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/*===========================================================================*\
* *
* IsoEx *
* Copyright (C) 2002 by Computer Graphics Group, RWTH Aachen *
* www.rwth-graphics.de *
* *
*---------------------------------------------------------------------------*
* *
* License *
* *
* This library is free software; you can redistribute it and/or modify it *
* under the terms of the GNU Library General Public License as published *
* by the Free Software Foundation, version 2. *
* *
* This library is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Library General Public License for more details. *
* *
* You should have received a copy of the GNU Library General Public *
* License along with this library; if not, write to the Free Software *
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *
* *
\*===========================================================================*/
//=============================================================================
//
// CLASS ExtendedMarchingCubesT - IMPLEMENTATION
//
//=============================================================================
#define ISOEX_AEXTMARCHINGCUBEST_C
//== INCLUDES =================================================================
#include <IsoEx/Extractors/AExtendedMarchingCubesT.hh>
#include <IsoEx/Extractors/MCTablesIsoEx.hh>
#include <IsoEx/Math/MatrixT.hh>
#include <IsoEx/Math/svd.hh>
#include <vector>
#include <float.h>
#include <iostream>
#include <omp.h>
#include "IsoSurfGen/ProgressBar.h"
//== NAMESPACES ===============================================================
namespace IsoEx
{
//== IMPLEMENTATION ==========================================================
template <class Mesh, class Grid, class Real>
AExtendedMarchingCubesT<Mesh, Grid, Real>::
AExtendedMarchingCubesT(const Grid &_grid,
Mesh &_mesh,
double _iso_value,
double _feature_angle,
const int buffer,
bool verbose)
: grid_(_grid),
mesh_(_mesh),
feature_angle_(_feature_angle / 180.0 * M_PI),
n_edges_(0),
n_corners_(0)
{
int xsize = grid_.x_resolution() - 1;
int ysize = grid_.y_resolution() - 1;
int zsize = grid_.z_resolution() - 1;
/////////////////////////////////////////////////////////////////////
std::vector<TinyVector<Real, 3>> edge_start, edge_end, intersection, normals;
std::vector<Real> start_fvalue, end_fvalue;
edge_start.reserve(buffer + 12);
edge_end.reserve(buffer + 12);
intersection.reserve(buffer + 12);
normals.reserve(buffer + 12);
start_fvalue.reserve(buffer + 12);
end_fvalue.reserve(buffer + 12);
print_progress_bar(0.0f, verbose);
int counter = 0;
int prev_start = 0;
TinyVector<Real, 3> ipoint[8];
int label[12] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048};
int edgepair[12][2] = {{0, 1}, {1, 2}, {3, 2}, {0, 3}, {4, 5}, {5, 6}, {7, 6}, {4, 7}, {0, 4}, {1, 5}, {2, 6}, {3, 7}};
PointIdx corner[8];
Real values[8];
int max_size = std::max(std::max(xsize, ysize), zsize);
std::vector<int> cache_cube;
cache_cube.reserve(max_size * max_size * 2);
for (int c = 0; c < xsize * ysize * zsize; c++)
{
// determine cube type
unsigned char cubetype(0);
for (unsigned int i = 0; i < 8; ++i)
{
if (!grid_.is_inside(grid_.point_idx(c, i), _iso_value))
cubetype |= (1 << i);
}
// trivial reject ?
if (cubetype == 0 || cubetype == 255)
;
else
{
cache_cube.push_back(c);
cache_cube.push_back(cubetype);
}
}
for (int s = 0; s < cache_cube.size(); s += 2)
{
int c = cache_cube[s];
for (int i = 0; i < 8; ++i)
{
corner[i] = grid_.point_idx(c, i);
values[i] = grid_.scalar_distance(corner[i]);
}
unsigned char cubetype = cache_cube[s + 1];
for (int i = 0; i < 8; i++)
{
const typename Mesh::Point &p = grid_.point(corner[i]);
ipoint[i][0] = p[0];
ipoint[i][1] = p[1];
ipoint[i][2] = p[2];
}
for (int i = 0; i < 12; i++)
{
if ((edgeTable[cubetype] & label[i]) && is_unprocessed_edge(corner[edgepair[i][0]], corner[edgepair[i][1]]))
{
edge_start.push_back(ipoint[edgepair[i][0]]);
edge_end.push_back(ipoint[edgepair[i][1]]);
start_fvalue.push_back(values[edgepair[i][0]]);
end_fvalue.push_back(values[edgepair[i][1]]);
counter++;
}
}
if (counter != 0 && (counter >= buffer || s + 2 == cache_cube.size()))
{
edge_start.resize(counter);
edge_end.resize(counter);
start_fvalue.resize(counter);
end_fvalue.resize(counter);
intersection.resize(counter);
normals.resize(counter);
grid_.directed_distance(edge_start, edge_end, start_fvalue, end_fvalue, intersection, normals, _iso_value);
for (int n = prev_start; n <= s; n += 2)
{
CubeIdx _idx = cache_cube[n];
PointIdx corner[8];
VertexHandle samples[12];
unsigned char cubetype(0);
unsigned int i, j;
unsigned int n_components, n_vertices;
int *indices;
VertexHandle vh;
std::vector<VertexHandle> vhandles;
// get corner vertices
for (i = 0; i < 8; ++i)
corner[i] = grid_.point_idx(_idx, i);
cubetype = cache_cube[n + 1];
for (int i = 0; i < 12; i++)
{
if ((edgeTable[cubetype] & label[i]))
{
int mid = query_store_id(corner[edgepair[i][0]], corner[edgepair[i][1]]);
samples[i] = add_vertex(corner[edgepair[i][0]], corner[edgepair[i][1]], intersection[mid], normals[mid]);
}
}
// connect samples by triangles
n_components = triTable[cubetype][1][0];
indices = &triTable[cubetype][1][n_components + 1];
for (i = 1; i <= n_components; ++i) // sheets in this voxel
{
// current sheet contains n_vertices vertices
n_vertices = triTable[cubetype][1][i];
// collect vertices of n-gon
vhandles.clear();
for (j = 0; j < n_vertices; ++j)
vhandles.push_back(samples[indices[j]]);
// look for a feature
vh = find_feature(vhandles);
// feature -> create triangle fan around feature vertex
if (vh.is_valid())
{
vhandles.push_back(vhandles[0]);
for (j = 0; j < n_vertices; ++j)
mesh_.add_face(vhandles[j], vhandles[j + 1], vh);
}
// no feature -> old marching cubes triangle table
else
{
for (j = 0; polyTable[n_vertices][j] != -1; j += 3)
mesh_.add_face(samples[indices[polyTable[n_vertices][j]]],
samples[indices[polyTable[n_vertices][j + 1]]],
samples[indices[polyTable[n_vertices][j + 2]]]);
}
indices += n_vertices;
}
}
prev_start = s + 2;
counter = 0;
edgemap.clear();
edge_start.resize(0);
edge_end.resize(0);
start_fvalue.resize(0);
end_fvalue.resize(0);
intersection.resize(0);
normals.resize(0);
print_progress_bar((s + 2.0f) / cache_cube.size(), verbose);
if (s + 2 == cache_cube.size())
printf("\n");
}
}
/////////////////////////////////////////////////////////////////////
flip_edges();
std::cerr << "\nFound "
<< n_edges_ << " edge features, "
<< n_corners_ << " corner features\n";
}
//-----------------------------------------------------------------------------
template <class Mesh, class Grid, class Real>
typename AExtendedMarchingCubesT<Mesh, Grid, Real>::VertexHandle
AExtendedMarchingCubesT<Mesh, Grid, Real>::
add_vertex(PointIdx _p0, PointIdx _p1, const TinyVector<Real, 3> &_point, const TinyVector<Real, 3> &_normal)
{
// find vertex if it has been computed already
VertexHandle vh = edge2vertex_.find(_p0, _p1);
if (vh.is_valid())
return vh;
typename Mesh::Point point(_point[0], _point[1], _point[2]), normal(_normal[0], _normal[1], _normal[2]);
// add vertex
vh = mesh_.add_vertex(point);
mesh_.set_normal(vh, normal);
edge2vertex_.insert(_p0, _p1, vh);
return vh;
}
//-----------------------------------------------------------------------------
template <class Mesh, class Grid, class Real>
bool
AExtendedMarchingCubesT<Mesh, Grid, Real>::
is_unprocessed_edge(PointIdx _p0, PointIdx _p1)
{
std::pair<PointIdx, PointIdx> edge(_p0, _p1);
auto iter = edgemap.find(edge);
if (iter == edgemap.end())
{
unsigned int esize = (unsigned int)edgemap.size();
edgemap[edge] = esize;
return true;
}
return false;
}
//-----------------------------------------------------------------------------
template <class Mesh, class Grid, class Real>
int
AExtendedMarchingCubesT<Mesh, Grid, Real>::
query_store_id(PointIdx _p0, PointIdx _p1)
{
std::pair<PointIdx, PointIdx> edge(_p0, _p1);
auto iter = edgemap.find(edge);
if (iter == edgemap.end())
{
std::cout << "This query is illegal!" << std::endl;
return -1;
}
return iter->second;
}
//-----------------------------------------------------------------------------
template <class Mesh, class Grid, class Real>
typename AExtendedMarchingCubesT<Mesh, Grid, Real>::VertexHandle
AExtendedMarchingCubesT<Mesh, Grid, Real>::
find_feature(const VertexHandleVector &_vhandles)
{
unsigned int i, j, nV = _vhandles.size(), rank;
// collect point & normals;
std::vector<typename Mesh::Point> p, n;
p.resize(nV);
n.resize(nV);
for (i = 0; i < nV; ++i)
{
p[i] = mesh_.point(_vhandles[i]);
n[i] = mesh_.normal(_vhandles[i]);
}
// move barycenter of points into
typename Mesh::Point cog(0, 0, 0);
for (i = 0; i < nV; ++i)
cog += p[i];
cog /= (float)nV;
for (i = 0; i < nV; ++i)
p[i] -= cog;
// normal angle criterion
double c, min_c, max_c;
typename Mesh::Point axis;
for (min_c = 1.0, i = 0; i < nV; ++i)
for (j = 0; j < nV; ++j)
if ((c = (n[i] | n[j])) < min_c)
{
min_c = c;
axis = n[i] % n[j];
}
// angle to small, no feature -> return invalid vertex handle
if (min_c > cos(feature_angle_))
return Mesh::InvalidVertexHandle;
// ok, we have a feature
// is it edge or corner, i.e. rank 2 or 3 ?
axis.normalize();
for (min_c = 1.0, max_c = -1.0, i = 0; i < nV; ++i)
{
c = (axis | n[i]);
if (c < min_c)
min_c = c;
if (c > max_c)
max_c = c;
}
c = std::max(fabs(min_c), fabs(max_c));
c = sqrt(1.0 - c * c);
rank = (c > cos(feature_angle_) ? 2 : 3);
if (rank == 2)
++n_edges_;
else
++n_corners_;
// setup linear system (find intersection of tangent planes)
Math::MatrixT<double> A(nV, 3);
Math::VectorT<double> b(nV);
for (i = 0; i < nV; ++i)
{
A(i, 0) = n[i][0];
A(i, 1) = n[i][1];
A(i, 2) = n[i][2];
b(i) = (p[i] | n[i]);
}
// SVD of matrix A
Math::MatrixT<double> V(3, 3);
Math::VectorT<double> S(nV);
Math::svd_decomp(A, S, V);
// rank == 2 -> suppress smallest singular value
if (rank == 2)
{
double smin = FLT_MAX;
unsigned int sminid = 0;
unsigned int srank = std::min(nV, 3u);
for (i = 0; i < srank; ++i)
if (S(i) < smin)
{
smin = S(i);
sminid = i;
}
S(sminid) = 0.0;
}
// SVD backsubstitution -> least squares, least norm solution x
Math::VectorT<double> x(3);
Math::svd_backsub(A, S, V, b, x);
// transform x to world coords
typename Mesh::Point point(x(0), x(1), x(2));
// typename Mesh::Point point(x[0], x[1], x[2]);
point += cog;
// insert the feature-point
VertexHandle vh = mesh_.add_vertex(point);
mesh_.status(vh).set_feature(true);
return vh;
}
//-----------------------------------------------------------------------------
template <class Mesh, class Grid, class Real>
void AExtendedMarchingCubesT<Mesh, Grid, Real>::flip_edges()
{
VertexHandle v0, v1, v2, v3;
typename Mesh::HalfedgeHandle he;
typename Mesh::EdgeIter e_it(mesh_.edges_begin()), e_end(mesh_.edges_end());
for (; e_it != e_end; ++e_it)
{
if (mesh_.is_flip_ok(*e_it))
{
he = mesh_.halfedge_handle(*e_it, 0);
v0 = mesh_.to_vertex_handle(he);
he = mesh_.next_halfedge_handle(he);
v1 = mesh_.to_vertex_handle(he);
he = mesh_.halfedge_handle(*e_it, 1);
v2 = mesh_.to_vertex_handle(he);
he = mesh_.next_halfedge_handle(he);
v3 = mesh_.to_vertex_handle(he);
// flip edge if it would connect two features (v1, v3)
// and not disconnect two others (v0, v2) afterwards
// (maybe we should check for flipping triangle normals)
if (mesh_.status(v1).feature() && mesh_.status(v3).feature() && !mesh_.status(v0).feature() && !mesh_.status(v2).feature())
mesh_.flip(*e_it);
}
}
}
//=============================================================================
} // namespace IsoEx
//=============================================================================