From c31d6713bd1f7f1e9ec2493d60fd9f07dcde344c Mon Sep 17 00:00:00 2001
From: Pierre Alliez <Pierre.Alliez@sophia.inria.fr>
Date: Sat, 12 Jul 2008 09:48:23 +0000
Subject: [PATCH] added rendering file another attempt to simplify a polyhedron
 (the basic one this time) but it does not compile...

---
 .../demo/Polyhedron/MainWindow_simplify.cpp   |  9 ++-
 Polyhedron/demo/Polyhedron/Scene.h            |  2 +-
 .../demo/Polyhedron/include/CGAL/gl_render.h  | 72 +++++++++++++++++++
 3 files changed, 77 insertions(+), 6 deletions(-)
 create mode 100644 Polyhedron/demo/Polyhedron/include/CGAL/gl_render.h

diff --git a/Polyhedron/demo/Polyhedron/MainWindow_simplify.cpp b/Polyhedron/demo/Polyhedron/MainWindow_simplify.cpp
index 903243aed68..926df4b784b 100644
--- a/Polyhedron/demo/Polyhedron/MainWindow_simplify.cpp
+++ b/Polyhedron/demo/Polyhedron/MainWindow_simplify.cpp
@@ -5,23 +5,22 @@
 #include <CGAL/Surface_mesh_simplification/edge_collapse.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_stop_predicate.h>
 
+
 void MainWindow::on_actionSimplify_triggered()
 {
   if(onePolygonIsSelected())
   {
     int index = getSelectedPolygonIndex();
     Polyhedron* pMesh = scene->polyhedron(index);
+
     // simplify
-    //unsigned int nb_edges = 1000; // TODO: should be an option 
-    //namespace SMS = CGAL::Surface_mesh_simplification ;
+    unsigned int nb_edges = 1000; // TODO: should be an option 
+    //namespace SMS = CGAL::Surface_mesh_simplification;
     //SMS::Count_stop_predicate< Polyhedron > stop(nb_edges); // target # edges
     //SMS::edge_collapse( *pMesh, stop,
     //                     CGAL::vertex_index_map(boost::get(CGAL::vertex_external_index,*pMesh))
     //		                       .edge_index_map(boost::get(CGAL::edge_external_index,*pMesh)));
 
-    // recompute normals
-    //pMesh->compute_normals();
-
     // Tell the scene that polyhedron #index has been changed
     scene->polyhedronChanged(index);
   }
diff --git a/Polyhedron/demo/Polyhedron/Scene.h b/Polyhedron/demo/Polyhedron/Scene.h
index 45751547a2e..f85b6f9adc3 100644
--- a/Polyhedron/demo/Polyhedron/Scene.h
+++ b/Polyhedron/demo/Polyhedron/Scene.h
@@ -18,7 +18,7 @@
 
 // surface
 #include <CGAL/Polyhedron_3.h>
-#include <CGAL/enriched_polyhedron.h>
+//#include <CGAL/enriched_polyhedron.h>
 
 typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
 typedef Kernel::FT FT;
diff --git a/Polyhedron/demo/Polyhedron/include/CGAL/gl_render.h b/Polyhedron/demo/Polyhedron/include/CGAL/gl_render.h
new file mode 100644
index 00000000000..476aa2afa3e
--- /dev/null
+++ b/Polyhedron/demo/Polyhedron/include/CGAL/gl_render.h
@@ -0,0 +1,72 @@
+#ifndef RENDER
+#define RENDER
+
+#include <GL/glu.h>
+
+template <class Polyhedron>
+void gl_render(Polyhedron& polyhedron)
+{
+	typedef typename Polyhedron::Traits Kernel;
+	typedef typename Kernel::Point_3 Point;
+	typedef typename Kernel::Vector_3 Vector;
+
+	typedef typename Polyhedron::Halfedge_handle                    Halfedge_handle;
+	typedef typename Polyhedron::Facet_handle                       Facet_handle;
+	typedef typename Polyhedron::Vertex_handle                      Vertex_handle;
+
+	typedef typename Polyhedron::Vertex_iterator                    Vertex_iterator;
+	typedef typename Polyhedron::Facet_iterator                     Facet_iterator;
+	typedef typename Polyhedron::Halfedge_iterator                  Halfedge_iterator;
+	typedef typename Polyhedron::Edge_iterator                      Edge_iterator;
+
+	typedef typename Polyhedron::Halfedge_around_vertex_circulator  HV_circulator;
+	typedef typename Polyhedron::Halfedge_around_facet_circulator   HF_circulator;
+
+	Facet_iterator f;
+	for(f = polyhedron.facets_begin();
+	    f != polyhedron.facets_end();
+	    f++)
+	{
+		::glBegin(GL_POLYGON);
+
+		// compute normal
+		Vector n = compute_normal<Polyhedron::Facet,Kernel>(*f);
+		::glNormal3d(n.x(),n.y(),n.z());
+
+		// revolve around current face to get vertices
+		HF_circulator he = f->facet_begin();
+		do
+		{
+			const Point& p = he->vertex()->point();
+			::glVertex3d(p.x(),p.y(),p.z());
+		}
+		while(++he != f->facet_begin());
+		::glEnd();
+	}
+}
+
+template <class Facet, class Kernel>
+typename Kernel::Vector_3 compute_normal(Facet& f)
+{
+	typedef typename Kernel::Point_3 Point;
+	typedef typename Kernel::Vector_3 Vector;
+	typedef typename Facet::Halfedge_around_facet_circulator HF_circulator;
+	Vector normal = CGAL::NULL_VECTOR;
+	HF_circulator he = f.facet_begin();
+	do
+	{
+		const Point& prev = he->prev()->vertex()->point();
+		const Point& curr = he->vertex()->point();
+		const Point& next = he->next()->vertex()->point();
+		Vector n = CGAL::cross_product(next-curr,prev-curr);
+		normal = normal + (n / std::sqrt(n*n));
+	}
+	while (++he != f.facet_begin());
+	return normal / std::sqrt(normal * normal);
+}
+
+#endif // RENDER
+
+
+
+