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Replaced smooth_outward in multi-material segmentation with a function that removes duplicate points with angle threshold. It should fix #7838 and #6892.

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The main contribution of the smooth_outward function for multi-material segmentation was the removal of duplicate points in polygons using MutablePolygon::remove_duplicates().
But the issue with this function is that it deletes points only based on their distances, which could cause problems like in #7838.
This commit is contained in:
Lukáš Hejl 2022-02-07 13:36:09 +01:00
parent 9ea7427ce7
commit a4ecf2f2a6
1 changed files with 45 additions and 1 deletions
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46
src/libslic3r/MultiMaterialSegmentation.cpp
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@ -1676,6 +1676,50 @@ static bool has_layer_only_one_color(const std::vector<std::vector<ColoredLine>>
return true;
}
// Remove nearly duplicate points. If a distance between two points is less than point_eps
// and if the angle between its surrounding lines is less than max_angle, the point will be removed.
void remove_duplicates_points(MutablePolygon &polygon, double point_eps, double max_angle)
{
if (polygon.size() >= 3) {
auto eps2 = point_eps * point_eps;
auto begin = polygon.begin();
auto it = begin;
for (++it; it != begin;) {
auto prev = it.prev();
auto next = (it.next() == polygon.end() ? begin : it.next());
if ((*it - *prev).cast<double>().squaredNorm() < eps2) {
Vec2i64 vector1 = (*it - *prev).cast<int64_t>();
Vec2i64 vector2 = (*next - *prev).cast<int64_t>();
if (double angle = atan2(cross2(vector1, vector2), vector1.dot(vector2)); angle < max_angle) {
it = it.remove();
continue;
}
}
++it;
}
}
}
// Remove nearly duplicate points. If a distance between two points is less than point_eps
// and if the angle between its surrounding lines is less than max_angle, the point will be removed.
inline ExPolygons remove_duplicates_points(ExPolygons expolygons, double point_eps, double max_angle)
{
MutablePolygon mp;
for (ExPolygon &expolygon : expolygons) {
mp.assign(expolygon.contour, expolygon.contour.size() * 2);
remove_duplicates_points(mp, point_eps, max_angle);
mp.polygon(expolygon.contour);
for (Polygon &hole : expolygon.holes) {
mp.assign(hole, hole.size() * 2);
remove_duplicates_points(mp, point_eps, max_angle);
mp.polygon(hole);
}
expolygon.holes.erase(std::remove_if(expolygon.holes.begin(), expolygon.holes.end(), [](const auto &p) { return p.empty(); }), expolygon.holes.end());
}
expolygons.erase(std::remove_if(expolygons.begin(), expolygons.end(), [](const auto &p) { return p.empty(); }), expolygons.end());
return expolygons;
}
std::vector<std::vector<ExPolygons>> multi_material_segmentation_by_painting(const PrintObject &print_object, const std::function<void()> &throw_on_cancel_callback)
{
const size_t num_extruders = print_object.print()->config().nozzle_diameter.size();
@ -1711,7 +1755,7 @@ std::vector<std::vector<ExPolygons>> multi_material_segmentation_by_painting(con
// Such close points sometimes caused that the Voronoi diagram has self-intersecting edges around these vertices.
// This consequently leads to issues with the extraction of colored segments by function extract_colored_segments.
// Calling expolygons_simplify fixed these issues.
input_expolygons[layer_idx] = smooth_outward(expolygons_simplify(offset_ex(ex_polygons, -10.f * float(SCALED_EPSILON)), 5 * SCALED_EPSILON), 10 * coord_t(SCALED_EPSILON));
input_expolygons[layer_idx] = remove_duplicates_points(expolygons_simplify(offset_ex(ex_polygons, -10.f * float(SCALED_EPSILON)), 5 * SCALED_EPSILON), scaled<double>(0.01), PI/6);
#ifdef MMU_SEGMENTATION_DEBUG_INPUT
{