Re: [PyOpenGL-Users] glVertexAttribPointer(); loading platform-specific functions

[Paulo S. <nit...@gm...>]

Joshua Davis from http://www.joshuadavis.com/ :O ? awesome, be welcome! \o/

anyway, i don't know if it is your very first approach on OpenGL using
PyOpenGL - i think i'm even struggling with it way much more than you
- my very first approaches were trying to analyse some pyweek games
like http://pyweek.org/e/GNAG/ , but it uses Pyglet instead (which
also uses OpenGL as well) - in the case you can't fix what you try to
do with PyOpenGL, maybe would be a good idea trying Pyglet also...

cheers!

On 8/13/09, Joshua Davis <joshuardavis@q.com> wrote:
> I have some questions that probably boil down to my inexperience with
> Python. My setup is PyOpenGL-3.0.0c1 on Python 2.5.x on Mac OS X. I'm
> trying to modernize my OpenGL to use VBOs and vertex attributes,
> working through the tutorials at http://bazaar.launchpad.net/
> ~mcfletch/openglcontext/trunk/annotate/head:/tests/shader_4.py. When
> I execute code like this:
>
> vertexBufferObject = vbo.VBO(...)
> gl.glVertexAttribPointer(positionLocation, 3, GL_FLOAT, False, 24,
> vertexBufferObject)
>
> The second line generates this error:
>
> ctypes.ArgumentError: argument 6: <type 'exceptions.TypeError'>:
> Don't know how to convert parameter 6
>
> The following code is what I've been doing to get platform-specific
> (?) PyOpenGL functions. They often seem to require some massaging of
> argument types; is the same thing needed for glVertexAttribPointer()
> above?
>
> # This is adapted from http://www.pygame.org/wiki/GLSLExample.
> try:
>      from OpenGL import platform
>      gl = platform.OpenGL
> except ImportError:
>      try:
>          gl = cdll.LoadLibrary('libGL.so')
>      except OSError:
>          from ctypes.util import find_library
>          path = find_library('OpenGL')
>          gl = cdll.LoadLibrary(path)
> gl.glShaderSource.argtypes = [c_int, c_int, POINTER(c_char_p), POINTER
> (c_int)]
> gl.glGetShaderiv.argtypes = [c_int, c_int, POINTER(c_int)]
> gl.glGetShaderInfoLog.argtypes = [c_int, c_int, POINTER(c_int),
> c_char_p]
>
> Is there some newer, better way to load these functions? Is there
> some web tutorial that explains what's going on here, so that I can
> debug it myself next time?
>
> Thanks -- Josh
>
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