Hi I think the GL error is because your doing a GL call in the update process/thread and not the draw process/threads (You need a valid GL context which is typically owned by the draw process/threads)
Gordon __________________________________________________________ Gordon Tomlinson Email : gtomlinson @ overwatch.textron.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of brettwiesner Sent: Thursday, August 21, 2008 10:01 AM To: OpenSceneGraph Users Cc: [EMAIL PROTECTED] Subject: [osg-users] Update callbacks occur in between calls to glBegin andglEnd? Hi, I was wondering if update callbacks are suppose to occur in between calls to glBegin and glEnd? I think this test code demonstrates that they do. I'm using a glGet command (in this case glGetIntegerv) and checking for it's error code. From the open GL docs: "GL_INVALID_OPERATION is generated if glGet is executed between the execution of glBegin and the corresponding execution of glEnd." I'm making that call inside the update callback and getting that error, suggesting that the update callback occurs somewhere in between a glBegin and glEnd. Is this correct? Thanks, Brett class TestUpdateCallback : public osg::NodeCallback { public: void operator()(osg::Node* node, osg::NodeVisitor* nv) { // Clear any previous error. GLenum eError = glGetError(); // Make the call that will generate a new error. int maxUnits; glGetIntegerv(GL_MAX_TEXTURE_UNITS,&maxUnits); // Check the error eError = glGetError(); if(eError == GL_INVALID_OPERATION) { std::cout << "TestUpdateCallback: This update callback occurs in between glBegin and glEnd." << std::endl; } // Continue traverse. traverse(node,nv); } }; main() { std::string modelPath = testDataDir(); modelPath += "cow.osg"; osg::ref_ptr<osg::Node> modelNode = osgDB::readNodeFile(modelPath); modelNode->setUpdateCallback(new TestUpdateCallback); osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer; viewer->setUpViewOnSingleScreen(0); viewer->setSceneData(modelNode.get()); viewer->setCameraManipulator(new osgGA::TrackballManipulator()); viewer->run(); } _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.or g _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
