Function findDisorientedFaces

source/MRMesh/MRMeshFixer.cpp:302–371

}

Expected<FaceBitSet> findDisorientedFaces( const Mesh& mesh, const FindDisorientationParams& params )
{
    MR_TIMER;
    auto disorientedFaces = mesh.topology.getValidFaces();

    Mesh cpyMesh;
    const Mesh* targetMesh{ &mesh };
    EdgeBitSet outHoles;
    if ( params.virtualFillHoles && mesh.topology.findNumHoles( &outHoles ) > 0 )
    {
        cpyMesh = mesh;
        targetMesh = &cpyMesh;
        auto sb = subprogress( params.cb, 0.0f, 0.5f );
        int i = 0;
        int num = int( outHoles.count() );
        auto metric = getMinAreaMetric( mesh );
        for ( auto e : outHoles )
        {
            ++i;
            fillHole( cpyMesh, e, { .metric = metric } ); // use simplest filling
            if ( !reportProgress( sb, float( i ) / float( num ) ) )
                return unexpectedOperationCanceled();
        }
    }

    auto sb = subprogress( params.cb, targetMesh == &mesh ? 0.0f : 0.5f, 1.0f );

    auto keepGoing = BitSetParallelFor( mesh.topology.getValidFaces(), [&] ( FaceId f )
    {
        auto normal = Vector3d( mesh.normal( f ) );
        auto triCenter = Vector3d( mesh.triCenter( f ) );
        int counter = 0;
        auto interPred = [f, &counter] ( const MeshIntersectionResult& res )->bool
        {
            if ( res.proj.face != f ) // TODO: we should also try grouping intersections, to ignore too close ones (by some epsilon), to filter several layered areas
                ++counter;
            return true;
        };
        rayMeshIntersectAll( *targetMesh, Line3d( triCenter, normal ), interPred );
        bool pValid = counter % 2 == 0;
        auto pCounter = counter;
        bool nValid = true;
        int nCounter = INT_MAX;
        bool resValid = pValid;
        if ( params.mode != FindDisorientationParams::RayMode::Positive )
        {
            counter = 0;
            rayMeshIntersectAll( *targetMesh, Line3d( triCenter, -normal ), interPred );
            nValid = counter % 2 == 1;
            nCounter = counter - 1; // ideal face has 0-pCounter and 1-nCounter: so we decrement nCounter for fair compare

            resValid = pValid && nValid;
            if ( params.mode == FindDisorientationParams::RayMode::Shallowest && pValid != nValid )
            {
                if ( pCounter == nCounter )
                    resValid = true;
                else if ( nCounter < pCounter )
                    resValid = nValid;