Update on GSoC DUNE psurface work #2

Last week I am writing the code that take psurface object and writes its domain surface in vtk format. You can find the code  here git://gitorious.org/~xiaoxueiris/psurface/xiaoxueiriss-psurface.git.
It is a C-style code.  I only create some functions to treat the psurface subject.
The input is the psurface with format:
1.Patches
2.BaseGridVertexCoordss
3.BaseGridTriangles
and Plane graphs on each base grid triangles, saved as a list of nodes and a list of edges:
5. nodes
6.ParameterEdges
7.EdgePoint.
The out put is  the legency unstructured grid vtk file. The corner nodes of the triangles and the other nodes(intersection node, touching nodes, and interior nodes) are represented by d-dimensional float. The vtk file contain two kinds of cells: the triangle cell represent the BaseGridTriangle and the edge cell represent the list of edges on the triangle.  The information of the patches number and image position is not stored into vtk.

I have not test this code yet. I will use the 3 .am file to test if it works. 
There is two place that the code can be improved: 1)write it in a more object-oriented way, like dune-grid/dune/grid/io/file/vtk/vtkwriter.hh 2)write the output as XML File Formats instead of a legency one.