[PATCH weston] compositor: add a masking mechanism to weston_layer

[Giulio Camuffo]

2013/12/10 Pekka Paalanen <ppaalanen at gmail.com>:
> On Tue, 10 Dec 2013 11:13:42 +0100
> Giulio Camuffo <giuliocamuffo at gmail.com> wrote:
>
>> 2013/12/10 Jason Ekstrand <jason at jlekstrand.net>:
>> > Giulio,
>> > Couple thoughts.  First, you don't provide an implementation of the
>> > clipping in  any of the renderers.  Probably have to wait on the
>> > Collabora people for the RPi renderer, but we should have pixman
>> > and gl implementations of this.
>>
>> There is no need to add support in the renderers for that. The masking
>> is done in view_accumulate_damage(): the part of the view's
>> boundingbox that doesn't fit in the mask is added to the view's clip,
>> and the renderers then clip that away already.
>
> Does this work if the renderer paints the whole surface regardless of
> damage? Rpi-renderer does that, since every surface is on its own
> overlay.
>
> The whole damage tracking is kind of unused on the rpi-renderer, since
> the firmware will probably redraw everything anyway. Prohibiting damage
> will not prevent parts of a surface from being painted. Damage is just
> a hint saying what is not necessary to repaint.

No, the masking isn't done by not damaging the parts not in the mask,
but by adding the opposite of the mask in weston_view::clip. But i see
that the rpi renderer doesn't clip away that, so no, currently this
wouldn't work with it. I guess it could work though, right?

>
>
> Thanks,
> pq