t_dd_dmatmp: Check provoking vertex convention when rendering quads

When drawing quads using triangles we need to be careful to make
the provoking vertices match when flat shading.

v2: Major rebase on top of Ian's other t_dd_dmatmp.h work.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
1 file changed