Properly interface Julia with Geogram rather than calling compiled C binaries

[Kevin-Mattheus-Moerman]

@SimonDanisch @j-fu @sjkelly I was wondering if some of you would be interested in helping to create a Julia wrapper for Geogram. Geogram is an extremely powerful C++ library for geometry processing.

One impressive feature of Geogram is surface remeshing (which libraries like TetGen do not do well at all). This is the only feature I've currently enabled through this initial (poor) pass at a wrapper. I'm currently only using the Geogram binary vorpalite by simply using the following silly approach: run(vorpalite <settings and input/output file description>), where I am using .obj files as input and output. I am currently completely new to wrapping C++ functionality in Julia properly. But I know that you guys have probably done similar steps in the passed e.g. for TetGen etc.

Would you be interested in helping to implement a wrapper for Geogram properly? I think it could be a valuable addition to the Julia geometry processing ecosystem. I am mainly interested in surface remeshing at the moment but Geogram is also great for Voronoi (or general power diagram) tesselation, can do tetrahedral meshing, and even has basic hexahedral meshing capabilities. The project is really quite vast. Put perhaps we can take some initial steps to wrapping vorpalite first?

No worries if you are too busy just seeing if you are interested. Thanks.

[Kevin-Mattheus-Moerman]

@BrunoLevy are you and your team interested in helping with this? Perhaps you can run it as a project for some advanced enough students.

[j-fu]

I think this would be interesting, and I could provide consulting based on my experience with BinaryBuilder.jl and maintaining TetGen.jl, Triangulate.jl and AMGCLWrap.jl. Currently, I made quite a number of commitments already, so I can't do much more.

After a short look, some points here:

• What should be wrapped ? Everything with GUI or only the algorithms ?
• My general experience regarding Julia wrappers for C++ code is to write a C Wrapper first, access everything via ccall and write a Julia wrapper around that. E.g. TetGen.jl does this. Using CXXWrap.jl instead (in the moment) has the problem that with each Julia minor version, new binary builds need to be created, while access via ccall is Julia version agnostic and therefore doesn't need much maintenance once it works. I have no idea if the C Wrapper idea would be a feasible approach with the geogram API.

[BrunoLevy]

Hi @Kevin-Mattheus-Moerman and @j-fu, yes I can give some help and will be happy to discuss (but I cannot advise a new student though, because I'm overbooked already, it would be irresponsible and not good for the poor student !)

[Kevin-Mattheus-Moerman]

Thanks @j-fu.

• What should be wrapped?

I think the initial target is to wrap vorpalite for surface remeshing, the source of which seems to be here: https://github.com/BrunoLevy/geogram/blob/dfbe30e11a453be6524b3f99082a4f8e6bdffbcb/src/bin/vorpalite/main.cpp

My general experience regarding Julia wrappers for C++ code is to write a C Wrapper first, access everything via ccall and write a Julia wrapper around that.

Thanks for the advice. I'll have a look into ccall so. Thanks.

[gatocor]

Hi, I would like to participate. I would like to use geogram for my own package although more on the Voronoi/Delaunay functions. I will fork the project and see how far I can get on the wrappers.

[Kevin-Mattheus-Moerman]

@Aminofa70 looks like @gatocor is interested too. Are your efforts available on Github already?

[Aminofa70]

@Kevin-Mattheus-Moerman: This is my package https://github.com/Aminofa70/GeoPUPM.jl to use the Geogram for finite element mesh but now I have to modify the code because I can improve it based on ComodFerrite

The point now is calling Geogram in C.

I tired to use TetGen_jll.jl.

they are using
https://github.com/JuliaPackaging/BinaryBuilder.jl

The point is that I got some error mainly about my mac system that I couldn't solve it.
I would be more than happy to help.

I want to connect this package to ComodFerrite and do Finite element for stl files.

Very soon will be done.

[j-fu]

Hi @Aminofa70, what is happening with TetGen_jll.jl on your Mac ? After all IMHO BinaryBuilder ist the best way to go anyway. And why don't you use TetGen.jl directly - what is missing there ? If you feel a need to discuss this, please open an issue in TetGen.jl.

That said, if there I know the concrete code with C API calling Geogram to be made available via BinaryBuilder, I am still ready to help (will be a bit busy with a workshop the next two weeks though).

[Aminofa70]

Dear @j-fu, actually I tried to do the same steps in TetGen.jl for calling Geogram, but got errors several times.

Try to do lik: https://github.com/JuliaPackaging/Yggdrasil/blob/4b356db46aa840d5f427d0bd5bfba8287d2520e9/T/TetGen/build_tarballs.jl

We appreciate it if you could help us whenever you have time.

There is no problem with TetGen.jl and TetGen_jll.jl.

[gatocor]

I still got nothing, I am trying BinaryBuilder to build the Geogram X_jll libraries and I am having problems with mac. When building locally in my own laptop works though.