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{
ExtrusionEntityCollection
PerimeterGenerator::_traverse_loops(const PerimeterGeneratorLoops &loops,
Polylines &thin_walls) const
{
// loops is an arrayref of ::Loop objects
// turn each one into an ExtrusionLoop object
ExtrusionEntityCollection coll;
for (PerimeterGeneratorLoops::const_iterator loop = loops.begin();
loop != loops.end(); ++loop) {
bool is_external = loop->is_external();
ExtrusionRole role;
ExtrusionLoopRole loop_role;
role = is_external ? erExternalPerimeter : erPerimeter;
if (loop->is_internal_contour()) {
// Note that we set loop role to ContourInternalPerimeter
// also when loop is both internal and external (i.e.
// there's only one contour loop).
loop_role = elrContourInternalPerimeter;
} else {
loop_role = elrDefault;
}
// detect overhanging/bridging perimeters
ExtrusionPaths paths;
if (this->config->overhangs && this->layer_id > 0
&& !(this->object_config->support_material && this->object_config->support_material_contact_distance.value == 0)) {
// get non-overhang paths by intersecting this loop with the grown lower slices
{
Polylines polylines;
intersection((Polygons)loop->polygon, this->_lower_slices_p, &polylines);
for (Polylines::const_iterator polyline = polylines.begin(); polyline != polylines.end(); ++polyline) {
ExtrusionPath path(role);
path.polyline = *polyline;
path.mm3_per_mm = is_external ? this->_ext_mm3_per_mm : this->_mm3_per_mm;
path.width = is_external ? this->ext_perimeter_flow.width : this->perimeter_flow.width;
path.height = this->layer_height;
paths.push_back(path);
}
}
// get overhang paths by checking what parts of this loop fall
// outside the grown lower slices (thus where the distance between
// the loop centerline and original lower slices is >= half nozzle diameter
{
Polylines polylines;
diff((Polygons)loop->polygon, this->_lower_slices_p, &polylines);
for (Polylines::const_iterator polyline = polylines.begin(); polyline != polylines.end(); ++polyline) {
ExtrusionPath path(erOverhangPerimeter);
path.polyline = *polyline;
path.mm3_per_mm = this->_mm3_per_mm_overhang;
path.width = this->overhang_flow.width;
path.height = this->overhang_flow.height;
paths.push_back(path);
}
}
// reapply the nearest point search for starting point
// We allow polyline reversal because Clipper may have randomly
// reversed polylines during clipping.
paths = ExtrusionEntityCollection(paths).chained_path();
} else {
ExtrusionPath path(role);
path.polyline = loop->polygon.split_at_first_point();
path.mm3_per_mm = is_external ? this->_ext_mm3_per_mm : this->_mm3_per_mm;
path.width = is_external ? this->ext_perimeter_flow.width : this->perimeter_flow.width;
path.height = this->layer_height;
paths.push_back(path);
}
coll.append(ExtrusionLoop(paths, loop_role));
}
// append thin walls to the nearest-neighbor search (only for first iteration)
for (Polylines::const_iterator polyline = thin_walls.begin(); polyline != thin_walls.end(); ++polyline) {
ExtrusionPath path(erExternalPerimeter);
path.polyline = *polyline;
path.mm3_per_mm = this->_mm3_per_mm;
path.width = this->perimeter_flow.width;
path.height = this->layer_height;
coll.append(path);
}
thin_walls.clear();
// sort entities into a new collection using a nearest-neighbor search,
// preserving the original indices which are useful for detecting thin walls
ExtrusionEntityCollection sorted_coll;
coll.chained_path(&sorted_coll, false, &sorted_coll.orig_indices);
// traverse children and build the final collection
ExtrusionEntityCollection entities;
for (std::vector<size_t>::const_iterator idx = sorted_coll.orig_indices.begin();
idx != sorted_coll.orig_indices.end();
++idx) {
if (*idx >= loops.size()) {
// this is a thin wall
// let's get it from the sorted collection as it might have been reversed
size_t i = idx - sorted_coll.orig_indices.begin();
entities.append(*sorted_coll.entities[i]);
} else {
const PerimeterGeneratorLoop &loop = loops[*idx];
ExtrusionLoop eloop = *dynamic_cast<ExtrusionLoop*>(coll.entities[*idx]);
ExtrusionEntityCollection children = this->_traverse_loops(loop.children, thin_walls);
if (loop.is_contour) {
eloop.make_counter_clockwise();
entities.append(children.entities);
entities.append(eloop);
} else {
eloop.make_clockwise();
entities.append(eloop);
entities.append(children.entities);
}
}
}
return entities;
}
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;
}