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Diffstat (limited to 'libs/assimp/code/AssetLib/IFC/IFCBoolean.cpp')
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diff --git a/libs/assimp/code/AssetLib/IFC/IFCBoolean.cpp b/libs/assimp/code/AssetLib/IFC/IFCBoolean.cpp new file mode 100644 index 0000000..36912a7 --- /dev/null +++ b/libs/assimp/code/AssetLib/IFC/IFCBoolean.cpp @@ -0,0 +1,765 @@ +/* +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 |