Hi all, Good, I am happy it is all clearer now, and I am sorry it wasn't enough at first. So back to the original issue: I observe my problem of auto-changing near/far planes when I modify the LODScale via "camera->setLODScale(float)". This *always* happens whether or not culling is enabled, but of course I am not affected by this problem when culling is disabled because no matter what values my near/far planes have, my objects do not get culled. I enable culling via: camera->setCullingMode(getCurrent() | osg::CullSttings::near | osg::cullS::far) - I don't have the code in front of me but that is the idea. The problem I encounter is that since I am culling the near/far planes, some objects get culled from my scene if the near/far planes shift positions automatically. Robert already explained that with my current near/far computing settings I will get some slight changes to the near/far planes when changing the LODScale. Although this is undesirable for my application, it makes sense given Robert's earlier explanation. So Paul asks, what if I just keep the original culling mode? Well, that would be great, it looks great and I don't have the culling problem of the changing near/far planes, but there is one *crucial* issue: frame-rate. My terrain is too large and I need a decent level of detail, but it winds up drawing way too many triangles. I am attempting to find the optimal LODScale for my app, which can get me up from 10fps to about 25-30fps at a decent LODScale, and I also want to cull all those extra triangles, which can pump me up to 40-50 fps, at the cost of culling objects when not desired. I think I'll be alright, I need to play some more with the near/far compute settings. Thanks all for your interest in this topic,
-Jose On Mon, September 22, 2008 10:52 am, Paul Martz wrote: >> FYI, Roland is correct, the OSG just does culling on sides of >> the frustum by default. >> >> OpenGL does no culling, is just does near and far *clipping*. The >> OSG of course doesn't change this so will do near/far >> clipping and the only way to switch this off is to disable >> GL_DEPTH_TEST. > > Even that won't work; DEPTH_TEST is a fragment op, and clipping against > the > clip planes is done before rasterization. > >> It would seem that Paul and Gordon have confused the clipping >> and culling a little. > > Yes, I thought the original poster was talking about enabling OpenGL > near/far clipping (probably because I have seen so many newbies ask how to > disable this in the OpenGL forums and newsgroups). Clearly, the original > poster said "culling"... My mistake, and thanks to all for the > clarification. > > Back to the original issue: > > So, you see this problem when you enable OSG culling for near/far. What > happens if you leave this disabled (as osgviewer does)? > -Paul > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
