Add conic fill support to the tessellator
This started out as a sandbox to experiment with a Wang's formula
analog for rational quadratics, but it quickly became apparent that
running Wang's formula on the down-projected points was an upper bound
on what the rational version would have been (for both w<1 and w>1).
This CL therefore adds conic support by upgrading the tessellation
shaders to use ratoinal cubics, converting every path verb to a
rational cubic, and then running Wang's formula on the down-projected
points. In the future we can always drop in a better formula if we
work one out.
Bug: skia:10419
Change-Id: I97021ea56afea54fdbe76745bacd3251e350fd97
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/337156
Reviewed-by: Tyler Denniston <tdenniston@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
8 files changed