demo_plugin(triangulation_3_io_plugin triangulation_3_io_plugin KEYWORDS IO)
-#todo
-#target_link_libraries(triangulation_3_io_plugin PUBLIC scene_triangulation_3_item)
+target_link_libraries(triangulation_3_io_plugin PUBLIC scene_triangulation_3_item)
 
 
 if(VTK_FOUND)

Polyhedron/demo/Polyhedron/Plugins/IO/triangulation_3_io_plugin.cpp

@@ -1,8 +1,9 @@
 #include <CGAL/Three/Three.h>
 #include <CGAL/Three/Polyhedron_demo_io_plugin_interface.h>
-
+#include "T3_type.h"
 #include <iostream>
 #include <fstream>
+#include "Scene_triangulation_3_item.h"
 
 class Triangulation_3_io_plugin :
     public QObject,
@@ -27,20 +28,47 @@ public:
 
   //todo: same
   QString saveNameFilters() const override{
-    return "";
+    return ".tr_tst";
   }
 
   //todo
   bool canLoad(QFileInfo) const override{ return true; }
   QList<CGAL::Three::Scene_item*> load(QFileInfo fileinfo, bool& ok, bool add_to_scene=true) override{
+
     // Open file
-    std::ifstream ifs(fileinfo.filePath().toUtf8());
-    if(!ifs) {
-      std::cerr << "Error! Cannot open file " << (const char*)fileinfo.filePath().toUtf8() << std::endl;
-      ok = false;
-      return QList<CGAL::Three::Scene_item*>();
+    //std::ifstream ifs(fileinfo.filePath().toUtf8());
+    //if(!ifs) {
+    //  std::cerr << "Error! Cannot open file " << (const char*)fileinfo.filePath().toUtf8() << std::endl;
+    //  ok = false;
+    //  Scene_triangulation_3_item* new_item = new Scene_triangulation_3_item();
+    //  return QList<CGAL::Three::Scene_item*>();
+    //}
+
+    //temp {
+    T3* tr = new Tr();
+    CGAL::Random rng;
+    typedef T3::Point Point;
+    typedef T3::Cell_handle Cell_handle;
+
+    while (tr->number_of_vertices() < 20)
+      tr->insert(Point(rng.get_double(-1., 1.), rng.get_double(-1., 1.), rng.get_double(-1., 1.)));
+
+    const typename T3::Geom_traits::Plane_3
+        plane(Point_3(0, 0, 0), Point_3(0, 1, 0), Point_3(0, 0, 1));
+
+    for (Cell_handle c : tr->finite_cell_handles())
+    {
+      if (plane.has_on_positive_side(
+            CGAL::centroid(Point_3(c->vertex(0)->point()), Point_3(c->vertex(1)->point()),
+                           Point_3(c->vertex(2)->point()),Point_3( c->vertex(3)->point()))))
+        c->set_subdomain_index(1);
+      else
+        c->set_subdomain_index(2);
     }
 
+    CGAL_assertion(tr->is_valid(true));
+    //}
+
 
     QString ext = fileinfo.suffix();
     bool res = true;
@@ -55,14 +83,13 @@ public:
       ok = false;
       return QList<CGAL::Three::Scene_item*>();
     }
-    //Scene_lcc_item* new_item = new Scene_lcc_item(lcc);
+    Scene_triangulation_3_item* new_item = new Scene_triangulation_3_item(tr);
     //new_item->setName(fileinfo.fileName());
-    //new_item->invalidateOpenGLBuffers();
-    //if(add_to_scene)
-    //  CGAL::Three::Three::scene()->addItem(new_item);
-    //ok = true;
-    //return QList<CGAL::Three::Scene_item*>()<<new_item;
-    return false;
+    new_item->invalidateOpenGLBuffers();
+    if(add_to_scene)
+      CGAL::Three::Three::scene()->addItem(new_item);
+    ok = true;
+    return QList<CGAL::Three::Scene_item*>()<<new_item;
   }
 
 

Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp

@@ -58,7 +58,7 @@ QVector4D cgal_plane_to_vector4d(EPICK::Plane_3 plane) {
     static_cast<float>(-plane.d()) };
 }
 
-// The special Scene_item only for triangles
+
 class Scene_intersection_item : public CGAL::Three::Scene_item_rendering_helper
 {
   Q_OBJECT

Polyhedron/demo/Polyhedron/Scene_c3t3_item.h

@@ -24,8 +24,6 @@
 #include <CGAL/Three/Scene_item_with_properties.h>
 
 struct Scene_c3t3_item_priv;
-class Scene_spheres_item;
-class Scene_intersection_item;
 using namespace CGAL::Three;
   class SCENE_C3T3_ITEM_EXPORT Scene_c3t3_item
   : public Scene_group_item, public Scene_item_with_properties

Polyhedron/demo/Polyhedron/Scene_triangulation_3_item.cpp

@@ -0,0 +1,727 @@
+#include "config.h"
+#include "Scene_triangulation_3_item.h"
+#include <CGAL/Three/Three.h>
+#include <CGAL/Three/Triangle_container.h>
+#include <CGAL/Three/Edge_container.h>
+#include <CGAL/Three/Point_container.h>
+
+
+using namespace CGAL::Three;
+typedef Triangle_container Tc;
+typedef Edge_container Ec;
+typedef Point_container Pc;
+typedef Viewer_interface Vi;
+
+QVector4D cgal_plane_to_vector4d(EPICK::Plane_3 plane) {
+  return {
+    static_cast<float>(-plane.a()),
+    static_cast<float>(-plane.b()),
+    static_cast<float>(-plane.c()),
+    static_cast<float>(-plane.d()) };
+}
+
+class Scene_intersection_item : public CGAL::Three::Scene_item_rendering_helper
+{
+  Q_OBJECT
+public :
+  Scene_intersection_item(Scene_triangulation_3_item* parent)
+  :is_fast(false)
+  {
+    setParent(parent);
+    alphaSlider = NULL;
+    m_alpha = 1.0f;
+    setTriangleContainer(0, new Tc(Vi::PROGRAM_C3T3, false));
+    setEdgeContainer(0, new Ec(Vi::PROGRAM_NO_SELECTION, false));
+  }
+  bool isFinite() const Q_DECL_OVERRIDE{ return false; }
+  ~Scene_intersection_item()
+  {
+    if(alphaSlider)
+         delete alphaSlider;
+  }
+  void compute_bbox() const Q_DECL_OVERRIDE{}
+
+  void gl_initialization(Vi* viewer)
+  {
+    if(!isInit(viewer))
+      initGL(viewer);
+    computeElements();
+    initializeBuffers(viewer);
+  }
+  void init_vectors(
+      std::vector<float> *p_vertices,
+      std::vector<float> *p_normals,
+      std::vector<float> *p_edges,
+      std::vector<float> *p_colors,
+      std::vector<float> *p_bary)
+  {
+    vertices = p_vertices;
+    normals = p_normals;
+    edges = p_edges;
+    colors = p_colors;
+    barycenters = p_bary;
+  }
+  void setColor(QColor c) Q_DECL_OVERRIDE
+  {
+    qobject_cast<Scene_triangulation_3_item*>(this->parent())->setColor(c);
+    Scene_item::setColor(c);
+  }
+  // Indicates if rendering mode is supported
+  bool supportsRenderingMode(RenderingMode m) const Q_DECL_OVERRIDE{
+    return (m != Gouraud && m != PointsPlusNormals && m != Points && m != ShadedPoints);
+  }
+  void computeElements() const Q_DECL_OVERRIDE
+  {
+    getTriangleContainer(0)->reset_vbos(ALL);
+    getEdgeContainer(0)->reset_vbos(ALL);
+
+    getTriangleContainer(0)->allocate(Tc::Flat_vertices,
+          vertices->data(), static_cast<int>(vertices->size()*sizeof(float)));
+    getTriangleContainer(0)->allocate(Tc::Flat_normals, normals->data(),
+                              static_cast<int>(normals->size()*sizeof(float)));
+    getTriangleContainer(0)->allocate(Tc::FColors, colors->data(),
+                             static_cast<int>(colors->size()*sizeof(float)));
+    getTriangleContainer(0)->allocate(Tc::Facet_centers, barycenters->data(),
+                                  static_cast<int>(barycenters->size()*sizeof(float)));
+    getEdgeContainer(0)->allocate(Ec::Vertices, edges->data(),
+                            static_cast<int>(edges->size()*sizeof(float)));
+    setBuffersFilled(true);
+  }
+  void initializeBuffers(CGAL::Three::Viewer_interface *viewer)const Q_DECL_OVERRIDE
+  {
+    //vao containing the data for the facets
+    {
+      getTriangleContainer(0)->initializeBuffers(viewer);
+      getTriangleContainer(0)->setFlatDataSize(vertices->size());
+    }
+    //vao containing the data for the lines
+    {
+      getEdgeContainer(0)->initializeBuffers(viewer);
+      getEdgeContainer(0)->setFlatDataSize(edges->size());
+    }
+  }
+
+  //Displays the item
+  void draw(CGAL::Three::Viewer_interface* viewer) const Q_DECL_OVERRIDE
+  {
+    if(is_fast)
+      return;
+
+    if(!alphaSlider)
+    {
+      alphaSlider = new QSlider(::Qt::Horizontal);
+      alphaSlider->setMinimum(0);
+      alphaSlider->setMaximum(255);
+      alphaSlider->setValue(255);
+    }
+    viewer->makeCurrent();
+    const EPICK::Plane_3& plane = qobject_cast<Scene_triangulation_3_item*>(this->parent())->plane();
+    QVector4D cp = cgal_plane_to_vector4d(plane);
+    getTriangleContainer(0)->setPlane(-cp);
+    getTriangleContainer(0)->setShrinkFactor(1.0);
+    // positions_poly is also used for the faces in the cut plane
+    // and changes when the cut plane is moved
+    getTriangleContainer(0)->setAlpha(alpha());
+    getTriangleContainer(0)->draw(viewer, false);
+  }
+  void drawEdges(CGAL::Three::Viewer_interface* viewer) const Q_DECL_OVERRIDE
+  {
+    if(is_fast)
+      return;
+    const EPICK::Plane_3& plane = qobject_cast<Scene_triangulation_3_item*>(this->parent())->plane();
+    QVector4D cp = cgal_plane_to_vector4d(plane);
+    getEdgeContainer(0)->setPlane(cp);
+    getEdgeContainer(0)->setColor(QColor(Qt::black));
+    getEdgeContainer(0)->draw(viewer, true);
+
+  }
+
+  void setFast(bool b)
+  {
+    is_fast = b;
+  }
+
+  void addTriangle(const Tr::Bare_point& pa, const Tr::Bare_point& pb,
+                   const Tr::Bare_point& pc, const CGAL::Color color)
+  {
+    const CGAL::qglviewer::Vec offset = Three::mainViewer()->offset();
+    Geom_traits::Vector_3 n = cross_product(pb - pa, pc - pa);
+    n = n / CGAL::sqrt(n*n);
+
+    auto push_normal = [this](auto n) {
+      normals->push_back(static_cast<float>(n.x()));
+      normals->push_back(static_cast<float>(n.y()));
+      normals->push_back(static_cast<float>(n.z()));
+    };
+
+    auto push_vertex = [this, &offset](const auto& p) {
+      this->vertices->push_back(static_cast<float>(p.x()+offset.x));
+      this->vertices->push_back(static_cast<float>(p.y()+offset.y));
+      this->vertices->push_back(static_cast<float>(p.z()+offset.z));
+    };
+
+    auto push_edge = [this, &offset](const auto& pa, const auto& pb) {
+      this->edges->push_back(static_cast<float>(pa.x()+offset.x));
+      this->edges->push_back(static_cast<float>(pa.y()+offset.y));
+      this->edges->push_back(static_cast<float>(pa.z()+offset.z));
+      this->edges->push_back(static_cast<float>(pb.x()+offset.x));
+      this->edges->push_back(static_cast<float>(pb.y()+offset.y));
+      this->edges->push_back(static_cast<float>(pb.z()+offset.z));
+    };
+
+    for (int i = 0; i<3; i++)
+    {
+      push_normal(n);
+    }
+    push_vertex(pa);
+    push_vertex(pb);
+    push_vertex(pc);
+
+    push_edge(pa, pb);
+    push_edge(pb, pc);
+    push_edge(pc, pa);
+
+    for(int i=0; i<3; i++)
+    {
+      colors->push_back((float)color.red()/255);
+      colors->push_back((float)color.green()/255);
+      colors->push_back((float)color.blue()/255);
+
+      barycenters->push_back(static_cast<float>((pa[0]+pb[0]+pc[0])/3.0 + offset.x));
+      barycenters->push_back(static_cast<float>((pa[1]+pb[1]+pc[1])/3.0 + offset.y));
+      barycenters->push_back(static_cast<float>((pa[2]+pb[2]+pc[2])/3.0 + offset.z));
+    }
+  }
+
+  Scene_item* clone() const Q_DECL_OVERRIDE{return 0;}
+  QString toolTip() const Q_DECL_OVERRIDE{return QString();}
+  QMenu* contextMenu() Q_DECL_OVERRIDE
+  {
+    QMenu* menu = Scene_item::contextMenu();
+
+    const char* prop_name = "Menu modified by Scene_surface_mesh_item.";
+    bool menuChanged = menu->property(prop_name).toBool();
+
+    if(!menuChanged) {
+      menu->addSeparator();
+      QMenu *container = new QMenu(tr("Alpha value"));
+      container->menuAction()->setProperty("is_groupable", true);
+      QWidgetAction *sliderAction = new QWidgetAction(0);
+      sliderAction->setDefaultWidget(alphaSlider);
+      connect(alphaSlider, &QSlider::valueChanged,
+              [this](){
+        setAlpha(alphaSlider->value());
+        redraw();
+      });
+
+      container->addAction(sliderAction);
+      menu->addMenu(container);
+      setProperty("menu_changed", true);
+      menu->setProperty(prop_name, true);
+    }
+    return menu;
+  }
+  float alpha() const Q_DECL_OVERRIDE
+  {
+    return m_alpha ;
+  }
+
+  void setAlpha(int a) Q_DECL_OVERRIDE
+  {
+    m_alpha = a / 255.0f;
+    redraw();
+  }
+private:
+
+  //contains the data
+  mutable std::vector<float> *vertices;
+  mutable std::vector<float> *normals;
+  mutable std::vector<float> *edges;
+  mutable std::vector<float> *colors;
+  mutable std::vector<float> *barycenters;
+  mutable bool is_fast;
+  mutable QSlider* alphaSlider;
+  mutable float m_alpha ;
+}; //end of class Scene_triangle_item
+
+struct Scene_triangulation_3_item_priv{
+  mutable std::size_t positions_poly_size;
+  mutable std::size_t positions_lines_size;
+
+  mutable std::vector<float> positions_lines;
+  mutable std::vector<float> positions_poly;
+  mutable std::vector<float> normals;
+  mutable std::vector<float> f_colors;
+  QVector<QColor> colors;
+  QVector<QColor> colors_subdomains;
+  typedef std::set<int> Indices;
+  Indices surface_patch_indices_;
+  bool need_changed;
+  Indices subdomain_indices_;
+  QSlider* alphaSlider;
+  Scene_triangulation_3_item* item;
+  bool show_tetrahedra;
+  CGAL::qglviewer::ManipulatedFrame* frame;
+  mutable std::map<CGAL::Three::Viewer_interface*, bool> are_intersection_buffers_filled;
+  bool areInterBufFilled(CGAL::Three::Viewer_interface* viewer)
+  {
+    if(are_intersection_buffers_filled.find(viewer) != are_intersection_buffers_filled.end())
+      return are_intersection_buffers_filled[viewer];
+    return false;
+  }
+
+
+  void initialize_intersection_buffers(CGAL::Three::Viewer_interface *viewer);
+  void computeIntersections(CGAL::Three::Viewer_interface* viewer);
+
+  void draw_triangle(const Tr::Bare_point& pa,
+                     const Tr::Bare_point& pb,
+                     const Tr::Bare_point& pc) const;
+  void draw_triangle_edges(const Tr::Bare_point& pa,
+                           const Tr::Bare_point& pb,
+                           const Tr::Bare_point& pc) const;
+
+  void push_normal(std::vector<float>& normals, const EPICK::Vector_3& n) const
+  {
+    normals.push_back(static_cast<float>(n.x()));
+    normals.push_back(static_cast<float>(n.y()));
+    normals.push_back(static_cast<float>(n.z()));
+  }
+  void push_point(std::vector<float>& points, const EPICK::Point_3& p,
+                  const CGAL::qglviewer::Vec& offset) const
+  {
+    points.push_back(static_cast<float>(p.x()+offset.x));
+    points.push_back(static_cast<float>(p.y()+offset.y));
+    points.push_back(static_cast<float>(p.z()+offset.z));
+  }
+  void push_edge(std::vector<float>& edges,
+                 const EPICK::Point_3& pa,
+                 const EPICK::Point_3& pb,
+                 const CGAL::qglviewer::Vec& offset) const
+  {
+    push_point(edges, pa, offset);
+    push_point(edges, pb, offset);
+  }
+  void compute_color_map(const QColor& c)
+  {
+    typedef Indices::size_type size_type;
+
+    const size_type nb_domains = subdomain_indices_.size();
+
+    double i = 0;
+    for (Indices::iterator it = subdomain_indices_.begin(),
+           end = subdomain_indices_.end(); it != end; ++it, i += 1.)
+    {
+      double hue = c.hueF() + 1. / double(nb_domains) * i;
+      if (hue > 1) { hue -= 1.; }
+      colors_subdomains[*it] = QColor::fromHsvF(hue, c.saturationF(), c.valueF());
+    }
+    const size_type nb_patch_indices = surface_patch_indices_.size();
+    i = 0;
+    for (Indices::iterator it = surface_patch_indices_.begin(),
+           end = surface_patch_indices_.end(); it != end; ++it, i += 1.)
+    {
+      double hue = c.hueF() + 1. / double(nb_patch_indices) * i;
+      if (hue > 1) { hue -= 1.; }
+      colors[*it] = QColor::fromHsvF(hue, c.saturationF(), c.valueF());
+    }
+  }
+
+  //!Allows OpenGL 2.0 context to get access to glDrawArraysInstanced.
+  typedef void (APIENTRYP PFNGLDRAWARRAYSINSTANCEDARBPROC) (GLenum mode, GLint first, GLsizei count, GLsizei primcount);
+  //!Allows OpenGL 2.0 context to get access to glVertexAttribDivisor.
+  typedef void (APIENTRYP PFNGLVERTEXATTRIBDIVISORARBPROC) (GLuint index, GLuint divisor);
+  //!Allows OpenGL 2.0 context to get access to gkFrameBufferTexture2D.
+  PFNGLDRAWARRAYSINSTANCEDARBPROC glDrawArraysInstanced;
+  //!Allows OpenGL 2.0 context to get access to glVertexAttribDivisor.
+  PFNGLVERTEXATTRIBDIVISORARBPROC glVertexAttribDivisor;
+  Scene_intersection_item *intersection;
+  T3* t3;
+  bool last_intersection;
+
+};
+
+struct Set_show_tetrahedra {
+  Scene_triangulation_3_item_priv* priv;
+  Set_show_tetrahedra(Scene_triangulation_3_item_priv* priv) : priv(priv) {}
+  void operator()(bool b) {
+    priv->show_tetrahedra = b;
+    priv->item->show_intersection(b);
+  }
+};
+
+void Scene_triangulation_3_item_priv::draw_triangle(const Tr::Bare_point& pa,
+                                                    const Tr::Bare_point& pb,
+                                                    const Tr::Bare_point& pc) const
+{
+  Geom_traits::Vector_3 n = cross_product(pb - pa, pc - pa);
+  n = n / CGAL::sqrt(n*n);
+  const CGAL::qglviewer::Vec offset = Three::mainViewer()->offset();
+
+  for (int i = 0; i<3; i++)
+  {
+    push_normal(normals, n);
+  }
+  push_point(positions_poly, pa, offset);
+  push_point(positions_poly, pb, offset);
+  push_point(positions_poly, pc, offset);
+
+}
+
+void Scene_triangulation_3_item_priv::draw_triangle_edges(const Tr::Bare_point& pa,
+                                               const Tr::Bare_point& pb,
+                                               const Tr::Bare_point& pc) const
+{
+  const CGAL::qglviewer::Vec offset = Three::mainViewer()->offset();
+  push_edge(positions_lines, pa, pb, offset);
+  push_edge(positions_lines, pb, pc, offset);
+  push_edge(positions_lines, pc, pa, offset);
+}
+
+Scene_triangulation_3_item::Scene_triangulation_3_item()
+{
+  d = new Scene_triangulation_3_item_priv();
+  common_constructor();
+}
+Scene_triangulation_3_item::Scene_triangulation_3_item(T3* t3)
+{
+  d = new Scene_triangulation_3_item_priv();
+  d->t3 = t3;
+  common_constructor();
+}
+
+Scene_triangulation_3_item::~Scene_triangulation_3_item()
+{
+  delete d->t3;
+  delete d;
+}
+
+
+void Scene_triangulation_3_item::common_constructor()
+{
+  compute_bbox();
+  connect(d->frame, SIGNAL(modified()), this, SLOT(frame_changed()));
+  changed();
+  setRenderingMode(FlatPlusEdges);
+
+  setTriangleContainer(0, new Tc(Vi::PROGRAM_WITH_LIGHT, false));  setEdgeContainer(0, new Ec(Vi::PROGRAM_NO_SELECTION, false));
+  setPointContainer(0, new Pc(Vi::PROGRAM_NO_SELECTION, false));
+  d->show_tetrahedra = true;
+  d->last_intersection = !d->show_tetrahedra;
+  for(auto v : CGAL::QGLViewer::QGLViewerPool())
+  {
+    v->installEventFilter(this);
+  }
+}
+
+void Scene_triangulation_3_item::invalidateOpenGLBuffers()
+{
+  setBuffersFilled(false);
+  getTriangleContainer(0)->reset_vbos(ALL);
+  getEdgeContainer(0)->reset_vbos(ALL);
+  getPointContainer(0)->reset_vbos(ALL);
+
+  Q_FOREACH(CGAL::QGLViewer* v, CGAL::QGLViewer::QGLViewerPool())
+  {
+    CGAL::Three::Viewer_interface* viewer = static_cast<CGAL::Three::Viewer_interface*>(v);
+    if(viewer == NULL)
+      continue;
+    setBuffersInit(viewer, false);
+  }
+
+  compute_bbox();
+}
+
+void
+Scene_triangulation_3_item::frame_changed()
+{
+  if(!d)
+    return;
+  d->need_changed = true;
+  QTimer::singleShot(0,this, SLOT(updateCutPlane()));
+}
+
+void Scene_triangulation_3_item::changed()
+{
+  // Update colors
+  // Fill indices map and get max subdomain value
+  d->surface_patch_indices_.clear();
+  d->subdomain_indices_.clear();
+
+  int max = 0;
+  for (Tr::Finite_cells_iterator cit = d->t3->finite_cells_begin(),
+    end = d->t3->finite_cells_end(); cit != end; ++cit)
+  {
+    max = (std::max)(max, cit->subdomain_index());
+    d->subdomain_indices_.insert(cit->subdomain_index());
+  }
+  const int max_subdomain_index = max;
+  for (Tr::Finite_facets_iterator fit = d->t3->finite_facets_begin(),
+    end = d->t3->finite_facets_end(); fit != end; ++fit)
+  {
+    max = (std::max)(max, fit->first->surface_patch_index(fit->second));
+    d->surface_patch_indices_.insert(fit->first->surface_patch_index(fit->second));
+  }
+
+  d->colors.resize(max + 1);
+  d->colors_subdomains.resize(max_subdomain_index + 1);
+  d->compute_color_map(color_);
+
+}
+
+const T3& Scene_triangulation_3_item::triangulation() const
+{
+  return *d->t3;
+}
+
+T3& Scene_triangulation_3_item::triangulation()
+{
+  return *d->t3;
+}
+
+
+void Scene_triangulation_3_item::compute_bbox() const
+{
+  if (isEmpty())
+    _bbox = Bbox();
+  else {
+    bool bbox_init = false;
+    CGAL::Bbox_3 result;
+    for (Tr::Finite_vertices_iterator
+         vit = d->t3->finite_vertices_begin(),
+         end = d->t3->finite_vertices_end();
+         vit != end; ++vit)
+    {
+      if (bbox_init)
+        result = result + vit->point().bbox();
+      else
+      {
+        result = vit->point().bbox();
+        bbox_init = true;
+      }
+    }
+    _bbox = Bbox(result.xmin(), result.ymin(), result.zmin(),
+                 result.xmax(), result.ymax(), result.zmax());
+  }
+}
+
+Scene_triangulation_3_item* Scene_triangulation_3_item::clone() const  {}
+
+QString Scene_triangulation_3_item::toolTip() const { return QString(); }
+
+void Scene_triangulation_3_item::draw(CGAL::Three::Viewer_interface* viewer) const
+{
+  Scene_triangulation_3_item* ncthis = const_cast<Scene_triangulation_3_item*>(this);
+  if(!visible())
+    return;
+
+  if(!isInit(viewer))
+    initGL(viewer);
+  if ( getBuffersFilled() &&
+       ! getBuffersInit(viewer))
+  {
+    initializeBuffers(viewer);
+    setBuffersInit(viewer, true);
+  }
+  if(!getBuffersFilled())
+  {
+    computeElements();
+    initializeBuffers(viewer);
+  }
+  if(renderingMode() == Flat ||
+     renderingMode() == FlatPlusEdges)
+  {
+    getTriangleContainer(0)->setAlpha(alpha());
+    getTriangleContainer(0)->draw(viewer, false);
+  }
+  if(d->show_tetrahedra){
+    ncthis->show_intersection(true);
+    if(!d->frame->isManipulated())
+      d->intersection->setFast(false);
+    else
+      d->intersection->setFast(true);
+
+    if(!d->frame->isManipulated() && !d->areInterBufFilled(viewer))
+    {
+      //initGL
+      ncthis->d->computeIntersections(viewer);
+      d->are_intersection_buffers_filled[viewer] = true;
+      ncthis->show_intersection(true);
+    }
+  }
+}
+
+void Scene_triangulation_3_item::drawEdges(CGAL::Three::Viewer_interface* viewer) const
+{
+  if(!visible())
+    return;
+  if(renderingMode() == Wireframe ||
+     renderingMode() == FlatPlusEdges )
+  {
+    if(renderingMode() == FlatPlusEdges)
+    {
+      GLint renderMode;
+      viewer->glGetIntegerv(GL_RENDER_MODE, &renderMode);
+      if(renderMode == GL_SELECT) return;
+    }
+    if(!isInit(viewer))
+      initGL(viewer);
+    if ( getBuffersFilled() &&
+         ! getBuffersInit(viewer))
+    {
+      initializeBuffers(viewer);
+      setBuffersInit(viewer, true);
+    }
+    if(!getBuffersFilled())
+    {
+      computeElements();
+      initializeBuffers(viewer);
+    }
+    getEdgeContainer(0)->setColor(QColor(Qt::black));
+    getEdgeContainer(0)->draw(viewer, true);
+  }
+}
+
+void Scene_triangulation_3_item::drawPoints(CGAL::Three::Viewer_interface * viewer) const
+{
+  if(!visible())
+    return;
+  if(renderingMode() == Points)
+  {
+    if(!isInit(viewer))
+      initGL(viewer);
+    if ( getBuffersFilled() &&
+         ! getBuffersInit(viewer))
+    {
+      initializeBuffers(viewer);
+      setBuffersInit(viewer, true);
+    }
+    if(!getBuffersFilled())
+    {
+      computeElements();
+      initializeBuffers(viewer);
+    }
+
+    getPointContainer(0)->setColor(this->color());
+    getPointContainer(0)->draw(viewer, true);
+  }
+}
+
+
+void Scene_triangulation_3_item::initializeBuffers(Viewer_interface *viewer) const
+{
+  //vao containing the data for the facets
+  {
+    getTriangleContainer(0)->initializeBuffers(viewer);
+    getTriangleContainer(0)->setFlatDataSize(
+          d->positions_poly_size);
+
+    d->positions_poly.clear();
+    d->positions_poly.shrink_to_fit();
+    d->normals.clear();
+    d->normals.shrink_to_fit();
+    d->f_colors.clear();
+    d->f_colors.shrink_to_fit();
+  }
+
+  //vao containing the data for the lines
+  {
+    getEdgeContainer(0)->initializeBuffers(viewer);
+    getEdgeContainer(0)->setFlatDataSize(
+          d->positions_lines_size);
+  }
+  //vao containing the data for the points
+  {
+    getPointContainer(0)->initializeBuffers(viewer);
+    getPointContainer(0)->setFlatDataSize(
+          d->positions_lines_size);
+
+    d->positions_lines.clear();
+    d->positions_lines.shrink_to_fit();
+  }
+}
+
+void Scene_triangulation_3_item::computeElements() const {
+
+  QApplication::setOverrideCursor(Qt::WaitCursor);
+
+  if(!d->alphaSlider)
+   {
+     d->alphaSlider = new QSlider(::Qt::Horizontal);
+     d->alphaSlider->setMinimum(0);
+     d->alphaSlider->setMaximum(255);
+     d->alphaSlider->setValue(255);
+   }
+
+  d->positions_poly.clear();
+  d->normals.clear();
+  d->positions_lines.clear();
+  d->f_colors.clear();
+  {
+    Geom_traits::Construct_point_3 wp2p
+      = d->t3->geom_traits().construct_point_3_object();
+
+    for (Tr::Facet_iterator
+      fit = d->t3->facets_begin(),
+      end = d->t3->facets_end();
+    fit != end; ++fit)
+    {
+      const Tr::Cell_handle& cell = fit->first;
+      const int& index = fit->second;
+      const Tr::Bare_point& pa = wp2p(cell->vertex((index + 1) & 3)->point());
+      const Tr::Bare_point& pb = wp2p(cell->vertex((index + 2) & 3)->point());
+      const Tr::Bare_point& pc = wp2p(cell->vertex((index + 3) & 3)->point());
+
+      QColor color = d->colors[cell->surface_patch_index(index)];
+      d->f_colors.push_back((float)color.redF());d->f_colors.push_back((float)color.greenF());d->f_colors.push_back((float)color.blueF());
+      d->f_colors.push_back((float)color.redF());d->f_colors.push_back((float)color.greenF());d->f_colors.push_back((float)color.blueF());
+      d->f_colors.push_back((float)color.redF());d->f_colors.push_back((float)color.greenF());d->f_colors.push_back((float)color.blueF());
+      d->draw_triangle(pb, pa, pc);
+      d->draw_triangle_edges(pa, pb, pc);
+    }
+  }
+
+  getTriangleContainer(0)->allocate(
+        Tc::Flat_vertices, d->positions_poly.data(),
+        static_cast<int>(d->positions_poly.size()*sizeof(float)));
+
+  getTriangleContainer(0)->allocate(
+        Tc::Flat_normals,
+        d->normals.data(),
+        static_cast<int>(d->normals.size()*sizeof(float)));
+
+  getTriangleContainer(0)->allocate(
+        Tc::FColors,
+        d->f_colors.data(),
+        static_cast<int>(d->f_colors.size()*sizeof(float)));
+
+  d->positions_poly_size = d->positions_poly.size();
+
+  getEdgeContainer(0)->allocate(
+        Ec::Vertices,
+        d->positions_lines.data(),
+        static_cast<int>(d->positions_lines.size()*sizeof(float)));
+  d->positions_lines_size = d->positions_lines.size();
+
+  getPointContainer(0)->allocate(
+        Pc::Vertices,
+        d->positions_lines.data(),
+        static_cast<int>(d->positions_lines.size()*sizeof(float)));
+
+  setBuffersFilled(true);
+  QApplication::restoreOverrideCursor();
+}
+
+void Scene_triangulation_3_item::updateCutPlane()
+{ // just handle deformation - paint like selection is handled in eventFilter()
+  if(!d)
+    return;
+  if(d->need_changed) {
+    for(auto v : CGAL::QGLViewer::QGLViewerPool())
+    {
+      CGAL::Three::Viewer_interface* viewer = static_cast<CGAL::Three::Viewer_interface*>(v);
+      d->are_intersection_buffers_filled[viewer] = false;
+    }
+    d->need_changed = false;
+  }
+}

Polyhedron/demo/Polyhedron/Scene_triangulation_3_item.h

@@ -0,0 +1,84 @@
+#ifndef SCENE_TRIANGULATION_3_ITEM_H
+#define SCENE_TRIANGULATION_3_ITEM_H
+
+#include "T3_type.h"
+
+#include <QVector>
+#include <QColor>
+#include <QMenu>
+
+#include <QtCore/qglobal.h>
+#include <CGAL/Qt/qglviewer.h>
+#include <QOpenGLVertexArrayObject>
+#include <QOpenGLBuffer>
+#include <QOpenGLShaderProgram>
+
+#include <CGAL/Three/Viewer_interface.h>
+#include <CGAL/Three/Scene_item_rendering_helper.h>
+
+#ifdef scene_triangulation_3_item_EXPORTS
+#  define mesh_3_demo_scene_triangulation_3_item_EXPORTS 1
+#endif
+
+#ifdef mesh_3_demo_scene_triangulation_3_item_EXPORTS
+#  define SCENE_TRIANGULATION_3_ITEM_EXPORT Q_DECL_EXPORT
+#else
+#  define SCENE_TRIANGULATION_3_ITEM_EXPORT Q_DECL_IMPORT
+#endif
+
+struct Scene_triangulation_3_item_priv;
+using namespace CGAL::Three;
+class SCENE_TRIANGULATION_3_ITEM_EXPORT Scene_triangulation_3_item
+    : public Scene_item_rendering_helper
+{
+  Q_OBJECT
+public:
+  typedef CGAL::qglviewer::ManipulatedFrame ManipulatedFrame;
+
+  Scene_triangulation_3_item();
+  Scene_triangulation_3_item(T3* t3);
+  ~Scene_triangulation_3_item();
+
+  void common_constructor();
+  void invalidateOpenGLBuffers() Q_DECL_OVERRIDE;
+  void changed();
+  const T3& triangulation() const;
+  T3& triangulation();
+  bool isFinite() const Q_DECL_OVERRIDE { return true; }
+  bool isEmpty() const Q_DECL_OVERRIDE {
+    //todo
+    return false;
+  }
+
+  void compute_bbox() const Q_DECL_OVERRIDE;
+  Scene_item::Bbox bbox() const Q_DECL_OVERRIDE
+  {
+    //todo
+    return Scene_item::bbox();
+  }
+  void frame_changed();
+  Scene_triangulation_3_item* clone() const  Q_DECL_OVERRIDE;
+
+  QString toolTip() const Q_DECL_OVERRIDE;
+
+  // Indicate if rendering mode is supported
+  bool supportsRenderingMode(RenderingMode m) const  Q_DECL_OVERRIDE{
+    return (m != Gouraud && m != PointsPlusNormals && m != Points && m != ShadedPoints);
+  }
+
+  void draw(CGAL::Three::Viewer_interface* viewer) const Q_DECL_OVERRIDE;
+  void drawEdges(CGAL::Three::Viewer_interface* viewer) const Q_DECL_OVERRIDE;
+  void drawPoints(CGAL::Three::Viewer_interface * viewer) const Q_DECL_OVERRIDE;
+
+public Q_SLOTS:
+  void initializeBuffers(Viewer_interface *) const Q_DECL_OVERRIDE;
+  void computeElements() const Q_DECL_OVERRIDE;
+  void reset_intersection_item();
+  void show_intersection(bool b);
+
+protected:
+  friend struct Scene_triangulation_3_item_priv;
+  Scene_triangulation_3_item_priv* d;
+};
+
+#endif // SCENE_TRIANGULATION_3_ITEM_H

Polyhedron/demo/Polyhedron/T3_type.h

@@ -0,0 +1,7 @@
+#ifndef CGAL_DEMO_T3_TYPE_H
+#define CGAL_DEMO_T3_TYPE_H
+#include "C3t3_type.h"
+#include <CGAL/Triangulation_3.h>
+
+typedef CGAL::Triangulation_3<C3t3::Triangulation::Geom_traits, C3t3::Triangulation::Triangulation_data_structure> T3;
+#endif // CGAL_DEMO_T3_TYPE_H