Start each pipeline with (x,y) in (dr,dg) registers for the shader.
Image shaders need to do some geometry work before sampling the image colors:
1) determine dst coordinates
2) map back to src coordinates
3) tiling
Feeding (x,y) through as (dr,dg) registers makes step 1) easy, perhaps trivial, while leaving (r,g,b,a) with their usual meanings, "the color", starting with the paint color.
This is easy to tweak into something like (x+0.5, y+0.5, 1) in (dr,dg,db) once this lands. Mostly I just want to get all the uninteresting boilerplate out of the way first.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4791
CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
Change-Id: Ia07815d942ded6672dc1df785caf80a508fc8f37
Reviewed-on: https://skia-review.googlesource.com/4791
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
9 files changed
