On 3/31/11 4:19 PM, Nathan Kidd wrote:
> This is the real problem with the specific case I'm looking at, though 
> not from a "make VirtualGL as theoretically compatible as possible" 
> perspective. I recognize, however, that in the face of potential 
> breakage the latter may not be a goal at all.

Yeah, I had to develop a philosophy about it pretty early on that
basically states:  VirtualGL will asymptotically approach compatibility
over time, but it will never reach it.  For instance, applications that
expect to be able to synchronize X11 and OpenGL output don't work right
unless you use an esoteric setting in VirtualGL that kills performance.
 Similarly, if an application expects there to be a correlation between
X11 visuals and 3D FB configs, it likely won't get what it expects out
of VirtualGL.  The only way for us to do the "right thing" here would be
to tightly integrate with an X server and have it supply the visuals.
For instance, we could extend Mesa to make calls down into librrfaker.so
instead of using preloading.  However, this would benefit only specific
X proxies, such as TigerVNC, that use Mesa, and it would also require
using indirect rendering, which has drawbacks (ref: Background article
on VirtualGL.org.)  In general, I don't think it's good for VirtualGL to
make assumptions about the X server (such as assuming that it has a
certain number of visuals), and it also isn't good for the X server to
make assumptions about VirtualGL (such as assuming that it needs a
certain number of visuals.)


> I'm content to bow to your experience in the matter :) if somebody comes 
> along in the future with an app that manually chooses its visual via 
> glXGetConfig and requires say, a stencil buffer, we could always 
> introduce a "VGL_DEFAULTCONFIGWITHSTENCIL" option to modify the attrib 
> list like your patch below does.  This approach would work with any X 
> proxy, regardless of number of visuals advertised.

Yeah, as much as it seems like a game of whack-a-mole, IMHO it is the
best approach for situations like this.  The fact that only a couple of
apps have experienced this problem in the 7 years we've been active as
an open source project tells me that it's a rare situation.


> I'm waiting to hear back on this test but hopefully will get a result soon.

Sounds good.  Keep me posted.

------------------------------------------------------------------------------
Create and publish websites with WebMatrix
Use the most popular FREE web apps or write code yourself; 
WebMatrix provides all the features you need to develop and 
publish your website. http://p.sf.net/sfu/ms-webmatrix-sf
_______________________________________________
VirtualGL-Users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/virtualgl-users

Reply via email to