[Bf-committers] C++ DLL in blender modifier

[Lukas Gersthofer]

Hello Henrique,

modifiers in Blender are written in C and are embedded in the source code,
thus ctypes is not an option, but thanks for your reply!
To clear things up:
My modifier calls a function implemented in my DLL which simply takes the
mesh (vertex positions, face indices) as input, processes it and returns an
integer result code. But the positions are not changed and the result code
is random garbage (e.g. -310671472). I guess there's something wrong with
the call (e.g. wrong calling convention) and therefore the stacks are
incompatible (parameters and return value get messed up). I compiled the
library with the same build settings as set in Blender (x64, Release). I am
using Visual Studio 2013 if that helps.

So I'm still looking for the solution. :-(


On Sun, Jun 12, 2016 at 9:44 PM, Henrique Nunes Jung <henriquenj at gmail.com>
wrote:

> Hello Lukas
>
> I have done something related a couple of weeks ago. I didn't implemented a
> modifier, instead I implemented a RenderEngine. My engine is written in
> C++, so I created a C wrapper around it and called from Blender using
> ctypes [1]. I didn't understand how you are calling your C functions, from
> what I  recall __declspec is just to make your functions available as entry
> points on the DLL. Anyway I suggest you to take a look at ctypes, because I
> have successfully use it to call C functions using python from Blender. You
> can look at my plugin at github[2].
>
> Hope it helps
> Henrique Jung
>
> [1] https://docs.python.org/3.5/library/ctypes.html
> [2] https://github.com/henriquenj/rendergirl/tree/master/BlenderPlugin
>
> On 11 June 2016 at 17:08, Lukas Gersthofer <lukasgersthofer at gmail.com>
> wrote:
>
> > Dear Blender Dev community,
> >
> > I encountered a problem while implementing a new modifier. The modifier
> > aims at optimizing the physical properties (center of mass, moments of
> > inertia, etc.) of a shape. After 3D printing the model is able to stand
> in
> > an upright position, rotate around a given axis, etc. (see
> >
> >
> https://www.cg.tuwien.ac.at/research/publications/2015/musialski-2015-souos/musialski-2015-souos-preprint.pdf
> > )
> > The implementation of the algorithm is in C++ and I created a DLL which
> has
> > a C API as well. Now I wanted to integrate the algorithm into blender as
> a
> > modifier. The modifier is almost done but the API call doesn't work
> > properly. There are no errors but the return values are random bullshit.
> > The calling convention I use is __declspec.
> >
> > If you need further insight into the code, I can share my repository with
> > you. The algorithm is going to be open source as soon as all features are
> > implemented and are working properly.
> >
> > I would really appreciate a helpful anwer cause I'm really struggling
> with
> > this problem and because it is my bachelor thesis I wanted to try
> > everything to finish it!
> >
> > --
> > mit freundlichen Grüßen / with kind regards
> >
> > Lukas Gersthofer
> > Vienna University of Technology
> > _______________________________________________
> > Bf-committers mailing list
> > Bf-committers at blender.org
> > https://lists.blender.org/mailman/listinfo/bf-committers
> >
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-- 
mit freundlichen Grüßen / with kind regards

Lukas Gersthofer
Vienna University of Technology