Add function IsDelaunay to check if results are valid

poly2tri/common/shapes.cc

@@ -389,4 +389,21 @@ bool Triangle::IsCounterClockwise() const
          0;
 }
 
+bool IsDelaunay(const std::vector<p2t::Triangle*>& triangles)
+{
+  for (const auto triangle : triangles) {
+    for (const auto other : triangles) {
+      if (triangle == other) {
+        continue;
+      }
+      for (int i = 0; i < 3; ++i) {
+        if (triangle->CircumcicleContains(*other->GetPoint(i))) {
+          return false;
+        }
+      }
+    }
+  }
+  return true;
+}
+
 }

poly2tri/common/shapes.h

@@ -324,6 +324,9 @@ inline void Triangle::IsInterior(bool b)
   interior_ = b;
 }
 
+/// Is this set a valid delaunay triangulation?
+bool IsDelaunay(const std::vector<p2t::Triangle*>&);
+
 }
 
 #endif

unittest/main.cpp

@@ -2,18 +2,75 @@
 #define BOOST_TEST_MODULE Poly2triTest
 #include <boost/test/unit_test.hpp>
 #include <poly2tri/poly2tri.h>
+#include <fstream>
 #include <iostream>
 
-BOOST_AUTO_TEST_CASE(BasicTest) {
-	std::vector<p2t::Point*> polyline{
-		new p2t::Point(0, 0), new p2t::Point(1, 0), new p2t::Point(1, 1),
-	};
-	p2t::CDT cdt{polyline};
-	cdt.Triangulate();
-	const auto result = cdt.GetTriangles();
-	assert(result.size() == 1);
-	BOOST_CHECK_EQUAL(*result[0]->GetPoint(0), *polyline[0]);
-	BOOST_CHECK_EQUAL(*result[0]->GetPoint(1), *polyline[1]);
-	BOOST_CHECK_EQUAL(*result[0]->GetPoint(2), *polyline[2]);
-	result[0]->DebugPrint();
+BOOST_AUTO_TEST_CASE(BasicTest)
+{
+  std::vector<p2t::Point*> polyline{
+    new p2t::Point(0, 0),
+    new p2t::Point(1, 0),
+    new p2t::Point(1, 1),
+  };
+  p2t::CDT cdt{ polyline };
+  cdt.Triangulate();
+  const auto result = cdt.GetTriangles();
+  BOOST_REQUIRE_EQUAL(result.size(), 1);
+  BOOST_CHECK_EQUAL(*result[0]->GetPoint(0), *polyline[0]);
+  BOOST_CHECK_EQUAL(*result[0]->GetPoint(1), *polyline[1]);
+  BOOST_CHECK_EQUAL(*result[0]->GetPoint(2), *polyline[2]);
+  BOOST_CHECK(p2t::IsDelaunay(result));
+  for (const auto p : polyline) {
+    delete p;
+  }
+}
+
+BOOST_AUTO_TEST_CASE(QuadTest)
+{
+  std::vector<p2t::Point*> polyline{ new p2t::Point(0, 0), new p2t::Point(0, 1),
+                                     new p2t::Point(1, 1), new p2t::Point(1, 0) };
+  p2t::CDT cdt{ polyline };
+  cdt.Triangulate();
+  const auto result = cdt.GetTriangles();
+  BOOST_REQUIRE_EQUAL(result.size(), 2);
+  BOOST_CHECK(p2t::IsDelaunay(result));
+  for (const auto p : polyline) {
+    delete p;
+  }
+}
+
+BOOST_AUTO_TEST_CASE(TestbedFilesTest)
+{
+  for (const auto& filename : { "custom.dat", "diamond.dat", "star.dat", "test.dat" }) {
+    std::vector<p2t::Point*> polyline;
+    // Load pointset from file
+    // Parse and tokenize data file
+    std::string line;
+    std::ifstream myfile(std::string("../testbed/data/") + filename);
+    if (!myfile.is_open()) {
+      myfile.open(std::string("testbed/data/") + filename);
+    }
+    BOOST_REQUIRE(myfile.is_open());
+    while (!myfile.eof()) {
+      getline(myfile, line);
+      if (line.empty()) {
+        break;
+      }
+      std::istringstream iss(line);
+      std::vector<std::string> tokens;
+      copy(std::istream_iterator<std::string>(iss), std::istream_iterator<std::string>(),
+           std::back_inserter<std::vector<std::string>>(tokens));
+      double x = std::stod(tokens[0]);
+      double y = std::stod(tokens[1]);
+      polyline.push_back(new p2t::Point(x, y));
+    }
+    p2t::CDT cdt{ polyline };
+    cdt.Triangulate();
+    const auto result = cdt.GetTriangles();
+    BOOST_REQUIRE(result.size() * 3 > polyline.size());
+    BOOST_CHECK_MESSAGE(p2t::IsDelaunay(result), filename + std::to_string(polyline.size()));
+    for (const auto p : polyline) {
+      delete p;
+    }
+  }
 }