Re: [Meshlab-devel] octree

[skunkwerk <sku...@gm...>]

Is anyone familiar with any functions for triangulation or tesselation?
because that's the way i'm thinking of splitting triangles...

/vcglib/wrap/gl has a file named glu_tesselator.h
i'm not sure what the "outlines" to the tesselate function are supposed to
be.  or which indices to pass to it - those of the model's vertices
(m.vert)?

the use on line 178 of import_dae.h seems to indicate that the indices are
just a local, empty vector of ints and hte outlines are just the vertices -
is this correct?

there's also a triangulate function in hole.h, but it doesn't seem to do
much

any suggestions?

imran

On Fri, Aug 1, 2008 at 9:27 AM, skunkwerk <sku...@gm...> wrote:

> thanks Fabio, i'll try it out.  I was also looking for where in the code it
> splits triangles that intersect the plane you're dividing with - I remember
> Paolo said something about how the refine.h file can clip triangles; do you
> know of any code that uses this?
>
> is Paolo on vacation or something?
>
> imran
>
>
> On Thu, Jul 31, 2008 at 1:47 PM, fabio ganovelli <
> fab...@gm...> wrote:
>
>> 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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