Polylines PolylineCollection::_chained_path_from(
const Polylines &src,
Point start_near,
bool no_reverse,
bool move_from_src)
{
std::vector<Chaining> endpoints;
endpoints.reserve(src.size());
for (size_t i = 0; i < src.size(); ++ i) {
Chaining c;
c.first = src[i].first_point();
if (! no_reverse)
c.last = src[i].last_point();
c.idx = i;
endpoints.push_back(c);
}
Polylines retval;
while (! endpoints.empty()) {
// find nearest point
int endpoint_index = nearest_point_index<double>(endpoints, start_near, no_reverse);
assert(endpoint_index >= 0 && endpoint_index < endpoints.size() * 2);
if (move_from_src) {
retval.push_back(std::move(src[endpoints[endpoint_index/2].idx]));
} else {
retval.push_back(src[endpoints[endpoint_index/2].idx]);
}
if (endpoint_index & 1)
retval.back().reverse();
endpoints.erase(endpoints.begin() + endpoint_index/2);
start_near = retval.back().last_point();
}
return retval;
}
void FillGyroid::_fill_surface_single(
const FillParams ¶ms,
unsigned int thickness_layers,
const std::pair<float, Point> &direction,
ExPolygon &expolygon,
Polylines &polylines_out)
{
// no rotation is supported for this infill pattern
BoundingBox bb = expolygon.contour.bounding_box();
coord_t distance = coord_t(scale_(this->spacing) / (params.density*this->scaling));
// align bounding box to a multiple of our grid module
bb.merge(_align_to_grid(bb.min, Point(2*M_PI*distance, 2*M_PI*distance)));
// generate pattern
Polylines polylines = make_gyroid_waves(
scale_(this->z),
params.density*this->scaling,
this->spacing,
ceil(bb.size().x / distance) + 1.,
ceil(bb.size().y / distance) + 1.);
// move pattern in place
for (Polyline &polyline : polylines)
polyline.translate(bb.min.x, bb.min.y);
// clip pattern to boundaries
polylines = intersection_pl(polylines, (Polygons)expolygon);
// connect lines
if (! params.dont_connect && ! polylines.empty()) { // prevent calling leftmost_point() on empty collections
ExPolygon expolygon_off;
{
ExPolygons expolygons_off = offset_ex(expolygon, (float)SCALED_EPSILON);
if (! expolygons_off.empty()) {
// When expanding a polygon, the number of islands could only shrink. Therefore the offset_ex shall generate exactly one expanded island for one input island.
assert(expolygons_off.size() == 1);
std::swap(expolygon_off, expolygons_off.front());
}
}
Polylines chained = PolylineCollection::chained_path_from(
std::move(polylines),
PolylineCollection::leftmost_point(polylines), false); // reverse allowed
bool first = true;
for (Polyline &polyline : chained) {
if (! first) {
// Try to connect the lines.
Points &pts_end = polylines_out.back().points;
const Point &first_point = polyline.points.front();
const Point &last_point = pts_end.back();
// TODO: we should also check that both points are on a fill_boundary to avoid
// connecting paths on the boundaries of internal regions
// TODO: avoid crossing current infill path
if (first_point.distance_to(last_point) <= 5 * distance &&
expolygon_off.contains(Line(last_point, first_point))) {
// Append the polyline.
pts_end.insert(pts_end.end(), polyline.points.begin(), polyline.points.end());
continue;
}
}
// The lines cannot be connected.
polylines_out.emplace_back(std::move(polyline));
first = false;
}
}
}