[AGL] D bindings and the extensions mechanism

[<to...@te...>]

The only set of D headers for openGL that is currently maintained,
DerelictGL[1], contains its own extension loading mechanism.  So I'm
wondering if I should just use that, instead of AllegroGL's system.  My
understanding of AllegroGL is that it contains two more or less
independent parts: the Allegro/OpenGL interoperability, and the
extension loading.  Since I'll be needing only the former, I wonder if
it would be possible to disable AllegroGL's extension loading.  Would
that be a simple feature to add to AllegroGL?

So far, using derelict's extension loading system doesn't seem to
conflict with AllegroGL's.  So it's probably possible to just have both
enabled.  Just seems like a waste to load the extensions twice, though.

I'm not completely sure that I'll end up using Derelict's extension
loading instead of AllegroGL's yet.  But since it can reduce DAllegroGL
to only one or two files, it's a tempting option.  The downside is that
the users have to add an extra function call (DerelictGL.load()) to
their initialization code, plus DerelictGL.loadExtensions() if they want
extensions, and DerelictGLU.load() if they need GLU stuff.  In return
for that, they get the DLL file automatically loaded at runtime,
exceptions thrown if the DLL itself or any extensions they are importing
are missing, etc.

Whether I should keep the allegro_gl_extensions_* structs or not, is
another question.  DerelictGL has something like it, but it could be a
bit confusing that something mentioned in AllegroGL's docs doesn't work
in DAllegroGL.  So maybe I should keep that part.

Any opinions are welcome. :)


[1] http://www.dsource.org/projects/derelict