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Diffstat (limited to 'src/libslic3r/PerimeterGenerator.cpp')
| -rw-r--r-- | src/libslic3r/PerimeterGenerator.cpp | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/src/libslic3r/PerimeterGenerator.cpp b/src/libslic3r/PerimeterGenerator.cpp new file mode 100644 index 000000000..de8aeeb2a --- /dev/null +++ b/src/libslic3r/PerimeterGenerator.cpp @@ -0,0 +1,480 @@ +#include "PerimeterGenerator.hpp" +#include "ClipperUtils.hpp" +#include "ExtrusionEntityCollection.hpp" +#include <cmath> +#include <cassert> + +namespace Slic3r { + +void PerimeterGenerator::process() +{ + // other perimeters + this->_mm3_per_mm = this->perimeter_flow.mm3_per_mm(); + coord_t perimeter_width = this->perimeter_flow.scaled_width(); + coord_t perimeter_spacing = this->perimeter_flow.scaled_spacing(); + + // external perimeters + this->_ext_mm3_per_mm = this->ext_perimeter_flow.mm3_per_mm(); + coord_t ext_perimeter_width = this->ext_perimeter_flow.scaled_width(); + coord_t ext_perimeter_spacing = this->ext_perimeter_flow.scaled_spacing(); + coord_t ext_perimeter_spacing2 = this->ext_perimeter_flow.scaled_spacing(this->perimeter_flow); + + // overhang perimeters + this->_mm3_per_mm_overhang = this->overhang_flow.mm3_per_mm(); + + // solid infill + coord_t solid_infill_spacing = this->solid_infill_flow.scaled_spacing(); + + // Calculate the minimum required spacing between two adjacent traces. + // This should be equal to the nominal flow spacing but we experiment + // with some tolerance in order to avoid triggering medial axis when + // some squishing might work. Loops are still spaced by the entire + // flow spacing; this only applies to collapsing parts. + // For ext_min_spacing we use the ext_perimeter_spacing calculated for two adjacent + // external loops (which is the correct way) instead of using ext_perimeter_spacing2 + // which is the spacing between external and internal, which is not correct + // and would make the collapsing (thus the details resolution) dependent on + // internal flow which is unrelated. + coord_t min_spacing = perimeter_spacing * (1 - INSET_OVERLAP_TOLERANCE); + coord_t ext_min_spacing = ext_perimeter_spacing * (1 - INSET_OVERLAP_TOLERANCE); + + // prepare grown lower layer slices for overhang detection + if (this->lower_slices != NULL && this->config->overhangs) { + // We consider overhang any part where the entire nozzle diameter is not supported by the + // lower layer, so we take lower slices and offset them by half the nozzle diameter used + // in the current layer + double nozzle_diameter = this->print_config->nozzle_diameter.get_at(this->config->perimeter_extruder-1); + this->_lower_slices_p = offset(*this->lower_slices, float(scale_(+nozzle_diameter/2))); + } + + // we need to process each island separately because we might have different + // extra perimeters for each one + for (const Surface &surface : this->slices->surfaces) { + // detect how many perimeters must be generated for this island + int loop_number = this->config->perimeters + surface.extra_perimeters - 1; // 0-indexed loops + ExPolygons last = union_ex(surface.expolygon.simplify_p(SCALED_RESOLUTION)); + ExPolygons gaps; + if (loop_number >= 0) { + // In case no perimeters are to be generated, loop_number will equal to -1. + std::vector<PerimeterGeneratorLoops> contours(loop_number+1); // depth => loops + std::vector<PerimeterGeneratorLoops> holes(loop_number+1); // depth => loops + ThickPolylines thin_walls; + // we loop one time more than needed in order to find gaps after the last perimeter was applied + for (int i = 0;; ++ i) { // outer loop is 0 + // Calculate next onion shell of perimeters. + ExPolygons offsets; + if (i == 0) { + // the minimum thickness of a single loop is: + // ext_width/2 + ext_spacing/2 + spacing/2 + width/2 + offsets = this->config->thin_walls ? + offset2_ex( + last, + -(ext_perimeter_width / 2 + ext_min_spacing / 2 - 1), + +(ext_min_spacing / 2 - 1)) : + offset_ex(last, - ext_perimeter_width / 2); + // look for thin walls + if (this->config->thin_walls) { + // the following offset2 ensures almost nothing in @thin_walls is narrower than $min_width + // (actually, something larger than that still may exist due to mitering or other causes) + coord_t min_width = scale_(this->ext_perimeter_flow.nozzle_diameter / 3); + ExPolygons expp = offset2_ex( + // medial axis requires non-overlapping geometry + diff_ex(to_polygons(last), + offset(offsets, ext_perimeter_width / 2), + true), + - min_width / 2, min_width / 2); + // the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop + for (ExPolygon &ex : expp) + ex.medial_axis(ext_perimeter_width + ext_perimeter_spacing2, min_width, &thin_walls); + } + } else { + //FIXME Is this offset correct if the line width of the inner perimeters differs + // from the line width of the infill? + coord_t distance = (i == 1) ? ext_perimeter_spacing2 : perimeter_spacing; + offsets = this->config->thin_walls ? + // This path will ensure, that the perimeters do not overfill, as in + // prusa3d/Slic3r GH #32, but with the cost of rounding the perimeters + // excessively, creating gaps, which then need to be filled in by the not very + // reliable gap fill algorithm. + // Also the offset2(perimeter, -x, x) may sometimes lead to a perimeter, which is larger than + // the original. + offset2_ex(last, + - (distance + min_spacing / 2 - 1), + min_spacing / 2 - 1) : + // If "detect thin walls" is not enabled, this paths will be entered, which + // leads to overflows, as in prusa3d/Slic3r GH #32 + offset_ex(last, - distance); + // look for gaps + if (this->config->gap_fill_speed.value > 0 && this->config->fill_density.value > 0) + // not using safety offset here would "detect" very narrow gaps + // (but still long enough to escape the area threshold) that gap fill + // won't be able to fill but we'd still remove from infill area + append(gaps, diff_ex( + offset(last, -0.5 * distance), + offset(offsets, 0.5 * distance + 10))); // safety offset + } + if (offsets.empty()) { + // Store the number of loops actually generated. + loop_number = i - 1; + // No region left to be filled in. + last.clear(); + break; + } else if (i > loop_number) { + // If i > loop_number, we were looking just for gaps. + break; + } + for (const ExPolygon &expolygon : offsets) { + contours[i].emplace_back(PerimeterGeneratorLoop(expolygon.contour, i, true)); + if (! expolygon.holes.empty()) { + holes[i].reserve(holes[i].size() + expolygon.holes.size()); + for (const Polygon &hole : expolygon.holes) + holes[i].emplace_back(PerimeterGeneratorLoop(hole, i, false)); + } + } + last = std::move(offsets); + } + + // nest loops: holes first + for (int d = 0; d <= loop_number; ++ d) { + PerimeterGeneratorLoops &holes_d = holes[d]; + // loop through all holes having depth == d + for (int i = 0; i < (int)holes_d.size(); ++ i) { + const PerimeterGeneratorLoop &loop = holes_d[i]; + // find the hole loop that contains this one, if any + for (int t = d + 1; t <= loop_number; ++ t) { + for (int j = 0; j < (int)holes[t].size(); ++ j) { + PerimeterGeneratorLoop &candidate_parent = holes[t][j]; + if (candidate_parent.polygon.contains(loop.polygon.first_point())) { + candidate_parent.children.push_back(loop); + holes_d.erase(holes_d.begin() + i); + -- i; + goto NEXT_LOOP; + } + } + } + // if no hole contains this hole, find the contour loop that contains it + for (int t = loop_number; t >= 0; -- t) { + for (int j = 0; j < (int)contours[t].size(); ++ j) { + PerimeterGeneratorLoop &candidate_parent = contours[t][j]; + if (candidate_parent.polygon.contains(loop.polygon.first_point())) { + candidate_parent.children.push_back(loop); + holes_d.erase(holes_d.begin() + i); + -- i; + goto NEXT_LOOP; + } + } + } + NEXT_LOOP: ; + } + } + // nest contour loops + for (int d = loop_number; d >= 1; -- d) { + PerimeterGeneratorLoops &contours_d = contours[d]; + // loop through all contours having depth == d + for (int i = 0; i < (int)contours_d.size(); ++ i) { + const PerimeterGeneratorLoop &loop = contours_d[i]; + // find the contour loop that contains it + for (int t = d - 1; t >= 0; -- t) { + for (int j = 0; j < contours[t].size(); ++ j) { + PerimeterGeneratorLoop &candidate_parent = contours[t][j]; + if (candidate_parent.polygon.contains(loop.polygon.first_point())) { + candidate_parent.children.push_back(loop); + contours_d.erase(contours_d.begin() + i); + -- i; + goto NEXT_CONTOUR; + } + } + } + NEXT_CONTOUR: ; + } + } + // at this point, all loops should be in contours[0] + ExtrusionEntityCollection entities = this->_traverse_loops(contours.front(), thin_walls); + // if brim will be printed, reverse the order of perimeters so that + // we continue inwards after having finished the brim + // TODO: add test for perimeter order + if (this->config->external_perimeters_first || + (this->layer_id == 0 && this->print_config->brim_width.value > 0)) + entities.reverse(); + // append perimeters for this slice as a collection + if (! entities.empty()) + this->loops->append(entities); + } // for each loop of an island + + // fill gaps + if (! gaps.empty()) { + // collapse + double min = 0.2 * perimeter_width * (1 - INSET_OVERLAP_TOLERANCE); + double max = 2. * perimeter_spacing; + ExPolygons gaps_ex = diff_ex( + //FIXME offset2 would be enough and cheaper. + offset2_ex(gaps, -min/2, +min/2), + offset2_ex(gaps, -max/2, +max/2), + true); + ThickPolylines polylines; + for (const ExPolygon &ex : gaps_ex) + ex.medial_axis(max, min, &polylines); + if (! polylines.empty()) { + ExtrusionEntityCollection gap_fill = this->_variable_width(polylines, + erGapFill, this->solid_infill_flow); + this->gap_fill->append(gap_fill.entities); + /* Make sure we don't infill narrow parts that are already gap-filled + (we only consider this surface's gaps to reduce the diff() complexity). + Growing actual extrusions ensures that gaps not filled by medial axis + are not subtracted from fill surfaces (they might be too short gaps + that medial axis skips but infill might join with other infill regions + and use zigzag). */ + //FIXME Vojtech: This grows by a rounded extrusion width, not by line spacing, + // therefore it may cover the area, but no the volume. + last = diff_ex(to_polygons(last), gap_fill.polygons_covered_by_width(10.f)); + } + } + + // create one more offset to be used as boundary for fill + // we offset by half the perimeter spacing (to get to the actual infill boundary) + // and then we offset back and forth by half the infill spacing to only consider the + // non-collapsing regions + coord_t inset = + (loop_number < 0) ? 0 : + (loop_number == 0) ? + // one loop + ext_perimeter_spacing / 2 : + // two or more loops? + perimeter_spacing / 2; + // only apply infill overlap if we actually have one perimeter + if (inset > 0) + inset -= scale_(this->config->get_abs_value("infill_overlap", unscale<double>(inset + solid_infill_spacing / 2))); + // simplify infill contours according to resolution + Polygons pp; + for (ExPolygon &ex : last) + ex.simplify_p(SCALED_RESOLUTION, &pp); + // collapse too narrow infill areas + coord_t min_perimeter_infill_spacing = solid_infill_spacing * (1. - INSET_OVERLAP_TOLERANCE); + // append infill areas to fill_surfaces + this->fill_surfaces->append( + offset2_ex( + union_ex(pp), + - inset - min_perimeter_infill_spacing / 2, + min_perimeter_infill_spacing / 2), + stInternal); + } // for each island +} + +ExtrusionEntityCollection PerimeterGenerator::_traverse_loops( + const PerimeterGeneratorLoops &loops, ThickPolylines &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 + extrusion_paths_append( + paths, + intersection_pl(loop->polygon, this->_lower_slices_p), + role, + is_external ? this->_ext_mm3_per_mm : this->_mm3_per_mm, + is_external ? this->ext_perimeter_flow.width : this->perimeter_flow.width, + this->layer_height); + + // 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 + extrusion_paths_append( + paths, + diff_pl(loop->polygon, this->_lower_slices_p), + erOverhangPerimeter, + this->_mm3_per_mm_overhang, + this->overhang_flow.width, + this->overhang_flow.height); + + // reapply the nearest point search for starting point + // We allow polyline reversal because Clipper may have randomly + // reversed polylines during clipping. + paths = (ExtrusionPaths)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) + if (!thin_walls.empty()) { + ExtrusionEntityCollection tw = this->_variable_width + (thin_walls, erExternalPerimeter, this->ext_perimeter_flow); + + coll.append(tw.entities); + 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, erMixed, &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; +} + +static inline ExtrusionPaths thick_polyline_to_extrusion_paths(const ThickPolyline &thick_polyline, ExtrusionRole role, Flow &flow, const float tolerance) +{ + ExtrusionPaths paths; + ExtrusionPath path(role); + ThickLines lines = thick_polyline.thicklines(); + + for (int i = 0; i < (int)lines.size(); ++i) { + const ThickLine& line = lines[i]; + + const coordf_t line_len = line.length(); + if (line_len < SCALED_EPSILON) continue; + + double thickness_delta = fabs(line.a_width - line.b_width); + if (thickness_delta > tolerance) { + const unsigned short segments = ceil(thickness_delta / tolerance); + const coordf_t seg_len = line_len / segments; + Points pp; + std::vector<coordf_t> width; + { + pp.push_back(line.a); + width.push_back(line.a_width); + for (size_t j = 1; j < segments; ++j) { + pp.push_back((line.a.cast<double>() + (line.b - line.a).cast<double>().normalized() * (j * seg_len)).cast<coord_t>()); + + coordf_t w = line.a_width + (j*seg_len) * (line.b_width-line.a_width) / line_len; + width.push_back(w); + width.push_back(w); + } + pp.push_back(line.b); + width.push_back(line.b_width); + + assert(pp.size() == segments + 1); + assert(width.size() == segments*2); + } + + // delete this line and insert new ones + lines.erase(lines.begin() + i); + for (size_t j = 0; j < segments; ++j) { + ThickLine new_line(pp[j], pp[j+1]); + new_line.a_width = width[2*j]; + new_line.b_width = width[2*j+1]; + lines.insert(lines.begin() + i + j, new_line); + } + + -- i; + continue; + } + + const double w = fmax(line.a_width, line.b_width); + if (path.polyline.points.empty()) { + path.polyline.append(line.a); + path.polyline.append(line.b); + // Convert from spacing to extrusion width based on the extrusion model + // of a square extrusion ended with semi circles. + flow.width = unscale<float>(w) + flow.height * (1. - 0.25 * PI); + #ifdef SLIC3R_DEBUG + printf(" filling %f gap\n", flow.width); + #endif + path.mm3_per_mm = flow.mm3_per_mm(); + path.width = flow.width; + path.height = flow.height; + } else { + thickness_delta = fabs(scale_(flow.width) - w); + if (thickness_delta <= tolerance) { + // the width difference between this line and the current flow width is + // within the accepted tolerance + path.polyline.append(line.b); + } else { + // we need to initialize a new line + paths.emplace_back(std::move(path)); + path = ExtrusionPath(role); + -- i; + } + } + } + if (path.polyline.is_valid()) + paths.emplace_back(std::move(path)); + return paths; +} + +ExtrusionEntityCollection PerimeterGenerator::_variable_width(const ThickPolylines &polylines, ExtrusionRole role, Flow flow) const +{ + // This value determines granularity of adaptive width, as G-code does not allow + // variable extrusion within a single move; this value shall only affect the amount + // of segments, and any pruning shall be performed before we apply this tolerance. + ExtrusionEntityCollection coll; + const double tolerance = scale_(0.05); + for (const ThickPolyline &p : polylines) { + ExtrusionPaths paths = thick_polyline_to_extrusion_paths(p, role, flow, tolerance); + // Append paths to collection. + if (! paths.empty()) { + if (paths.front().first_point() == paths.back().last_point()) + coll.append(ExtrusionLoop(std::move(paths))); + else + coll.append(std::move(paths)); + } + } + return coll; +} + +bool PerimeterGeneratorLoop::is_internal_contour() const +{ + // An internal contour is a contour containing no other contours + if (! this->is_contour) + return false; + for (const PerimeterGeneratorLoop &loop : this->children) + if (loop.is_contour) + return false; + return true; +} + +} |