delete lowp plus
I have figured out how to implement lowp clamp_1/clamp_a, and
implementing clamp_1 would make lowp plus active.
But... the way we have factored blend modes requires us to be able to
lerp between the dst and possibly-out-of-range src values. This is not
possible in lowp. If we try to multiply with values in [0x8001,0xffff],
we'll just get garbage. We'll clamp them back in range, but sadly
clamped garbage is still garbage.
So the simplest thing to do is keep plus blends in floats. This CL
doesn't even change that... we'd use floats before and after it. It
just removes the lowp plus stage code that is both dead and buggy.
As far as I can tell, no other drawing is currently gated by lowp
missing clamp_1 or clamp_a.
Change-Id: I55b73c840614f1bff9cd610dff90ca5e2b5c73e5
Reviewed-on: https://skia-review.googlesource.com/19909
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
4 files changed