Hi John, Back face culling will only be effective at improving performance on applications that are fill limited, if the bottleneck is elsewhere then you won't see an improvement in performance.
I cannot say whether you are fill limited or not, the way to check it is to change the size of the viewport and then look at the performance - if performance goes up as you reduce the viewport size then you are fill limited. Robert. On 27 May 2012 19:12, John Moore <[email protected]> wrote: > Hello, > I am developing an application for iphone and ipod touch using > openscenegraph. It is an augmented reality application and I have to load a > very complex model. The original 3d model has 5 million vertices. > Since I am using a mobile platform which is limited in computational power I > simplified the model using 3d studio max. I reduced the size of the model > from 500Mb to 4.2 Mb using proOptimizer. > The model now has in total about 36,000 vertices and about 53,000 faces. > > I am able to render it but frame rate is slow. I'd like to improve > performance using back face culling. The point is I don't know how to > activate it (if it is possible): > I tried with these lines of code but frame rate is still low: > > Code: > > osg::StateSet* ss = _root->getOrCreateStateSet(); > osg::CullFace* cf = new osg::CullFace(osg::CullFace::BACK ); > ss->setAttribute( cf ); > > > > I am using OpenGL ES 2.0 and shaders. > > I setup the camera in this way: > > Code: > > //set the clear color of the camera to be transparent > _viewer->getCamera()->setClearColor(osg::Vec4(0.0f, 0.0f, 0.0f, 0.0f)); > //set the clear mask for the camera > _viewer->getCamera()->setClearMask(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); > _viewer->getCamera()->setRenderOrder(osg::CameraNode::PRE_RENDER); > _viewer->getCamera()->setComputeNearFarMode(osgUtil::CullVisitor::DO_NOT_COMPUTE_NEAR_FAR); > > > > > I use DO_NOT_COMPUTE_NEAR_FAR because I need to set manually projection and > viewMatrix at every drawing cycle. > > I also initially set viewport like this: > > Code: > > _viewer->getCamera()->setViewport(new osg::Viewport(0, 0, > graphicsContext->getTraits()->width, graphicsContext->getTraits()->height)); > > > > > The hierarchy of my object is structured as: > > _root is a osg::MatrixTransform > > my 3d model is divided in subparts. > all the subparts of my 3d model are direct child of _root and are of type > osg::Node > > I hope you can give me some tips to improve performance. If you need some > other information about my setup I will be glad to give it. > > Thank you. > > Greetings, > John > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=47880#47880 > > > > > > _______________________________________________ > 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
