Re: [Meshlab-devel] octree

[fabio g. <fab...@gm...>]

Hi,
I think you overseen  the project metro? (vcglib/apps/metro)
In the file sampling.h of that project you can read the declaration:

typedef Octree<FaceType, typename MetroMesh::ScalarType > MetroMeshOctree;

and some lines later the definition:

MetroMeshOctree oS2;

and finally the population:

if(Flags & SamplingFlags::USE_OCTREE)      
oS2.Set(S2.face.begin(),S2.face.end());

which (just like the other SI structure) is done with the function Set 
which takes
the  iterators to the first and the last element to store.

However, you can also find the implementation in the file 
vcglib/space/octree.h
(line 231)

        /*!
        * Populate the octree
        */
        template < class OBJECT_ITERATOR >
        void Set(const OBJECT_ITERATOR & bObj, const OBJECT_ITERATOR & 
eObj /*, vcg::CallBackPos *callback=NULL*/)

with an English comment :)

cheers,
Fabio



> thanks Fabio,
>    i looked at the files you mentioned... an octree would work fine 
> for my needs, if i could figure out how to use the code in meshlab - 
> is there a function somewhere to actually populate an octree from a 
> given model?  the initialize function in octree_template.h doesn't 
> seem to do much, and the comments are in Italian!
>
> imran
>
> On Thu, Jul 31, 2008 at 2:41 AM, fabio ganovelli 
> <fab...@gm... <mailto:fab...@gm...>> wrote:
>
>     The files in /vcglib/vcg/space/index implement a few spatial indexing
>     data structures
>     and algorithms (regular grid, octree, spatial hashing..) with a common
>     interface.
>     This means that you have function to get the closest k elements in the
>     spatial index
>     without caring if it is a grid or an octree. See
>     vcg/complex/trimesh/closest.h to get the picture of how it is
>     done. Even
>     better, look at the project metro in vcglib/apps/metro which computes
>     "point to mesh" distance with (optionally) all the spatial
>     indexing data
>     structures.
>
>     At the present the spatial indexing ds include vicinity tests and
>     (ordered) ray intersection test, but no z sorting and no generic BSP.
>
>     cheers,
>     Fabio
>
>
>     > I'm looking to create a binary space partitioning (BSP) tree in
>     > meshlab, to use when rendering on another platform for correct
>     > z-sorting.  I noticed two files already present: octree.h in
>     > /vcglib/vcg/space/index, and aabb_binary_tree.h in
>     > /vcglib/vcg/space/index (written by m_di_benedetto
>     > <http://sourceforge.net/users/m_di_benedetto/>)?  Does anyone know
>     > what these files do, and if they could be of any use for what i'm
>     > trying to do?
>     >
>     > thanks
>     > imran
>     >
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