VNC-List digest, Vol 1 #1270 - 7 msgs

[Robin Hill]

On Mon Mar 14, 2005 at 02:31:01PM +0530, Gobbledegeek wrote:

> > If you're running Xvnc then it _is_ the Xfree server.  This is totally
> > independent of whatever graphics card is in there - you can run it at a
> > resolution unsupported by the graphics card if you want.  Xvnc then acts
> > just like any other X server - you can run whatever window maanager &
> > apps you like - the only limitation is the extensions supported (most
> > VNC implementations don't support RENDER for example) and you won't be
> > able to take advantage of any hardware acceleration.
> 
> So Xvnc wont use the server  h/w graphics card at all with its
> optimizations  for computing screen display like anti-aliasing,
> alpha-blending and z-buffer etc? What if I run a 3d game or run
> something that uses openGL on the server?  Then what about a win32 vnc
> server and a linux vnc thin client with me running a DirectX
> application.  Let me guess -  DirectX will call cpu SSE2/3
> instructions in some cases, but what about all those calculations that
> a gpu is optimized for?
> 
VNC works with the in-memory display buffer, before it gets passed to
the graphics card for any additional processing.  So, for example, when
connecting to a Windows VNC server you'll find that any applications
using the GPU for DirectDraw functionality (such as Media Player) will
show as only a black box (since the CPU is leaving the rendering of this
to the GPU).  Most of the time this doesn't matter as anything needing to
use the GPU for accelerated rendering won't update quickly enough over a
VNC connection.  Similar things happen with a UNIX/Linux VNC server (though
there tends to be fewer applications making use of the GPU) - so while I
can use VNC to navigate the menus on my MythTV system, as soon as I
start the TV mode (or DVDs, videos, etc) all I get is a black box.

HTH,
        Robin
-- 
     ___        
    ( ' }     |       Robin Hill        <robin "at" robinhill.me.uk> |
   / / )      | Little Jim says ....                            |
  // !!       |      "He fallen in de water !!"                 |