Updated the Gregory patch tessellation shaders to account for
transition edges.
Changed the implementation of OsdGetTessParameterizationTriangle()
to take the input parametric location as a 3-component value. This
allows the edge parameterization to be more numerically robust and
consistent.
Also, corrected some minor discrepancies between the various
tessellation shader configurations.
Updated Metal shaders to add support for drawing triangle
patches. This matches the current GLSL implementation.
- BoxSplineTriangle and GregoryTriangle patch shaders
- tess factor and tess evalutation for triangle patches
- improved adaptive tessellation code organization and function names
- quartic Bezier triangle patch evaluation
- OsdGetPatchIsTriangleRotated() function added
- OsdInterpolatePatchCoordTriangle() function added
Fixed smooth face-varying interpolation for the Metal viewer
when using screen-space tessellation. The location to evaluate
the face-varying value needs to match the computed tess location
instead of the intrinsic position_in_patch.
