std::string
GCode::extrude(ExtrusionLoop loop, std::string description, double speed)
{
// get a copy; don't modify the orientation of the original loop object otherwise
// next copies (if any) would not detect the correct orientation
// extrude all loops ccw
bool was_clockwise = loop.make_counter_clockwise();
// find the point of the loop that is closest to the current extruder position
// or randomize if requested
Point last_pos = this->last_pos();
if (this->config.spiral_vase) {
loop.split_at(last_pos);
} else if (this->config.seam_position == spNearest || this->config.seam_position == spAligned) {
Polygon polygon = loop.polygon();
// simplify polygon in order to skip false positives in concave/convex detection
// (loop is always ccw as polygon.simplify() only works on ccw polygons)
Polygons simplified = polygon.simplify(scale_(EXTRUDER_CONFIG(nozzle_diameter))/2);
// restore original winding order so that concave and convex detection always happens
// on the right/outer side of the polygon
if (was_clockwise) {
for (Polygons::iterator p = simplified.begin(); p != simplified.end(); ++p)
p->reverse();
}
// concave vertices have priority
Points candidates;
for (Polygons::const_iterator p = simplified.begin(); p != simplified.end(); ++p) {
Points concave = p->concave_points(PI*4/3);
candidates.insert(candidates.end(), concave.begin(), concave.end());
}
// if no concave points were found, look for convex vertices
if (candidates.empty()) {
for (Polygons::const_iterator p = simplified.begin(); p != simplified.end(); ++p) {
Points convex = p->convex_points(PI*2/3);
candidates.insert(candidates.end(), convex.begin(), convex.end());
}
}
// retrieve the last start position for this object
if (this->layer != NULL && this->_seam_position.count(this->layer->object()) > 0) {
last_pos = this->_seam_position[this->layer->object()];
}
Point point;
if (this->config.seam_position == spNearest) {
if (candidates.empty()) candidates = polygon.points;
last_pos.nearest_point(candidates, &point);
// On 32-bit Linux, Clipper will change some point coordinates by 1 unit
// while performing simplify_polygons(), thus split_at_vertex() won't
// find them anymore.
if (!loop.split_at_vertex(point)) loop.split_at(point);
} else if (!candidates.empty()) {
Points non_overhang;
for (Points::const_iterator p = candidates.begin(); p != candidates.end(); ++p) {
if (!loop.has_overhang_point(*p))
non_overhang.push_back(*p);
}
if (!non_overhang.empty())
candidates = non_overhang;
last_pos.nearest_point(candidates, &point);
if (!loop.split_at_vertex(point)) loop.split_at(point); // see note above
} else {
if (this->config.seam_position == spAlwaysHideSeam){
if (loop.role == elrContourInternalPerimeter) {
Polygon polygon = loop.polygon();
Point centroid = polygon.centroid();
point = Point(polygon.bounding_box().max.x, centroid.y);
point.rotate(rand() % 2*PI, centroid);
}
}
}
else{
std::string
GCode::extrude(ExtrusionLoop loop, std::string description, double speed)
{
// get a copy; don't modify the orientation of the original loop object otherwise
// next copies (if any) would not detect the correct orientation
// extrude all loops ccw
bool was_clockwise = loop.make_counter_clockwise();
SeamPosition seam_position = this->config.seam_position;
if (loop.role == elrSkirt) seam_position = spNearest;
// find the point of the loop that is closest to the current extruder position
// or randomize if requested
Point last_pos = this->last_pos();
if (this->config.spiral_vase) {
loop.split_at(last_pos);
} else if (seam_position == spNearest || seam_position == spAligned) {
const Polygon polygon = loop.polygon();
// simplify polygon in order to skip false positives in concave/convex detection
// (loop is always ccw as polygon.simplify() only works on ccw polygons)
Polygons simplified = polygon.simplify(scale_(EXTRUDER_CONFIG(nozzle_diameter))/2);
// restore original winding order so that concave and convex detection always happens
// on the right/outer side of the polygon
if (was_clockwise) {
for (Polygons::iterator p = simplified.begin(); p != simplified.end(); ++p)
p->reverse();
}
// concave vertices have priority
Points candidates;
for (Polygons::const_iterator p = simplified.begin(); p != simplified.end(); ++p) {
Points concave = p->concave_points(PI*4/3);
candidates.insert(candidates.end(), concave.begin(), concave.end());
}
// if no concave points were found, look for convex vertices
if (candidates.empty()) {
for (Polygons::const_iterator p = simplified.begin(); p != simplified.end(); ++p) {
Points convex = p->convex_points(PI*2/3);
candidates.insert(candidates.end(), convex.begin(), convex.end());
}
}
// retrieve the last start position for this object
if (this->layer != NULL && this->_seam_position.count(this->layer->object()) > 0) {
last_pos = this->_seam_position[this->layer->object()];
}
Point point;
if (seam_position == spNearest) {
if (candidates.empty()) candidates = polygon.points;
last_pos.nearest_point(candidates, &point);
// On 32-bit Linux, Clipper will change some point coordinates by 1 unit
// while performing simplify_polygons(), thus split_at_vertex() won't
// find them anymore.
if (!loop.split_at_vertex(point)) loop.split_at(point);
} else if (!candidates.empty()) {
Points non_overhang;
for (Points::const_iterator p = candidates.begin(); p != candidates.end(); ++p) {
if (!loop.has_overhang_point(*p))
non_overhang.push_back(*p);
}
if (!non_overhang.empty())
candidates = non_overhang;
last_pos.nearest_point(candidates, &point);
if (!loop.split_at_vertex(point)) loop.split_at(point); // see note above
} else {
point = last_pos.projection_onto(polygon);
loop.split_at(point);
}
if (this->layer != NULL)
this->_seam_position[this->layer->object()] = point;
} else if (seam_position == spRandom) {
if (loop.role == elrContourInternalPerimeter) {
Polygon polygon = loop.polygon();
Point centroid = polygon.centroid();
last_pos = Point(polygon.bounding_box().max.x, centroid.y);
last_pos.rotate(fmod((float)rand()/16.0, 2.0*PI), centroid);
}
loop.split_at(last_pos);
}
// clip the path to avoid the extruder to get exactly on the first point of the loop;
// if polyline was shorter than the clipping distance we'd get a null polyline, so
// we discard it in that case
double clip_length = this->enable_loop_clipping
? scale_(EXTRUDER_CONFIG(nozzle_diameter)) * LOOP_CLIPPING_LENGTH_OVER_NOZZLE_DIAMETER
: 0;
// get paths
ExtrusionPaths paths;
loop.clip_end(clip_length, &paths);
if (paths.empty()) return "";
// apply the small perimeter speed
if (paths.front().is_perimeter() && loop.length() <= SMALL_PERIMETER_LENGTH) {
if (speed == -1) speed = this->config.get_abs_value("small_perimeter_speed");
}
// extrude along the path
std::string gcode;
for (ExtrusionPaths::const_iterator path = paths.begin(); path != paths.end(); ++path)
gcode += this->_extrude(*path, description, speed);
// reset acceleration
gcode += this->writer.set_acceleration(this->config.default_acceleration.value);
if (this->wipe.enable)
this->wipe.path = paths.front().polyline; // TODO: don't limit wipe to last path
// make a little move inwards before leaving loop
if (paths.back().role == erExternalPerimeter && this->layer != NULL && this->config.perimeters > 1) {
// detect angle between last and first segment
// the side depends on the original winding order of the polygon (left for contours, right for holes)
Point a = paths.front().polyline.points[1]; // second point
Point b = *(paths.back().polyline.points.end()-3); // second to last point
if (was_clockwise) {
// swap points
Point c = a; a = b; b = c;
}
double angle = paths.front().first_point().ccw_angle(a, b) / 3;
// turn left if contour, turn right if hole
if (was_clockwise) angle *= -1;
// create the destination point along the first segment and rotate it
// we make sure we don't exceed the segment length because we don't know
// the rotation of the second segment so we might cross the object boundary
Line first_segment(
paths.front().polyline.points[0],
paths.front().polyline.points[1]
);
double distance = std::min(
scale_(EXTRUDER_CONFIG(nozzle_diameter)),
first_segment.length()
);
Point point = first_segment.point_at(distance);
point.rotate(angle, first_segment.a);
// generate the travel move
gcode += this->writer.travel_to_xy(this->point_to_gcode(point), "move inwards before travel");
}
return gcode;
}
bool
BridgeDetector::detect_angle()
{
if (this->_edges.empty() || this->_anchors.empty()) return false;
/* Outset the bridge expolygon by half the amount we used for detecting anchors;
we'll use this one to clip our test lines and be sure that their endpoints
are inside the anchors and not on their contours leading to false negatives. */
Polygons clip_area;
offset(this->expolygon, &clip_area, +this->extrusion_width/2);
/* we'll now try several directions using a rudimentary visibility check:
bridge in several directions and then sum the length of lines having both
endpoints within anchors */
// we test angles according to configured resolution
std::vector<double> angles;
for (int i = 0; i <= PI/this->resolution; ++i)
angles.push_back(i * this->resolution);
// we also test angles of each bridge contour
{
Polygons pp = this->expolygon;
for (Polygons::const_iterator p = pp.begin(); p != pp.end(); ++p) {
Lines lines = p->lines();
for (Lines::const_iterator line = lines.begin(); line != lines.end(); ++line)
angles.push_back(line->direction());
}
}
/* we also test angles of each open supporting edge
(this finds the optimal angle for C-shaped supports) */
for (Polylines::const_iterator edge = this->_edges.begin(); edge != this->_edges.end(); ++edge) {
if (edge->first_point().coincides_with(edge->last_point())) continue;
angles.push_back(Line(edge->first_point(), edge->last_point()).direction());
}
// remove duplicates
double min_resolution = PI/180.0; // 1 degree
std::sort(angles.begin(), angles.end());
for (size_t i = 1; i < angles.size(); ++i) {
if (xd::Geometry::directions_parallel(angles[i], angles[i-1], min_resolution)) {
angles.erase(angles.begin() + i);
--i;
}
}
/* compare first value with last one and remove the greatest one (PI)
in case they are parallel (PI, 0) */
if (xd::Geometry::directions_parallel(angles.front(), angles.back(), min_resolution))
angles.pop_back();
BridgeDirectionComparator bdcomp(this->extrusion_width);
double line_increment = this->extrusion_width;
bool have_coverage = false;
for (std::vector<double>::const_iterator angle = angles.begin(); angle != angles.end(); ++angle) {
Polygons my_clip_area = clip_area;
ExPolygons my_anchors = this->_anchors;
// rotate everything - the center point doesn't matter
for (Polygons::iterator it = my_clip_area.begin(); it != my_clip_area.end(); ++it)
it->rotate(-*angle, Point(0,0));
for (ExPolygons::iterator it = my_anchors.begin(); it != my_anchors.end(); ++it)
it->rotate(-*angle, Point(0,0));
// generate lines in this direction
BoundingBox bb;
for (ExPolygons::const_iterator it = my_anchors.begin(); it != my_anchors.end(); ++it)
bb.merge((Points)*it);
Lines lines;
for (coord_t y = bb.min.y; y <= bb.max.y; y += line_increment)
lines.push_back(Line(Point(bb.min.x, y), Point(bb.max.x, y)));
Lines clipped_lines;
intersection(lines, my_clip_area, &clipped_lines);
// remove any line not having both endpoints within anchors
for (size_t i = 0; i < clipped_lines.size(); ++i) {
Line &line = clipped_lines[i];
if (!xd::Geometry::contains(my_anchors, line.a)
|| !xd::Geometry::contains(my_anchors, line.b)) {
clipped_lines.erase(clipped_lines.begin() + i);
--i;
}
}
std::vector<double> lengths;
double total_length = 0;
for (Lines::const_iterator line = clipped_lines.begin(); line != clipped_lines.end(); ++line) {
double len = line->length();
lengths.push_back(len);
total_length += len;
}
if (total_length) have_coverage = true;
// sum length of bridged lines
bdcomp.dir_coverage[*angle] = total_length;
/* The following produces more correct results in some cases and more broken in others.
TODO: investigate, as it looks more reliable than line clipping. */
// $directions_coverage{$angle} = sum(map $_->area, @{$self->coverage($angle)}) // 0;
// max length of bridged lines
bdcomp.dir_avg_length[*angle] = !lengths.empty()
? *std::max_element(lengths.begin(), lengths.end())
: 0;
}
// if no direction produced coverage, then there's no bridge direction
if (!have_coverage) return false;
// sort directions by score
std::sort(angles.begin(), angles.end(), bdcomp);
this->angle = angles.front();
if (this->angle >= PI) this->angle -= PI;
// #ifdef SLIC3R_DEBUG
// printf(" Optimal infill angle is %d degrees\n", (int)Slic3r::Geometry::rad2deg(this->angle));
// #endif
return true;
}
inline void polygons_rotate(Polygons &polys, double angle)
{
for (Polygons::iterator p = polys.begin(); p != polys.end(); ++p)
p->rotate(angle);
}
void
BridgeDetector::coverage(double angle, Polygons* coverage) const
{
// Clone our expolygon and rotate it so that we work with vertical lines.
ExPolygon expolygon = this->expolygon;
expolygon.rotate(PI/2.0 - angle, Point(0,0));
/* Outset the bridge expolygon by half the amount we used for detecting anchors;
we'll use this one to generate our trapezoids and be sure that their vertices
are inside the anchors and not on their contours leading to false negatives. */
ExPolygons grown;
offset(expolygon, &grown, this->extrusion_width/2.0);
// Compute trapezoids according to a vertical orientation
Polygons trapezoids;
for (ExPolygons::const_iterator it = grown.begin(); it != grown.end(); ++it)
it->get_trapezoids2(&trapezoids, PI/2.0);
// get anchors, convert them to Polygons and rotate them too
Polygons anchors;
for (ExPolygons::const_iterator anchor = this->_anchors.begin(); anchor != this->_anchors.end(); ++anchor) {
Polygons pp = *anchor;
for (Polygons::iterator p = pp.begin(); p != pp.end(); ++p)
p->rotate(PI/2.0 - angle, Point(0,0));
anchors.insert(anchors.end(), pp.begin(), pp.end());
}
Polygons covered;
for (Polygons::const_iterator trapezoid = trapezoids.begin(); trapezoid != trapezoids.end(); ++trapezoid) {
Lines lines = trapezoid->lines();
Lines supported;
intersection(lines, anchors, &supported);
// not nice, we need a more robust non-numeric check
for (size_t i = 0; i < supported.size(); ++i) {
if (supported[i].length() < this->extrusion_width) {
supported.erase(supported.begin() + i);
i--;
}
}
if (supported.size() >= 2) covered.push_back(*trapezoid);
}
// merge trapezoids and rotate them back
Polygons _coverage;
union_(covered, &_coverage);
for (Polygons::iterator p = _coverage.begin(); p != _coverage.end(); ++p)
p->rotate(-(PI/2.0 - angle), Point(0,0));
// intersect trapezoids with actual bridge area to remove extra margins
// and append it to result
intersection(_coverage, this->expolygon, coverage);
/*
if (0) {
my @lines = map @{$_->lines}, @$trapezoids;
$_->rotate(-(PI/2 - $angle), [0,0]) for @lines;
require "Slic3r/SVG.pm";
Slic3r::SVG::output(
"coverage_" . rad2deg($angle) . ".svg",
expolygons => [$self->expolygon],
green_expolygons => $self->_anchors,
red_expolygons => $coverage,
lines => \@lines,
);
}
*/
}
