This change restores the use of 4-bits in Far::PatchParam to
encode the refinement level of a patch. This restores one bit
that was stolen to allow for more general encoding of boundary
edge and transition edge masks. In order to accommodate all
of the bits that are required, the transition edge mask bits
are now stored along with the faceId bits.
Also, accessors are now exposed directly as members of Far::PatchParam
and the internal bitfield class is no longer directly exposed.
In osd layer, we use GLPatchTable (D3D11PatchTable) as a
device-specific representation of FarPatchTables instead of
DrawContext. GLPatchTable may be used not only for drawing
but also for GPU eval APIs (not yet supported though.
We may add CudaPatchTable etc as needed).
The legacy gregory patch drawing buffers are carved out to
the separate class, named GLLegacyGregoryPatchTable.
Also face-varying data are split into client side for now, until
we add new and more robust face-varying drawing structure
(scheduled at 3.1 release)
Tentatively replicate PatchArray structure in GLPatchTables. It will
be revised in the upcoming change.
Shifting hard-coded SRV locations of legacy gregory buffers in HLSL shaders.
