#include <set>
#include <regex>
#include <mystdlib.h>
#include "global.hpp"
#include "debugging.hpp"
#include "boundarylayer.hpp"
#include "meshfunc.hpp"
namespace netgen
{
// checks if a segment is intersecting a plane, spanned by three points, lam will be set s.t. p_intersect = seg[0] + lam * (seg[1]-seg[0])
bool isIntersectingPlane ( const array<Point<3>, 2> & seg, const array<Point<3>, 3> & trig, double & lam)
{
auto n = Cross(trig[1]-trig[0], trig[2]-trig[0]);
auto v0n = (seg[0]-trig[0])*n;
auto v1n = (seg[1]-trig[0])*n;
if(v0n * v1n >= 0)
return false;
lam = -v0n/(v1n-v0n);
lam *= 0.9;
if(lam < -1e-8 || lam>1+1e-8)
return false;
return true;
}
bool isIntersectingPlane ( const array<Point<3>, 2> & seg, const ArrayMem<Point<3>, 4> & face, double & lam)
{
lam = 1.0;
bool intersect0 = isIntersectingPlane( seg, array<Point<3>, 3>{face[0], face[1], face[2]}, lam );
if(face.Size()==3)
return intersect0;
double lam1 = 1.0;
bool intersect1 = isIntersectingPlane( seg, array<Point<3>, 3>{face[2], face[3], face[0]}, lam1 );
lam = min(lam, lam1);
return intersect0 || intersect1;
}
bool isIntersectingTrig ( const array<Point<3>, 2> & seg, const array<Point<3>, 3> & trig, double & lam)
{
if(!isIntersectingPlane(seg, trig, lam))
return false;
//buffer enlargement of triangle
auto pt0 = trig[0];
auto pt1 = trig[1];
auto pt2 = trig[2];
Point<3> center = { (pt0[0] + pt1[0] + pt2[0]) / 3.0, (pt0[1] + pt1[1] + pt2[1]) / 3.0, (pt0[2] + pt1[2] + pt2[2]) / 3.0 };
array<Point<3>, 3> larger_trig = {
center + (pt0 - center) * 1.1,
center + (pt1 - center) * 1.1,
center + (pt2 - center) * 1.1, };
auto p = seg[0] + lam/0.9*(seg[1]-seg[0]);
auto n_trig = Cross(trig[1]-trig[0], trig[2]-trig[0]).Normalize();
for(auto i : Range(3))
{
// check if p0 and p are on same side of segment p1-p2
auto p0 = larger_trig[i];
auto p1 = larger_trig[(i+1)%3];
auto p2 = larger_trig[(i+2)%3];
// auto n = Cross(p2-p1, n_trig);
auto v0 = (p2-p1).Normalize();
auto v1 = (p0-p1).Normalize();
auto inside_dir = (v1 - (v1*v0) * v0).Normalize();
auto v2 = (p-p1).Normalize();
if(inside_dir * v1 < 0)
inside_dir = -inside_dir;
if( (inside_dir*v2) < 0 )
return false;
}
return true;
};
bool isIntersectingFace( const array<Point<3>, 2> & seg, const ArrayMem<Point<3>, 4> & face, double & lam )
{
lam = 1.0;
double lam0 = 1.0;
bool intersect0 = isIntersectingTrig( seg, {face[0], face[1], face[2]}, lam0 );
if(intersect0)
lam = min(lam, lam0);
if(face.Size()==3)
return intersect0;
double lam1 = 1.0;
bool intersect1 = isIntersectingTrig( seg, {face[2], face[3], face[0]}, lam1 );
if(intersect1)
lam = min(lam, lam1);
return intersect0 || intersect1;
}
array<Point<3>, 2> BoundaryLayerTool :: GetMappedSeg( PointIndex pi )
{
return { mesh[pi], mesh[pi] + height*limits[pi]*growthvectors[pi] * 1.5 };
}
ArrayMem<Point<3>, 4> BoundaryLayerTool :: GetFace( SurfaceElementIndex sei )
{
const auto & sel = mesh[sei];
ArrayMem<Point<3>, 4> points(sel.GetNP());
for(auto i : Range(sel.GetNP()))
points[i] = mesh[sel[i]];
return points;
}
ArrayMem<Point<3>, 4> BoundaryLayerTool :: GetMappedFace( SurfaceElementIndex sei )
{
const auto & sel = mesh[sei];
ArrayMem<Point<3>, 4> points(sel.GetNP());
for(auto i : Range(sel.GetNP()))
points[i] = mesh[sel[i]] + height * limits[sel[i]]*growthvectors[sel[i]];
return points;
}
ArrayMem<Point<3>, 4> BoundaryLayerTool :: GetMappedFace( SurfaceElementIndex sei, int face )
{
if(face == -1) return GetFace(sei);
if(face == -2) return GetMappedFace(sei);
const auto & sel = mesh[sei];
auto np = sel.GetNP();
auto pi0 = sel[face % np];
auto pi1 = sel[(face+1) % np];
ArrayMem<Point<3>, 4> points(4);
points[0] = points[3] = mesh[pi0];
points[1] = points[2] = mesh[pi1];
points[3] += height * limits[pi0]*growthvectors[pi0];
points[2] += height * limits[pi1]*growthvectors[pi1];
return points;
}
Vec<3> BoundaryLayerTool :: getEdgeTangent(PointIndex pi, int edgenr)
{
Vec<3> tangent = 0.0;
ArrayMem<PointIndex,2> pts;
for(auto segi : topo.GetVertexSegments(pi))
{
auto & seg = mesh[segi];
if(seg.edgenr != edgenr+1)
continue;
PointIndex other = seg[0]+seg[1]-pi;
if(!pts.Contains(other))
pts.Append(other);
}
if(pts.Size() != 2)
throw Exception("Something went wrong in getEdgeTangent!");
tangent = mesh[pts[1]] - mesh[pts[0]];
return tangent.Normalize();
}
void BoundaryLayerTool :: LimitGrowthVectorLengths()
{
static Timer tall("BoundaryLayerTool::LimitGrowthVectorLengths"); RegionTimer rtall(tall);
limits.SetSize(np);
limits = 1.0;
// Function to calculate the dot product of two 3D vectors
// Is there netgen native function for this?
const auto Dot = [](Vec<3> a, Vec<3> b) {
return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
};
auto parallel_limiter = [&](PointIndex pi1, PointIndex pi2, SurfaceElementIndex si) {
MeshPoint& a_base = mesh[pi1];
MeshPoint& b_base = mesh[pi2];
MeshPoint a_end = mesh[pi1] + height * limits[pi1] * growthvectors[pi1];
MeshPoint b_end = mesh[pi2] + height * limits[pi2] * growthvectors[pi2];
double ab_base = (b_base - a_base).Length();
Vec<3> a_vec = (a_end - a_base);
Vec<3> b_vec = (b_end - b_base);
// Calculate parallel projections
Vec<3> ab_base_norm = (b_base - a_base).Normalize();
double a_vec_x = Dot(a_vec, ab_base_norm);
double b_vec_x = Dot(b_vec, -ab_base_norm);
double ratio_parallel = (a_vec_x + b_vec_x) / ab_base;
double PARALLEL_RATIO_LIMIT = 0.85;
if (ratio_parallel > PARALLEL_RATIO_LIMIT) {
// Adjust limits, vectors, and projections if parallel ratio exceeds the limit
double corrector = PARALLEL_RATIO_LIMIT / ratio_parallel;
limits[pi1] *= corrector;
limits[pi2] *= corrector;
}
};
auto perpendicular_limiter = [&](PointIndex pi1, PointIndex pi2, SurfaceElementIndex si) {
// this part is same as in parallel limiter, but note that limits contents are already changed
MeshPoint& a_base = mesh[pi1];
MeshPoint& b_base = mesh[pi2];
MeshPoint a_end = mesh[pi1] + height * limits[pi1] * growthvectors[pi1];
MeshPoint b_end = mesh[pi2] + height * limits[pi2] * growthvectors[pi2];
double ab_base = (b_base - a_base).Length();
Vec<3> a_vec = (a_end - a_base);
Vec<3> b_vec = (b_end - b_base);
// Calculate parallel projections
Vec<3> ab_base_norm = (b_base - a_base).Normalize();
double a_vec_x = Dot(a_vec, ab_base_norm);
double b_vec_x = Dot(b_vec, -ab_base_norm);
// double ratio_parallel = (a_vec_x + b_vec_x) / ab_base;
// Calculate surface normal at point si
Vec<3> surface_normal = getNormal(mesh[si]);
double a_vec_y = abs(Dot(a_vec, surface_normal));
double b_vec_y = abs(Dot(b_vec, surface_normal));
double diff_perpendicular = abs(a_vec_y - b_vec_y);
double tan_alpha = diff_perpendicular / (ab_base - a_vec_x - b_vec_x);
double TAN_ALPHA_LIMIT = 0.36397; // Approximately 20 degrees in radians
if (tan_alpha > TAN_ALPHA_LIMIT) {
if (a_vec_y > b_vec_y) {
double correction = (TAN_ALPHA_LIMIT / tan_alpha * diff_perpendicular + b_vec_y) / a_vec_y;
limits[pi1] *= correction;
}
else {
double correction = (TAN_ALPHA_LIMIT / tan_alpha * diff_perpendicular + a_vec_y) / b_vec_y;
limits[pi2] *= correction;
}
}
};
auto neighbour_limiter = [&](PointIndex pi1, PointIndex pi2, SurfaceElementIndex si) {
parallel_limiter(pi1, pi2, si);
perpendicular_limiter(pi1, pi2, si);
};
auto modifiedsmooth = [&](size_t nsteps) {
for ([[maybe_unused]] auto i : Range(nsteps))
for (SurfaceElementIndex sei : mesh.SurfaceElements().Range())
{
// assuming triangle
neighbour_limiter(mesh[sei].PNum(1), mesh[sei].PNum(2), sei);
neighbour_limiter(mesh[sei].PNum(2), mesh[sei].PNum(3), sei);
neighbour_limiter(mesh[sei].PNum(3), mesh[sei].PNum(1), sei);
}
};
/*
auto smooth = [&] (size_t nsteps) {
for([[maybe_unused]] auto i : Range(nsteps))
for(const auto & sel : mesh.SurfaceElements())
{
double min_limit = 999;
for(auto pi : sel.PNums())
min_limit = min(min_limit, limits[pi]);
for(auto pi : sel.PNums())
limits[pi] = min(limits[pi], 1.4*min_limit);
}
};
*/
// check for self-intersection within new elements (prisms/hexes)
auto self_intersection = [&] () {
for(SurfaceElementIndex sei : mesh.SurfaceElements().Range())
{
auto facei = mesh[sei].GetIndex();
if(facei < nfd_old && !params.surfid.Contains(facei))
continue;
auto sel = mesh[sei];
auto np = sel.GetNP();
// check if a new edge intesects the plane of any opposing face
double lam;
for(auto i : Range(np))
for(auto fi : Range(np-2))
if(isIntersectingPlane(GetMappedSeg(sel[i]), GetMappedFace(sei, i+fi+1), lam))
if(lam < 1.0)
limits[sel[i]] *= lam;
}
};
// first step: intersect with other surface elements that are boundary of domain the layer is grown into
// second (and subsequent) steps: intersect with other boundary layers, allow restriction by 20% in each step
auto changed_domains = domains;
if(!params.outside)
changed_domains.Invert();
bool limit_reached = true;
double lam_lower_limit = 1.0;
int step = 0;
while(limit_reached || step<3)
{
Array<double, PointIndex> new_limits;
new_limits.SetSize(np);
new_limits = 1.0;
if(step>1)
lam_lower_limit *= 0.8;
limit_reached = false;
// build search tree with all surface elements (bounding box of a surface element also covers the generated boundary layer)
Box<3> bbox(Box<3>::EMPTY_BOX);
for(auto pi : mesh.Points().Range())
{
bbox.Add(mesh[pi]);
bbox.Add(mesh[pi]+limits[pi]*height*growthvectors[pi]);
}
BoxTree<3> tree(bbox);
for(auto sei : mesh.SurfaceElements().Range())
{
const auto & sel = mesh[sei];
Box<3> box(Box<3>::EMPTY_BOX);
const auto& fd = mesh.GetFaceDescriptor(sel.GetIndex());
if(!changed_domains.Test(fd.DomainIn()) &&
!changed_domains.Test(fd.DomainOut()))
continue;
for(auto pi : sel.PNums())
box.Add(mesh[pi]);
// also add moved points to bounding box
if(params.surfid.Contains(sel.GetIndex()))
for(auto pi : sel.PNums())
box.Add(mesh[pi]+limits[pi]*height*growthvectors[pi]);
tree.Insert(box, sei);
}
for(auto pi : mesh.Points().Range())
{
if(mesh[pi].Type() == INNERPOINT)
continue;
if(growthvectors[pi].Length2() == 0.0)
continue;
Box<3> box(Box<3>::EMPTY_BOX);
auto seg = GetMappedSeg(pi);
box.Add(seg[0]);
box.Add(seg[1]);
double lam = 1.0;
tree.GetFirstIntersecting(box.PMin(), box.PMax(), [&](SurfaceElementIndex sei)
{
const auto & sel = mesh[sei];
if(sel.PNums().Contains(pi))
return false;
auto face = GetMappedFace(sei, -2);
double lam_ = 999;
bool is_bl_sel = params.surfid.Contains(sel.GetIndex());
if (step == 0)
{
face = GetMappedFace(sei, -1);
if (isIntersectingFace(seg, face, lam_))
{
if (is_bl_sel)
lam_ *= params.limit_safety;
lam = min(lam, lam_);
}
}
if(step==1)
{
if(isIntersectingFace(seg, face, lam_))
{
if(is_bl_sel) // allow only half the distance if the opposing surface element has a boundary layer too
lam_ *= params.limit_safety;
lam = min(lam, lam_);
}
}
// if the opposing surface element has a boundary layer, we need to additionally intersect with the new faces
if(step>1 && is_bl_sel)
{
for(auto facei : Range(-1, sel.GetNP()))
{
auto face = GetMappedFace(sei, facei);
if(isIntersectingFace(seg, face, lam_)) // && lam_ > other_limit)
{
lam = min(lam, lam_);
}
}
}
return false;
});
if(lam<1)
{
if(lam<lam_lower_limit && step>1)
{
limit_reached = true;
lam = lam_lower_limit;
}
}
new_limits[pi] = min(limits[pi], lam* limits[pi]);
}
step++;
limits = new_limits;
if (step > 0)
modifiedsmooth(1);
}
self_intersection();
modifiedsmooth(1);
for(auto pi : Range(growthvectors))
growthvectors[pi] *= limits[pi];
}
// depending on the geometry type, the mesh contains segments multiple times (once for each face)
bool HaveSingleSegments( const Mesh & mesh )
{
auto& topo = mesh.GetTopology();
NgArray<SurfaceElementIndex> surf_els;
for(auto segi : Range(mesh.LineSegments()))
{
mesh.GetTopology().GetSegmentSurfaceElements(segi+1, surf_els);
if(surf_els.Size()<2)
continue;
auto seg = mesh[segi];
auto pi0 = min(seg[0], seg[1]);
auto pi1 = max(seg[0], seg[1]);
auto p0_segs = topo.GetVertexSegments(seg[0]);
for(auto segi_other : p0_segs)
{
if(segi_other == segi)
continue;
auto seg_other = mesh[segi_other];
auto pi0_other = min(seg_other[0], seg_other[1]);
auto pi1_other = max(seg_other[0], seg_other[1]);
if( pi0_other == pi0 && pi1_other == pi1 )
return false;
}
// found segment with multiple adjacent surface elements but no other segments with same points -> have single segments
return true;
}
return true;
}
// duplicates segments (and sets seg.si accordingly) to have a unified data structure for all geometry types
Array<Segment> BuildSegments( Mesh & mesh )
{
Array<Segment> segments;
// auto& topo = mesh.GetTopology();
NgArray<SurfaceElementIndex> surf_els;
for(auto segi : Range(mesh.LineSegments()))
{
auto seg = mesh[segi];
mesh.GetTopology().GetSegmentSurfaceElements(segi+1, surf_els);
for(auto seli : surf_els)
{
const auto & sel = mesh[seli];
seg.si = sel.GetIndex();
auto np = sel.GetNP();
for(auto i : Range(np))
{
if(sel[i] == seg[0])
{
if(sel[(i+1)%np] != seg[1])
swap(seg[0], seg[1]);
break;
}
}
segments.Append(seg);
}
}
return segments;
}
void MergeAndAddSegments( Mesh & mesh, FlatArray<Segment> new_segments)
{
INDEX_2_HASHTABLE<bool> already_added( mesh.LineSegments().Size() + 2*new_segments.Size() );
for(auto & seg : mesh.LineSegments())
{
INDEX_2 i2 (seg[0], seg[1]);
i2.Sort();
if(!already_added.Used(i2))
already_added.Set(i2, true);
}
for(auto & seg : new_segments)
{
INDEX_2 i2 (seg[0], seg[1]);
i2.Sort();
if(!already_added.Used(i2))
{
mesh.AddSegment(seg);
already_added.Set(i2, true);
}
}
}
void BoundaryLayerTool :: InterpolateSurfaceGrowthVectors()
{
static Timer tall("InterpolateSurfaceGrowthVectors"); RegionTimer rtall(tall);
static Timer tsmooth("InterpolateSurfaceGrowthVectors-Smoothing");
auto np = mesh.GetNP();
BitArray is_point_on_bl_surface(np+1);
is_point_on_bl_surface.Clear();
BitArray is_point_on_other_surface(np+1);
is_point_on_other_surface.Clear();
Array<Vec<3>, PointIndex> normals(np);
for(auto pi : Range(growthvectors))
normals[pi] = growthvectors[pi];
ParallelForRange( mesh.SurfaceElements().Range(), [&] ( auto myrange )
{
for(SurfaceElementIndex sei : myrange)
{
auto facei = mesh[sei].GetIndex();
if(facei < nfd_old && !params.surfid.Contains(facei))
{
for(auto pi : mesh[sei].PNums())
if(mesh[pi].Type() == SURFACEPOINT)
is_point_on_other_surface.SetBitAtomic(pi);
}
else
{
for(auto pi : mesh[sei].PNums())
if(mesh[pi].Type() == SURFACEPOINT)
is_point_on_bl_surface.SetBitAtomic(pi);
}
}
});
Array<PointIndex> points;
for(PointIndex pi : mesh.Points().Range())
{
if(is_point_on_bl_surface[pi])
{
points.Append(pi);
growthvectors[pi] = 0.0;
}
if(is_point_on_other_surface[pi])
{
points.Append(pi);
}
}
// smooth tangential part of growth vectors from edges to surface elements
RegionTimer rtsmooth(tsmooth);
for([[maybe_unused]] auto i : Range(10))
{
for(auto pi : points)
{
auto sels = p2sel[pi];
Vec<3> new_gw = growthvectors[pi];
// int cnt = 1;
std::set<PointIndex> suround;
suround.insert(pi);
auto normal = normals[pi];
for(auto sei: sels)
{
const auto & sel = mesh[sei];
for(auto pi1 : sel.PNums())
if(suround.count(pi1)==0)
{
suround.insert(pi1);
auto gw_other = growthvectors[pi1];
auto normal_other = getNormal(mesh[sei]);
auto tangent_part = gw_other - (gw_other*normal_other)*normal_other;
if(is_point_on_bl_surface[pi])
new_gw += tangent_part;
else
new_gw += gw_other;
}
}
growthvectors[pi] = 1.0/suround.size() * new_gw;
}
}
for(auto pi : points)
growthvectors[pi] += normals[pi];
}
BoundaryLayerTool::BoundaryLayerTool(Mesh & mesh_, const BoundaryLayerParameters & params_)
: mesh(mesh_), topo(mesh_.GetTopology()), params(params_)
{
static Timer timer("BoundaryLayerTool::ctor");
RegionTimer regt(timer);
//for(auto & seg : mesh.LineSegments())
//seg.edgenr = seg.epgeominfo[1].edgenr;
height = 0.0;
for (auto h : params.heights)
height += h;
max_edge_nr = -1;
for(const auto& seg : mesh.LineSegments())
if(seg.edgenr > max_edge_nr)
max_edge_nr = seg.edgenr;
int ndom = mesh.GetNDomains();
ndom_old = ndom;
new_mat_nrs.SetSize(mesh.FaceDescriptors().Size() + 1);
new_mat_nrs = -1;
for(auto [bcname, matname] : params.new_mat)
{
mesh.SetMaterial(++ndom, matname);
regex pattern(bcname);
for(auto i : Range(1, mesh.GetNFD()+1))
{
auto& fd = mesh.GetFaceDescriptor(i);
if(regex_match(fd.GetBCName(), pattern))
new_mat_nrs[i] = ndom;
}
}
domains = params.domains;
if(!params.outside)
domains.Invert();
topo.SetBuildVertex2Element(true);
mesh.UpdateTopology();
have_single_segments = HaveSingleSegments(mesh);
if(have_single_segments)
segments = BuildSegments(mesh);
else
segments = mesh.LineSegments();
np = mesh.GetNP();
ne = mesh.GetNE();
nse = mesh.GetNSE();
nseg = segments.Size();
p2sel = mesh.CreatePoint2SurfaceElementTable();
nfd_old = mesh.GetNFD();
moved_surfaces.SetSize(nfd_old+1);
moved_surfaces.Clear();
si_map.SetSize(nfd_old+1);
for(auto i : Range(nfd_old+1))
si_map[i] = i;
}
void BoundaryLayerTool :: CreateNewFaceDescriptors()
{
surfacefacs.SetSize(nfd_old+1);
surfacefacs = 0.0;
// create new FaceDescriptors
for(auto i : Range(1, nfd_old+1))
{
const auto& fd = mesh.GetFaceDescriptor(i);
string name = fd.GetBCName();
if(params.surfid.Contains(i))
{
if(auto isIn = domains.Test(fd.DomainIn()); isIn != domains.Test(fd.DomainOut()))
{
int new_si = mesh.GetNFD()+1;
surfacefacs[i] = isIn ? 1. : -1.;
// -1 surf nr is so that curving does not do anything
FaceDescriptor new_fd(-1, isIn ? new_mat_nrs[i] : fd.DomainIn(),
isIn ? fd.DomainOut() : new_mat_nrs[i], -1);
new_fd.SetBCProperty(new_si);
mesh.AddFaceDescriptor(new_fd);
si_map[i] = new_si;
moved_surfaces.SetBit(i);
mesh.SetBCName(new_si-1, "mapped_" + name);
}
// curving of surfaces with boundary layers will often
// result in pushed through elements, since we do not (yet)
// curvature through layers.
// Therefore we disable curving for these surfaces.
if(!params.keep_surfaceindex)
mesh.GetFaceDescriptor(i).SetSurfNr(-1);
}
}
for(auto si : params.surfid)
if(surfacefacs[si] == 0.0)
throw Exception("Surface " + to_string(si) + " is not a boundary of the domain to be grown into!");
}
void BoundaryLayerTool ::CreateFaceDescriptorsSides()
{
BitArray face_done(mesh.GetNFD()+1);
face_done.Clear();
for(const auto& sel : mesh.SurfaceElements())
{
auto facei = sel.GetIndex();
if(face_done.Test(facei))
continue;
bool point_moved = false;
// bool point_fixed = false;
for(auto pi : sel.PNums())
{
if(growthvectors[pi].Length() > 0)
point_moved = true;
/*
else
point_fixed = true;
*/
}
if(point_moved && !moved_surfaces.Test(facei))
{
int new_si = mesh.GetNFD()+1;
const auto& fd = mesh.GetFaceDescriptor(facei);
// auto isIn = domains.Test(fd.DomainIn());
// auto isOut = domains.Test(fd.DomainOut());
int si = params.sides_keep_surfaceindex ? facei : -1;
// domin and domout can only be set later
FaceDescriptor new_fd(si, -1,
-1, si);
new_fd.SetBCProperty(new_si);
mesh.AddFaceDescriptor(new_fd);
si_map[facei] = new_si;
mesh.SetBCName(new_si-1, fd.GetBCName());
face_done.SetBit(facei);
}
}
}
void BoundaryLayerTool :: CalculateGrowthVectors()
{
growthvectors.SetSize(np);
growthvectors = 0.;
for(auto pi : mesh.Points().Range())
{
const auto & p = mesh[pi];
if(p.Type() == INNERPOINT)
continue;
std::map<int, Vec<3>> normals;
// calculate one normal vector per face (average with angles as weights for multiple surface elements within a face)
for(auto sei : p2sel[pi])
{
const auto & sel = mesh[sei];
auto facei = sel.GetIndex();
if(!params.surfid.Contains(facei))
continue;
auto n = surfacefacs[sel.GetIndex()] * getNormal(sel);
int itrig = sel.PNums().Pos(pi);
itrig += sel.GetNP();
auto v0 = (mesh[sel.PNumMod(itrig+1)] - mesh[pi]).Normalize();
auto v1 = (mesh[sel.PNumMod(itrig-1)] - mesh[pi]).Normalize();
if(normals.count(facei)==0)
normals[facei] = {0.,0.,0.};
normals[facei] += acos(v0*v1)*n;
}
for(auto & [facei, n] : normals)
n *= 1.0/n.Length();
// combine normal vectors for each face to keep uniform distances
auto & np = growthvectors[pi];
ArrayMem<Vec<3>, 3> ns;
for (auto &[facei, n] : normals) {
ns.Append(n);
}
ArrayMem<Vec<3>, 3> removed;
// reduce to full rank of max 3
while(true)
{
if(ns.Size() <= 1)
break;
if(ns.Size() == 2 && ns[0] * ns[1] < 1 - 1e-6)
break;
if (ns.Size() == 3)
{
DenseMatrix mat(3,3);
for(auto i : Range(3))
for(auto j : Range(3))
mat(i,j) = ns[i][j];
if(fabs(mat.Det()) > 1e-6)
break;
}
int maxpos1;
int maxpos2;
double val = 0;
for (auto i : Range(ns))
{
for (auto j : Range(i + 1, ns.Size()))
{
double ip = ns[i] * ns[j];
if(ip > val)
{
val = ip;
maxpos1 = i;
maxpos2 = j;
}
}
}
removed.Append(ns[maxpos1]);
removed.Append(ns[maxpos2]);
ns[maxpos1] = 0.5 * (ns[maxpos1] + ns[maxpos2]);
ns.DeleteElement(maxpos2);
}
if(ns.Size() == 0)
continue;
if(ns.Size() == 1)
np = ns[0];
else if(ns.Size() == 2)
{
np = ns[0];
auto n = ns[1];
auto npn = np * n;
auto npnp = np * np;
auto nn = n * n;
if(nn-npn*npn/npnp == 0) { np = n; continue; }
np += (nn - npn)/(nn - npn*npn/npnp) * (n - npn/npnp * np);
}
else // ns.Size() == 3
{
DenseMatrix mat(3,3);
for(auto i : Range(3))
for(auto j : Range(3))
mat(i, j) = ns[i] * ns[j];
Vector rhs(3);
rhs = 1.;
Vector res(3);
DenseMatrix inv(3, ns.Size());
CalcInverse(mat, inv);
inv.Mult(rhs, res);
for(auto i : Range(ns))
np += res[i] * ns[i];
}
for(auto& n : removed)
if(n * np < 0)
cout << "WARNING: Growth vector at point " << pi << " in opposite direction to face normal!" << endl << "Growthvector = " << np << ", face normal = " << n << endl;
}
}
Array<Array<pair<SegmentIndex, int>>, SegmentIndex> BoundaryLayerTool :: BuildSegMap()
{
// Bit array to keep track of segments already processed
BitArray segs_done(nseg+1);
segs_done.Clear();
// map for all segments with same points
// points to pair of SegmentIndex, int
// int is type of other segment, either:
// 0 == adjacent surface grows layer
// 1 == adjacent surface doesn't grow layer, but layer ends on it
// 2 == adjacent surface is interior surface that ends on layer
// 3 == adjacent surface is exterior surface that ends on layer (not allowed yet)
Array<Array<pair<SegmentIndex, int>>, SegmentIndex> segmap(segments.Size());
// moved segments
is_edge_moved.SetSize(max_edge_nr+1);
is_edge_moved = false;
// boundaries to project endings to
is_boundary_projected.SetSize(nfd_old+1);
is_boundary_projected.Clear();
is_boundary_moved.SetSize(nfd_old+1);
is_boundary_moved.Clear();
for(auto si : Range(segments))
{
if(segs_done[si]) continue;
const auto& segi = segments[si];
if(!moved_surfaces.Test(segi.si)) continue;
segs_done.SetBit(si);
segmap[si].Append(make_pair(si, 0));
moved_segs.Append(si);
is_edge_moved.SetBit(segi.edgenr);
for(auto sj : Range(segments))
{
if(segs_done.Test(sj)) continue;
const auto& segj = segments[sj];
if((segi[0] == segj[0] && segi[1] == segj[1]) ||
(segi[0] == segj[1] && segi[1] == segj[0]))
{
segs_done.SetBit(sj);
int type;
if(moved_surfaces.Test(segj.si))
type = 0;
else if(const auto& fd = mesh.GetFaceDescriptor(segj.si); domains.Test(fd.DomainIn()) && domains.Test(fd.DomainOut()))
{
type = 2;
if(fd.DomainIn() == 0 || fd.DomainOut() == 0)
is_boundary_projected.SetBit(segj.si);
}
else if(const auto& fd = mesh.GetFaceDescriptor(segj.si); !domains.Test(fd.DomainIn()) && !domains.Test(fd.DomainOut()))
{
type = 3;
is_boundary_moved.SetBit(segj.si);
}
else
{
type = 1;
// in case 1 we project the growthvector onto the surface
is_boundary_projected.SetBit(segj.si);
}
segmap[si].Append(make_pair(sj, type));
}
}
}
return segmap;
}
BitArray BoundaryLayerTool :: ProjectGrowthVectorsOnSurface()
{
BitArray in_surface_direction(nfd_old+1);
in_surface_direction.Clear();
// project growthvector on surface for inner angles
if(params.grow_edges)
{
for(const auto& sel : mesh.SurfaceElements())
if(is_boundary_projected.Test(sel.GetIndex()))
{
auto n = getNormal(sel);
for(auto i : Range(sel.PNums()))
{
auto pi = sel.PNums()[i];
if(growthvectors[pi].Length2() == 0.)
continue;
auto next = sel.PNums()[(i+1)%sel.GetNV()];
auto prev = sel.PNums()[i == 0 ? sel.GetNV()-1 : i-1];
auto v1 = (mesh[next] - mesh[pi]).Normalize();
auto v2 = (mesh[prev] - mesh[pi]).Normalize();
auto v3 = growthvectors[pi];
v3.Normalize();
auto tol = v1.Length() * 1e-12;
if((v1 * v3 > -tol) && (v2 * v3 > -tol))
in_surface_direction.SetBit(sel.GetIndex());
else
continue;
if(!params.project_boundaries.Contains(sel.GetIndex()))
continue;
auto& g = growthvectors[pi];
auto ng = n * g;
auto gg = g * g;
auto nn = n * n;
// if(fabs(ng*ng-nn*gg) < 1e-12 || fabs(ng) < 1e-12) continue;
auto a = -ng*ng/(ng*ng-nn * gg);
auto b = ng*gg/(ng*ng-nn*gg);
g += a*g + b*n;
}
}
}
else
{
for(const auto& seg : segments)
{
int count = 0;
for(const auto& seg2 : segments)
if(((seg[0] == seg2[0] && seg[1] == seg2[1]) || (seg[0] == seg2[1] && seg[1] == seg2[0])) && params.surfid.Contains(seg2.si))
count++;
if(count == 1)
{
growthvectors[seg[0]] = {0., 0., 0.};
growthvectors[seg[1]] = {0., 0., 0.};
}
}
}
return in_surface_direction;
}
void BoundaryLayerTool :: InterpolateGrowthVectors()
{
// interpolate tangential component of growth vector along edge
for(auto edgenr : Range(max_edge_nr))
{
// if(!is_edge_moved[edgenr+1]) continue;
// build sorted list of edge
Array<PointIndex> points;
// find first vertex on edge
double edge_len = 0.;
auto is_end_point = [&] (PointIndex pi)
{
// if(mesh[pi].Type() == FIXEDPOINT)
// return true;
// return false;
auto segs = topo.GetVertexSegments(pi);
if(segs.Size() == 1)
return true;
auto first_edgenr = mesh[segs[0]].edgenr;
for(auto segi : segs)
if(mesh[segi].edgenr != first_edgenr)
return true;
return false;
};
bool any_grows = false;
for(const auto& seg : segments)
{
if(seg.edgenr-1 == edgenr)
{
if(growthvectors[seg[0]].Length2() != 0 ||
growthvectors[seg[1]].Length2() != 0)
any_grows = true;
if(points.Size() == 0 && is_end_point(seg[0]))
{
points.Append(seg[0]);
points.Append(seg[1]);
edge_len += (mesh[seg[1]] - mesh[seg[0]]).Length();
}
}
}
if(!any_grows)
continue;
if(!points.Size())
throw Exception("Could not find startpoint for edge " + ToString(edgenr));
while(true)
{
bool point_found = false;
for(auto si : topo.GetVertexSegments(points.Last()))
{
const auto& seg = mesh[si];
if(seg.edgenr-1 != edgenr)
continue;
if(seg[0] == points.Last() && points[points.Size()-2] !=seg[1])
{
edge_len += (mesh[points.Last()] - mesh[seg[1]]).Length();
points.Append(seg[1]);
point_found = true;
break;
}
else if(seg[1] == points.Last() &&
points[points.Size()-2] != seg[0])
{
edge_len += (mesh[points.Last()] - mesh[seg[0]]).Length();
points.Append(seg[0]);
point_found = true;
break;
}
}
if(is_end_point(points.Last()))
break;
if(!point_found)
{
throw Exception(string("Could not find connected list of line segments for edge ") + edgenr);
}
}
if(growthvectors[points[0]].Length2() == 0 &&
growthvectors[points.Last()].Length2() == 0)
continue;
// tangential part of growth vectors
auto t1 = (mesh[points[1]]-mesh[points[0]]).Normalize();
auto gt1 = growthvectors[points[0]] * t1 * t1;
auto t2 = (mesh[points.Last()]-mesh[points[points.Size()-2]]).Normalize();
auto gt2 = growthvectors[points.Last()] * t2 * t2;
if(!is_edge_moved[edgenr+1])
{
if(growthvectors[points[0]] * (mesh[points[1]] - mesh[points[0]]) < 0)
gt1 = 0.;
if(growthvectors[points.Last()] * (mesh[points[points.Size()-2]] - mesh[points.Last()]) < 0)
gt2 = 0.;
}
double len = 0.;
for(size_t i = 1; i < points.Size()-1; i++)
{
auto pi = points[i];
len += (mesh[pi] - mesh[points[i-1]]).Length();
auto t = getEdgeTangent(pi, edgenr);
auto lam = len/edge_len;
auto interpol = (1-lam) * (gt1 * t) * t + lam * (gt2 * t) * t;
growthvectors[pi] += interpol;
}
}
InterpolateSurfaceGrowthVectors();
}
void BoundaryLayerTool :: InsertNewElements( FlatArray<Array<pair<SegmentIndex, int>>, SegmentIndex> segmap, const BitArray & in_surface_direction )
{
static Timer timer("BoundaryLayerTool::InsertNewElements"); RegionTimer rt(timer);
Array<Array<PointIndex>, PointIndex> mapto(np);
// insert new points
for (PointIndex pi = 1; pi <= np; pi++)
if (growthvectors[pi].Length2() != 0)
{
Point<3> p = mesh[pi];
for(auto i : Range(params.heights))
{
p += params.heights[i] * growthvectors[pi];
mapto[pi].Append(mesh.AddPoint(p));
}
}
// add 2d quads on required surfaces
map<pair<PointIndex, PointIndex>, int> seg2edge;
if(params.grow_edges)
{
for(auto sei : moved_segs)
{
// copy here since we will add segments and this would
// invalidate a reference!
// auto segi = segments[sei];
for(auto [sej, type] : segmap[sei])
{
auto segj = segments[sej];
if(type == 0)
{
Segment s;
s[0] = mapto[segj[0]].Last();
s[1] = mapto[segj[1]].Last();
s[2] = PointIndex::INVALID;
auto pair = s[0] < s[1] ? make_pair(s[0], s[1]) : make_pair(s[1], s[0]);
if(seg2edge.find(pair) == seg2edge.end())
seg2edge[pair] = ++max_edge_nr;
s.edgenr = seg2edge[pair];
s.si = si_map[segj.si];
new_segments.Append(s);
}
// here we need to grow the quad elements
else if(type == 1)
{
PointIndex pp1 = segj[1];
PointIndex pp2 = segj[0];
if(in_surface_direction.Test(segj.si))
{
Swap(pp1, pp2);
is_boundary_moved.SetBit(segj.si);
}
PointIndex p1 = pp1;
PointIndex p2 = pp2;
PointIndex p3, p4;
Segment s0;
s0[0] = p1;
s0[1] = p2;
s0[2] = PointIndex::INVALID;
s0.edgenr = segj.edgenr;
s0.si = segj.si;
new_segments.Append(s0);
for(auto i : Range(params.heights))
{
Element2d sel(QUAD);
p3 = mapto[pp2][i];
p4 = mapto[pp1][i];
sel[0] = p1;
sel[1] = p2;
sel[2] = p3;
sel[3] = p4;
for(auto i : Range(4))
{
sel.GeomInfo()[i].u = 0.0;
sel.GeomInfo()[i].v = 0.0;
}
sel.SetIndex(si_map[segj.si]);
mesh.AddSurfaceElement(sel);
// TODO: Too many, would be enough to only add outermost ones
Segment s1;
s1[0] = p2;
s1[1] = p3;
s1[2] = PointIndex::INVALID;
auto pair = make_pair(p2, p3);
if(seg2edge.find(pair) == seg2edge.end())
seg2edge[pair] = ++max_edge_nr;
s1.edgenr = seg2edge[pair];
s1.si = segj.si;
new_segments.Append(s1);
Segment s2;
s2[0] = p4;
s2[1] = p1;
s2[2] = PointIndex::INVALID;
pair = make_pair(p1, p4);
if(seg2edge.find(pair) == seg2edge.end())
seg2edge[pair] = ++max_edge_nr;
s2.edgenr = seg2edge[pair];
s2.si = segj.si;
new_segments.Append(s2);
p1 = p4;
p2 = p3;
}
Segment s3;
s3[0] = p3;
s3[1] = p4;
s3[2] = PointIndex::INVALID;
auto pair = p3 < p4 ? make_pair(p3, p4) : make_pair(p4, p3);
if(seg2edge.find(pair) == seg2edge.end())
seg2edge[pair] = ++max_edge_nr;
s3.edgenr = seg2edge[pair];
s3.si = segj.si;
new_segments.Append(s3);
}
}
}
}
BitArray fixed_points(np+1);
fixed_points.Clear();
BitArray moveboundarypoint(np+1);
moveboundarypoint.Clear();
for(SurfaceElementIndex si = 0; si < nse; si++)
{
// copy because surfaceels array will be resized!
auto sel = mesh[si];
if(moved_surfaces.Test(sel.GetIndex()))
{
Array<PointIndex> points(sel.PNums());
if(surfacefacs[sel.GetIndex()] > 0) Swap(points[0], points[2]);
for(auto j : Range(params.heights))
{
auto eltype = points.Size() == 3 ? PRISM : HEX;
Element el(eltype);
for(auto i : Range(points))
el[i] = points[i];
for(auto i : Range(points))
points[i] = mapto[sel.PNums()[i]][j];
if(surfacefacs[sel.GetIndex()] > 0) Swap(points[0], points[2]);
for(auto i : Range(points))
el[sel.PNums().Size() + i] = points[i];
auto new_index = new_mat_nrs[sel.GetIndex()];
if(new_index == -1)
throw Exception("Boundary " + ToString(sel.GetIndex()) + " with name " + mesh.GetBCName(sel.GetIndex()-1) + " extruded, but no new material specified for it!");
el.SetIndex(new_mat_nrs[sel.GetIndex()]);
mesh.AddVolumeElement(el);
}
Element2d newel = sel;
for(auto& p : newel.PNums())
p = mapto[p].Last();
newel.SetIndex(si_map[sel.GetIndex()]);
mesh.AddSurfaceElement(newel);
}
else
{
bool has_moved = false;
for(auto p : sel.PNums())
if(mapto[p].Size())
has_moved = true;
if(has_moved)
for(auto p : sel.PNums())
{
if(!mapto[p].Size())
{
fixed_points.SetBit(p);
if(is_boundary_moved.Test(sel.GetIndex()))
moveboundarypoint.SetBit(p);
}
}
}
if(is_boundary_moved.Test(sel.GetIndex()))
{
for(auto& p : mesh[si].PNums())
if(mapto[p].Size())
p = mapto[p].Last();
}
}
for(SegmentIndex sei = 0; sei < nseg; sei++)
{
auto& seg = segments[sei];
if(is_boundary_moved.Test(seg.si))
for(auto& p : seg.PNums())
if(mapto[p].Size())
p = mapto[p].Last();
}
for(ElementIndex ei = 0; ei < ne; ei++)
{
auto el = mesh[ei];
ArrayMem<PointIndex,4> fixed;
ArrayMem<PointIndex,4> moved;
bool moved_bnd = false;
for(const auto& p : el.PNums())
{
if(fixed_points.Test(p))
fixed.Append(p);
if(mapto[p].Size())
moved.Append(p);
if(moveboundarypoint.Test(p))
moved_bnd = true;
}
bool do_move, do_insert;
if(domains.Test(el.GetIndex()))
{
do_move = fixed.Size() && moved_bnd;
do_insert = do_move;
}
else
{
do_move = !fixed.Size() || moved_bnd;
do_insert = !do_move;
}
if(do_move)
{
for(auto& p : mesh[ei].PNums())
if(mapto[p].Size())
p = mapto[p].Last();
}
if(do_insert)
{
if(el.GetType() == TET)
{
if(moved.Size() == 3) // inner corner
{
PointIndex p1 = moved[0];
PointIndex p2 = moved[1];
PointIndex p3 = moved[2];
auto v1 = mesh[p1];
auto n = Cross(mesh[p2]-v1, mesh[p3]-v1);
auto d = mesh[mapto[p1][0]] - v1;
if(n*d > 0)
Swap(p2,p3);
PointIndex p4 = p1;
PointIndex p5 = p2;
PointIndex p6 = p3;
for(auto i : Range(params.heights))
{
Element nel(PRISM);
nel[0] = p4; nel[1] = p5; nel[2] = p6;
p4 = mapto[p1][i]; p5 = mapto[p2][i]; p6 = mapto[p3][i];
nel[3] = p4; nel[4] = p5; nel[5] = p6;
nel.SetIndex(el.GetIndex());
mesh.AddVolumeElement(nel);
}
}
if(moved.Size() == 2)
{
if(fixed.Size() == 1)
{
PointIndex p1 = moved[0];
PointIndex p2 = moved[1];
for(auto i : Range(params.heights))
{
PointIndex p3 = mapto[moved[1]][i];
PointIndex p4 = mapto[moved[0]][i];
Element nel(PYRAMID);
nel[0] = p1;
nel[1] = p2;
nel[2] = p3;
nel[3] = p4;
nel[4] = el[0] + el[1] + el[2] + el[3] - fixed[0] - moved[0] - moved[1];
if(Cross(mesh[p2]-mesh[p1], mesh[p4]-mesh[p1]) * (mesh[nel[4]]-mesh[nel[1]]) > 0)
Swap(nel[1], nel[3]);
nel.SetIndex(el.GetIndex());
mesh.AddVolumeElement(nel);
p1 = p4;
p2 = p3;
}
}
}
if(moved.Size() == 1 && fixed.Size() == 1)
{
PointIndex p1 = moved[0];
for(auto i : Range(params.heights))
{
Element nel = el;
PointIndex p2 = mapto[moved[0]][i];
for(auto& p : nel.PNums())
{
if(p == moved[0])
p = p1;
else if(p == fixed[0])
p = p2;
}
p1 = p2;
mesh.AddVolumeElement(nel);
}
}
}
else if(el.GetType() == PYRAMID)
{
if(moved.Size() == 2)
{
if(fixed.Size() != 2)
throw Exception("This case is not implemented yet! Fixed size = " + ToString(fixed.Size()));
PointIndex p1 = moved[0];
PointIndex p2 = moved[1];
for(auto i : Range(params.heights))
{
PointIndex p3 = mapto[moved[1]][i];
PointIndex p4 = mapto[moved[0]][i];
Element nel(PYRAMID);
nel[0] = p1;
nel[1] = p2;
nel[2] = p3;
nel[3] = p4;
nel[4] = el[0] + el[1] + el[2] + el[3] + el[4] - fixed[0] - fixed[1] - moved[0] - moved[1];
if(Cross(mesh[p2] - mesh[p1], mesh[p4]-mesh[p1]) * (mesh[nel[4]]-mesh[nel[1]]) > 0)
Swap(nel[1], nel[3]);
nel.SetIndex(el.GetIndex());
mesh.AddVolumeElement(nel);
p1 = p4;
p2 = p3;
}
}
else if(moved.Size() == 1)
throw Exception("This case is not implemented yet!");
}
else
throw Exception("Boundarylayer only implemented for tets and pyramids outside yet!");
}
}
}
void BoundaryLayerTool :: SetDomInOut()
{
for(auto i : Range(1, nfd_old+1))
if(moved_surfaces.Test(i))
{
if(auto dom = mesh.GetFaceDescriptor(si_map[i]).DomainIn(); dom > ndom_old)
mesh.GetFaceDescriptor(i).SetDomainOut(dom);
else
mesh.GetFaceDescriptor(i).SetDomainIn(mesh.GetFaceDescriptor(si_map[i]).DomainOut());
}
}
void BoundaryLayerTool :: SetDomInOutSides()
{
BitArray done(mesh.GetNFD()+1);
done.Clear();
for(auto sei : Range(mesh.SurfaceElements()))
{
auto& sel = mesh[sei];
auto index = sel.GetIndex();
if(done.Test(index))
continue;
done.SetBit(index);
auto& fd = mesh.GetFaceDescriptor(index);
if(fd.DomainIn() != -1)
continue;
int e1, e2;
mesh.GetTopology().GetSurface2VolumeElement(sei+1, e1, e2);
if(e1 == 0)
fd.SetDomainIn(0);
else
fd.SetDomainIn(mesh.VolumeElement(e1).GetIndex());
if(e2 == 0)
fd.SetDomainOut(0);
else
fd.SetDomainOut(mesh.VolumeElement(e2).GetIndex());
}
}
void BoundaryLayerTool :: AddSegments()
{
if(have_single_segments)
MergeAndAddSegments(mesh, new_segments);
else
{
for(auto & seg : new_segments)
mesh.AddSegment(seg);
}
}
void BoundaryLayerTool :: FixVolumeElements()
{
static Timer timer("BoundaryLayerTool::FixVolumeElements"); RegionTimer rt(timer);
BitArray is_inner_point(mesh.GetNP()+1);
is_inner_point.Clear();
auto changed_domains = domains;
if(!params.outside)
changed_domains.Invert();
for(ElementIndex ei : Range(ne))
if(changed_domains.Test(mesh[ei].GetIndex()))
for(auto pi : mesh[ei].PNums())
if(mesh[pi].Type() == INNERPOINT)
is_inner_point.SetBit(pi);
Array<PointIndex> points;
for(auto pi : mesh.Points().Range())
if(is_inner_point.Test(pi))
points.Append(pi);
auto p2el = mesh.CreatePoint2ElementTable(is_inner_point);
// smooth growth vectors to shift additional element layers to the inside and fix flipped tets
for([[maybe_unused]] auto step : Range(10))
{
for(auto pi : points)
{
Vec<3> average_gw = 0.0;
auto & els = p2el[pi];
size_t cnt = 0;
for(auto ei : els)
if(ei<ne)
for(auto pi1 : mesh[ei].PNums())
if(pi1<=np)
{
average_gw += growthvectors[pi1];
cnt++;
}
growthvectors[pi] = 1.0/cnt * average_gw;
}
}
for(auto pi : points)
{
mesh[pi] += height * growthvectors[pi];
growthvectors[pi] = 0.0;
}
}
void BoundaryLayerTool :: Perform()
{
CreateNewFaceDescriptors();
CalculateGrowthVectors();
CreateFaceDescriptorsSides();
auto segmap = BuildSegMap();
auto in_surface_direction = ProjectGrowthVectorsOnSurface();
if(params.limit_growth_vectors)
LimitGrowthVectorLengths();
InterpolateGrowthVectors();
FixVolumeElements();
InsertNewElements(segmap, in_surface_direction);
SetDomInOut();
AddSegments();
mesh.GetTopology().ClearEdges();
mesh.SetNextMajorTimeStamp();
mesh.UpdateTopology();
SetDomInOutSides();
MeshingParameters mp;
mp.optimize3d ="m";
mp.optsteps3d = 4;
OptimizeVolume(mp, mesh);
}
void GenerateBoundaryLayer(Mesh& mesh, const BoundaryLayerParameters& blp)
{
static Timer timer("Create Boundarylayers");
RegionTimer regt(timer);
BoundaryLayerTool tool(mesh, blp);
tool.Perform();
}
} // namespace netgen