QIDISlicer/src/libslic3r/GCode/SpiralVase.cpp

#include "SpiralVase.hpp"
#include "GCode.hpp"
#include <sstream>
#include <cmath>
#include <limits>

namespace Slic3r {

static AABBTreeLines::LinesDistancer<Linef> get_layer_distancer(const std::vector<Vec2f> &layer_points)
{
    Linesf lines;
    for (size_t idx = 1; idx < layer_points.size(); ++idx)
        lines.emplace_back(layer_points[idx - 1].cast<double>(), layer_points[idx].cast<double>());

    return AABBTreeLines::LinesDistancer{std::move(lines)};
}

std::string SpiralVase::process_layer(const std::string &gcode, bool last_layer)
{
    /*  This post-processor relies on several assumptions:
        - all layers are processed through it, including those that are not supposed
          to be transformed, in order to update the reader with the XY positions
        - each call to this method includes a full layer, with a single Z move
          at the beginning
        - each layer is composed by suitable geometry (i.e. a single complete loop)
        - loops were not clipped before calling this method  */
    
    // If we're not going to modify G-code, just feed it to the reader
    // in order to update positions.
    if (! m_enabled) {
        m_reader.parse_buffer(gcode);
        return gcode;
    }
    
    // Get total XY length for this layer by summing all extrusion moves.
    float total_layer_length = 0.f;
    float layer_height       = 0.f;
    float z = 0.f;
    
    {
        //FIXME Performance warning: This copies the GCodeConfig of the reader.
        GCodeReader r = m_reader;  // clone
        bool set_z = false;
        r.parse_buffer(gcode, [&total_layer_length, &layer_height, &z, &set_z]
            (GCodeReader &reader, const GCodeReader::GCodeLine &line) {
            if (line.cmd_is("G1")) {
                if (line.extruding(reader)) {
                    total_layer_length += line.dist_XY(reader);
                } else if (line.has(Z)) {
                    layer_height += line.dist_Z(reader);
                    if (!set_z) {
                        z = line.new_Z(reader);
                        set_z = true;
                    }
                }
            }
        });
    }
    
    // Remove layer height from initial Z.
    z -= layer_height;
    
    // FIXME Tapering of the transition layer and smoothing only works reliably with relative extruder distances.
    // For absolute extruder distances it will be switched off.
    // Tapering the absolute extruder distances requires to process every extrusion value after the first transition
    // layer.
    const bool transition_in  = m_transition_layer && m_config.use_relative_e_distances.value;
    const bool transition_out = last_layer && m_config.use_relative_e_distances.value;
    const bool smooth_spiral  = m_smooth_spiral && m_config.use_relative_e_distances.value;

    const AABBTreeLines::LinesDistancer previous_layer_distancer = get_layer_distancer(m_previous_layer);
    Vec2f                               last_point               = m_previous_layer.empty() ? Vec2f::Zero() : m_previous_layer.back();
    float len = 0.f;
    std::string        new_gcode, transition_gcode;
    std::vector<Vec2f> current_layer;
    m_reader.parse_buffer(gcode, [z, total_layer_length, layer_height, transition_in, transition_out, smooth_spiral, max_xy_smoothing = m_max_xy_smoothing,
                                  &len, &last_point, &new_gcode, &transition_gcode, &current_layer, &previous_layer_distancer]
        (GCodeReader &reader, GCodeReader::GCodeLine line) {
        if (line.cmd_is("G1")) {
            if (line.has_z()) {
                // If this is the initial Z move of the layer, replace it with a
                // (redundant) move to the last Z of previous layer.
                line.set(reader, Z, z);
                new_gcode += line.raw() + '\n';
                return;
            } else if (line.has_x() || line.has_y()) { // Sometimes lines have X/Y but the move is to the last position.
                if (const float dist_XY = line.dist_XY(reader); dist_XY > 0 && line.extruding(reader)) { // Exclude wipe and retract
                    len += dist_XY;
                    const float factor = len / total_layer_length;
                    if (transition_in)
                        // Transition layer, interpolate the amount of extrusion from zero to the final value.
                        line.set(reader, E, line.e() * factor, 5);
                    else if (transition_out) {
                        // We want the last layer to ramp down extrusion, but without changing z height!
                        // So clone the line before we mess with its Z and duplicate it into a new layer that ramps down E
                        // We add this new layer at the very end
                        GCodeReader::GCodeLine transition_line(line);
                        transition_line.set(reader, E, line.e() * (1.f - factor), 5);
                        transition_gcode += transition_line.raw() + '\n';
                    }

                    // This line is the core of Spiral Vase mode, ramp up the Z smoothly
                    line.set(reader, Z, z + factor * layer_height);

                    bool emit_gcode_line = true;
                    if (smooth_spiral) {
                        // Now we also need to try to interpolate X and Y
                        Vec2f p(line.x(), line.y());   // Get current x/y coordinates
                        current_layer.emplace_back(p); // Store that point for later use on the next layer

                        auto [nearest_distance, idx, nearest_pt] = previous_layer_distancer.distance_from_lines_extra<false>(p.cast<double>());
                        if (nearest_distance < max_xy_smoothing) {
                            // Interpolate between the point on this layer and the point on the previous layer
                            Vec2f target = nearest_pt.cast<float>() * (1.f - factor) + p * factor;

                            // We will emit a new g-code line only when XYZ positions differ from the previous g-code line.
                            emit_gcode_line = GCodeFormatter::quantize(last_point) != GCodeFormatter::quantize(target);

                            line.set(reader, X, target.x());
                            line.set(reader, Y, target.y());
                            // We need to figure out the distance of this new line!
                            float modified_dist_XY = (last_point - target).norm();
                            // Scale the extrusion amount according to change in length
                            line.set(reader, E, line.e() * modified_dist_XY / dist_XY, 5);
                            last_point = target;
            } else {
                            last_point = p;
                        }
                    }

                    if (emit_gcode_line)
                        new_gcode += line.raw() + '\n';
                    }
                    return;
                
                    /*  Skip travel moves: the move to first perimeter point will
                        cause a visible seam when loops are not aligned in XY; by skipping
                        it we blend the first loop move in the XY plane (although the smoothness
                        of such blend depend on how long the first segment is; maybe we should
                    enforce some minimum length?).
                    When smooth_spiral is enabled, we're gonna end up exactly where the next layer should
                    start anyway, so we don't need the travel move */
                }
            }
        new_gcode += line.raw() + '\n';
        if (transition_out)
            transition_gcode += line.raw() + '\n';
    });
    
    m_previous_layer = std::move(current_layer);
    return new_gcode + transition_gcode;
}

}