Merge pull request #3486 from efifogel/Ms_2-empty_ouetr_boundary-efif

Fixed face filtering in case one of the summands does not have an out…

Installation/CHANGES.md

@@ -68,10 +68,17 @@ Release date: March 2019
     `Arr_polyline_traits_2`, `Arr_polycurve_traits_2`, and
     `Arr_polycurve_basic_traits_2`.
 
+### 2D Minkowski Sums
+
+-   Fixed a bug in the function that computed the Minkowski sum using the
+    reduced-convolution method. In particular, correctly handled the case where
+    one of the summands does not have an outer boundaey.
+
 ### CGAL and the Boost Graph Library (BGL)
 
 -    Add function `write_wrl()` for writing into VRML 2.0 format.
 
+
 Release 4.13
 ------------
 

Minkowski_sum_2/include/CGAL/Minkowski_sum_2/AABB_collision_detector_2.h

@@ -83,22 +83,34 @@ public:
 
     // If t_q is inside of P, or t_p is inside of Q, one polygon is completely
     // inside of the other.
-    Point_2 t_q = *m_q.outer_boundary().vertices_begin() - Vector_2(ORIGIN, t);
-    Point_2 t_p = *m_p.outer_boundary().vertices_begin() + Vector_2(ORIGIN, t);
+
+    // Obtain a point on the boundary of m_q:
+    Point_2 t_q = (! m_q.outer_boundary().is_empty()) ?
+      *m_q.outer_boundary().vertices_begin() - Vector_2(ORIGIN, t) :
+      *m_q.holes_begin()->vertices_begin() - Vector_2(ORIGIN, t);
+
+    // Obtain a point on the boundary of m_p:
+    Point_2 t_p = (! m_p.outer_boundary().is_empty()) ?
+      *m_p.outer_boundary().vertices_begin() + Vector_2(ORIGIN, t) :
+      *m_p.holes_begin()->vertices_begin() + Vector_2(ORIGIN, t);
 
     // Use bounded_side_2() instead of on_bounded_side() because the latter
     // checks vor simplicity every time.
-    bool in_mp =
-      bounded_side_2(m_p.outer_boundary().vertices_begin(),
-                     m_p.outer_boundary().vertices_end(), t_q,
-                     m_p.outer_boundary().traits_member()) == ON_BOUNDED_SIDE;
+    bool in_mp(true);
+    if (! m_p.outer_boundary().is_empty())
+      in_mp =
+        bounded_side_2(m_p.outer_boundary().vertices_begin(),
+                       m_p.outer_boundary().vertices_end(), t_q,
+                       m_p.outer_boundary().traits_member()) == ON_BOUNDED_SIDE;
     if (m_p.number_of_holes() == 0) {
       if (in_mp) return true;
     }
-    bool in_mq =
-      bounded_side_2(m_q.outer_boundary().vertices_begin(),
-                     m_q.outer_boundary().vertices_end(), t_p,
-                     m_q.outer_boundary().traits_member()) == ON_BOUNDED_SIDE;
+    bool in_mq(true);
+    if (! m_q.outer_boundary().is_empty())
+      in_mq =
+        bounded_side_2(m_q.outer_boundary().vertices_begin(),
+                       m_q.outer_boundary().vertices_end(), t_p,
+                       m_q.outer_boundary().traits_member()) == ON_BOUNDED_SIDE;
     if (m_q.number_of_holes() == 0) {
       if (in_mq) return true;
     }

Minkowski_sum_2/include/CGAL/Minkowski_sum_2/Minkowski_sum_by_reduced_convolution_2.h

@@ -169,6 +169,9 @@ private:
     for (Face_iterator fit = arr.faces_begin(); fit != arr.faces_end(); ++fit) {
       // Check whether the face is on the M-sum's border.
 
+      // The unbounded face cannot contribute to the Minkowski sum
+      if (fit->is_unbounded()) continue;
+
       // If the face contains holes, it can't be on the Minkowski sum's border
       if (0 < fit->number_of_holes()) continue;
 
@@ -177,10 +180,8 @@ private:
 
       // When the reversed polygon 1, translated by a point inside of this face,
       // collides with polygon 2, this cannot be a hole
-      if (! is_outer_boundary_empty) {
-        Point_2 inner_point = get_point_in_face(fit);
-        if (collision_detector.check_collision(inner_point)) continue;
-      }
+      Point_2 inner_point = get_point_in_face(fit);
+      if (collision_detector.check_collision(inner_point)) continue;
 
       add_face(fit, holes);
     }

Minkowski_sum_2/test/Minkowski_sum_2/data/pwh10.dat

@@ -0,0 +1,3 @@
+8
+0 0 40 0 40 30 30 30 30 60 10 60 10 30 0 30
+0

Minkowski_sum_2/test/Minkowski_sum_2/data/pwh11.dat

@@ -0,0 +1,3 @@
+0
+1
+4 0 40 50 40 50 0 0 0

Minkowski_sum_2/test/Minkowski_sum_2/data/pwh12.dat

@@ -0,0 +1,10 @@
+8
+ 0  0
+40  0
+40 30
+30 30
+30 40
+10 40
+10 30
+ 0 30
+0

Minkowski_sum_2/test/Minkowski_sum_2/data/pwh9.dat

@@ -0,0 +1,3 @@
+0
+1
+4 0 40 50 60 50 0 0 0

Minkowski_sum_2/test/Minkowski_sum_2/test_minkowski_sum_with_holes.cmd

@@ -14,3 +14,9 @@ data/pwh7.dat data/pwh6.dat
 data/pwh2.dat data/pwh8.dat
 data/pwh8.dat data/pwh2.dat
 data/pwh8.dat data/pwh8.dat
+data/pwh9.dat data/pwh10.dat
+data/pwh10.dat data/pwh9.dat
+data/pwh11.dat data/pwh10.dat
+data/pwh10.dat data/pwh11.dat
+data/pwh9.dat data/pwh12.dat
+data/pwh12.dat data/pwh9.dat