void
uniform_sampling (vtkSmartPointer<vtkPolyData> polydata, size_t n_samples, pcl::PointCloud<pcl::PointXYZ> & cloud_out)
{
polydata->BuildCells ();
vtkSmartPointer<vtkCellArray> cells = polydata->GetPolys ();
double p1[3], p2[3], p3[3], totalArea = 0;
std::vector<double> cumulativeAreas (cells->GetNumberOfCells (), 0);
size_t i = 0;
vtkIdType npts = 0, *ptIds = NULL;
for (cells->InitTraversal (); cells->GetNextCell (npts, ptIds); i++)
{
polydata->GetPoint (ptIds[0], p1);
polydata->GetPoint (ptIds[1], p2);
polydata->GetPoint (ptIds[2], p3);
totalArea += vtkTriangle::TriangleArea (p1, p2, p3);
cumulativeAreas[i] = totalArea;
}
cloud_out.points.resize (n_samples);
cloud_out.width = static_cast<uint32_t> (n_samples);
cloud_out.height = 1;
for (i = 0; i < n_samples; i++)
{
Eigen::Vector4f p;
randPSurface (polydata, &cumulativeAreas, totalArea, p);
cloud_out.points[i].x = p[0];
cloud_out.points[i].y = p[1];
cloud_out.points[i].z = p[2];
}
}
void
uniform_sampling (vtkSmartPointer<vtkPolyData> polydata, size_t n_samples, bool calc_normal, bool calc_color, pcl::PointCloud<pcl::PointXYZRGBNormal> & cloud_out)
{
polydata->BuildCells ();
vtkSmartPointer<vtkCellArray> cells = polydata->GetPolys ();
double p1[3], p2[3], p3[3], totalArea = 0;
std::vector<double> cumulativeAreas (cells->GetNumberOfCells (), 0);
vtkIdType npts = 0, *ptIds = NULL;
size_t cellId = 0;
for (cells->InitTraversal (); cells->GetNextCell (npts, ptIds); cellId++)
{
polydata->GetPoint (ptIds[0], p1);
polydata->GetPoint (ptIds[1], p2);
polydata->GetPoint (ptIds[2], p3);
totalArea += vtkTriangle::TriangleArea (p1, p2, p3);
cumulativeAreas[cellId] = totalArea;
}
cloud_out.points.resize (n_samples);
cloud_out.width = static_cast<pcl::uint32_t> (n_samples);
cloud_out.height = 1;
for (size_t i = 0; i < n_samples; i++)
{
Eigen::Vector3f p;
Eigen::Vector3f n (0, 0, 0);
Eigen::Vector3f c (0, 0, 0);
randPSurface (polydata, &cumulativeAreas, totalArea, p, calc_normal, n, calc_color, c);
cloud_out.points[i].x = p[0];
cloud_out.points[i].y = p[1];
cloud_out.points[i].z = p[2];
if (calc_normal)
{
cloud_out.points[i].normal_x = n[0];
cloud_out.points[i].normal_y = n[1];
cloud_out.points[i].normal_z = n[2];
}
if (calc_color)
{
cloud_out.points[i].r = static_cast<uint8_t>(c[0]);
cloud_out.points[i].g = static_cast<uint8_t>(c[1]);
cloud_out.points[i].b = static_cast<uint8_t>(c[2]);
}
}
}