Re: GSK review and ideas

[Emmanuele Bassi <ebassi gmail com>]

Hi;

On 16 December 2016 at 15:08, Owen Taylor <otaylor redhat com> wrote:

> > First of all, generally you have to supply entire buffers that have
> > valid content everywhere. If you're lucky you can use extensions like
> > buffer age so that you can track which part of the back buffer is up-
> > to-date, but that requires double or tripple buffering, which itself
> > brings up the memory use and possibly the the power use.
>
> I don't think we need to count on luck to have the buffer age extension
> - it is widely available on Xorg and Wayland and we have the ability to
> fix cases where it is missing.

That's, sadly, not true when you start moving on embedded hardware,
especially on the low end of the price point spectrum — which is where
switching to GL for rendering would benefit us.

> P.S. - when thinking about power consumption, not only does clipping
> allow actually not processing pixels, if you combine it with culling,
> you greatly reduce the number of objects you are walking over and the
> amount of setup that is being sent to the rendering API.

I agree: culling at the scene graph level — i.e. before reaching the
render tree — is probably where we're going to win the most, because
drawing widgets — especially with CSS — is still the expensive bit,
compared to submitting pixels to the screen.

Ciao,
 Emmanuele.

-- 
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[@] ebassi [@gmail.com]