예제 #1
0
void
BridgeDetector::unsupported_edges(double angle, Polylines* unsupported) const
{
    // get bridge edges (both contour and holes)
    Polylines bridge_edges;
    {
        Polygons pp = this->expolygon;
        bridge_edges.insert(bridge_edges.end(), pp.begin(), pp.end());  // this uses split_at_first_point()
    }

    // get unsupported edges
    Polygons grown_lower;
    offset(this->lower_slices, &grown_lower, +this->extrusion_width);
    Polylines _unsupported;
    diff(bridge_edges, grown_lower, &_unsupported);

    /*  Split into individual segments and filter out edges parallel to the bridging angle
        TODO: angle tolerance should probably be based on segment length and flow width,
        so that we build supports whenever there's a chance that at least one or two bridge
        extrusions would be anchored within such length (i.e. a slightly non-parallel bridging
        direction might still benefit from anchors if long enough) */
    double angle_tolerance = PI / 180.0 * 5.0;
    for (Polylines::const_iterator polyline = _unsupported.begin(); polyline != _unsupported.end(); ++polyline) {
        Lines lines = polyline->lines();
        for (Lines::const_iterator line = lines.begin(); line != lines.end(); ++line) {
            if (!xd::Geometry::directions_parallel(line->direction(), angle))
                unsupported->push_back(*line);
        }
    }

    /*
    if (0) {
        require "Slic3r/SVG.pm";
        Slic3r::SVG::output(
            "unsupported_" . rad2deg($angle) . ".svg",
            expolygons          => [$self->expolygon],
            green_expolygons    => $self->_anchors,
            red_expolygons      => union_ex($grown_lower),
            no_arrows           => 1,
            polylines           => \@bridge_edges,
            red_polylines       => $unsupported,
        );
    }
    */
}
예제 #2
0
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;
}