Hi Wojciech, I've just reviewed your change and it looks benign, and I don't foresee any problematic side effects on drivers that don't required this double wglMakeCurrent() calling. The cost of wall wglMakeCurrent() twice I don't see as something that is likely to cause particular performance problems as the OSG shouldn't be called makeCurrent too often anyway. Given all this I think it'd be better to do try and do automatically tests to check whether this double call is required or not, as this would just complicate the code and potentially lead to more bugs.
However, what is clear that if calling wglMakeCurrent() twice fixes the problems, you are seeing, without any other changes to the OSG then this is a pretty clear pointer to a driver bug. Robert. On Mon, May 12, 2008 at 1:28 PM, Wojciech Lewandowski <[EMAIL PROTECTED]> wrote: > Hi again, > > I have modified GraphicsWindowWin32::makeCurrentImplementation method. Code > attached. This modification solves both garbage in > TriangleStrip/TriangleFans and FBO problems. So a complete succes for me ;-) > > I am posting it on osg users forum instead of osg submissions because I > expecty we want some discussion before submitting it. > > I don't know how this workaroud should be additionaly wrapped. In this form > its alredy rather non aggressive - second wglMakeCurrent will be called > fairly seldom. What additional conditions we would like to see tested > before applying this worakoround. Any suggestions ? Should I check > GL_VENDOR, GL_RENDERER, GL_VERSION strings ? Does OSG offer some methods to > query OS, drivers version ? > > Maybe othe places in the code are more appriopriate for this call. > > Cheers, > Wojtek > > > > Hi Everyone, > > > > Lets get back to the main topic of this thread ie garbage in Multicore CPU > / > > NVidia / DualView / Window XP. > > > > I attached my OpenGL repro for those who are interested. I would be > grateful > > if somoene could check if my threading code is OK (and maybe simplify it). > > If it is, I will try to submit the bug to NVidia. > > > > Check out what happens when repeatMakeCurrent variable gets changed to > non > > zero value. This causes repetition of wglMakeCurrent and fixes the issue. > I > > will try to check this method in OSG next week. > > > > I am heading back home for the weekend. I will stay online but I don't > have > > multicore CPU there so I won't be able to check codes till monday. > > > > Cheers, > > Wojtek Lewandowski > > > > > > > > > Hi Robert, Paul and J-S, > > > > > > I don't think I was clear enough. Its too early to say that > wglMakeCurrent > > > will be a good workaround for OSG. > > > I only said that it "relaxed" the problem in my OpenGL repro. > > > > > > It looks like first wglMakeCurrent (when renderer thread is started) > does > > > not initialize properly some internal OpenGL context data. If I repeat > it > > > in second frame everything becomes correct. So if wglMakeCurrent was a > > > solution it would be needed only once more on frame. > > > > > > But I learned all this using my open gl repro without Display Lists and > to > > > be honest I did not checked what will happen if DisplayLists are > generated > > > on a first frame (like OSG does). I suspect they might stay screwed even > > > if second wglMAkeCurrent gets called. I am currently trying to check > this > > > out. I just need some more time to investigate. > > > > > > I got some questions regarding this issue so I decided to inform guys > for > > > whom this is relevant by posting on osg-users. I am certainly far from > > > proposing fixes at this moment. > > > > > > Wojtek > > > > > > > > > > > > > Hi Wojciech, > > > > > > > > On Fri, May 9, 2008 at 2:16 PM, Wojciech Lewandowski > > > > <[EMAIL PROTECTED]> wrote: > > > > > > > > > Problem could be relaxed when wglMakeCurrent gets called before each > > > > > frame > > > > > rendering. I noticed that artifacts appeared when wglMakeCurrent was > > > > > called > > > > > only once while worker rendering thread initialization . When > > > > > wglMakeCurrent > > > > > was called every frame artifacts did not appear. > > > > > > > > > > > > > wglMakeCurrent "shouldn't" be required if one has a thread per > > > > context, one a thread does a wglMakeCurrent() it shouldn't release the > > > > context till this thread calls release context (done with > > > > wglMakeCurrent(_hdc, NULL)). > > > > > > > > As you are finding that the wglMakeCurrent() per frame is required, > > > > this either suggests that the OpenGL driver is playing fast and loose > > > > with the graphics context behind the scenes so the app looses the > > > > context being current, in which case this is very much a driver bug, > > > > or that the OSG itself is doing makeCurrent on the context from > > > > another thread or releasing the context when it shouldn't. > > > > > > > > Could you put some debug output into GraphicsWindowWin32.cpp's > > > > makeCurrentImplementation(..) and relaseContextImplementation(..) to > > > > see if there are being called when you wouldn't expect, printing out > > > > the > > > > pointer to the current thread would be useful as well. > > > > > > > > Robert. > > > > _______________________________________________ > > > > osg-users mailing list > > > > osg-users@lists.openscenegraph.org > > > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > > > > > > > _______________________________________________ > > > osg-users mailing list > > > osg-users@lists.openscenegraph.org > > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > > > > > > > > -------------------------------------------------------------------------------- > > > > > _______________________________________________ > > osg-users mailing list > > osg-users@lists.openscenegraph.org > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
