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clip_clipper_polygon_with_subject_bbox() and diff_clipped() extracted

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from TreeSupports to ClipperUtils to be generally available.
diff_clipped() is an optimized version clipping the "clipping" polygon
using clip_clipper_polygon_with_subject_bbox().
To be used with complex clipping polygons, where majority
of the clipping polygons are outside of the source polygon.
This commit is contained in:
Vojtech Bubnik 2022-11-15 16:54:26 +01:00
parent db3f696888
commit babc8a88a1
3 changed files with 117 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

96
src/libslic3r/ClipperUtils.cpp
View File

@ -48,6 +48,100 @@ err:
namespace ClipperUtils {
Points EmptyPathsProvider::s_empty_points;
Points SinglePathProvider::s_end;
// Clip source polygon to be used as a clipping polygon with a bouding box around the source (to be clipped) polygon.
// Useful as an optimization for expensive ClipperLib operations, for example when clipping source polygons one by one
// with a set of polygons covering the whole layer below.
template<typename PointType>
inline void clip_clipper_polygon_with_subject_bbox_templ(const std::vector<PointType> &src, const BoundingBox &bbox, std::vector<PointType> &out)
{
out.clear();
const size_t cnt = src.size();
if (cnt < 3)
return;
enum class Side {
Left = 1,
Right = 2,
Top = 4,
Bottom = 8
};
auto sides = [bbox](const PointType &p) {
return int(p.x() < bbox.min.x()) * int(Side::Left) +
int(p.x() > bbox.max.x()) * int(Side::Right) +
int(p.y() < bbox.min.y()) * int(Side::Bottom) +
int(p.y() > bbox.max.y()) * int(Side::Top);
};
int sides_prev = sides(src.back());
int sides_this = sides(src.front());
const size_t last = cnt - 1;
for (size_t i = 0; i < last; ++ i) {
int sides_next = sides(src[i + 1]);
if (// This point is inside. Take it.
sides_this == 0 ||
// Either this point is outside and previous or next is inside, or
// the edge possibly cuts corner of the bounding box.
(sides_prev & sides_this & sides_next) == 0) {
out.emplace_back(src[i]);
sides_prev = sides_this;
} else {
// All the three points (this, prev, next) are outside at the same side.
// Ignore this point.
}
sides_this = sides_next;
}
// Never produce just a single point output polygon.
if (! out.empty())
if (int sides_next = sides(out.front());
// The last point is inside. Take it.
sides_this == 0 ||
// Either this point is outside and previous or next is inside, or
// the edge possibly cuts corner of the bounding box.
(sides_prev & sides_this & sides_next) == 0)
out.emplace_back(src.back());
}
void clip_clipper_polygon_with_subject_bbox(const Points &src, const BoundingBox &bbox, Points &out)
{ clip_clipper_polygon_with_subject_bbox_templ(src, bbox, out); }
void clip_clipper_polygon_with_subject_bbox(const ZPoints &src, const BoundingBox &bbox, ZPoints &out)
{ clip_clipper_polygon_with_subject_bbox_templ(src, bbox, out); }
template<typename PointType>
[[nodiscard]] std::vector<PointType> clip_clipper_polygon_with_subject_bbox_templ(const std::vector<PointType> &src, const BoundingBox &bbox)
{
std::vector<PointType> out;
clip_clipper_polygon_with_subject_bbox(src, bbox, out);
return out;
}
[[nodiscard]] Points clip_clipper_polygon_with_subject_bbox(const Points &src, const BoundingBox &bbox)
{ return clip_clipper_polygon_with_subject_bbox_templ(src, bbox); }
[[nodiscard]] ZPoints clip_clipper_polygon_with_subject_bbox(const ZPoints &src, const BoundingBox &bbox)
{ return clip_clipper_polygon_with_subject_bbox_templ(src, bbox); }
void clip_clipper_polygon_with_subject_bbox(const Polygon &src, const BoundingBox &bbox, Polygon &out)
{
clip_clipper_polygon_with_subject_bbox(src.points, bbox, out.points);
}
[[nodiscard]] Polygon clip_clipper_polygon_with_subject_bbox(const Polygon &src, const BoundingBox &bbox)
{
Polygon out;
clip_clipper_polygon_with_subject_bbox(src.points, bbox, out.points);
return out;
}
[[nodiscard]] Polygons clip_clipper_polygons_with_subject_bbox(const Polygons &src, const BoundingBox &bbox)
{
Polygons out;
out.reserve(src.size());
for (const Polygon &p : src)
out.emplace_back(clip_clipper_polygon_with_subject_bbox(p, bbox));
return out;
}
}
static ExPolygons PolyTreeToExPolygons(ClipperLib::PolyTree &&polytree)
@ -537,6 +631,8 @@ Slic3r::Polygons diff(const Slic3r::Polygon &subject, const Slic3r::Polygon &cli
{ return _clipper(ClipperLib::ctDifference, ClipperUtils::SinglePathProvider(subject.points), ClipperUtils::SinglePathProvider(clip.points), do_safety_offset); }
Slic3r::Polygons diff(const Slic3r::Polygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)
{ return _clipper(ClipperLib::ctDifference, ClipperUtils::PolygonsProvider(subject), ClipperUtils::PolygonsProvider(clip), do_safety_offset); }
Slic3r::Polygons diff_clipped(const Slic3r::Polygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)
{ return diff(subject, ClipperUtils::clip_clipper_polygons_with_subject_bbox(clip, get_extents(subject).inflated(SCALED_EPSILON)), do_safety_offset); }
Slic3r::Polygons diff(const Slic3r::Polygons &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset)
{ return _clipper(ClipperLib::ctDifference, ClipperUtils::PolygonsProvider(subject), ClipperUtils::ExPolygonsProvider(clip), do_safety_offset); }
Slic3r::Polygons diff(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)

20
src/libslic3r/ClipperUtils.hpp
View File

@ -24,6 +24,8 @@ using Slic3r::ClipperLib::jtSquare;
namespace Slic3r {
class BoundingBox;
static constexpr const float ClipperSafetyOffset = 10.f;
static constexpr const Slic3r::ClipperLib::JoinType DefaultJoinType = Slic3r::ClipperLib::jtMiter;
@ -306,6 +308,21 @@ namespace ClipperUtils {
const SurfacesPtr &m_surfaces;
size_t m_size;
};
// For ClipperLib with Z coordinates.
using ZPoint = Vec3i32;
using ZPoints = std::vector<Vec3i32>;
// Clip source polygon to be used as a clipping polygon with a bouding box around the source (to be clipped) polygon.
// Useful as an optimization for expensive ClipperLib operations, for example when clipping source polygons one by one
// with a set of polygons covering the whole layer below.
void clip_clipper_polygon_with_subject_bbox(const Points &src, const BoundingBox &bbox, Points &out);
void clip_clipper_polygon_with_subject_bbox(const ZPoints &src, const BoundingBox &bbox, ZPoints &out);
[[nodiscard]] Points clip_clipper_polygon_with_subject_bbox(const Points &src, const BoundingBox &bbox);
[[nodiscard]] ZPoints clip_clipper_polygon_with_subject_bbox(const ZPoints &src, const BoundingBox &bbox);
void clip_clipper_polygon_with_subject_bbox(const Polygon &src, const BoundingBox &bbox, Polygon &out);
[[nodiscard]] Polygon clip_clipper_polygon_with_subject_bbox(const Polygon &src, const BoundingBox &bbox);
[[nodiscard]] Polygons clip_clipper_polygons_with_subject_bbox(const Polygons &src, const BoundingBox &bbox);
}
// offset Polygons
@ -391,6 +408,9 @@ Slic3r::Lines _clipper_ln(ClipperLib::ClipType clipType, const Slic3r::Lines &su
Slic3r::Polygons diff(const Slic3r::Polygon &subject, const Slic3r::Polygon &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
Slic3r::Polygons diff(const Slic3r::Polygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
Slic3r::Polygons diff(const Slic3r::Polygons &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
// Optimized version clipping the "clipping" polygon using clip_clipper_polygon_with_subject_bbox().
// To be used with complex clipping polygons, where majority of the clipping polygons are outside of the source polygon.
Slic3r::Polygons diff_clipped(const Slic3r::Polygons &src, const Slic3r::Polygons &clipping, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
Slic3r::Polygons diff(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
Slic3r::Polygons diff(const Slic3r::ExPolygons &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
Slic3r::Polygons diff(const Slic3r::Surfaces &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);

72
src/libslic3r/TreeSupport.cpp
View File

@ -115,76 +115,6 @@ static inline void check_self_intersections(const ExPolygon &expoly, const std::
#endif // _WIN32
}
static inline void clip_for_diff(const Polygon &src, const BoundingBox &bbox, Polygon &out)
{
out.clear();
const size_t cnt = src.points.size();
if (cnt < 3)
return;
enum class Side {
Left = 1,
Right = 2,
Top = 4,
Bottom = 8
};
auto sides = [bbox](const Point &p) {
return int(p.x() < bbox.min.x()) * int(Side::Left) +
int(p.x() > bbox.max.x()) * int(Side::Right) +
int(p.y() < bbox.min.y()) * int(Side::Bottom) +
int(p.y() > bbox.max.y()) * int(Side::Top);
};
int sides_prev = sides(src.points.back());
int sides_this = sides(src.points.front());
const size_t last = cnt - 1;
for (size_t i = 0; i < last; ++ i) {
int sides_next = sides(src.points[i + 1]);
if (// This point is inside. Take it.
sides_this == 0 ||
// Either this point is outside and previous or next is inside, or
// the edge possibly cuts corner of the bounding box.
(sides_prev & sides_this & sides_next) == 0) {
out.points.emplace_back(src.points[i]);
sides_prev = sides_this;
} else {
// All the three points (this, prev, next) are outside at the same side.
// Ignore this point.
}
sides_this = sides_next;
}
// For the last point, if src is completely outside bbox, then out.points will be empty. Just use the first point instead.
int sides_next = sides(out.points.empty() ? src.points.front() : out.points.front());
if (// The last point is inside. Take it.
sides_this == 0 ||
// Either this point is outside and previous or next is inside, or
// the edge possibly cuts corner of the bounding box.
(sides_prev & sides_this & sides_next) == 0)
out.points.emplace_back(src.points.back());
}
[[nodiscard]] static inline Polygon clip_for_diff(const Polygon &src, const BoundingBox &bbox)
{
Polygon out;
clip_for_diff(src, bbox, out);
return out;
}
[[nodiscard]] static inline Polygons clip_for_diff(const Polygons &src, const BoundingBox &bbox)
{
Polygons out;
out.reserve(src.size());
for (const Polygon &p : src)
out.emplace_back(clip_for_diff(p, bbox));
return out;
}
[[nodiscard]] static inline Polygons diff_clipped(const Polygons &src, const Polygons &clipping)
{
return diff(src, clip_for_diff(clipping, get_extents(src).inflated(SCALED_EPSILON)));
}
static constexpr const auto tiny_area_threshold = sqr(scaled<double>(0.001));
static std::vector<std::pair<TreeSupportSettings, std::vector<size_t>>> group_meshes(const Print &print, const std::vector<size_t> &print_object_ids)
@ -821,7 +751,7 @@ static std::optional<std::pair<Point, size_t>> polyline_sample_next_point_at_dis
Polygons collision_trimmed_buffer;
auto collision_trimmed = [&collision_trimmed_buffer, &collision, &ret, distance]() -> const Polygons& {
if (collision_trimmed_buffer.empty() && ! collision.empty())
collision_trimmed_buffer = clip_for_diff(collision, get_extents(ret).inflated(std::max(0, distance) + SCALED_EPSILON));
collision_trimmed_buffer = ClipperUtils::clip_clipper_polygons_with_subject_bbox(collision, get_extents(ret).inflated(std::max(0, distance) + SCALED_EPSILON));
return collision_trimmed_buffer;
};