Support touching holes

Author: Marc Kramer

poly2tri/sweep/sweep_context.cc

@@ -49,11 +49,16 @@ void SweepContext::AddHole(const std::vector<Point*>& polyline)
 {
   InitEdges(polyline);
   for (auto i : polyline) {
-    points_.push_back(i);
+    if (point_set_.insert(i).second) {
+      points_.push_back(i);
+    }
   }
 }
 
 void SweepContext::AddPoint(Point* point) {
+  if (!point_set_.insert(point).second) {
+    throw std::runtime_error("Point already exists");
+  }
   points_.push_back(point);
 }
 

poly2tri/sweep/sweep_context.h

@@ -34,6 +34,7 @@
 #include <list>
 #include <vector>
 #include <cstddef>
+#include <unordered_set>
 
 namespace p2t {
 
@@ -136,6 +137,7 @@ friend class Sweep;
 std::vector<Triangle*> triangles_;
 std::list<Triangle*> map_;
 std::vector<Point*> points_;
+std::unordered_set<Point*> point_set_;
 
 // Advancing front
 AdvancingFront* front_;