I believe your texture filtering mode is generating intermediate alpha values, which then blend a portion of the distant background in before the other "face" of the tree is drawn behind.
Switching to GL_NEAREST will probably avert this, but will look ugly in other ways. Alpha to coverage might help you here: http://www.humus.name/?page=3D&ID=61
_______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org