[Mesa-dev] [PATCH 0/2 v3] Add support for clip distances in Gallium

[Bryan Cain]

This is the third revision of my changes to add support for gl_ClipDistance
with Gallium.  The difference between this set and v2 is that this set does
not add a new TGSI_PROPERTY indicating the number of clip distances used.
Instead, the UsageMask of the CLIPDIST output registers is set to indicate
which clip distances are used.  Some changes to ureg were necessary to set
the UsageMask to a value other than XYZW.