The support of user clipping planes has been added to GLSL Hacker 0.8.0+. User clipping planes are very easy to use: you need a GLSL program that deals with gl_ClipDistance and you need to enable one of the available user clipping planes with gh_renderer.enable_state("GL_CLIP_DISTANCE0").
A demo is available in the
host_api/Clip_Planes/ folder of the
code sample pack v2.25.0.
This demo is based on this article:
http://github.prideout.net/clip-planes/
