From bf20b43ea5a13788a50c8a9fe592f79c679d14f2 Mon Sep 17 00:00:00 2001
From: Guillaume Damiand <guillaume.damiand@liris.cnrs.fr>
Date: Fri, 7 Sep 2018 20:19:41 +0200
Subject: [PATCH] Start to implement 2D mode for viewers; nyf.

---
 GraphicsView/include/CGAL/Buffer_for_vao.h    | 24 ++++++++
 .../include/CGAL/Qt/Basic_viewer_qt.h         | 56 +++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/GraphicsView/include/CGAL/Buffer_for_vao.h b/GraphicsView/include/CGAL/Buffer_for_vao.h
index 0ff36cc96cd..ed1f819f71d 100644
--- a/GraphicsView/include/CGAL/Buffer_for_vao.h
+++ b/GraphicsView/include/CGAL/Buffer_for_vao.h
@@ -161,6 +161,9 @@ public:
     m_flat_normal_buffer(flat_normal),
     m_gouraud_normal_buffer(gouraud_normal),
     m_bb(bbox),
+    m_zero_x(true),
+    m_zero_y(true),
+    m_zero_z(true),
     m_face_started(false)
   {}
 
@@ -171,6 +174,10 @@ public:
     if (m_index_buffer!=NULL)          { m_index_buffer->clear(); }
     if (m_flat_normal_buffer!=NULL)    { m_flat_normal_buffer->clear(); }
     if (m_gouraud_normal_buffer!=NULL) { m_gouraud_normal_buffer->clear(); }
+
+    m_zero_x=true;
+    m_zero_y=true;
+    m_zero_z=true;
   }
 
   bool is_empty() const
@@ -198,6 +205,15 @@ public:
   bool has_gouraud_normal() const
   { return m_gouraud_normal_buffer!=NULL; }
 
+  bool has_zero_x() const
+  { return m_zero_x; }  
+
+  bool has_zero_y() const
+  { return m_zero_y; }  
+
+  bool has_zero_z() const
+  { return m_zero_z; }  
+
   // 1.1) Add a point, without color. Return the index of the added point.
   template<typename KPoint>
   std::size_t add_point(const KPoint& kp)
@@ -209,6 +225,10 @@ public:
 
     if (m_bb!=NULL)
     { (*m_bb)=(*m_bb)+p.bbox(); }
+    
+    if (m_zero_x && p.x()!=0) { m_zero_x=false; }
+    if (m_zero_y && p.y()!=0) { m_zero_y=false; }
+    if (m_zero_z && p.z()!=0) { m_zero_z=false; }
 
     return m_pos_buffer->size()-3;
   }
@@ -808,6 +828,10 @@ protected:
   std::vector<BufferType>* m_gouraud_normal_buffer;
 
   CGAL::Bbox_3* m_bb;
+
+  bool m_zero_x; /// True iff all points have x==0
+  bool m_zero_y; /// True iff all points have y==0
+  bool m_zero_z; /// True iff all points have z==0
   
   // Local variables, used when we started a new face.
   bool m_face_started;
diff --git a/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h b/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
index 78376d06bce..c8bbd4c128e 100644
--- a/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
+++ b/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
@@ -42,6 +42,8 @@
 
 #include <CGAL/Buffer_for_vao.h>
 #include <CGAL/Qt/CreateOpenGLContext.h>
+#include <CGAL/Qt/constraint.h>
+#include <CGAL/Qt/manipulatedFrame.h>
 #include <CGAL/Random.h>
 
 namespace CGAL
@@ -217,6 +219,8 @@ public:
 
     for (int i=0; i<NB_VAO_BUFFERS; ++i)
       vao[i].destroy();
+
+    delete frame;
   }
 
   void clear()
@@ -240,6 +244,39 @@ public:
   const CGAL::Bbox_3& bounding_box() const
   { return m_bounding_box; }
 
+  bool has_zero_x() const
+  {
+    return
+      m_buffer_for_mono_points.has_zero_x() && 
+      m_buffer_for_colored_points.has_zero_x() &&
+      m_buffer_for_mono_segments.has_zero_x() &&
+      m_buffer_for_colored_segments.has_zero_x() &&
+      m_buffer_for_mono_faces.has_zero_x() &&
+      m_buffer_for_colored_faces.has_zero_x();
+  }  
+
+  bool has_zero_y() const
+  {
+    return
+      m_buffer_for_mono_points.has_zero_y() && 
+      m_buffer_for_colored_points.has_zero_y() &&
+      m_buffer_for_mono_segments.has_zero_y() &&
+      m_buffer_for_colored_segments.has_zero_y() &&
+      m_buffer_for_mono_faces.has_zero_y() &&
+      m_buffer_for_colored_faces.has_zero_y();
+  }
+  
+  bool has_zero_z() const
+  {
+    return
+      m_buffer_for_mono_points.has_zero_z() && 
+      m_buffer_for_colored_points.has_zero_z() &&
+      m_buffer_for_mono_segments.has_zero_z() &&
+      m_buffer_for_colored_segments.has_zero_z() &&
+      m_buffer_for_mono_faces.has_zero_z() &&
+      m_buffer_for_colored_faces.has_zero_z();
+  }
+  
   template<typename KPoint>
   void add_point(const KPoint& p)
   { m_buffer_for_mono_points.add_point(p); }
@@ -719,6 +756,19 @@ protected:
 
       rendering_program_face.release();
     }
+
+    if (!is_empty() && (has_zero_x() || has_zero_y() || has_zero_z()))
+    {
+      camera()->setType(CGAL::qglviewer::Camera::ORTHOGRAPHIC);
+      //      Camera Constraint:
+      constraint.setRotationConstraintType(CGAL::qglviewer::AxisPlaneConstraint::FORBIDDEN);
+      constraint.setTranslationConstraintType(CGAL::qglviewer::AxisPlaneConstraint::FREE);
+      constraint.setRotationConstraintDirection(CGAL::qglviewer::Vec((has_zero_x()?1:0),
+                                                                     (has_zero_y()?1:0),
+                                                                     (has_zero_z()?1:0)));
+
+      frame->setConstraint(&constraint);
+    }
   }
 
   virtual void redraw()
@@ -763,6 +813,9 @@ protected:
 
     compile_shaders();
 
+    frame = new qglviewer::ManipulatedFrame;
+    setManipulatedFrame(frame);
+      
     CGAL::Bbox_3 bb;
     if (bb==bounding_box()) // Case of "empty" bounding box
     {    
@@ -984,6 +1037,9 @@ private:
 
   bool m_are_buffers_initialized;
   CGAL::Bbox_3 m_bounding_box;
+
+  qglviewer::ManipulatedFrame *frame;
+  CGAL::qglviewer::LocalConstraint constraint;
   
   // The following enum gives the indices of different elements of arrays vectors.
   enum