First rough draft of alignment-based IfcFixedReferenceSweptAreaSolid

src/ifcgeom/kernels/opencascade/loft.cpp

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+/********************************************************************************
+ *                                                                              *
+ * This file is part of IfcOpenShell.                                           *
+ *                                                                              *
+ * IfcOpenShell is free software: you can redistribute it and/or modify         *
+ * it under the terms of the Lesser GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3.0 of the License, or          *
+ * (at your option) any later version.                                          *
+ *                                                                              *
+ * IfcOpenShell is distributed in the hope that it will be useful,              *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of               *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                 *
+ * Lesser GNU General Public License for more details.                          *
+ *                                                                              *
+ * You should have received a copy of the Lesser GNU General Public License     *
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
+ *                                                                              *
+ ********************************************************************************/
+
+#include "OpenCascadeKernel.h"
+#include "base_utils.h"
+
+#include <TopExp.hxx>
+#include <BRepFill_Filling.hxx>
+#include <BRepTools_WireExplorer.hxx>
+#include <BRepBuilderAPI_MakeEdge.hxx>
+
+using namespace ifcopenshell::geometry;
+using namespace ifcopenshell::geometry::kernels;
+using namespace IfcGeom;
+using namespace IfcGeom::util;
+
+bool OpenCascadeKernel::convert(const taxonomy::loft::ptr loft, TopoDS_Shape& result) {
+	// @todo this approach based on BRepFill_Filling is both slow, as well as
+	// potentially incorrect as there is no guarantee that the wires for
+	// subsequently placed profiles are traversed from an equivalent start vertex.
+	
+	if (loft->children.size() < 2) {
+		return false;
+	}
+	
+	TopTools_ListOfShape faces;
+	TopoDS_Compound comp;
+	BRep_Builder BB;
+	BB.MakeCompound(comp);
+
+	for (auto it = loft->children.begin(); it < loft->children.end() - 1; ++it) {
+		auto jt = it + 1;
+		std::array<taxonomy::face::ptr, 2> fa = { *it, *jt };
+		std::array<TopoDS_Shape, 2> shps;
+		std::array<TopoDS_Wire, 2> ws;
+		for (int i = 0; i < 2; ++i) {
+			if (!convert(fa[i], shps[i])) {
+				return false;
+			}
+			if (shps[i].ShapeType() != TopAbs_FACE) {
+				return false;
+			}
+			ws[i] = BRepTools::OuterWire(TopoDS::Face(shps[i]));
+		}
+		if (it == loft->children.begin()) {
+			// faces.Append(shps[0]);
+			BB.Add(comp, shps[0]);
+		}
+		if (jt == loft->children.end() - 1) {
+			// faces.Append(shps[1]);
+			BB.Add(comp, shps[1]);
+		}
+		BRepTools_WireExplorer a(ws[0]);
+		BRepTools_WireExplorer b(ws[1]);
+		for (; a.More() && b.More(); a.Next(), b.Next()) {
+			BRepFill_Filling fill;
+			auto& e1 = a.Current();
+			auto e3 = TopoDS::Edge(b.Current().Reversed());
+			
+			// Documentation says unconnected edges are automatically connected, but this is not the case
+			TopoDS_Vertex e1a, e1b, e3a, e3b;
+			TopExp::Vertices(e1, e1a, e1b, true);
+			TopExp::Vertices(e3, e3a, e3b, true);
+			auto e2 = BRepBuilderAPI_MakeEdge(e1b, e3a).Edge();
+			auto e4 = BRepBuilderAPI_MakeEdge(e3b, e1a).Edge();
+			
+			fill.Add(e1, GeomAbs_C0);
+			fill.Add(e2, GeomAbs_C0);
+			fill.Add(e3, GeomAbs_C0);
+			fill.Add(e4, GeomAbs_C0);
+			fill.Build();
+			// faces.Append(fill.Face());
+			BB.Add(comp, fill.Face());
+		}
+	}
+
+	// create_solid_from_faces(faces, result, settings_.get<settings::Precision>().get());
+	result = comp;
+
+	return true;
+}
+
+bool OpenCascadeKernel::convert_impl(const taxonomy::loft::ptr loft, IfcGeom::ConversionResults& results) {
+	TopoDS_Shape shape;
+	if (!convert(loft, shape)) {
+		return false;
+	}
+	results.emplace_back(ConversionResult(
+		loft->instance->data().id(),
+		loft->matrix,
+		new OpenCascadeShape(shape),
+		loft->surface_style
+	));
+	return true;
+}