[Mesa-dev] [PATCH 0/6] Enable Pixman for Mesa

[Matt Turner]

On Wed, Jun 25, 2014 at 5:38 AM, Juha-Pekka Heikkila
<juhapekka.heikkila at gmail.com> wrote:
> This is my old set which enable using Pixman on Mesa for some texture
> conversion fast paths. As is this passes Piglit quick set on my IVB.

Pixman doesn't actually have fast paths for swizzling, like we're
using in this series. I imagine improvements we're seeing here are
simply because Mesa's code is slow.

I never pursued this idea for a couple of reasons. One is that we
should probably use the GPU to do the conversions in the ideal case.
Also, pixman doesn't support floating-point formats. Some work has
been done in the last year or so to make this much easier to implement
though.

The first reason above shouldn't block other improvements, and the
second reason is fixable with some contributions to pixman. And pixman
is really a trivial dependency, so that shouldn't be a problem.

Soren thinks this is worth doing and I trust him.

I think a worthwhile goal would be to add support to pixman for doing
a bunch of the conversions Mesa requires and then dropping the code in
Mesa. Are you interested in doing that? I know Jason (Cc'd) is working
on cleaning up a bunch of this code.

Are you planning to contribute swizzling fast paths to pixman? The
power-of-two-sized-component formats should be really easy to optimize
using the SSE shuffle instructions.