Slic3r/xs/src/Flow.cpp

#include "Flow.hpp"
#include <cmath>

namespace Slic3r {

/* This constructor builds a Flow object from an extrusion width config setting
   and other context properties. */
Flow
Flow::new_from_config_width(FlowRole role, const ConfigOptionFloatOrPercent &width, float nozzle_diameter, float height, float bridge_flow_ratio) {
    // we need layer height unless it's a bridge
    if (height <= 0 && bridge_flow_ratio == 0) CONFESS("Invalid flow height supplied to new_from_config_width()");
    
    float w;
    if (bridge_flow_ratio > 0) {
        // if bridge flow was requested, calculate bridge width
        w = Flow::_bridge_width(nozzle_diameter, bridge_flow_ratio);
    } else if (!width.percent && width.value == 0) {
        // if user left option to 0, calculate a sane default width
        w = Flow::_auto_width(role, nozzle_diameter, height);
    } else {
        // if user set a manual value, use it
        w = width.get_abs_value(height);
    }
    
    return Flow(w, height, nozzle_diameter, bridge_flow_ratio > 0);
}

/* This constructor builds a Flow object from a given centerline spacing. */
Flow
Flow::new_from_spacing(float spacing, float nozzle_diameter, float height, bool bridge) {
    // we need layer height unless it's a bridge
    if (height <= 0 && !bridge) CONFESS("Invalid flow height supplied to new_from_spacing()");

    float w = Flow::_width_from_spacing(spacing, nozzle_diameter, height, bridge);
    return Flow(w, height, nozzle_diameter, bridge);
}

/* This method returns the centerline spacing between two adjacent extrusions 
   having the same extrusion width (and other properties). */
float
Flow::spacing() const {
    if (this->bridge) {
        return this->width + BRIDGE_EXTRA_SPACING;
    }
    
    float min_flow_spacing;
    if (this->width >= (this->nozzle_diameter + this->height)) {
        // rectangle with semicircles at the ends
        min_flow_spacing = this->width - this->height * (1 - PI/4.0);
    } else {
        // rectangle with shrunk semicircles at the ends
        min_flow_spacing = this->nozzle_diameter * (1 - PI/4.0) + this->width * PI/4.0;
    }
    return this->width - OVERLAP_FACTOR * (this->width - min_flow_spacing);
}

/* This method returns the centerline spacing between an extrusion using this
   flow and another one using another flow.
   this->spacing(other) shall return the same value as other.spacing(*this) */
float
Flow::spacing(const Flow &other) const {
    assert(this->height == other.height);
    assert(this->bridge == other.bridge);
    
    if (this->bridge) {
        return this->width/2 + other.width/2 + BRIDGE_EXTRA_SPACING;
    }
    
    return this->spacing()/2 + other.spacing()/2;
}

/* This method returns extrusion volume per head move unit. */
double
Flow::mm3_per_mm() const {
    if (this->bridge) {
        return (this->width * this->width) * PI/4.0;
    } else if (this->width >= (this->nozzle_diameter + this->height)) {
        // rectangle with semicircles at the ends
        return this->width * this->height + (this->height*this->height) / 4.0 * (PI-4.0);
    } else {
        // rectangle with shrunk semicircles at the ends
        return this->nozzle_diameter * this->height * (1 - PI/4.0) + this->height * this->width * PI/4.0;
    }
}

/* This static method returns bridge width for a given nozzle diameter. */
float
Flow::_bridge_width(float nozzle_diameter, float bridge_flow_ratio) {
    if (bridge_flow_ratio == 1) return nozzle_diameter;  // optimization to avoid sqrt()
    return sqrt(bridge_flow_ratio * (nozzle_diameter*nozzle_diameter));
}

/* This static method returns a sane extrusion width default. */
float
Flow::_auto_width(FlowRole role, float nozzle_diameter, float height) {
    // here we calculate a sane default by matching the flow speed (at the nozzle) and the feed rate
    float volume = (nozzle_diameter*nozzle_diameter) * PI/4.0;
    float shape_threshold = nozzle_diameter * height + (height*height) * PI/4.0;
    float width;
    if (volume >= shape_threshold) {
        // rectangle with semicircles at the ends
        width = ((nozzle_diameter*nozzle_diameter) * PI + (height*height) * (4.0 - PI)) / (4.0 * height);
    } else {
        // rectangle with squished semicircles at the ends
        width = nozzle_diameter * (nozzle_diameter/height - 4.0/PI + 1);
    }
    
    float min = nozzle_diameter * 1.05;
    float max = -1;
    if (role == frExternalPerimeter || role == frSupportMaterial) {
        min = max = nozzle_diameter;
    } else /*if (role != frInfill)*/ {
        // do not limit width for sparse infill so that we use full native flow for it
        max = nozzle_diameter * 1.7;
    }
    if (max != -1 && width > max) width = max;
    if (width < min) width = min;
    
    return width;
}

/* This static method returns the extrusion width value corresponding to the supplied centerline spacing. */
float
Flow::_width_from_spacing(float spacing, float nozzle_diameter, float height, bool bridge) {
    if (bridge) {
        return spacing - BRIDGE_EXTRA_SPACING;
    }
    
    float w_threshold = height + nozzle_diameter;
    float s_threshold = w_threshold - OVERLAP_FACTOR * (w_threshold - (w_threshold - height * (1 - PI/4.0)));
    
    if (spacing >= s_threshold) {
        // rectangle with semicircles at the ends
        return spacing + OVERLAP_FACTOR * height * (1 - PI/4.0);
    } else {
        // rectangle with shrunk semicircles at the ends
        return (spacing + nozzle_diameter * OVERLAP_FACTOR * (PI/4.0 - 1)) / (1 + OVERLAP_FACTOR * (PI/4.0 - 1));
    }
}

#ifdef SLIC3RXS
REGISTER_CLASS(Flow, "Flow");
#endif

}