[vtkusers] Adjacency graph of a labeled mesh

[Gwenael Guillard]

Hi,
I have a vtkPolyData such that each point point has a label. A given 
label, m, define a connected area of the mesh Am. A region can not be a 
subset of another.
My question is : how to recover the adjacency graph of this mesh? That 
is to say, given a label m, how to find all region Am0,..Amn, such that 
they are a neighbour of region Am?

Example (supposed to be a 3D mesh)

1111111 2222222
1111111 2222222
1111111 2222222
3333333 4444444
3333333 4444444
3333333 4444444

should return
region 1 is linked to regions 2 and 3
region 2 is linked to regions 1 and 4
region 3 is linked to regions 1 and 4
region 4 is linked to regions 2 and 3



Thank you very much

Gwenael