Re: [Wxlua-users] extending GLFW with wx / using wxlua as library in a c-project

[John L. <jla...@gm...>]

On 9/3/05, Eike Decker <ei...@cu...> wrote:
> Hi
> Thanks for the answer and positive feedback on a C compatible header.
> I am sorry that I haven't described the full "problem" in my last
> request, but I didn't thought it was necessary, but it seems to be more
> complicated than I thought (surprise surprise).

It always is... :(
=20
> The project I talked about is a 3D engine that can be extended by using
> lua and it looks currently quite nice
> (http://chilli.degnet.de/~e_decker/lux/index.php/Main/Screenshots -

Looks nice.

> website is under construction...). - anyhow: We are currently using GLFW
> as windowenvironment for OpenGL which replaced Glut (we want to be
> plattformindependent). Now, the idea about wx was, that we could use it
> to extend the engine with GUI elements for making editors, etc.

wxLua would be perfect for this, except for the problems...

> I have now tried out the loadlib function in lua to load the dll like thi=
s:
>  luaopen =3D loadlib("wxLua.dll", "wxLua")
>=20
> unfortunately, calling luaopen in lua itself crashs the application
> somewhere deeply in the dll and I can't debug this. Meanwhile I am also
> not sure anymore if it is really possible to extend the engine this way
> since we need our own mainloop. I guess that creating a new window using
> WX makes the engine crash since GLFW did this before - but it's only a
> guess, I haven't spend too much time on this window-stuff programming...

wxLua relies on the wxWidgets main loop and I don't think that this is
avoidable because of the required notification events.

Typically you create a wxApp instance that initializes the wxWidgets
main loop. (this is a good site for the wxWidgets docs)
http://www.lpthe.jussieu.fr/~zeitlin/wxWindows/docs/wxwin_wxappoverview.htm=
l#wxappoverview

However I have seen people handle initializing the mainloop their own way, =
see
http://www.lpthe.jussieu.fr/~zeitlin/wxWindows/docs/wxwin_wxapp.html#wxappm=
ainloop
Also search for IMPLEMENT_APP_NO_MAIN on google
http://lists.wxwidgets.org/archive/wx-users/msg33172.html

"To use your own "int main()" you'll need to use the
IMPLEMENT_APP_NO_MAIN() macro and use wxEntry. On the wiki there's a
topic about using wxWidgets in DLLs which is somewhat similar to
this."
http://wiki.wxwidgets.org/wiki.pl?Creating_A_DLL_Of_An_Application

** I have never tried to use DLLs nor anything like this so I can't be
of much help, but maybe the above will get you started and give you
some ideas.

> As a possibility, we could switch from GLFW to WX - but this would cause
> much more work on this (a little bit minor) problem than we wanted to spe=
nd.

Switching over to wxWidgets is an option, it'll add a lot of features,
some useful data structures, and whatnot, but might be a lot of work.

> Any creative ideas how to solve this problem without spending too much
> work in rewriting the C core of the engine?

As as aside, I don't want to start a war here, but C++ is perfect for
GUI libs because you can encapsulate the data for a window in a class
and use inheritance to reuse code. A button for example, has fore,
back colours, size, position and of course so would a generic window,
the button just adds a member for the label.

You can always compile C w/ C++ if you do this when including headers
extern "C"
{
    #include "cheader.h"
}

I don't know much about the loss in performance of compiling C code as
C++, but what what I've seen (Great computer language shootout IIRC)
it wasn't too significant.

Good luck,
    John Labenski