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

[daniel heckenberg]

Hi Gem people,

After the various discussions on image formats I've delved into the
possibilities of using C++ generic programming (templates)  for efficient,
data format independent image processing code.

I started working on some proof of concept classes with a mind to testing
just how good/bad the performance would actually be in practice.  Then I
decided to do the google sanity check to see if anyone had done this
before... and the answer is yes.

Ullrich Koethe has developed a library called VIGRA which provides generic
programming classes for computer vision... and has published some papers
giving performance comparisons:
http://kogs-www.informatik.uni-hamburg.de/~koethe/vigra/

So... it certainly is possible to use templates to good effect for the
image format problem.  Whether VIGRA is a good fit for GEM I haven't yet
established... 

I'll continue to look into this unless anyone can point out why this might
be a waste of time...

In other business:
nvidia has included a NV_pixel_data_range extension in its latest list of
published extensions:
http://www.nvidia.com/dev_content/nvopenglspecs/GL_NV_pixel_data_range.txt

this should allow much faster texture uploads under windows and linux when
using nvidia drivers.

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)
http://glew.sourceforge.net/

Daniel