[Xorg] Implementing "Xv" extension on DDX which don'tsupportitin hardware...

[Egbert Eich]

Keith Packard writes:
 > 
 > Around 10 o'clock on Jul 19, Egbert Eich wrote:
 > 
 > > It would probably 
 > > make more sense to allow the client to pass information on 
 > > 'undisplayable' areas as a bitmap and let the driver deal with 
 > > this.
 > 
 > Easier to just map an ARGB window on top and composite it with the video 
 > image.  That works quite nicely today and doesn't require any new 
 > semantics anywhere.
 > 

The FillKeyHelper() doesn't know anything about composite so I'm not
sure if it will do the right thing.
It may be very interestiong to see a composite window mapped on top
of a video. If color keying is used it is composited with color key
- not the video image. When the color value of the pixel changes the
video will no longer be displayed but the composition of color key
and window content mapped on top.
Today you can already see this with a transparent (soft) cursor mapped on
top of a video. It works in a sense that it doesn't produce complete junk
but doesn't look like what one may expect.
We may be able to fix this if we display the video as a 3D texture
as most modern chips support it. In fact some drivers can already do
that.

 Egbert.