[PD-dev] [GEM] generic programming for image processing and more

[daniel heckenberg]

chris clepper writes:

> >This introduces the more general problem of how to handle openGL extensions
> >under GEM.  At the moment extensions are handled at compile time and in a
> >fairly ad-hoc way... perhaps something like GLEW would be useful (altho it
> >doesnt support OS X)
> 
> we already do this on OSX.  we have some sgi code that checks for the 
> string in the driver.  it's very simple and should be cross-platform.

ok... great.

does that code handle the annoying explicit binding requirement for
extension functions under windows? (a call to wglGetProcAddress is required
for each extension function)

i had a play around with the nvidia pixel_data_range extension last
night... strangely enough it seems that the GL_BGR texture format can't be
used with this extension... annoying because that format and YUV are
usually the only pixel formats that Windows video codecs can produce
without explicit conversions... Also, GL_RGBA can't be used, only
GL_BGRA... so here's another case where pixel formats can be problematic,
hardware dependent and complicated...

daniel