[vtkusers] OpenGL library problem.

[Jianlong Zhou]

hi, all

I derived classes from vtkOpenGLVolumeTextureMapper2D 
vtkVolumeTextureMapper2D and I use the OpenGL function "glTexImage3D" in my 
class. At the same time I add "glext.h" file to my include list. But when I compile files, I 
always get the following errors:

error C2065: 'glTexImage3D' : undeclared identifier
vtkMyVolumeTextureMapper.cxx

My grphics card is GeForce 4 and I have installed the latest graphics driver.

Anyone know how to solve this problem?

Thank you in advance.

Best regards,

Jianlong