[Boost-commit] svn:boost r77308 - in trunk/boost/geometry: algorithms/detail/overlay strategies strategies/cartesian

Subject: [Boost-commit] svn:boost r77308 - in trunk/boost/geometry: algorithms/detail/overlay strategies strategies/cartesian
From: barend.gehrels_at_[hidden]
Date: 2012-03-11 16:37:53

Author: barendgehrels
Date: 2012-03-11 16:37:51 EDT (Sun, 11 Mar 2012)
New Revision: 77308
URL: http://svn.boost.org/trac/boost/changeset/77308

Log:
[geometry] Finetuned robustness fixes of this weekend and fixed (again) for case #ggl_list_20110820_christophe
Text files modified: 
   trunk/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp |    18 +++++++++++-------                      
   trunk/boost/geometry/strategies/cartesian/cart_intersect.hpp     |    20 ++++++++++++++++++++                    
   trunk/boost/geometry/strategies/side_info.hpp                    |     7 +++++++                                 
   3 files changed, 38 insertions(+), 7 deletions(-)

Modified: trunk/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp
==============================================================================
--- trunk/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp	(original)
+++ trunk/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp	2012-03-11 16:37:51 EDT (Sun, 11 Mar 2012)
@@ -589,14 +589,15 @@
 
             if (side_pk != side_p || side_qk != side_q)
             {
-                //std::cout << " -> Collinear " 
+                //std::cout << "ROBUSTNESS -> Collinear " 
                 //    << " arr: " << arrival
                 //    << " prod: " << product
                 //    << " dir: " << side_p << " " << side_q
                 //    << " rev: " << side_pk << " " << side_qk
                 //    << std::endl;
 
-                handle_robustness(ti, product, side_p, side_q, side_pk, side_qk);
+                handle_robustness(ti, arrival, product, 
+                            side_p, side_q, side_pk, side_qk);
             }
             else
             {
@@ -607,16 +608,19 @@
     }
 
     static inline void handle_robustness(TurnInfo& ti,
-                    int product, 
+                    int arrival, int product, 
                     int side_p, int side_q,
                     int side_pk, int side_qk)
     {
         bool take_ui = product == 1;
-        if ((product == 1 && side_p == 1 && side_pk != 1)
-            || (product == -1 && side_q == 1 && side_qk != 1))
+        if (product == arrival)
         {
-            //std::cout << " -> Reverse" << std::endl;
-            take_ui = ! take_ui;
+            if ((product == 1 && side_p == 1 && side_pk != 1)
+                || (product == -1 && side_q == 1 && side_qk != 1))
+            {
+                //std::cout << "ROBUSTNESS: -> Reverse" << std::endl;
+                take_ui = ! take_ui;
+            }
         }
 
         ui_else_iu(take_ui, ti);

Modified: trunk/boost/geometry/strategies/cartesian/cart_intersect.hpp
==============================================================================
--- trunk/boost/geometry/strategies/cartesian/cart_intersect.hpp	(original)
+++ trunk/boost/geometry/strategies/cartesian/cart_intersect.hpp	2012-03-11 16:37:51 EDT (Sun, 11 Mar 2012)
@@ -203,6 +203,26 @@
                                 promoted_type const zero = 0;
                                 promoted_type const one = 1;
                                 promoted_type const epsilon = std::numeric_limits<double>::epsilon();
+
+                if (sides.crossing() && math::abs(da-d) < 0.1)
+                {
+                    // ROBUSTNESS: the r value can in epsilon-cases be 1.14, while (with perfect arithmetic)
+                    // it should be one. If segments are crossing (we can see that with the sides)
+                    // and one is inside the other, there must be an intersection point.
+                    // We correct for that.
+                    // TODO: find more cases (this only solves case called ggl_list_20110820_christophe in unit tests
+                    if (r > one)
+                    {
+                        // std::cout << "ROBUSTNESS: correction of r " << r << std::endl;
+                        r = one;
+                    }
+                    else if (r < zero)
+                    {
+                        // std::cout << "ROBUSTNESS: correction of r " << r << std::endl;
+    					r = zero;
+                    }
+                }
+
                                 if (r < zero)
                                 {
                                         if (r < -epsilon)

Modified: trunk/boost/geometry/strategies/side_info.hpp
==============================================================================
--- trunk/boost/geometry/strategies/side_info.hpp	(original)
+++ trunk/boost/geometry/strategies/side_info.hpp	2012-03-11 16:37:51 EDT (Sun, 11 Mar 2012)
@@ -67,6 +67,13 @@
             && sides[1].second == 0;
     }
 
+    inline bool crossing() const
+    {
+        return sides[0].first * sides[0].second == -1
+            && sides[1].first * sides[1].second == -1;
+    }
+
+
     template <int Which>
     inline bool zero() const
     {