Comment # 16 on bug 57875 from Henri Verbeet

(In reply to comment #15)
> I've written an extension proposal for a new mesa extension that exposes the
> CLIP_DISABLE bit. The proposal is attached, please review and comment. There
> are some TODOs I'm not quite sure how to deal with, see the list in "Status".
> 
  - It probably makes sense to mention "depth" in the extension name somewhere,
we really only care about the near and far clipping planes. E.g.
MESA_depth_clip.
  - Perhaps it makes more sense to write the extension in terms of
ARB_depth_clamp. I.e., provide a subset of ARB_depth_clamp, that only disables
depth clipping, and generates undefined results in the depth test, except for
perhaps GL_ALWAYS / GL_NEVER. (Also, note that you can't really make fragment
depth values undefined before / in the fragment shader, because you have
interactions with e.g. texture filtering as well.) It would avoid the perhaps
somewhat questionable "ARB_depth_clamp must not be supported", and you can just
defer to ARB_depth_clamp for most of the issues etc. The interaction between
the two extensions just becomes that if ARB_depth_clamp is also supported you
get defined depth test results.