[Xorg] Re: Damage/Composite + direct rendering clients

[Alex Deucher]

--- Andy Ritger <aritger at nvidia.com> wrote:
> 
> 
> On Mon, 17 May 2004, Alex Deucher wrote:
> 
> > 
> > --- Andy Ritger <aritger at nvidia.com> wrote:
> > > 
> > [snip]
> > > 
> > > - A Video Overlay Xv Adaptor is obviously fundamentally
> incompatible
> > >   with Damage/Composite.  Should X drivers no longer advertise
> > >   Video Overlay Xv adaptors if they are running in an X server
> that
> > >   includes Composite support?
> > > 
> > 
> > Many video overlays support alpha blending with the graphics layer,
> > it's just that support was never implemented since xfree86 never
> > supported it.  I wrote a patch for radeon a while back.  As I
> recall,
> > it should also be possible with r128 and savage hardware, although
> I
> > haven't tested on those chips as of yet. it may also be possible on
> > other chips.
> > radeon patch:
> > http://www.botchco.com/alex/radeon/Xv/xv_alpha/radeon_xvalpha.diff
> > 
> > OT: radeon patch that enables Xv gamma correction:
> >
>
http://www.botchco.com/alex/radeon/Xv/xv_gamma/radeon_video_gamma.diff
> > 
> > Alex
> 
> Thanks, Alex, but how would this fit in with the Composite
> extension's notion of redirecting windows to offscreen storage?

I don't know.  I'm not really too familiar with how composite works
unfortunately.  On radeon my understanding is that the overlay will
blend with whatever is being displayed on the graphics layer (either
globally or per pixel).  So as long as you set the right overlay alpha
value it should just work without needing to composite to an offscreen
surface. In global or per pixel mode, you don't need to draw a
colorkey.  it will blend the video in whatever position you put it. 
Global mode blends the graphics and video globally.  The per pixel mode
is probably what we would want, but it requires ARGB graphics.  the A
value is then used to set the graphics opacity or transparency.
r128, as I recall, only supports global mode. I think savage can do per
pixel, but I haven't tried it.

Alex

> 
> Thanks,
> - Andy
> 
> > > 
> > > 
> > > Feedback very welcome.
> > > 
> > > Thanks,
> > > - Andy
> > > 
> > > 
> > 
> > 



	
		
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