Top-most windows

[Keith Packard]

On Tue, 2006-01-10 at 09:41 -0800, Deron Johnson wrote:

> Whether it is a "topmost" window or a "composite priority" window, I am
> strongly in favor of it. It solves all of the known problems, not just
> some of them and it is clean and easy to implement. And it doesn't
> require significant changes to OpenGL, which we have less control over.
> I believe that the issues surrounding topmost window semantics can be
> mitigated.

Given the existance of GLX APIs based on FBConfigs, and the potential to
additional modify GLX to enable IncludeInferiors rendering, it seems to
me that all of our discussions should now be focused on mitigating the
effect on a GL-based compositing manager in the short term. 

With a clear goal of drawing the composited desktop to the root window
(which is how Composite was intended to be used), and a clear path to
making that work, anything else seems like an unnecessary diversion.

The additional motivation for this position is that Mesa cannot today be
used as a GL-based compositing manager; it has no way of redirecting GL
rendering to arbitrary off-screen buffers. So, we have no credible free
software solution which can take advantage of any of the proposed
changes in any case. And, the changes necessary to make Mesa able to be
used in a GL-based compositing manager happen to be reasonably well
associated with the changes needed to make it possible to draw to the
root window, leading me to conclude that in waiting for Mesa to be able
to draw to off-screen buffers, we will simultaneously gain the ability
to draw to the root window, leaving any changes introduced at this time
dead weight that will exist for time eternal in our code base.

-keith

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : http://lists.x.org/archives/xorg-arch/attachments/20060110/b784dcfb/attachment-0003.pgp