diff --git a/src/libslic3r/Layer.cpp b/src/libslic3r/Layer.cpp index 7962f0376..2d1132283 100644 --- a/src/libslic3r/Layer.cpp +++ b/src/libslic3r/Layer.cpp @@ -1,11 +1,14 @@ #include "Layer.hpp" #include "ClipperZUtils.hpp" #include "ClipperUtils.hpp" +#include "Point.hpp" +#include "Polygon.hpp" #include "Print.hpp" #include "Fill/Fill.hpp" #include "ShortestPath.hpp" #include "SVG.hpp" #include "BoundingBox.hpp" +#include "clipper/clipper.hpp" #include @@ -180,6 +183,31 @@ static void connect_layer_slices( break; } } + if (!found) { + // The check above might sometimes fail when the polygons overlap only on points, which causes the clipper to detect no intersection. + // The problem happens rarely, mostly on simple polygons (in terms of number of points), but regardless of size! + // example of failing link on two layers, each with single polygon without holes. + // layer A = Polygon{(-24931238,-11153865),(-22504249,-8726874),(-22504249,11477151),(-23261469,12235585),(-23752371,12727276),(-25002495,12727276),(-27502745,10227026),(-27502745,-12727274),(-26504645,-12727274)} + // layer B = Polygon{(-24877897,-11100524),(-22504249,-8726874),(-22504249,11477151),(-23244827,12218916),(-23752371,12727276),(-25002495,12727276),(-27502745,10227026),(-27502745,-12727274),(-26504645,-12727274)} + // note that first point is not identical, and the check above picks (-24877897,-11100524) as the first contour point (polynode.Contour.front()). + // that point is sadly slightly outisde of the layer A, so no link is detected, eventhough they are overlaping "completely" + Polygon contour_poly; + for (const auto& p : polynode.Contour) { + contour_poly.points.emplace_back(p.x(), p.y()); + } + BoundingBox contour_aabb{contour_poly.points}; + for (int l = int(m_above.lslices_ex.size()) - 1; l >= 0; --l) { + LayerSlice &lslice = m_above.lslices_ex[l]; + // it is potentially slow, but should be executed rarely + if (contour_aabb.overlap(lslice.bbox) && !intersection(Polygons{contour_poly}, m_above.lslices[l]).empty()) { + found = true; + j = l; + assert(i >= 0 && i < m_below.lslices_ex.size()); + assert(j >= 0 && j < m_above.lslices_ex.size()); + break; + } + } + } } else { // Index of an island above. Look-it up in the island below. assert(j < m_offset_end); @@ -194,6 +222,23 @@ static void connect_layer_slices( break; } } + if (!found) { // Explanation for aditional check is above. + Polygon contour_poly; + for (const auto &p : polynode.Contour) { + contour_poly.points.emplace_back(p.x(), p.y()); + } + BoundingBox contour_aabb{contour_poly.points}; + for (int l = int(m_below.lslices_ex.size()) - 1; l >= 0; --l) { + LayerSlice &lslice = m_below.lslices_ex[l]; + if (contour_aabb.overlap(lslice.bbox) && !intersection(Polygons{contour_poly}, m_below.lslices[l]).empty()) { + found = true; + i = l; + assert(i >= 0 && i < m_below.lslices_ex.size()); + assert(j >= 0 && j < m_above.lslices_ex.size()); + break; + } + } + } } } else { assert(assert_intersection_valid(i, j));