convert SkVMBlitter over to floats
As we've learned there's not much advantage to working directly in i32
ops over f32... it's the same size, kind of a wash speed-wise, and f32
supports all operations we want where i32 supports only a subset. If we
really want to go fast, we need to focus on i16 operations, which are
both significantly faster and operate on twice as much data at a time.
(This is the same split as SkRasterPipeline, highp f32 and lowp i16.)
For now port everything to f32, with i16 to follow, perhaps much later.
There's a little here we could spin off to land first (uniformF, better
unpremul) but I think it might be easiest to land all at once.
Commit-Queue: Mike Klein <firstname.lastname@example.org>
Reviewed-by: Mike Reed <email@example.com>
14 files changed