Hi Mike,
Take a look at OpenGL's two-sided lighting support via glLightModel/GL_LIGHT_MODEL_TWO_SIDE (and exposed in OSG with osg::LightModel). I think that's the more elegant solution your looking for. Mike Wittman [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> ___________________________________________________ Seismic Micro-Technology, Inc. 8584 Katy Freeway, Suite 400 / Houston, Texas 77024 Tel. +1 (713) 464-6188 Fax. +1 (713) 464-6440 Web: www.seismicmicro.com <blocked::blocked::http://www.seismicmicro.com> ___________________________________________________ Seismic through Simulation with KINGDOM, (RC)2, and SURE! - CONTACT US TODAY for more information. ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michele Bosi Sent: Tuesday, August 28, 2007 4:45 PM To: [email protected] Subject: [osg-users] Flipping the normals Hello, I've a relatively easy task to accomplish, that is to render a mesh both from inside and outside. To do this i put the mesh under two different Geodes, in one i set the front face to "clock wise" on the other I set the front face to "counter clock wise" turning on the backface culling (or putting the object into a single Geode turning off the backface culling). The problem is that in one case (when I render the "interior" of the mesh) the polygons are not lit since the normals are (of course) not flipped, that is they remain oriented "outward". My question is: how can I flip the normals? should I create two distinct meshes, one with the original normals and the other with inverted normals (modifying manually the normal buffers, and doubling the memory usage) or there is a more elegant way to do that, for example a node/state like GL_PLEASE_FLIP_MY_NORMALS that can take care of this task automatically? Cheers, Mike
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