[vtkusers] Using 3D textures on the Mac

[David Gobbi]

Hi All,

I'm having some trouble with vtkVolumeTextureMapper3D on
the Mac.  When I try to use it, it gives the following error:

vtkOpenGLVolumeTextureMapper3D (0x177e6000): required extensions not 
supported

I checked to see which extension it couldn't find, and it was
glTexImage3DEXT.  The silly thing is that Mac OS X 10.4
supports glTexImage3D directly (i.e. not as an extension).
When I changed the code to use glTexImage3D, it worked
fine.

I have two questions:

1) has any other Mac user seen the same issue with
    vtkVolumeTextureMapper3D?

2) how would people feel if I added a couple macros to the
    code so that, on OS X, it uses vtkgl::TexImage3D instead of
    vtkgl::TexImage3DEXT?

 - David