{1K,1K} ought to work fine for F16 precision. 16 bit floats step by 1.0
between 1024 and 2048, so they should be able to just barely represent
distinct coordinates for each pixel. If precision drops below 16 bit
we'll start seeing banding because we can't distinguish coordinates.
Swap out the colors a little so that it's clear which images are the 1K
(black+green) and which are the old 100K (black+white).
Change-Id: I92761c3aa67cab57332e6f00a421c63c1d9d990a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201041
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
rcp(rsqrt(x)) doesn't have enough precision when x is a coordinate.
(It's fine when x is a color, like in the softlight blend mode.)
Adds a GM to test this. It used to look quite ugly.
Change-Id: Icec295c2e2f50ae7a5e3e33c62270f632a58f65c
Reviewed-on: https://skia-review.googlesource.com/16914
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
