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

[Anthony Liguori <anthony@codemonkey.ws>]

Stefano Stabellini wrote:
> Daniel P. Berrange wrote:
>
>   
>> The problem with OpenGL is that it has horrible rendering issues if you
>> are also using a compositing window manager like Compiz. You need an X
>> server & driver which supports Redirected Direct Rendering [1]. No distro 
>> currently has any official support for this yet. 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.
>>     
>
>
> I don't think this should impact our choice, these are all issues that
> will be solved sooner or later (hopefully sooner).
>   

Practically speaking, it's a royal pain.  It means it has to be disabled 
by default.  What's most annoying is that Ubuntu enables compiz by 
default so there are a lot of users that will be affected.

There are a lot of outstanding SDL/VNC patches right now.  I'm going to 
spend time testing/applying them tomorrow.  OpenGL support is neat but 
I'm on the fence about whether it's the right thing to apply it.

I'd like to see if it really makes a difference performance wise to 
render with OpenGL.  I've had good results in the past using software 
bilinear interpolation to do scaling.  If OpenGL doesn't provide a 
measurable performance advantage, doing it in software may be the right 
thing to do.

Regards,

Anthony Liguori

>> 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
>>
>>     
>
> SDL doesn't offer this feature, and OpenGL is not just for 3D.
>
>
>