Re: Question about FRONT BUFFER?

[Amir B. <uf...@rz...>]

On Thu, 2004-09-23 at 10:13, Jacek Rosik wrote:
> Hi,
> 
> Note, that what I'm writing is based on radeon driver. I haven't
> investigated other drivers much.
> 
> W liście z czw, 23-09-2004, godz. 01:13, Amir Bukhari pisze: 
> > Is the frontbuffer shared between all contexts, or for each Context there
> > will be a different frontbuffer?
> > 
> Yes, frontbuffer is shared between all context and X server. 
> 
> > In direct rendering I understand that frontbuffer point to the visible
> > framebuffer of the card (write to screen). Using at the end the position of
> > the window and its clips mask you will write to the frontbuffer
> > (framebuffer), correct me if I am wrong please!
> > 
> 
> Correct. Note that backbuffer is also shared by all contexts, but
> drawables may have different clip rects for front and back because we
> don't have 2d windows in backbuffer.
> 
> Your goal is to redirect output of GLcore (indirect software renderer)
> to pixmap, right? From my latest investigations of GLcore it seems that
> it can use both windows and pixmaps as it's frontbuffer. I haven't tried
> the latter but I think it'll work (I hope). I think You just need to
> allocate pixmap and tell mesa to render to it. You don't have to worry
> about backbuffer as it is always allocated in host's memory and not used
> outside GLcore.

Yes, I want to redirect output of GLcore  to pixmap. GLcore get it own
framebuffer pointer from GLX - it did use the one defined in Window
structure- and use clip rects to write to it, but when I a window is
redirect with Composite, there is no clip rects, therefor it always
write to framebuffer. As you said I will try to let GLcore to redirect
output to pixmap. the problem I want to do this with Composite. I take a
look now on how best Composite could communicate with GLX/GLcore.
 
thanks for your answer, it help me more.

> 
> BTW: I'm working on forcing GLcore to render into other parts of card's
> memory than front buffer (specifically front right buffer). Maybe this
> may be helpful. If I'll come up with workable solution I'll let You
> know. Any pointers?
> 
> best,