https://bugs.winehq.org/show_bug.cgi?id=35900
--- Comment #3 from Stefan Dösinger stefan@codeweavers.com --- If I remember correctly GeForce8+ GPUs support it, but GeForce 7 and earlier do not. d3d9-class radeon GPUs have support for dxtn volume textures.
There's an equivalent GL extension called GL_NV_texture_compression_vtc, but it uses a different block layout than d3d, so using it isn't trivial.