Re: Full screen color management

[Richard Hughes <hughsient gmail com>]

On 6 September 2011 13:40, Emmanuele Bassi <ebassi gmail com> wrote:
> oh, you wanted *actual* proper feedback? ;-)

Yes! :-)

> how is the shader approach structured?

Well, at the moment the test code is a fragment shader which is
attached to each actor using clutter_actor_set_shader (which I notice
is now deprecated). I was going to wrap all the color stuff up in a
GcmIccEffect and just add an effect to each actor. The question then
becomes what to do with an actor that straddles two outputs in a
multhead setup. Logically it makes sense to cut the actor up and use
the correct screen profile on each part (using a 1bit bitmask or a
uniform xoffset in the shader perhaps?) but it might be simpler just
to choose the output profile that the actor most covers.

As for masking out areas that already have color correction, I'm not
sure. I'm tempted to just opt-out whole actors at the moment, although
from a mutter point of view that means you don't get color corrected
toolbars and that kind of thing. This can be quite a gradual thing, we
don't have to do everything at once as long as we've got an good
opt-out story for the Pixars and Dreamworks of this world.

Richard.

p.s. the test code I'm using is
http://git.gnome.org/browse/gnome-color-manager/tree/tools/gcm-glsl-demo.c
although this will change quite a lot in the next few weeks.