[HOpenGL] noticing freeglut vs not

[Sven Panne]

On Thursday 13 November 2008 03:24:29 Conal Elliott wrote:
> I'm looking for a way to use MainLoopReturns when freeglut is present and
> not when it isn't.  I could use some help.  I figure that the
> implementation has some way to generate that error message, and maybe we
> could similarly just do a standard ungraceful exit if freeglut is missing.
>
> The great thing about MainLoopReturns is that it plays nicely with ghci.
> Closing a window returns to ghci for more fun.
>
> Some more info at http://trac.haskell.org/FieldTrip/ticket/8 .
>
> Any ideas?

Currently the GLUT binding uses dynamic lookup to get freeglut-only API 
entries (see /GLUT/Graphics/UI/GLUT/Extensions.hs, cbits/HsGLUT.c, 
include/HsGLUTExt.h) and uses throwIfNull to test for non-existent API 
entries. Therefore, e.g. actionOnWindowClose should throw an exception when 
"classic" GLUT is used. I am not sure if I understand your request: Do you 
want a new API entry for the GLUT binding or a different behavior of the 
current entries?

Cheers,
   S.