VTK：高度场的基本可视化

Question

I've got a basic hello world program of libvtk working as follows:

#include "vtkGraphLayoutView.h"
#include "vtkRandomGraphSource.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"

int main(int, char*[])
{
  vtkRandomGraphSource* source = vtkRandomGraphSource::New();

  vtkGraphLayoutView* view = vtkGraphLayoutView::New();
  view->SetRepresentationFromInputConnection(source->GetOutputPort());

  view->ResetCamera();
  view->Render();
  view->GetInteractor()->Start();

  source->Delete();
  view->Delete();

  return 0;
}

compile with:

$ g++ -I/usr/include/vtk-5.6 hello_vtk.cpp -lvtkInfovis -lvtkViews -lvtkFiltering

execute with:

$ ./a.out

I have two sets of data I want to visualize, both as heightfields:

The first is of the form:

double x1[N*M];

representing an N x M heightfield where height at (i, j) is x[N*j + i]

The second is of the form:

map<pair<double, double>, double> x2;

where there is a sample of a continuous surface from (i,j) of height h represented by:

x2[make_pair(i,j)] = h

Clearly an instance of x2 could be interpolated if necessary into an x1.

My question is which classes should be used and what is a sketch of the implementation necessary to visualize x1 and/or x2 in VTK?

(Is there any top down documentation of VTK? It seems to be an extremely large library and the only reference I could find is the doxygene which requires linear time searching to find what you are looking for)

Answer 1

You have to get your data into a VTK data structure (probably a vtkImageData or vtkStructuredGrid). You can check out this example: http://www.vtk.org/Wiki/VTK/Examples/Cxx/Meshes/Color_a_mesh_by_height that should have a lot of elements you need to do this.

Note: the example uses a vtkPolyData data structure, but this is probably overkill for this type of regular/grid data.