Previously, when converting a program, the pipeline stage could assume
that an input to main() of type half4/float4 was always the input color.
This was a good assumption since the only possible inputs were
coordinates, or the input color.
This CL now recognizes that when a second float4 is passed to the main()
function, it should be a SK_DEST_COLOR_BUILTIN. This will let blend
functions pass in two colors.
ProgramToSkVM now takes a dest-color argument as well, but existing call
sites won't reference it (since they aren't for blend functions). I've
just passed the input-color a second time, since the value will never
actually be accessed.
Change-Id: I4214586bda605c6d287aa25b1b099e6ef5ba15a4
Bug: skia:12080
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/417261
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
