Hi Frank, My best guess is that your projection matrix isn't wide enough to encompass your scene and near/far clipping is clipping out the fragments. This may well look like culling, often users do mistake clipping with culling so chase up the wrong part of the pipeline.
Robert. On Thu, Nov 13, 2008 at 4:18 PM, <[EMAIL PROTECTED]> wrote: > Greetings osg community, > > I'm have written a custom MatrixManipulator for a 2D scene and I am > experiencing a strange problem. As I pan and zoom around, some of the > nodes in the scene disappear abruptly as if they are being culled > inappropriately. However, disabling culling has no effect. > > The behavior is erratic and unpredictable which smells to me like I'm on > the border of a floating point inequality. I have discovered two ways > that seem to make the problem go away. > > One: > > One of the transformations I use to construct the view matrix is > > osg::Matrixd::rotate( osg::Quat( PI, osg::Vec3d( 1.0, 0.0, 0.0 ) ) ) > > If I replace that with > > osg::Matrixd::scale( osg::Vec3d( 1.0, -1.0, 1.0 ) ) > > the problem seems to go away. > > Two: > > All of the nodes in my seen that exhibit this problem have a 2D > bounding box. i.e. > > osg::BoundingBox const & bb = pGeode->getBoundingBox(); > assert( bb.zMax() - bb.zMin() < 1e-5 ); > > If I give the nodes some depth so that the above assert would fail, > the problem seems to go away. > > I suspect that these are not actual solutions. In any case, I would like > to understand what is happening under the covers. Any ideas? > > Frank > > _______________________________________________ > 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
