[HOpenGL] Exiting application

[Sven Panne]

David Waern wrote:
> How are you supposed to handle the event of a user who closes the hopengl
> window? I see no way to detect this with the API. The main loop of hopengl
> just keeps running.

To be exact, it's the GLUT part of HOpenGL which misses the functionality you
want. But this is a direct consequence of the GLUT library, and there is not much
HOpenGL can do about it. The freeglut library (http://freeglut.sourceforge.net/)
has some extensions in this direction, but it's not yet very widespread and
there is no support for those extensions in HOpenGL currently (but this might
change some day).

> Also, when I have the hopengl mainloop running and I destroy the current
> window (or exit with System.Exit.exitWith), both ghci and hugs just dies
> along with the app.

When you destroy the last window, GLUT exits the application internally, so it's
not a Haskell issue. Using exitWith exits ghci/hugs, that's what it is supposed
to do, isn't it? :-)

> Am i doing something wrong?

No, not at all. GLUT is only meant as a simple UI library, if you want something
more polished, you can try gtk+hs (http://www.cse.unsw.edu.au/~chak/haskell/gtk/)
or wxHaskell (http://wxhaskell.sourceforge.net/). Both have OpenGL support, so
you can continue using the OpenGL package of HOpenGL for rendering, and both have
more sensible ways of handling your windowing issues.

Cheers,
    S.