diff --git a/tests/libslic3r/test_clipper_utils.cpp b/tests/libslic3r/test_clipper_utils.cpp index c69c686521..02f158ac95 100644 --- a/tests/libslic3r/test_clipper_utils.cpp +++ b/tests/libslic3r/test_clipper_utils.cpp @@ -1,7 +1,9 @@ #include +#include #include #include +#include #include #include "libslic3r/ClipperUtils.hpp" @@ -300,7 +302,38 @@ TEST_CASE("Traversing Clipper PolyTree", "[ClipperUtils]") { } } -TEST_CASE("Tiled diff and intersection cover the same area as the plain calls", "[ClipperUtils]") { +// Rings flattened to x,y,x,y... and sorted, with each ring rotated to start at its lowest point: two +// encodings of the same geometry compare equal however the pieces came back or wherever a ring started. +static std::vector> canonical_rings(const ExPolygons &expolygons) +{ + std::vector> rings; + const auto add = [&rings](const Polygon &poly) { + if (poly.points.empty()) + return; + Points pts = poly.points; + std::rotate(pts.begin(), + std::min_element(pts.begin(), pts.end(), [](const Point &a, const Point &b) { + return std::make_pair(a.x(), a.y()) < std::make_pair(b.x(), b.y()); + }), + pts.end()); + std::vector flat; + flat.reserve(pts.size() * 2); + for (const Point &p : pts) { + flat.emplace_back(p.x()); + flat.emplace_back(p.y()); + } + rings.emplace_back(std::move(flat)); + }; + for (const ExPolygon &expoly : expolygons) { + add(expoly.contour); + for (const Polygon &hole : expoly.holes) + add(hole); + } + std::sort(rings.begin(), rings.end()); + return rings; +} + +TEST_CASE("Tiled diff and intersection return the same polygons as the plain calls", "[ClipperUtils]") { // A grid of disjoint framed squares, enough of them to be split into several tiles. const int n = 40; const coord_t cell = scaled(2.), side = scaled(1.5), frame = scaled(0.3); @@ -327,19 +360,19 @@ TEST_CASE("Tiled diff and intersection cover the same area as the plain calls", } polygons_append(clip, to_polygons(big)); - const auto xor_area = [](const ExPolygons &a, const ExPolygons &b) { return area(diff_ex(a, b)) + area(diff_ex(b, a)); }; const ApplySafetyOffset safety = GENERATE(ApplySafetyOffset::No, ApplySafetyOffset::Yes); - const double tolerance = double(scaled(0.001)) * double(span); + + // The point of the fixture: below 128 pieces the helpers fall back to a single tile and the tiled + // path under test is never taken. + REQUIRE(ClipperUtils::tile_expolygons(subject, 32).size() > 1); const ExPolygons diff_plain = diff_ex(subject, clip, safety); const ExPolygons diff_tiled = diff_ex_by_piece(subject, clip, safety); REQUIRE(area(diff_plain) > 0.); - CHECK_THAT(area(diff_tiled), Catch::Matchers::WithinRel(area(diff_plain), 1e-9)); - CHECK(xor_area(diff_tiled, diff_plain) < tolerance); + CHECK(canonical_rings(diff_tiled) == canonical_rings(diff_plain)); const ExPolygons intersection_plain = intersection_ex(subject, clip, safety); const ExPolygons intersection_tiled = intersection_ex_by_piece(subject, clip, safety); REQUIRE(area(intersection_plain) > 0.); - CHECK_THAT(area(intersection_tiled), Catch::Matchers::WithinRel(area(intersection_plain), 1e-9)); - CHECK(xor_area(intersection_tiled, intersection_plain) < tolerance); + CHECK(canonical_rings(intersection_tiled) == canonical_rings(intersection_plain)); }