[cairo] Re: [Mesa3d-dev] OpenGL and Cairo

Vladimir Vukicevic vladimir at pobox.com
Wed Apr 21 17:14:31 PDT 2004

David Reveman wrote:

> On Tue, 2004-04-20 at 12:57 -0700, Jon Smirl wrote:
>>This was my general conclusion too. I'm ok with creating a separate 2D API but
>>I'm concerned about how well it maps back into OpenGL. From my minor contact
>>with Cairo people I think they ignored OpenGL in the begining since OpenGL is
>>missing text support. Looking at Longhorn, xserver/cairo on top of mesa-solo (or
>>a closed source equivalent) is our only hope for competing. xrender isn't even
> Glitz; the library used for cairo's OpenGL backend, is a xrender-like
> interface on top of OpenGL. It provides a very similar API to xrender
> and all operations are hardware accelerated. Compared to the current
> xrender implementations, glitz performs very well.
> I think xrender is good, we just need it fully hardware accelerated and
> glitz proves that it's possible to do this using OpenGL. I don't know if
> this acceleration is good enough compared to Longhorn. Is the current
> performance of cairo's OpenGL backend enough? Results from comparing
> performance of cairo's OpenGL backend and Longhorn/MacOSX would be very
> interesting.
> If we find xrender inadequate, we can always extend it with more
> functionality design to perform well using OpenGL, right?  

In addition to asking whether Cairo+glitz+OpenGL will be good enough to 
compete, I wonder if GLX will be able to stand up to the task. 
Specifically, if you need opengl across the entire desktop, will GLX be 
able to handle the multiple contexts and other interactions needed? 
What if I want to run a native OpenGL app (3d editor, game, etc.) on top 
of this OpenGL-based desktop?   If you limit things to interacting with 
2d windows + xrender for compositing those windows at the top level, 
things might get simpler, but I think you would also lose functionality 
at that point.

mesa-solo looks quite interesting, but unless I'm missing something, at 
that point you would essentially be dumping X -- I'm not sure that is 
really a feasable thing?

	- Vlad

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