runtime shader children on skvm backend
Mostly plumbing and misc instructions to draw threshold_rt.
Backends differ in what we return when sampling alpha-only
images, so I've switched threshold_rt to use the .a channel,
which everyone agrees on.
I'm pretty confused about what CTM and local matrix to pass
to the child program() calls, so I've just passed no-ops.
Change-Id: I004b428b4e5e27f3963a27dea0ef44e1f57bc3e0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297384
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed