Xgl and direct rendering

[Matthias Hopf]

On Mar 01, 06 09:55:26 +0100, Michel Dänzer wrote:
> On Tue, 2006-02-28 at 19:23 +0100, Matthias Hopf wrote:
> > On Feb 27, 06 15:18:34 -0500, Owen Taylor wrote:
> > > It may be that the only interesting case is full-screen video, which
> > > is the easiest case to design, since the compositing manager basically
> > > just has to get out of the way.
> > It definitively isn't.
> What isn't what? :)

It is not the only interesting case ;)
Being vague by intention :P

> > > This "get-out-of-the-way-I'm-going-fullscreen" protocol is also needed
> > > for fullscreen 3D games with direct rendering.
> > This shouldn't be much of a problem, the composition manager should know
> > when a single nontransparent window is shown fullscreen.
> Sure, but a mechanism to have the fullscreen front buffer be scanned out
> directly by the display hardware would still be nice.

Right... But that isn't easily possible, as a front buffer suddenly
might become transparent, or moved to the background, and then we would
have to switch to an off-screen buffer, which is not doable right now.

> > Talked with many vendors and programmes, and all agreed that using pixel
> > shaders is the way to go. Eventually, native support for YUV textures
> > might go away in the future as well.
> 
> Not sure how this relates to the discussion about (not) using the
> overlay, but I'd like to add a couple of points to that discussion:
> 
>       * Hardware overlays seem to be losing scaling and/or colour
>         conversion capabilities in newer hardware generations, so some
>         kind of shaders will still need to be involved with them.

Basically my point.

>       * Video playback is not the only use for overlays.

What other uses do you see for overlays? Just curious.
No, I do not consider mouse pointers to be overlays, though they share
many properties.

> I'm leaning towards not putting too much effort into using the overlay
> for video playback in a composited environment based on these and other
> points.

IMHO for composition environments using overlay for video is a no-go.

Matthias

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