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Optimisation for can_cross_perimeter with big perimeters.
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@supermerill
supermerill committed Nov 9, 2024
1 parent 6766292 commit e2debc6
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Showing 2 changed files with 151 additions and 18 deletions.
154 changes: 138 additions & 16 deletions src/libslic3r/GCode.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7388,6 +7388,41 @@ bool GCodeGenerator::needs_retraction(const Polyline& travel, ExtrusionRole role
return true;
}

struct GridIntersectTest
{
explicit GridIntersectTest(const EdgeGrid::Grid &grid, const Line &&line) : grid(grid), test_line(line) {}

bool operator()(coord_t iy, coord_t ix)
{
// Called with a row and colum of the grid cell, which is intersected by a line.
auto cell_data_range = grid.cell_data_range(iy, ix);
this->intersect = false;
for (auto it_contour_and_segment = cell_data_range.first; it_contour_and_segment != cell_data_range.second; ++it_contour_and_segment) {
// End points of the line segment and their vector.
auto segment = grid.segment(*it_contour_and_segment);
if (Geometry::segments_intersect(segment.first, segment.second, test_line.a, test_line.b)) {
this->intersect = true;
return false;
}
}
// Continue traversing the grid along the edge.
return true;
}

const EdgeGrid::Grid &grid;
Line test_line;
bool intersect = false;

};

void GCodeGenerator::SliceIsland::create_hole_bb() {
if (this->hole_boundingboxes.size() == this->expolygon.holes.size())
return;
this->hole_boundingboxes.clear();
for (const Polygon &poly : this->expolygon.holes) {
this->hole_boundingboxes.emplace_back(poly.points);
}
}
bool GCodeGenerator::can_cross_perimeter(const Polyline& travel, bool offset)
{
if (m_layer != nullptr) {
Expand All @@ -7412,14 +7447,42 @@ bool GCodeGenerator::can_cross_perimeter(const Polyline& travel, bool offset)
BoundingBox bb{ex.contour.points};
// simplify as much as possible
for (ExPolygon &ex_simpl : ex.simplify(m_layer_slices_offseted.diameter)) {
m_layer_slices_offseted.slices.emplace_back(std::move(ex_simpl), std::move(bb));
#ifdef CAN_CROSS_PERIMETER_USE_GRID
int nbpt = ex_simpl.contour.size();
//for(const Polygon &hole : ex_simpl.holes) nbpt += hole.size();
if (nbpt > 100) {
EdgeGrid::Grid grid;
grid.set_bbox(bb);
// resolution: ~ 100 col/row
coordf_t max_dist = std::max(bb.max.x() - bb.min.x(), bb.max.y() - bb.min.x());
grid.create(ex_simpl, (max_dist/100));//m_layer_slices_offseted.diameter * 4); // What is a good value?
m_layer_slices_offseted.slices.emplace_back(std::move(ex_simpl), std::move(bb), std::move(grid));
} else
#endif
{
m_layer_slices_offseted.slices.emplace_back(std::move(ex_simpl), std::move(bb));
}
}
}
m_layer_slices_offseted.slices_offsetted.clear();
for (ExPolygon &ex : slices_offsetted) {
BoundingBox bb{ex.contour.points};
for (ExPolygon &ex_simpl : ex.simplify(m_layer_slices_offseted.diameter)) {
m_layer_slices_offseted.slices_offsetted.emplace_back(std::move(ex_simpl), std::move(bb));
#ifdef CAN_CROSS_PERIMETER_USE_GRID
int nbpt = ex_simpl.contour.size();
//for(const Polygon &hole : ex_simpl.holes) nbpt += hole.size();
if (nbpt > 100) {
EdgeGrid::Grid grid;
grid.set_bbox(bb);
// resolution: ~ 100 col/row
coordf_t max_dist = std::max(bb.max.x() - bb.min.x(), bb.max.y() - bb.min.x());
grid.create(ex_simpl, (max_dist/100));
m_layer_slices_offseted.slices_offsetted.emplace_back(std::move(ex_simpl), std::move(bb), std::move(grid));
} else
#endif
{
m_layer_slices_offseted.slices_offsetted.emplace_back(std::move(ex_simpl), std::move(bb));
}
}
}
}
Expand All @@ -7446,36 +7509,95 @@ bool GCodeGenerator::can_cross_perimeter(const Polyline& travel, bool offset)
// svg.Close();
//}
// test if a expoly contains the entire travel
for (const std::pair<ExPolygon, BoundingBox> &expoly_2_bb :
for (SliceIsland &expoly_2_bb :
offset ? m_layer_slices_offseted.slices_offsetted : m_layer_slices_offseted.slices) {
// first check if it's roughtly inside the bb, to reject quickly.
auto sec = expoly_2_bb.second;
BoundingBox sec = expoly_2_bb.boundingbox;
if (travel.size() > 1 &&
(expoly_2_bb.second.contains(travel.front()) ||
expoly_2_bb.second.contains(travel.back()) ||
expoly_2_bb.second.contains(travel.points[travel.size() / 2]) ||
expoly_2_bb.second.cross(travel) )
(expoly_2_bb.boundingbox.contains(travel.front()) ||
expoly_2_bb.boundingbox.contains(travel.back()) ||
expoly_2_bb.boundingbox.contains(travel.points[travel.size() / 2]) ||
expoly_2_bb.boundingbox.cross(travel) )
) {
// first, check if it's inside the contour (still, it can go over holes)
Polylines diff_result = diff_pl(travel, expoly_2_bb.first.contour);
if (diff_result.size() == 1 && diff_result.front() == travel)
//if (!diff_pl(travel, expoly_2_bb.first.contour).empty())
continue;
//second, check if it's crossing this contour
if (!diff_result.empty()) {
//has_intersect = true;
bool has_front = contains(expoly_2_bb.expolygon.contour, travel.front(), true);
bool has_back = contains(expoly_2_bb.expolygon.contour, travel.back(), true);
if (!has_front || !has_back) {
// has_intersect = true;
return true;
}
assert(travel.size() >= 2);
#ifdef CAN_CROSS_PERIMETER_USE_GRID
// Can't find any performance improvement, need more testing
if (travel.size() == 2 && expoly_2_bb.grid) {
// TODO: put each line from expoly_2_bb.first.contour into a kdtree, and only do a
// line-to-line from lines that are inside the square crossed by travel
GridIntersectTest tester(*expoly_2_bb.grid, Line(travel.front(), travel.back()));
expoly_2_bb.grid->visit_cells_intersecting_line(tester.test_line.a, tester.test_line.b, tester);
if (!tester.intersect) {
// inside or outside?
// whatever, check all
continue;
} else {
// cross something, stop here.
return true;
}
//diff_result = diff_pl(travel, expoly_2_bb.expolygon.contour); // extremly costly
} else
#endif
{
//std::chrono::high_resolution_clock clock;
#if 1
// A little faster than diff_pl
Line travel_line;
Point whatever;
for (size_t idx_travel = travel.size() - 1; idx_travel > 0; --idx_travel) {
travel_line.a = travel.points[idx_travel];
travel_line.b = travel.points[idx_travel - 1];
if (expoly_2_bb.expolygon.contour.first_intersection(travel_line, &whatever) ||
Line(expoly_2_bb.expolygon.contour.first_point(), expoly_2_bb.expolygon.contour.last_point()).intersection(travel_line, &whatever)) {
return true;
}
}
// no intersect detected
// if inside the contour, then we need to check for holes.
if (!expoly_2_bb.expolygon.contour.contains(travel.front())) {
// if not, go to next island
continue;
}
#else
Polylines diff_result = diff_pl(travel, expoly_2_bb.expolygon.contour); // extremly costly
if (diff_result.size() == 1 && diff_result.front() == travel) {
// outside of this contour, try with another one
continue;
}
if (!diff_result.empty()) {
//has_intersect = true;
return true;
}
#endif
}
//second, check if it's crossing this contour
// third, check if it's going over a hole
// TODO: kdtree to get the ones interesting
//bool has_intersect = false;
Line travel_line;
Point whatever;
for (const Polygon &hole : expoly_2_bb.first.holes) {
expoly_2_bb.create_hole_bb();
for (size_t i = 0; i < expoly_2_bb.expolygon.holes.size(); ++i) {
const Polygon &hole = expoly_2_bb.expolygon.holes[i];
const BoundingBox &hole_bb = expoly_2_bb.hole_boundingboxes[i];
m_throw_if_canceled();
for (size_t idx_travel = travel.size() - 1; idx_travel > 0; --idx_travel) {
travel_line.a = travel.points[idx_travel];
travel_line.b = travel.points[idx_travel - 1];
if (hole.size() > 10) {
// bb.cross call 4 intersections (one for each side), do it only if the hole has enough lines.
if (!hole_bb.cross(travel_line) && !hole_bb.contains(travel_line.a)) {
// don't cross bb and not inside, so it's not for this hole.
continue;
}
}
if (hole.first_intersection(travel_line, &whatever) ||
Line(hole.first_point(), hole.last_point()).intersection(travel_line, &whatever)) {
//has_intersect = true;
Expand Down
15 changes: 13 additions & 2 deletions src/libslic3r/GCode.hpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -481,9 +481,20 @@ class GCodeGenerator : ExtrusionVisitorConst {
uint16_t m_print_object_instance_id = -1;
// For crossing perimeter retraction detection (contain the layer & nozzle widdth used to construct it)
// !!!! not thread-safe !!!! if threaded per layer, please store it in the thread.
struct SliceIsland{
ExPolygon expolygon;
BoundingBox boundingbox;
std::vector<BoundingBox> hole_boundingboxes;
SliceIsland(ExPolygon &&exp, BoundingBox &&bb) : boundingbox(std::move(bb)), expolygon(std::move(exp)) {}
#ifdef CAN_CROSS_PERIMETER_USE_GRID
std::optional<EdgeGrid::Grid> grid;
SliceIsland(ExPolygon &&exp, BoundingBox &&bb, EdgeGrid::Grid &&g) : boundingbox(std::move(bb)), expolygon(std::move(exp)), grid(std::move(g)) {}
#endif
void create_hole_bb();
};
struct SliceOffsetted {
std::vector<std::pair<ExPolygon, BoundingBox>> slices;
std::vector<std::pair<ExPolygon, BoundingBox>> slices_offsetted;
std::vector<SliceIsland> slices;
std::vector<SliceIsland> slices_offsetted;
const Layer* layer;
coord_t diameter;
} m_layer_slices_offseted{ {},{},nullptr, 0};
Expand Down

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