Function _createHorizontalAlignment

src/ifcparse/IfcAlignmentHelper.cpp:75–179

creates a horizontal alignment using a vector of PI points and curve radii returns a list of object definitions, curve segments, and a composite curve

// creates a horizontal alignment using a vector of PI points and curve radii
// returns a list of object definitions, curve segments, and a composite curve
std::tuple<typename aggregate_of<Ifc4x3_add2::IfcObjectDefinition>::ptr, typename aggregate_of<Ifc4x3_add2::IfcSegment>::ptr, Ifc4x3_add2::IfcCompositeCurve*> _createHorizontalAlignment(IfcHierarchyHelper<Ifc4x3_add2>& file, const std::vector<std::pair<double, double>>& points, const std::vector<double>& radii,bool include_geometry) {
    typename aggregate_of<Ifc4x3_add2::IfcObjectDefinition>::ptr horizontal_segments(new aggregate_of<Ifc4x3_add2::IfcObjectDefinition>()); // business logic
    typename aggregate_of<Ifc4x3_add2::IfcSegment>::ptr horizontal_curve_segments(include_geometry ? new aggregate_of<Ifc4x3_add2::IfcSegment>() : nullptr);             // geometry

    auto point_iter = points.begin();
    double xBT, yBT, xPI, yPI;

    boost::tie(xBT, yBT) = *point_iter;

    point_iter++;
    boost::tie(xPI, yPI) = *point_iter;

    double xFT, yFT;
    for (auto radius : radii) {
        // back tangent
        auto dxBT = xPI - xBT;
        auto dyBT = yPI - yBT;
        auto angleBT = atan2(dyBT, dxBT);
        auto lengthBT = sqrt(dxBT * dxBT + dyBT * dyBT);

        // forward tangent
        point_iter++;
        std::tie(xFT, yFT) = *point_iter;
        auto dxFT = xFT - xPI;
        auto dyFT = yFT - yPI;
        auto angleFT = atan2(dyFT, dxFT);

        auto delta = angleFT - angleBT;

        auto tangent = fabs(radius * tan(delta / 2));

        auto lc = fabs(radius * delta);

        radius *= delta / fabs(delta);

        auto xPC = xPI - tangent * cos(angleBT);
        auto yPC = yPI - tangent * sin(angleBT);

        auto xPT = xPI + tangent * cos(angleFT);
        auto yPT = yPI + tangent * sin(angleFT);

        auto tangent_run = lengthBT - tangent;

        // create back tangent run
        {
            auto pt = file.addDoublet<Ifc4x3_add2::IfcCartesianPoint>(xBT, yBT);
            auto design_parameters = new Ifc4x3_add2::IfcAlignmentHorizontalSegment(boost::none, boost::none, pt, angleBT, 0.0, 0.0, tangent_run, boost::none, Ifc4x3_add2::IfcAlignmentHorizontalSegmentTypeEnum::IfcAlignmentHorizontalSegmentType_LINE);
            auto alignment_segment = new Ifc4x3_add2::IfcAlignmentSegment(IfcParse::IfcGlobalId(), nullptr, boost::none, boost::none, boost::none, nullptr, nullptr, design_parameters);
            horizontal_segments->push(alignment_segment);

            if (include_geometry) {
                horizontal_curve_segments->push(mapAlignmentHorizontalSegment(design_parameters).first);
            }
        }

        // create circular curve
        {
            auto pc = file.addDoublet<Ifc4x3_add2::IfcCartesianPoint>(xPC, yPC);