Function findSignedDistance

source/MRMesh/MRMeshMeshDistance.cpp:213–274

}

MeshMeshSignedDistanceResult findSignedDistance( const MeshPart & a, const MeshPart & b, const AffineXf3f* rigidB2A, float upDistLimitSq )
{
    MR_TIMER;
    auto res = findDistance( a, b, rigidB2A, upDistLimitSq > 0.0f ? upDistLimitSq : FLT_TRUE_MIN );
    if ( res.distSq == FLT_TRUE_MIN )
        res.distSq = 0.0f;
    if ( !res.a || !res.b )
    {   // findDistance returns the limit sentinel when nothing closer was found
        assert( res.distSq == upDistLimitSq );
        return { res.a, res.b, MeshMeshCollisionStatus::NotColliding, std::sqrt( res.distSq ) };
    }
    assert( res.distSq == 0.0f || res.distSq < upDistLimitSq );
    std::vector<FaceFace> collisions;
    auto status = findCollisionStatus( a, b, res, rigidB2A, &collisions );
    if ( status == MeshMeshCollisionStatus::Touching )
        return { res.a, res.b,status, 0 }; // two meshes touch one another but do not intersect
    if ( status != MeshMeshCollisionStatus::Colliding )
    {
        auto dist = status == MeshMeshCollisionStatus::BothOutside ? std::sqrt( res.distSq ) : -std::sqrt( res.distSq );
        return { res.a, res.b,status, dist };
    }

    // colliding

    auto zoneAndDistancesAB = findSignedDistanceOneWay( a, b, collisions, false, rigidB2A );
    auto zoneAndDistancesBA = findSignedDistanceOneWay( a, b, collisions, true, rigidB2A );

    MeshMeshSignedDistanceResult signedRes;
    signedRes.status = status;
    signedRes.signedDist = FLT_MAX;

    auto getTriByVert = [&]( const MeshTopology& topology, VertId id )->FaceId
    {
        for ( auto e : orgRing( topology, id ) )
            if ( auto f = topology.left( e ) )
                return f;
        return FaceId{};
    };

    for ( VertId id : zoneAndDistancesAB.vertBS )
    {
        const auto& [proj, dist] = zoneAndDistancesAB.projectons[id];
        if ( proj.valid() && dist < signedRes.signedDist )
        {
            signedRes.a = { getTriByVert( a.mesh.topology,id ), a.mesh.points[id] };
            signedRes.b = proj;
            signedRes.signedDist = dist;
        }
    }

    for ( VertId id : zoneAndDistancesBA.vertBS )
    {
        const auto& [proj, dist] = zoneAndDistancesBA.projectons[id];
        if ( proj.valid() && dist < signedRes.signedDist )
        {
            signedRes.a = proj;
            signedRes.b = { getTriByVert( b.mesh.topology,id ), b.mesh.points[id] };
            signedRes.signedDist = dist;