delete src/mesh/assimp-master

1 files changed, 0 insertions, 765 deletions

diff --git a/src/mesh/assimp-master/code/AssetLib/IFC/IFCBoolean.cpp b/src/mesh/assimp-master/code/AssetLib/IFC/IFCBoolean.cpp
deleted file mode 100644
index 36912a7..0000000
--- a/src/mesh/assimp-master/code/AssetLib/IFC/IFCBoolean.cpp
+++ /dev/null
@@ -1,765 +0,0 @@
-/*
-Open Asset Import Library (assimp)
-----------------------------------------------------------------------
-
-Copyright (c) 2006-2022, assimp team
-All rights reserved.
-
-Redistribution and use of this software in source and binary forms,
-with or without modification, are permitted provided that the
-following conditions are met:
-
-* Redistributions of source code must retain the above
-  copyright notice, this list of conditions and the
-  following disclaimer.
-
-* Redistributions in binary form must reproduce the above
-  copyright notice, this list of conditions and the
-  following disclaimer in the documentation and/or other
-  materials provided with the distribution.
-
-* Neither the name of the assimp team, nor the names of its
-  contributors may be used to endorse or promote products
-  derived from this software without specific prior
-  written permission of the assimp team.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-----------------------------------------------------------------------
-*/
-
-/** @file  IFCBoolean.cpp
- *  @brief Implements a subset of Ifc boolean operations
- */
-
-#ifndef ASSIMP_BUILD_NO_IFC_IMPORTER
-
-#include "AssetLib/IFC/IFCUtil.h"
-#include "Common/PolyTools.h"
-#include "PostProcessing/ProcessHelper.h"
-
-
-#include <iterator>
-#include <tuple>
-
-namespace Assimp {
-namespace IFC {
-
-// ------------------------------------------------------------------------------------------------
-// Calculates intersection between line segment and plane. To catch corner cases, specify which side you prefer.
-// The function then generates a hit only if the end is beyond a certain margin in that direction, filtering out
-// "very close to plane" ghost hits as long as start and end stay directly on or within the given plane side.
-bool IntersectSegmentPlane(const IfcVector3 &p, const IfcVector3 &n, const IfcVector3 &e0,
-        const IfcVector3 &e1, bool assumeStartOnWhiteSide, IfcVector3 &out) {
-    const IfcVector3 pdelta = e0 - p, seg = e1 - e0;
-    const IfcFloat dotOne = n * seg, dotTwo = -(n * pdelta);
-
-    // if segment ends on plane, do not report a hit. We stay on that side until a following segment starting at this
-    // point leaves the plane through the other side
-    if (std::abs(dotOne + dotTwo) < ai_epsilon)
-        return false;
-
-    // if segment starts on the plane, report a hit only if the end lies on the *other* side
-    if (std::abs(dotTwo) < ai_epsilon) {
-        if ((assumeStartOnWhiteSide && dotOne + dotTwo < ai_epsilon) || (!assumeStartOnWhiteSide && dotOne + dotTwo > -ai_epsilon)) {
-            out = e0;
-            return true;
-        } else {
-            return false;
-        }
-    }
-
-    // ignore if segment is parallel to plane and far away from it on either side
-    // Warning: if there's a few thousand of such segments which slowly accumulate beyond the epsilon, no hit would be registered
-    if (std::abs(dotOne) < ai_epsilon)
-        return false;
-
-    // t must be in [0..1] if the intersection point is within the given segment
-    const IfcFloat t = dotTwo / dotOne;
-    if (t > 1.0 || t < 0.0)
-        return false;
-
-    out = e0 + t * seg;
-    return true;
-}
-
-// ------------------------------------------------------------------------------------------------
-void FilterPolygon(std::vector<IfcVector3> &resultpoly) {
-    if (resultpoly.size() < 3) {
-        resultpoly.clear();
-        return;
-    }
-
-    IfcVector3 vmin, vmax;
-    ArrayBounds(resultpoly.data(), static_cast<unsigned int>(resultpoly.size()), vmin, vmax);
-
-    // filter our IfcFloat points - those may happen if a point lies
-    // directly on the intersection line or directly on the clipping plane
-    const IfcFloat epsilon = (vmax - vmin).SquareLength() / 1e6f;
-    FuzzyVectorCompare fz(epsilon);
-    std::vector<IfcVector3>::iterator e = std::unique(resultpoly.begin(), resultpoly.end(), fz);
-
-    if (e != resultpoly.end())
-        resultpoly.erase(e, resultpoly.end());
-
-    if (!resultpoly.empty() && fz(resultpoly.front(), resultpoly.back()))
-        resultpoly.pop_back();
-}
-
-// ------------------------------------------------------------------------------------------------
-void WritePolygon(std::vector<IfcVector3> &resultpoly, TempMesh &result) {
-    FilterPolygon(resultpoly);
-
-    if (resultpoly.size() > 2) {
-        result.mVerts.insert(result.mVerts.end(), resultpoly.begin(), resultpoly.end());
-        result.mVertcnt.push_back(static_cast<unsigned int>(resultpoly.size()));
-    }
-}
-
-// ------------------------------------------------------------------------------------------------
-void ProcessBooleanHalfSpaceDifference(const Schema_2x3::IfcHalfSpaceSolid *hs, TempMesh &result,
-        const TempMesh &first_operand,
-        ConversionData & /*conv*/) {
-    ai_assert(hs != nullptr);
-
-    const Schema_2x3::IfcPlane *const plane = hs->BaseSurface->ToPtr<Schema_2x3::IfcPlane>();
-    if (!plane) {
-        IFCImporter::LogError("expected IfcPlane as base surface for the IfcHalfSpaceSolid");
-        return;
-    }
-
-    // extract plane base position vector and normal vector
-    IfcVector3 p, n(0.f, 0.f, 1.f);
-    if (plane->Position->Axis) {
-        ConvertDirection(n, plane->Position->Axis.Get());
-    }
-    ConvertCartesianPoint(p, plane->Position->Location);
-
-    if (!IsTrue(hs->AgreementFlag)) {
-        n *= -1.f;
-    }
-
-    // clip the current contents of `meshout` against the plane we obtained from the second operand
-    const std::vector<IfcVector3> &in = first_operand.mVerts;
-    std::vector<IfcVector3> &outvert = result.mVerts;
-
-    std::vector<unsigned int>::const_iterator begin = first_operand.mVertcnt.begin(),
-                                              end = first_operand.mVertcnt.end(), iit;
-
-    outvert.reserve(in.size());
-    result.mVertcnt.reserve(first_operand.mVertcnt.size());
-
-    unsigned int vidx = 0;
-    for (iit = begin; iit != end; vidx += *iit++) {
-
-        unsigned int newcount = 0;
-        bool isAtWhiteSide = (in[vidx] - p) * n > -ai_epsilon;
-        for (unsigned int i = 0; i < *iit; ++i) {
-            const IfcVector3 &e0 = in[vidx + i], e1 = in[vidx + (i + 1) % *iit];
-
-            // does the next segment intersect the plane?
-            IfcVector3 isectpos;
-            if (IntersectSegmentPlane(p, n, e0, e1, isAtWhiteSide, isectpos)) {
-                if (isAtWhiteSide) {
-                    // e0 is on the right side, so keep it
-                    outvert.push_back(e0);
-                    outvert.push_back(isectpos);
-                    newcount += 2;
-                } else {
-                    // e0 is on the wrong side, so drop it and keep e1 instead
-                    outvert.push_back(isectpos);
-                    ++newcount;
-                }
-                isAtWhiteSide = !isAtWhiteSide;
-            } else {
-                if (isAtWhiteSide) {
-                    outvert.push_back(e0);
-                    ++newcount;
-                }
-            }
-        }
-
-        if (!newcount) {
-            continue;
-        }
-
-        IfcVector3 vmin, vmax;
-        ArrayBounds(&*(outvert.end() - newcount), newcount, vmin, vmax);
-
-        // filter our IfcFloat points - those may happen if a point lies
-        // directly on the intersection line. However, due to IfcFloat
-        // precision a bitwise comparison is not feasible to detect
-        // this case.
-        const IfcFloat epsilon = (vmax - vmin).SquareLength() / 1e6f;
-        FuzzyVectorCompare fz(epsilon);
-
-        std::vector<IfcVector3>::iterator e = std::unique(outvert.end() - newcount, outvert.end(), fz);
-
-        if (e != outvert.end()) {
-            newcount -= static_cast<unsigned int>(std::distance(e, outvert.end()));
-            outvert.erase(e, outvert.end());
-        }
-        if (fz(*(outvert.end() - newcount), outvert.back())) {
-            outvert.pop_back();
-            --newcount;
-        }
-        if (newcount > 2) {
-            result.mVertcnt.push_back(newcount);
-        } else
-            while (newcount-- > 0) {
-                result.mVerts.pop_back();
-            }
-    }
-    IFCImporter::LogVerboseDebug("generating CSG geometry by plane clipping (IfcBooleanClippingResult)");
-}
-
-// ------------------------------------------------------------------------------------------------
-// Check if e0-e1 intersects a sub-segment of the given boundary line.
-// note: this functions works on 3D vectors, but performs its intersection checks solely in xy.
-// New version takes the supposed inside/outside state as a parameter and treats corner cases as if
-// the line stays on that side. This should make corner cases more stable.
-// Two million assumptions! Boundary should have all z at 0.0, will be treated as closed, should not have
-// segments with length <1e-6, self-intersecting might break the corner case handling... just don't go there, ok?
-bool IntersectsBoundaryProfile(const IfcVector3 &e0, const IfcVector3 &e1, const std::vector<IfcVector3> &boundary,
-        const bool isStartAssumedInside, std::vector<std::pair<size_t, IfcVector3>> &intersect_results,
-        const bool halfOpen = false) {
-    ai_assert(intersect_results.empty());
-
-    // determine winding order - necessary to detect segments going "inwards" or "outwards" from a point directly on the border
-    // positive sum of angles means clockwise order when looking down the -Z axis
-    IfcFloat windingOrder = 0.0;
-    for (size_t i = 0, bcount = boundary.size(); i < bcount; ++i) {
-        IfcVector3 b01 = boundary[(i + 1) % bcount] - boundary[i];
-        IfcVector3 b12 = boundary[(i + 2) % bcount] - boundary[(i + 1) % bcount];
-        IfcVector3 b1_side = IfcVector3(b01.y, -b01.x, 0.0); // rotated 90° clockwise in Z plane
-        // Warning: rough estimate only. A concave poly with lots of small segments each featuring a small counter rotation
-        // could fool the accumulation. Correct implementation would be sum( acos( b01 * b2) * sign( b12 * b1_side))
-        windingOrder += (b1_side.x * b12.x + b1_side.y * b12.y);
-    }
-    windingOrder = windingOrder > 0.0 ? 1.0 : -1.0;
-
-    const IfcVector3 e = e1 - e0;
-
-    for (size_t i = 0, bcount = boundary.size(); i < bcount; ++i) {
-        // boundary segment i: b0-b1
-        const IfcVector3 &b0 = boundary[i];
-        const IfcVector3 &b1 = boundary[(i + 1) % bcount];
-        IfcVector3 b = b1 - b0;
-
-        // segment-segment intersection
-        // solve b0 + b*s = e0 + e*t for (s,t)
-        const IfcFloat det = (-b.x * e.y + e.x * b.y);
-        if (std::abs(det) < ai_epsilon) {
-            // no solutions (parallel lines)
-            continue;
-        }
-        IfcFloat b_sqlen_inv = 1.0 / b.SquareLength();
-
-        const IfcFloat x = b0.x - e0.x;
-        const IfcFloat y = b0.y - e0.y;
-        const IfcFloat s = (x * e.y - e.x * y) / det; // scale along boundary edge
-        const IfcFloat t = (x * b.y - b.x * y) / det; // scale along given segment
-        const IfcVector3 p = e0 + e * t;
-#ifdef ASSIMP_BUILD_DEBUG
-        const IfcVector3 check = b0 + b * s - p;
-        ai_assert((IfcVector2(check.x, check.y)).SquareLength() < 1e-5);
-#endif
-
-        // also calculate the distance of e0 and e1 to the segment. We need to detect the "starts directly on segment"
-        // and "ends directly at segment" cases
-        bool startsAtSegment, endsAtSegment;
-        {
-            // calculate closest point to each end on the segment, clamp that point to the segment's length, then check
-            // distance to that point. This approach is like testing if e0 is inside a capped cylinder.
-            IfcFloat et0 = (b.x * (e0.x - b0.x) + b.y * (e0.y - b0.y)) * b_sqlen_inv;
-            IfcVector3 closestPosToE0OnBoundary = b0 + std::max(IfcFloat(0.0), std::min(IfcFloat(1.0), et0)) * b;
-            startsAtSegment = (closestPosToE0OnBoundary - IfcVector3(e0.x, e0.y, 0.0)).SquareLength() < 1e-12;
-            IfcFloat et1 = (b.x * (e1.x - b0.x) + b.y * (e1.y - b0.y)) * b_sqlen_inv;
-            IfcVector3 closestPosToE1OnBoundary = b0 + std::max(IfcFloat(0.0), std::min(IfcFloat(1.0), et1)) * b;
-            endsAtSegment = (closestPosToE1OnBoundary - IfcVector3(e1.x, e1.y, 0.0)).SquareLength() < 1e-12;
-        }
-
-        // Line segment ends at boundary -> ignore any hit, it will be handled by possibly following segments
-        if (endsAtSegment && !halfOpen)
-            continue;
-
-        // Line segment starts at boundary -> generate a hit only if following that line would change the INSIDE/OUTSIDE
-        // state. This should catch the case where a connected set of segments has a point directly on the boundary,
-        // one segment not hitting it because it ends there and the next segment not hitting it because it starts there
-        // Should NOT generate a hit if the segment only touches the boundary but turns around and stays inside.
-        if (startsAtSegment) {
-            IfcVector3 inside_dir = IfcVector3(b.y, -b.x, 0.0) * windingOrder;
-            bool isGoingInside = (inside_dir * e) > 0.0;
-            if (isGoingInside == isStartAssumedInside)
-                continue;
-
-            // only insert the point into the list if it is sufficiently far away from the previous intersection point.
-            // This way, we avoid duplicate detection if the intersection is directly on the vertex between two segments.
-            if (!intersect_results.empty() && intersect_results.back().first == i - 1) {
-                const IfcVector3 diff = intersect_results.back().second - e0;
-                if (IfcVector2(diff.x, diff.y).SquareLength() < 1e-10)
-                    continue;
-            }
-            intersect_results.push_back(std::make_pair(i, e0));
-            continue;
-        }
-
-        // for a valid intersection, s and t should be in range [0,1]. Including a bit of epsilon on s, potential double
-        // hits on two consecutive boundary segments are filtered
-        if (s >= -ai_epsilon * b_sqlen_inv && s <= 1.0 + ai_epsilon * b_sqlen_inv && t >= 0.0 && (t <= 1.0 || halfOpen)) {
-            // only insert the point into the list if it is sufficiently far away from the previous intersection point.
-            // This way, we avoid duplicate detection if the intersection is directly on the vertex between two segments.
-            if (!intersect_results.empty() && intersect_results.back().first == i - 1) {
-                const IfcVector3 diff = intersect_results.back().second - p;
-                if (IfcVector2(diff.x, diff.y).SquareLength() < 1e-10)
-                    continue;
-            }
-            intersect_results.push_back(std::make_pair(i, p));
-        }
-    }
-
-    return !intersect_results.empty();
-}
-
-// ------------------------------------------------------------------------------------------------
-// note: this functions works on 3D vectors, but performs its intersection checks solely in xy.
-bool PointInPoly(const IfcVector3 &p, const std::vector<IfcVector3> &boundary) {
-    // even-odd algorithm: take a random vector that extends from p to infinite
-    // and counts how many times it intersects edges of the boundary.
-    // because checking for segment intersections is prone to numeric inaccuracies
-    // or double detections (i.e. when hitting multiple adjacent segments at their
-    // shared vertices) we do it thrice with different rays and vote on it.
-
-    // the even-odd algorithm doesn't work for points which lie directly on
-    // the border of the polygon. If any of our attempts produces this result,
-    // we return false immediately.
-
-    std::vector<std::pair<size_t, IfcVector3>> intersected_boundary;
-    size_t votes = 0;
-
-    IntersectsBoundaryProfile(p, p + IfcVector3(1.0, 0, 0), boundary, true, intersected_boundary, true);
-    votes += intersected_boundary.size() % 2;
-
-    intersected_boundary.clear();
-    IntersectsBoundaryProfile(p, p + IfcVector3(0, 1.0, 0), boundary, true, intersected_boundary, true);
-    votes += intersected_boundary.size() % 2;
-
-    intersected_boundary.clear();
-    IntersectsBoundaryProfile(p, p + IfcVector3(0.6, -0.6, 0.0), boundary, true, intersected_boundary, true);
-    votes += intersected_boundary.size() % 2;
-
-    return votes > 1;
-}
-
-// ------------------------------------------------------------------------------------------------
-void ProcessPolygonalBoundedBooleanHalfSpaceDifference(const Schema_2x3::IfcPolygonalBoundedHalfSpace *hs, TempMesh &result,
-        const TempMesh &first_operand,
-        ConversionData &conv) {
-    ai_assert(hs != nullptr);
-
-    const Schema_2x3::IfcPlane *const plane = hs->BaseSurface->ToPtr<Schema_2x3::IfcPlane>();
-    if (!plane) {
-        IFCImporter::LogError("expected IfcPlane as base surface for the IfcHalfSpaceSolid");
-        return;
-    }
-
-    // extract plane base position vector and normal vector
-    IfcVector3 p, n(0.f, 0.f, 1.f);
-    if (plane->Position->Axis) {
-        ConvertDirection(n, plane->Position->Axis.Get());
-    }
-    ConvertCartesianPoint(p, plane->Position->Location);
-
-    if (!IsTrue(hs->AgreementFlag)) {
-        n *= -1.f;
-    }
-
-    n.Normalize();
-
-    // obtain the polygonal bounding volume
-    std::shared_ptr<TempMesh> profile = std::shared_ptr<TempMesh>(new TempMesh());
-    if (!ProcessCurve(hs->PolygonalBoundary, *profile.get(), conv)) {
-        IFCImporter::LogError("expected valid polyline for boundary of boolean halfspace");
-        return;
-    }
-
-    // determine winding order by calculating the normal.
-    IfcVector3 profileNormal = TempMesh::ComputePolygonNormal(profile->mVerts.data(), profile->mVerts.size());
-
-    IfcMatrix4 proj_inv;
-    ConvertAxisPlacement(proj_inv, hs->Position);
-
-    // and map everything into a plane coordinate space so all intersection
-    // tests can be done in 2D space.
-    IfcMatrix4 proj = proj_inv;
-    proj.Inverse();
-
-    // clip the current contents of `meshout` against the plane we obtained from the second operand
-    const std::vector<IfcVector3> &in = first_operand.mVerts;
-    std::vector<IfcVector3> &outvert = result.mVerts;
-    std::vector<unsigned int> &outvertcnt = result.mVertcnt;
-
-    outvert.reserve(in.size());
-    outvertcnt.reserve(first_operand.mVertcnt.size());
-
-    unsigned int vidx = 0;
-    std::vector<unsigned int>::const_iterator begin = first_operand.mVertcnt.begin();
-    std::vector<unsigned int>::const_iterator end = first_operand.mVertcnt.end();
-    std::vector<unsigned int>::const_iterator iit;
-    for (iit = begin; iit != end; vidx += *iit++) {
-        // Our new approach: we cut the poly along the plane, then we intersect the part on the black side of the plane
-        // against the bounding polygon. All the white parts, and the black part outside the boundary polygon, are kept.
-        std::vector<IfcVector3> whiteside, blackside;
-
-        {
-            const IfcVector3 *srcVertices = &in[vidx];
-            const size_t srcVtxCount = *iit;
-            if (srcVtxCount == 0)
-                continue;
-
-            IfcVector3 polyNormal = TempMesh::ComputePolygonNormal(srcVertices, srcVtxCount, true);
-
-            // if the poly is parallel to the plane, put it completely on the black or white side
-            if (std::abs(polyNormal * n) > 0.9999) {
-                bool isOnWhiteSide = (srcVertices[0] - p) * n > -ai_epsilon;
-                std::vector<IfcVector3> &targetSide = isOnWhiteSide ? whiteside : blackside;
-                targetSide.insert(targetSide.end(), srcVertices, srcVertices + srcVtxCount);
-            } else {
-                // otherwise start building one polygon for each side. Whenever the current line segment intersects the plane
-                // we put a point there as an end of the current segment. Then we switch to the other side, put a point there, too,
-                // as a beginning of the current segment, and simply continue accumulating vertices.
-                bool isCurrentlyOnWhiteSide = ((srcVertices[0]) - p) * n > -ai_epsilon;
-                for (size_t a = 0; a < srcVtxCount; ++a) {
-                    IfcVector3 e0 = srcVertices[a];
-                    IfcVector3 e1 = srcVertices[(a + 1) % srcVtxCount];
-                    IfcVector3 ei;
-
-                    // put starting point to the current mesh
-                    std::vector<IfcVector3> &trgt = isCurrentlyOnWhiteSide ? whiteside : blackside;
-                    trgt.push_back(srcVertices[a]);
-
-                    // if there's an intersection, put an end vertex there, switch to the other side's mesh,
-                    // and add a starting vertex there, too
-                    bool isPlaneHit = IntersectSegmentPlane(p, n, e0, e1, isCurrentlyOnWhiteSide, ei);
-                    if (isPlaneHit) {
-                        if (trgt.empty() || (trgt.back() - ei).SquareLength() > 1e-12)
-                            trgt.push_back(ei);
-                        isCurrentlyOnWhiteSide = !isCurrentlyOnWhiteSide;
-                        std::vector<IfcVector3> &newtrgt = isCurrentlyOnWhiteSide ? whiteside : blackside;
-                        newtrgt.push_back(ei);
-                    }
-                }
-            }
-        }
-
-        // the part on the white side can be written into the target mesh right away
-        WritePolygon(whiteside, result);
-
-        // The black part is the piece we need to get rid of, but only the part of it within the boundary polygon.
-        // So we now need to construct all the polygons that result from BlackSidePoly minus BoundaryPoly.
-        FilterPolygon(blackside);
-
-        // Complicated, II. We run along the polygon. a) When we're inside the boundary, we run on until we hit an
-        // intersection, which means we're leaving it. We then start a new out poly there. b) When we're outside the
-        // boundary, we start collecting vertices until we hit an intersection, then we run along the boundary until we hit
-        // an intersection, then we switch back to the poly and run on on this one again, and so on until we got a closed
-        // loop. Then we continue with the path we left to catch potential additional polys on the other side of the
-        // boundary as described in a)
-        if (!blackside.empty()) {
-            // poly edge index, intersection point, edge index in boundary poly
-            std::vector<std::tuple<size_t, IfcVector3, size_t>> intersections;
-            bool startedInside = PointInPoly(proj * blackside.front(), profile->mVerts);
-            bool isCurrentlyInside = startedInside;
-
-            std::vector<std::pair<size_t, IfcVector3>> intersected_boundary;
-
-            for (size_t a = 0; a < blackside.size(); ++a) {
-                const IfcVector3 e0 = proj * blackside[a];
-                const IfcVector3 e1 = proj * blackside[(a + 1) % blackside.size()];
-
-                intersected_boundary.clear();
-                IntersectsBoundaryProfile(e0, e1, profile->mVerts, isCurrentlyInside, intersected_boundary);
-                // sort the hits by distance from e0 to get the correct in/out/in sequence. Manually :-( I miss you, C++11.
-                if (intersected_boundary.size() > 1) {
-                    bool keepSorting = true;
-                    while (keepSorting) {
-                        keepSorting = false;
-                        for (size_t b = 0; b < intersected_boundary.size() - 1; ++b) {
-                            if ((intersected_boundary[b + 1].second - e0).SquareLength() < (intersected_boundary[b].second - e0).SquareLength()) {
-                                keepSorting = true;
-                                std::swap(intersected_boundary[b + 1], intersected_boundary[b]);
-                            }
-                        }
-                    }
-                }
-                // now add them to the list of intersections
-                for (size_t b = 0; b < intersected_boundary.size(); ++b)
-                    intersections.push_back(std::make_tuple(a, proj_inv * intersected_boundary[b].second, intersected_boundary[b].first));
-
-                // and calculate our new inside/outside state
-                if (intersected_boundary.size() & 1)
-                    isCurrentlyInside = !isCurrentlyInside;
-            }
-
-            // we got a list of in-out-combinations of intersections. That should be an even number of intersections, or
-            // we are facing a non-recoverable error.
-            if ((intersections.size() & 1) != 0) {
-                IFCImporter::LogWarn("Odd number of intersections, can't work with that. Omitting half space boundary check.");
-                continue;
-            }
-
-            if (intersections.size() > 1) {
-                // If we started outside, the first intersection is a out->in intersection. Cycle them so that it
-                // starts with an intersection leaving the boundary
-                if (!startedInside)
-                    for (size_t b = 0; b < intersections.size() - 1; ++b)
-                        std::swap(intersections[b], intersections[(b + intersections.size() - 1) % intersections.size()]);
-
-                // Filter pairs of out->in->out that lie too close to each other.
-                for (size_t a = 0; intersections.size() > 0 && a < intersections.size() - 1; /**/) {
-                    if ((std::get<1>(intersections[a]) - std::get<1>(intersections[(a + 1) % intersections.size()])).SquareLength() < 1e-10)
-                        intersections.erase(intersections.begin() + a, intersections.begin() + a + 2);
-                    else
-                        a++;
-                }
-                if (intersections.size() > 1 && (std::get<1>(intersections.back()) - std::get<1>(intersections.front())).SquareLength() < 1e-10) {
-                    intersections.pop_back();
-                    intersections.erase(intersections.begin());
-                }
-            }
-
-            // no intersections at all: either completely inside the boundary, so everything gets discarded, or completely outside.
-            // in the latter case we're implementional lost. I'm simply going to ignore this, so a large poly will not get any
-            // holes if the boundary is smaller and does not touch it anywhere.
-            if (intersections.empty()) {
-                // starting point was outside -> everything is outside the boundary -> nothing is clipped -> add black side
-                // to result mesh unchanged
-                if (!startedInside) {
-                    outvertcnt.push_back(static_cast<unsigned int>(blackside.size()));
-                    outvert.insert(outvert.end(), blackside.begin(), blackside.end());
-                    continue;
-                } else {
-                    // starting point was inside the boundary -> everything is inside the boundary -> nothing is spared from the
-                    // clipping -> nothing left to add to the result mesh
-                    continue;
-                }
-            }
-
-            // determine the direction in which we're marching along the boundary polygon. If the src poly is faced upwards
-            // and the boundary is also winded this way, we need to march *backwards* on the boundary.
-            const IfcVector3 polyNormal = IfcMatrix3(proj) * TempMesh::ComputePolygonNormal(blackside.data(), blackside.size());
-            bool marchBackwardsOnBoundary = (profileNormal * polyNormal) >= 0.0;
-
-            // Build closed loops from these intersections. Starting from an intersection leaving the boundary we
-            // walk along the polygon to the next intersection (which should be an IS entering the boundary poly).
-            // From there we walk along the boundary until we hit another intersection leaving the boundary,
-            // walk along the poly to the next IS and so on until we're back at the starting point.
-            // We remove every intersection we "used up", so any remaining intersection is the start of a new loop.
-            while (!intersections.empty()) {
-                std::vector<IfcVector3> resultpoly;
-                size_t currentIntersecIdx = 0;
-
-                while (true) {
-                    ai_assert(intersections.size() > currentIntersecIdx + 1);
-                    std::tuple<size_t, IfcVector3, size_t> currintsec = intersections[currentIntersecIdx + 0];
-                    std::tuple<size_t, IfcVector3, size_t> nextintsec = intersections[currentIntersecIdx + 1];
-                    intersections.erase(intersections.begin() + currentIntersecIdx, intersections.begin() + currentIntersecIdx + 2);
-
-                    // we start with an in->out intersection
-                    resultpoly.push_back(std::get<1>(currintsec));
-                    // climb along the polygon to the next intersection, which should be an out->in
-                    size_t numPolyPoints = (std::get<0>(currintsec) > std::get<0>(nextintsec) ? blackside.size() : 0) + std::get<0>(nextintsec) - std::get<0>(currintsec);
-                    for (size_t a = 1; a <= numPolyPoints; ++a)
-                        resultpoly.push_back(blackside[(std::get<0>(currintsec) + a) % blackside.size()]);
-                    // put the out->in intersection
-                    resultpoly.push_back(std::get<1>(nextintsec));
-
-                    // generate segments along the boundary polygon that lie in the poly's plane until we hit another intersection
-                    IfcVector3 startingPoint = proj * std::get<1>(nextintsec);
-                    size_t currentBoundaryEdgeIdx = (std::get<2>(nextintsec) + (marchBackwardsOnBoundary ? 1 : 0)) % profile->mVerts.size();
-                    size_t nextIntsecIdx = SIZE_MAX;
-                    while (nextIntsecIdx == SIZE_MAX) {
-                        IfcFloat t = 1e10;
-
-                        size_t nextBoundaryEdgeIdx = marchBackwardsOnBoundary ? (currentBoundaryEdgeIdx + profile->mVerts.size() - 1) : currentBoundaryEdgeIdx + 1;
-                        nextBoundaryEdgeIdx %= profile->mVerts.size();
-                        // vertices of the current boundary segments
-                        IfcVector3 currBoundaryPoint = profile->mVerts[currentBoundaryEdgeIdx];
-                        IfcVector3 nextBoundaryPoint = profile->mVerts[nextBoundaryEdgeIdx];
-                        // project the two onto the polygon
-                        if (std::abs(polyNormal.z) > 1e-5) {
-                            currBoundaryPoint.z = startingPoint.z + (currBoundaryPoint.x - startingPoint.x) * polyNormal.x / polyNormal.z + (currBoundaryPoint.y - startingPoint.y) * polyNormal.y / polyNormal.z;
-                            nextBoundaryPoint.z = startingPoint.z + (nextBoundaryPoint.x - startingPoint.x) * polyNormal.x / polyNormal.z + (nextBoundaryPoint.y - startingPoint.y) * polyNormal.y / polyNormal.z;
-                        }
-
-                        // build a direction that goes along the boundary border but lies in the poly plane
-                        IfcVector3 boundaryPlaneNormal = ((nextBoundaryPoint - currBoundaryPoint) ^ profileNormal).Normalize();
-                        IfcVector3 dirAtPolyPlane = (boundaryPlaneNormal ^ polyNormal).Normalize() * (marchBackwardsOnBoundary ? -1.0 : 1.0);
-                        // if we can project the direction to the plane, we can calculate a maximum marching distance along that dir
-                        // until we finish that boundary segment and continue on the next
-                        if (std::abs(polyNormal.z) > 1e-5) {
-                            t = std::min(t, (nextBoundaryPoint - startingPoint).Length());
-                        }
-
-                        // check if the direction hits the loop start - if yes, we got a poly to output
-                        IfcVector3 dirToThatPoint = proj * resultpoly.front() - startingPoint;
-                        IfcFloat tpt = dirToThatPoint * dirAtPolyPlane;
-                        if (tpt > -1e-6 && tpt <= t && (dirToThatPoint - tpt * dirAtPolyPlane).SquareLength() < 1e-10) {
-                            nextIntsecIdx = intersections.size(); // dirty hack to end marching along the boundary and signal the end of the loop
-                            t = tpt;
-                        }
-
-                        // also check if the direction hits any in->out intersections earlier. If we hit one, we can switch back
-                        // to marching along the poly border from that intersection point
-                        for (size_t a = 0; a < intersections.size(); a += 2) {
-                            dirToThatPoint = proj * std::get<1>(intersections[a]) - startingPoint;
-                            tpt = dirToThatPoint * dirAtPolyPlane;
-                            if (tpt > -1e-6 && tpt <= t && (dirToThatPoint - tpt * dirAtPolyPlane).SquareLength() < 1e-10) {
-                                nextIntsecIdx = a; // switch back to poly and march on from this in->out intersection
-                                t = tpt;
-                            }
-                        }
-
-                        // if we keep marching on the boundary, put the segment end point to the result poly and well... keep marching
-                        if (nextIntsecIdx == SIZE_MAX) {
-                            resultpoly.push_back(proj_inv * nextBoundaryPoint);
-                            currentBoundaryEdgeIdx = nextBoundaryEdgeIdx;
-                            startingPoint = nextBoundaryPoint;
-                        }
-
-                        // quick endless loop check
-                        if (resultpoly.size() > blackside.size() + profile->mVerts.size()) {
-                            IFCImporter::LogError("Encountered endless loop while clipping polygon against poly-bounded half space.");
-                            break;
-                        }
-                    }
-
-                    // we're back on the poly - if this is the intersection we started from, we got a closed loop.
-                    if (nextIntsecIdx >= intersections.size()) {
-                        break;
-                    }
-
-                    // otherwise it's another intersection. Continue marching from there.
-                    currentIntersecIdx = nextIntsecIdx;
-                }
-
-                WritePolygon(resultpoly, result);
-            }
-        }
-    }
-    IFCImporter::LogVerboseDebug("generating CSG geometry by plane clipping with polygonal bounding (IfcBooleanClippingResult)");
-}
-
-// ------------------------------------------------------------------------------------------------
-void ProcessBooleanExtrudedAreaSolidDifference(const Schema_2x3::IfcExtrudedAreaSolid *as, TempMesh &result,
-        const TempMesh &first_operand,
-        ConversionData &conv) {
-    ai_assert(as != nullptr);
-
-    // This case is handled by reduction to an instance of the quadrify() algorithm.
-    // Obviously, this won't work for arbitrarily complex cases. In fact, the first
-    // operand should be near-planar. Luckily, this is usually the case in Ifc
-    // buildings.
-
-    std::shared_ptr<TempMesh> meshtmp = std::shared_ptr<TempMesh>(new TempMesh());
-    ProcessExtrudedAreaSolid(*as, *meshtmp, conv, false);
-
-    std::vector<TempOpening> openings(1, TempOpening(as, IfcVector3(0, 0, 0), meshtmp, std::shared_ptr<TempMesh>()));
-
-    result = first_operand;
-
-    TempMesh temp;
-
-    std::vector<IfcVector3>::const_iterator vit = first_operand.mVerts.begin();
-    for (unsigned int pcount : first_operand.mVertcnt) {
-        temp.Clear();
-
-        temp.mVerts.insert(temp.mVerts.end(), vit, vit + pcount);
-        temp.mVertcnt.push_back(pcount);
-
-        // The algorithms used to generate mesh geometry sometimes
-        // spit out lines or other degenerates which must be
-        // filtered to avoid running into assertions later on.
-
-        // ComputePolygonNormal returns the Newell normal, so the
-        // length of the normal is the area of the polygon.
-        const IfcVector3 &normal = temp.ComputeLastPolygonNormal(false);
-        if (normal.SquareLength() < static_cast<IfcFloat>(1e-5)) {
-            IFCImporter::LogWarn("skipping degenerate polygon (ProcessBooleanExtrudedAreaSolidDifference)");
-            continue;
-        }
-
-        GenerateOpenings(openings, temp, false, true);
-        result.Append(temp);
-
-        vit += pcount;
-    }
-
-    IFCImporter::LogVerboseDebug("generating CSG geometry by geometric difference to a solid (IfcExtrudedAreaSolid)");
-}
-
-// ------------------------------------------------------------------------------------------------
-void ProcessBoolean(const Schema_2x3::IfcBooleanResult &boolean, TempMesh &result, ConversionData &conv) {
-    // supported CSG operations:
-    //   DIFFERENCE
-    if (const Schema_2x3::IfcBooleanResult *const clip = boolean.ToPtr<Schema_2x3::IfcBooleanResult>()) {
-        if (clip->Operator != "DIFFERENCE") {
-            IFCImporter::LogWarn("encountered unsupported boolean operator: ", (std::string)clip->Operator);
-            return;
-        }
-
-        // supported cases (1st operand):
-        //  IfcBooleanResult -- call ProcessBoolean recursively
-        //  IfcSweptAreaSolid -- obtain polygonal geometry first
-
-        // supported cases (2nd operand):
-        //  IfcHalfSpaceSolid -- easy, clip against plane
-        //  IfcExtrudedAreaSolid -- reduce to an instance of the quadrify() algorithm
-
-        const Schema_2x3::IfcHalfSpaceSolid *const hs = clip->SecondOperand->ResolveSelectPtr<Schema_2x3::IfcHalfSpaceSolid>(conv.db);
-        const Schema_2x3::IfcExtrudedAreaSolid *const as = clip->SecondOperand->ResolveSelectPtr<Schema_2x3::IfcExtrudedAreaSolid>(conv.db);
-        if (!hs && !as) {
-            IFCImporter::LogError("expected IfcHalfSpaceSolid or IfcExtrudedAreaSolid as second clipping operand");
-            return;
-        }
-
-        TempMesh first_operand;
-        if (const Schema_2x3::IfcBooleanResult *const op0 = clip->FirstOperand->ResolveSelectPtr<Schema_2x3::IfcBooleanResult>(conv.db)) {
-            ProcessBoolean(*op0, first_operand, conv);
-        } else if (const Schema_2x3::IfcSweptAreaSolid *const swept = clip->FirstOperand->ResolveSelectPtr<Schema_2x3::IfcSweptAreaSolid>(conv.db)) {
-            ProcessSweptAreaSolid(*swept, first_operand, conv);
-        } else {
-            IFCImporter::LogError("expected IfcSweptAreaSolid or IfcBooleanResult as first clipping operand");
-            return;
-        }
-
-        if (hs) {
-
-            const Schema_2x3::IfcPolygonalBoundedHalfSpace *const hs_bounded = clip->SecondOperand->ResolveSelectPtr<Schema_2x3::IfcPolygonalBoundedHalfSpace>(conv.db);
-            if (hs_bounded) {
-                ProcessPolygonalBoundedBooleanHalfSpaceDifference(hs_bounded, result, first_operand, conv);
-            } else {
-                ProcessBooleanHalfSpaceDifference(hs, result, first_operand, conv);
-            }
-        } else {
-            ProcessBooleanExtrudedAreaSolidDifference(as, result, first_operand, conv);
-        }
-    } else {
-        IFCImporter::LogWarn("skipping unknown IfcBooleanResult entity, type is ", boolean.GetClassName());
-    }
-}
-
-} // namespace IFC
-} // namespace Assimp
-
-#endif