C++ Polygons::empty方法代码示例

void
SLAPrint::_infill_layer(size_t i, const Fill* _fill)
{
    Layer &layer = this->layers[i];
    
    const float shell_thickness = this->config.get_abs_value("perimeter_extrusion_width", this->config.layer_height.value);
    
    // In order to detect what regions of this layer need to be solid,
    // perform an intersection with layers within the requested shell thickness.
    Polygons internal = layer.slices;
    for (size_t j = 0; j < this->layers.size(); ++j) {
        const Layer &other = this->layers[j];
        if (abs(other.print_z - layer.print_z) > shell_thickness) continue;
    
        if (j == 0 || j == this->layers.size()-1) {
            internal.clear();
            break;
        } else if (i != j) {
            internal = intersection(internal, other.slices);
            if (internal.empty()) break;
        }
    }
    
    // If we have no internal infill, just print the whole layer as a solid slice.
    if (internal.empty()) return;
    layer.solid = false;
    
    const Polygons infill = offset(layer.slices, -scale_(shell_thickness));
    
    // Generate solid infill
    layer.solid_infill << diff_ex(infill, internal, true);
    
    // Generate internal infill
    {
        std::auto_ptr<Fill> fill(_fill->clone());
        fill->layer_id = i;
        fill->z        = layer.print_z;
        
        ExtrusionPath templ(erInternalInfill);
        templ.width = fill->spacing;
        const ExPolygons internal_ex = intersection_ex(infill, internal);
        for (ExPolygons::const_iterator it = internal_ex.begin(); it != internal_ex.end(); ++it) {
            Polylines polylines = fill->fill_surface(Surface(stInternal, *it));
            layer.infill.append(polylines, templ);
        }
    }
    
    // Generate perimeter(s).
    layer.perimeters << diff_ex(
        layer.slices,
        offset(layer.slices, -scale_(shell_thickness))
    );
}

inline void        polygons_append(Polygons &dst, Polygons &&src) 
{
    if (dst.empty())
        dst = std::move(src);
    else
        std::move(std::begin(src), std::end(src), std::back_inserter(dst));
}

//.........这里部分代码省略.........
                    coord_t distance = (i == 1) ? ext_pspacing2 : pspacing;
                    
                    if (this->config->thin_walls) {
                        offsets = offset2(
                            last,
                            -(distance + min_spacing/2 - 1),
                            +(min_spacing/2 - 1)
                        );
                    } else {
                        offsets = offset(
                            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
                        ExPolygons diff_expp = diff_ex(
                            offset(last, -0.5*distance),
                            offset(offsets, +0.5*distance + 10)  // safety offset
                        );
                        for (ExPolygons::const_iterator ex = diff_expp.begin(); ex != diff_expp.end(); ++ex) {
                            if (fabs(ex->area()) >= gap_area_threshold) {
                                Polygons pp = *ex;
                                gaps.insert(gaps.end(), pp.begin(), pp.end());
                            }
                        }
                    }
                }
                
                if (offsets.empty()) break;
                if (i > loop_number) break; // we were only looking for gaps this time
                
                last = offsets;
                for (Polygons::const_iterator polygon = offsets.begin(); polygon != offsets.end(); ++polygon) {
                    PerimeterGeneratorLoop loop(*polygon, i);
                    loop.is_contour = polygon->is_counter_clockwise();
                    if (loop.is_contour) {
                        contours[i].push_back(loop);
                    } else {
                        holes[i].push_back(loop);
                    }
                }
            }
            
            // nest loops: holes first
            for (signed short d = 0; d <= loop_number; ++d) {
                PerimeterGeneratorLoops &holes_d = holes[d];
                
                // loop through all holes having depth == d
                for (signed short i = 0; i < holes_d.size(); ++i) {
                    const PerimeterGeneratorLoop &loop = holes_d[i];
                    
                    // find the hole loop that contains this one, if any
                    for (signed short t = d+1; t <= loop_number; ++t) {
                        for (signed short j = 0; j < 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;
                            }

void
SLAPrint::slice()
{
    TriangleMesh mesh = this->model->mesh();
    mesh.repair();
    
    // align to origin taking raft into account
    this->bb = mesh.bounding_box();
    if (this->config.raft_layers > 0) {
        this->bb.min.x -= this->config.raft_offset.value;
        this->bb.min.y -= this->config.raft_offset.value;
        this->bb.max.x += this->config.raft_offset.value;
        this->bb.max.y += this->config.raft_offset.value;
    }
    mesh.translate(0, 0, -bb.min.z);
    this->bb.translate(0, 0, -bb.min.z);
    
    // if we are generating a raft, first_layer_height will not affect mesh slicing
    const float lh       = this->config.layer_height.value;
    const float first_lh = this->config.first_layer_height.value;
    
    // generate the list of Z coordinates for mesh slicing
    // (we slice each layer at half of its thickness)
    this->layers.clear();
    {
        const float first_slice_lh = (this->config.raft_layers > 0) ? lh : first_lh;
        this->layers.push_back(Layer(first_slice_lh/2, first_slice_lh));
    }
    while (this->layers.back().print_z + lh/2 <= mesh.stl.stats.max.z) {
        this->layers.push_back(Layer(this->layers.back().print_z + lh/2, this->layers.back().print_z + lh));
    }
    
    // perform slicing and generate layers
    {
        std::vector<float> slice_z;
        for (size_t i = 0; i < this->layers.size(); ++i)
            slice_z.push_back(this->layers[i].slice_z);
        
        std::vector<ExPolygons> slices;
        TriangleMeshSlicer(&mesh).slice(slice_z, &slices);
        
        for (size_t i = 0; i < slices.size(); ++i)
            this->layers[i].slices.expolygons = slices[i];
    }
    
    // generate infill
    if (this->config.fill_density < 100) {
        std::auto_ptr<Fill> fill(Fill::new_from_type(this->config.fill_pattern.value));
        fill->bounding_box.merge(Point::new_scale(bb.min.x, bb.min.y));
        fill->bounding_box.merge(Point::new_scale(bb.max.x, bb.max.y));
        fill->spacing       = this->config.get_abs_value("infill_extrusion_width", this->config.layer_height.value);
        fill->angle         = Geometry::deg2rad(this->config.fill_angle.value);
        fill->density       = this->config.fill_density.value/100;
        
        parallelize<size_t>(
            0,
            this->layers.size()-1,
            boost::bind(&SLAPrint::_infill_layer, this, _1, fill.get()),
            this->config.threads.value
        );
    }
    
    // generate support material
    this->sm_pillars.clear();
    ExPolygons overhangs;
    if (this->config.support_material) {
        // flatten and merge all the overhangs
        {
            Polygons pp;
            for (std::vector<Layer>::const_iterator it = this->layers.begin()+1; it != this->layers.end(); ++it)
                pp += diff(it->slices, (it - 1)->slices);
            overhangs = union_ex(pp);
        }
        
        // generate points following the shape of each island
        Points pillars_pos;
        const coordf_t spacing = scale_(this->config.support_material_spacing);
        const coordf_t radius  = scale_(this->sm_pillars_radius());
        for (ExPolygons::const_iterator it = overhangs.begin(); it != overhangs.end(); ++it) {
            // leave a radius/2 gap between pillars and contour to prevent lateral adhesion
            for (float inset = radius * 1.5;; inset += spacing) {
                // inset according to the configured spacing
                Polygons curr = offset(*it, -inset);
                if (curr.empty()) break;
                
                // generate points along the contours
                for (Polygons::const_iterator pg = curr.begin(); pg != curr.end(); ++pg) {
                    Points pp = pg->equally_spaced_points(spacing);
                    for (Points::const_iterator p = pp.begin(); p != pp.end(); ++p)
                        pillars_pos.push_back(*p);
                }
            }
        }
        
        // for each pillar, check which layers it applies to
        for (Points::const_iterator p = pillars_pos.begin(); p != pillars_pos.end(); ++p) {
            SupportPillar pillar(*p);
            bool object_hit = false;
            
            // check layers top-down
//.........这里部分代码省略.........