Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window

[Daniel P. Berrange]

On Sun, Sep 07, 2008 at 10:48:39AM +0300, Avi Kivity wrote:
> Daniel P. Berrange wrote:
> >On Fri, Sep 05, 2008 at 05:44:55PM +0100, Stefano Stabellini wrote:
> >  
> >>Jamie Lokier wrote:
> >>    
> >>>Another way to map guest framebuffer to video memory is the XF86DGA
> >>>extension, which is great when you can use it.  I think VMware uses it
> >>>in full-screen mode.
> >>>      
> >>I went with OpenGL because I wanted the accelerated window resize
> >>feature, and because I think it will give us more opportunities for
> >>further improvements (for example using PBOs as soon as they are
> >>supported by at least one open source graphic card driver).
> >>    
> >
> >The problem with OpenGL is that it has horrible rendering issues if you
> >are also using a compositing window manager like Compiz. 
> 
> I would say that this is a compiz problem.

Not really. Its a limitation of current X server driver architecture
which is being addressed by DRI2 / Redirected direct rendering work

> >You need an X
> >server & driver which supports Redirected Direct Rendering [1]. No distro 
> >currently has any official support for this yet. 
> 
> Or a distro problem.

The distros can't do anything about it, until X driver architecture work
is done.

> >AFAIK, the next Fedora 10
> >will be the first to support it, and even then only on Intel hardware[2].
> >ATI is still a fair way off, and NVidia support is nowhere to be seen. For
> >accelerated resize of windows though you shouldn't need 3d - the graphics
> >driver 2-d hardware acceleration  support ought to be sufficient I'd
> >imagine
> 
> I don't see how distros can enable compiz if it breaks opengl 
> applications like this.

This is exactly why Fedora does not yet enable compiz by default. Many
users still enable it though.

Daniel
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