SPE-2298: Add detection of Voronoi diagram with parabolic edge without a focus point.

src/libslic3r/Geometry/Voronoi.cpp

@@ -35,6 +35,8 @@ VoronoiDiagram::construct_voronoi(const SegmentIterator segment_begin, const Seg
                 BOOST_LOG_TRIVIAL(warning) << "Detected Voronoi edge intersecting input segment, input polygons will be rotated back and forth.";
             } else if (m_issue_type == IssueType::FINITE_EDGE_WITH_NON_FINITE_VERTEX) {
                 BOOST_LOG_TRIVIAL(warning) << "Detected finite Voronoi vertex with non finite vertex, input polygons will be rotated back and forth.";
+            } else if (m_issue_type == IssueType::PARABOLIC_VORONOI_EDGE_WITHOUT_FOCUS_POINT) {
+                BOOST_LOG_TRIVIAL(warning) << "Detected parabolic Voronoi edges without focus point, input polygons will be rotated back and forth.";
             } else {
                 BOOST_LOG_TRIVIAL(error) << "Detected unknown Voronoi diagram issue, input polygons will be rotated back and forth.";
             }
@@ -48,6 +50,8 @@ VoronoiDiagram::construct_voronoi(const SegmentIterator segment_begin, const Seg
                     BOOST_LOG_TRIVIAL(error) << "Detected Voronoi edge intersecting input segment even after the rotation of input.";
                 } else if (m_issue_type == IssueType::FINITE_EDGE_WITH_NON_FINITE_VERTEX) {
                     BOOST_LOG_TRIVIAL(error) << "Detected finite Voronoi vertex with non finite vertex even after the rotation of input.";
+                } else if (m_issue_type == IssueType::PARABOLIC_VORONOI_EDGE_WITHOUT_FOCUS_POINT) {
+                    BOOST_LOG_TRIVIAL(error) << "Detected parabolic Voronoi edges without focus point even after the rotation of input.";
                 } else {
                     BOOST_LOG_TRIVIAL(error) << "Detected unknown Voronoi diagram issue even after the rotation of input.";
                 }
@@ -159,8 +163,8 @@ typename boost::polygon::enable_if<
     VoronoiDiagram::IssueType>::type
 VoronoiDiagram::detect_known_issues(const VoronoiDiagram &voronoi_diagram, SegmentIterator segment_begin, SegmentIterator segment_end)
 {
-    if (has_finite_edge_with_non_finite_vertex(voronoi_diagram)) {
+    if (const IssueType edge_issue_type = detect_known_voronoi_edge_issues(voronoi_diagram); edge_issue_type != IssueType::NO_ISSUE_DETECTED) {
-        return IssueType::FINITE_EDGE_WITH_NON_FINITE_VERTEX;
+        return edge_issue_type;
     } else if (const IssueType cell_issue_type = detect_known_voronoi_cell_issues(voronoi_diagram, segment_begin, segment_end); cell_issue_type != IssueType::NO_ISSUE_DETECTED) {
         return cell_issue_type;
     } else if (!VoronoiUtilsCgal::is_voronoi_diagram_planar_angle(voronoi_diagram, segment_begin, segment_end)) {
@@ -218,16 +222,20 @@ VoronoiDiagram::detect_known_voronoi_cell_issues(const VoronoiDiagram &voronoi_d
     return IssueType::NO_ISSUE_DETECTED;
 }
 
-bool VoronoiDiagram::has_finite_edge_with_non_finite_vertex(const VoronoiDiagram &voronoi_diagram)
+VoronoiDiagram::IssueType VoronoiDiagram::detect_known_voronoi_edge_issues(const VoronoiDiagram &voronoi_diagram)
 {
     for (const voronoi_diagram_type::edge_type &edge : voronoi_diagram.edges()) {
         if (edge.is_finite()) {
             assert(edge.vertex0() != nullptr && edge.vertex1() != nullptr);
             if (edge.vertex0() == nullptr || edge.vertex1() == nullptr || !VoronoiUtils::is_finite(*edge.vertex0()) || !VoronoiUtils::is_finite(*edge.vertex1()))
-                return true;
+                return IssueType::FINITE_EDGE_WITH_NON_FINITE_VERTEX;
+
+            if (edge.is_curved() && !edge.cell()->contains_point() && !edge.twin()->cell()->contains_point())
+                return IssueType::PARABOLIC_VORONOI_EDGE_WITHOUT_FOCUS_POINT;
         }
     }
-    return false;
+
+    return IssueType::NO_ISSUE_DETECTED;
 }
 
 template<typename SegmentIterator>

src/libslic3r/Geometry/Voronoi.hpp

@@ -48,7 +48,8 @@ public:
         MISSING_VORONOI_VERTEX,
         NON_PLANAR_VORONOI_DIAGRAM,
         VORONOI_EDGE_INTERSECTING_INPUT_SEGMENT,
-        UNKNOWN                                  // Repairs are disabled in the constructor.
+        PARABOLIC_VORONOI_EDGE_WITHOUT_FOCUS_POINT,
+        UNKNOWN                                     // Repairs are disabled in the constructor.
     };
 
     enum class State {
@@ -162,7 +163,10 @@ private:
         IssueType>::type
     detect_known_voronoi_cell_issues(const VoronoiDiagram &voronoi_diagram, SegmentIterator segment_begin, SegmentIterator segment_end);
 
-    static bool has_finite_edge_with_non_finite_vertex(const VoronoiDiagram &voronoi_diagram);
+    // Detect issues related to Voronoi edges, or that can be detected by iterating over Voronoi edges.
+    // The first type of issue that can be detected is a finite Voronoi edge with a non-finite vertex.
+    // The second type of issue that can be detected is a parabolic Voronoi edge without a focus point (produced by two segments).
+    static IssueType detect_known_voronoi_edge_issues(const VoronoiDiagram &voronoi_diagram);
 
     voronoi_diagram_type  m_voronoi_diagram;
     vertex_container_type m_vertices;

tests/libslic3r/test_voronoi.cpp

@@ -2217,3 +2217,68 @@ TEST_CASE("Invalid Voronoi diagram - Thin lines - SPE-1729", "[InvalidVoronoiDia
 
 //    REQUIRE(vd.is_valid());
 }
+
+TEST_CASE("Voronoi cell doesn't contain a source point - SPE-2298", "[VoronoiCellSourcePointSPE2298]")
+{
+    Polygon polygon = {
+         { 9854534,  -39739718}, {- 4154002, -34864557}, {-13073118, -31802214},
+         {-21265508, -29026626}, {-31388055, -25645073}, {-32409943, -25279942},
+         {-33418087, -24864987}, {-34400568, -24404312}, {-35354754, -23899358},
+         {-36278795, -23351325}, {-37170015, -22762146}, {-38025776, -22134628},
+         {-38845825, -21468175}, {-39627905, -20764801}, {-40370549, -20026061},
+         {-41072075, -19253859}, {-41731000, -18450032}, {-42345940, -17616466},
+         {-42915530, -16755283}, {-43438684, -15868338}, {-43914245, -14957822},
+         {-44341235, -14025879}, {-44718686, -13074712}, {-45045890, -12106566},
+         {-45322386, -11123499}, {-45547674, -10127656}, {-45721021, - 9121581},
+         {-45842174, - 8107658}, {-45910990, - 7088089}, {-45927405, - 6065217},
+         {-45891432, - 5041288}, {-45803222, - 4018728}, {-45663042, - 2999801},
+         {-45471245, - 1986784}, {-45230690, -  991761}, {-38655400,  23513180},
+         {-38366034,  24494742}, {-38025334,  25467666}, {-37636844,  26420074},
+         {-37200678,  27349843}, {-36718169,  28254419}, {-36191104,  29131704},
+         {-35620587,  29979748}, {-35007621,  30796895}, {-34353751,  31580950},
+         {-33660293,  32330182}, {-32928806,  33042775}, {-32160862,  33717057},
+         {-31358104,  34351432}, {-30522331,  34944323}, {-29655434,  35494277},
+         {-28759338,  35999922}, {-27835963,  36460011}, {-26921721,  36858494},
+         {-25914008,  37239556}, {-24919466,  37557049}, {-24204878,  37746930},
+         {-22880526,  38041931}, {-21833362,  38209050}, {-21449204,  38252031},
+         {-20775657,  38324377}, {-19711119,  38387480}, {-18638667,  38398812},
+         {-17762260,  38366962}, {-16480321,  38266321}, {-15396213,  38120856},
+         {-14327987,  37925343}, {- 5801522,  36175494}, {  7791637,  33457589},
+         { 15887399,  31878986}, { 28428609,  29478881}, { 28438392,  29512722},
+         { 27850323,  29743358}, { 27058729,  29970066}, { 14135560,  32452875},
+         {  6101685,  34019760}, {- 5352362,  36305237}, {-14423391,  38160442},
+         {-15528705,  38361745}, {-16625379,  38507834}, {-17721787,  38600631},
+         {-18812787,  38641330}, {-19563804,  38633844}, {-20975692,  38563412},
+         {-22036069,  38446419}, {-23087710,  38277136}, {-24123993,  38056689},
+         {-25141240,  37786307}, {-26138324,  37466465}, {-26851801,  37197652},
+         {-28067514,  36680229}, {-28988984,  36219404}, {-29886302,  35711371},
+         {-30754551,  35158840}, {-31124518,  34896643}, {-31589528,  34564743},
+         {-32392776,  33928220}, {-33161225,  33251721}, {-33454722,  32966117},
+         {-33891684,  32538320}, {-34585318,  31787066}, {-35239508,  31000793},
+         {-35527715,  30616853}, {-35851756,  30182731}, {-36422833,  29331982},
+         {-36950377,  28452000}, {-37265788,  27860633}, {-37432874,  27545549},
+         {-37870512,  26612217}, {-38261423,  25655915}, {-38581885,  24744387},
+         {-38902507,  23671594}, {-45523689, - 1006672}, {-45770290, - 2026713},
+         {-45963584, - 3043930}, {-46104330, - 4066310}, {-46192377, - 5092635},
+         {-46228310, - 6120019}, {-46211987, - 7145807}, {-46143426, - 8167812},
+         {-46022719, - 9183674}, {-45850055, -10191399}, {-45625772, -11188531},
+         {-45350245, -12172975}, {-45023965, -13142600}, {-44647538, -14095222},
+         {-44221691, -15028602}, {-43747176, -15940794}, {-43224933, -16829570},
+         {-42655872, -17693052}, {-42041183, -18529065}, {-41381752, -19335983},
+         {-40677899, -20112975}, {-39932077, -20856972}, {-39145730, -21566171},
+         {-38320552, -22238686}, {-37458030, -22872953}, {-36560036, -23467217},
+         {-35627745, -24020614}, {-34662272, -24532977}, {-33667551, -25000722},
+         {-32645434, -25422669}, {-31588226, -25801077}, {-24380013, -28208306},
+         {-24380013, -28208306}, {-13354262, -31942517}, {-13354261, -31942515},
+         {-2032305,  -35842454}, {  8025116, -39348505}, {  8820397, -39587703},
+         { 9636283,  -39751794}, {  9847092, -39773278}};
+
+    VD    vd;
+    Lines lines = to_lines(polygon);
+    vd.construct_voronoi(lines.begin(), lines.end());
+#ifdef VORONOI_DEBUG_OUT
+//    dump_voronoi_to_svg(debug_out_path("voronoi-cell-source-point-spe2298.svg").c_str(), vd, Points(), lines);
+#endif
+
+    REQUIRE(vd.is_valid());
+}