From cba8456715e6945bb120801f90a5d26269d92b27 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Mon, 2 Jan 2017 15:28:28 +0100
Subject: [PATCH] add constructions for the intersection point of a plane by a
 line and of 2 lines

this is undocumented and allow to have a lazy node for this construction
---
 .../include/CGAL/Kernel/function_objects.h    | 52 +++++++++++++++++++
 .../include/CGAL/Kernel/interface_macros.h    |  4 ++
 2 files changed, 56 insertions(+)

diff --git a/Kernel_23/include/CGAL/Kernel/function_objects.h b/Kernel_23/include/CGAL/Kernel/function_objects.h
index fee859a34fa..7569527299e 100644
--- a/Kernel_23/include/CGAL/Kernel/function_objects.h
+++ b/Kernel_23/include/CGAL/Kernel/function_objects.h
@@ -1104,6 +1104,31 @@ namespace CommonKernelFunctors {
     { return this->operator()(Return_base_tag(), min_hx, min_hy, min_hz, max_hx, max_hy, max_hz); }
   };
 
+  template <typename K>
+  class Construct_line_line_intersection_point_3
+  {
+    typedef typename K::Line_3 Line;
+    typedef typename K::Point_3 Point;
+    typename K::Construct_line_3 construct_line;
+  public:
+    typedef Point result_type;
+
+    Point
+    operator()(const Point& l11, const Point& l12,
+               const Point& l21, const Point& l22) const
+    {
+      Line l1 = construct_line(l11, l12);
+      Line l2 = construct_line(l21, l22);
+
+      typename cpp11::result_of<typename K::Intersect_3(Line,Line)>::type
+        res = typename K::Intersect_3()(l1,l2);
+      CGAL_assertion(res!=boost::none);
+      const Point* e_pt = boost::get<Point>(&(*res));
+      CGAL_assertion(e_pt!=NULL);
+      return *e_pt;
+    }
+  };
+
   template <typename K>
   class Construct_max_vertex_2
   {
@@ -1477,6 +1502,33 @@ namespace CommonKernelFunctors {
 
   };
 
+  template <typename K>
+  class Construct_plane_line_intersection_point_3
+  {
+    typedef typename K::Plane_3 Plane;
+    typedef typename K::Line_3 Line;
+    typedef typename K::Point_3 Point;
+    typename K::Construct_plane_3 construct_plane;
+    typename K::Construct_line_3 construct_line;
+  public:
+    typedef Point result_type;
+
+    Point
+    operator()(const Point& p1, const Point& p2, const Point& p3,
+               const Point& l1, const Point& l2) const
+    {
+      Plane plane = construct_plane(p1, p2, p3);
+      Line line = construct_line( l1, l2 );
+
+      typename cpp11::result_of<typename K::Intersect_3(Plane,Line)>::type
+        res = typename K::Intersect_3()(plane,line);
+      CGAL_assertion(res!=boost::none);
+      const Point* e_pt = boost::get<Point>(&(*res));
+      CGAL_assertion(e_pt!=NULL);
+      return *e_pt;
+    }
+  };
+
   template <typename K>
   class Construct_point_on_2
   {
diff --git a/Kernel_23/include/CGAL/Kernel/interface_macros.h b/Kernel_23/include/CGAL/Kernel/interface_macros.h
index 29e98635e06..68bbc804a91 100644
--- a/Kernel_23/include/CGAL/Kernel/interface_macros.h
+++ b/Kernel_23/include/CGAL/Kernel/interface_macros.h
@@ -302,6 +302,8 @@ CGAL_Kernel_cons(Construct_line_2,
 		 construct_line_2_object)
 CGAL_Kernel_cons(Construct_line_3,
 		 construct_line_3_object)
+CGAL_Kernel_cons(Construct_line_line_intersection_point_3,
+                 construct_line_line_intersection_point_3_object)
 CGAL_Kernel_cons(Construct_midpoint_2,
 		 construct_midpoint_2_object)
 CGAL_Kernel_cons(Construct_midpoint_3,
@@ -370,6 +372,8 @@ CGAL_Kernel_cons(Construct_perpendicular_vector_2,
 		 construct_perpendicular_vector_2_object)
 CGAL_Kernel_cons(Construct_plane_3,
 		 construct_plane_3_object)
+CGAL_Kernel_cons(Construct_plane_line_intersection_point_3,
+                 construct_plane_line_intersection_point_3_object)
 CGAL_Kernel_cons(Construct_point_on_2,
 		 construct_point_on_2_object)
 CGAL_Kernel_cons(Construct_point_on_3,