[Piglit] Patch to test for ARB_clip_control v2

[Mathias Fröhlich]

Hi,

On Saturday, October 25, 2014 09:41:02 Mathias Fröhlich wrote:
> Also interrestingly softpipe does not fail either.
> Probably nvc0 and softpipe are clipping based on the final depth buffer
> values in [0, 1] instead of the clip space z values either in [-1, 1]
> or [0, 1] depending on clip control depth state?
> The unclipped NV_depth_buffer_float extension would have made this much
> more sensitive to what is clipped exactly when.
> Without the unclipped depth buffer values from NV_... I would think it's not
> important which of the above variants is taken for clipping or clamping.
Actually that's not quite true what I said. I think that only holds if
near and far occupy the whole depth buffer range. If the near far range is
smaller this is different.

Mathias