Re: [PyOpenGL-Users] Enums from extensions

[JoN <jo...@we...>]

Allen, Hi

I have the same question regarding enums, it seems you have to, at the mo=
ment,
find their hex values in the system's include files and manually declare =
them in
your Python code.

Regarding the newer OpenGL extensions you were asking about:

I'm no expert and am scrambling for a foothold on the GL/Python learning =
curve
myself, but this is what (I _think_) I've gleaned so far:

GlewPy has been the traditional way of getting at the extensions, and the
author/s is always adding new extension access.

However, with the advent of Python ctypes (now included by default in 2.5=
, that
correct?), you can access the calls in the shared libraries (.so's on uni=
xen
like Linux, .dll's on windoze) directly, though you have to wrap your hea=
d
around how ctypes works.

This allows you to at least connect in the ARB extensions for the 'good s=
tuff',
say if you are stuck with OpenGL 1.5, or get the new function calls from =
OpenGL
2.0 and up.

And yes, exactly as you say, you can write wrapper code that makes Python=
 adapt
on the fly to whatever version of OpenGL is present.
Some good stuff on doing that is at the GLSL tutorial (Ok its for C but t=
he
calls still apply) at LightHouse3d:
http://www.lighthouse3d.com/opengl/glsl/index.php?ogloverview

Now -=20

The following is an excellent example from PyGame, that uses ctypes to ac=
cess
the fragment shaders and compile and run GLSL code on the GPU:

http://www.pygame.org/wiki/GLSLExample

This example works, I've got it running and have spoken to the author and=
 gone
further and got texturing working in the fragment shader from Python.

As examples of OpenGL access from Python go, thats reasonably close to 'S=
tate Of
The Art' technology for modern cards!


Highly recommend also joining the pygame users mailing list (see above si=
te),
I've got some very good info off people there so far.


Hope all that is of some use to you!

Jon


Quoting Allen Bierbaum <abi...@gm...>:

> I see in the documentation how I could import an extension and
> initialize it, but how do I get the enums from an extension?  For
> example right now I would like to use GL_DEPTH_COMPONENT24 in my code
> but I don't know how to get that from PyOpenGL.
>=20
> Any ideas?
>=20
> Also, this may have been asked before, but are there any plans to make
> it easier to use the newer "extension" features of OpenGL?  With the
> dynamic nature of python it seems like it would be possible to have
> PyOpenGL dynamically adapt it's interface to any given version of
> OpenGL on the fly.  For example asking PyOpenGL to present the
> standard interface for OpenGL 2.0 it could go out and find any of the
> needed extensions and name them like they are in the 2.0 spec.  This
> would be a great feature and would be unique to PyOpenGL since it
> can't be done in C or C++.
>=20
> Thanks,
> Allen
>=20
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>=20




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