[osg-submissions] EXT_texture_integer submission ShaderModel 4.0

[Robert Osfield]

HI Art,

I have several concerns that I have grapple with when see new features added

  1) They fit in well with existing codes
  2) They avoid breaking API unless really necceassary.
  3) The minimal and complete rule applies
  4) The addition doesn't introduce undue complexity into the interface or
      implementation.

You suggest for having multiple border color types or void* fails on
several counts and I won't be merging anything like this.

The least intrusive solution I can see it to go the Vec4d route as
case where required.  Doubles casting to ints should work without
precision loss until you get to reasonable large numbers.  It might
not be a perfect implementation for pure int texture formats but its
certainly far less intrusive and confusing than duplicating variables
and methods or using void*.

As for enums, I would suggest that the feature is generally more
information than just being something specific to the new int texture
extensions, we really have to avoid the enums being too cryptic too -
others have to use and maintain the code, the less obvious it is the
more mistakes will be made and the more bugs we'll have.

Robert.