Thank you all for suggestions, I'll try them as soon as possible and will let you know. Regards.
Alessandro On Mon, Jan 26, 2009 at 5:42 PM, Paul Martz <pma...@skew-matrix.com> wrote: > Yes, two sided lighting was what I was going to suggest, but you beat me to > it. > > Note that two sided lighting is deprecated in OpenGL 3.0, so you should > consider looking for a shader-based solution instead. In the shader, if the > dot product of the normal and eye vector is negative, just negate it, then > calculate lighting as usual. > > Paul Martz > Skew Matrix Software LLC > http://www.skew-matrix.com > +1 303 859 9466 > > -----Original Message----- > From: osg-users-boun...@lists.openscenegraph.org > [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of > frankmil...@jhmi.edu > Sent: Monday, January 26, 2009 8:44 AM > To: OpenSceneGraph Users > Subject: Re: [osg-users] Rendering double-sided surfaces. > > For sure the best thing to do would be to process the incoming data as > suggested. However, you might be able to get OpenGL to do what you want by > setting all material properties for both sides of the polygon and enabling > two sided lighting. Something like this. > > osg::ref_ptr< osg::LightModel > pLightModel = new osg::LightModel(); > pLightModel->setTwoSided( true ); > pState->setAttributeAndModes( pLightModel.get(), osg::StateAttribute::ON > ); > > osg::ref_ptr<osg::Material> pMaterial = new osg::Material(); > pMaterial->setColorMode( osg::Material::DIFFUSE ); > pMaterial->setAmbient( osg::Material::FRONT_AND_BACK, osg::Vec4( 0.0, 0.0, > 0.0, 1.0 ) ); > pMaterial->setSpecular( osg::Material::FRONT_AND_BACK, osg::Vec4( 1.0, > 1.0, 1.0, 1.0 ) ); > pMaterial->setShininess( osg::Material::FRONT_AND_BACK, 64.0f ); > pState->setAttributeAndModes( pMaterial.get(), osg::StateAttribute::ON ); > > I have never tried this for data like you have but it seems to me like it > should work. > > Frank > > On Mon, Jan 26, 2009 at 04:21:41PM +0100, alessandro terenzi wrote: > > Problem is that the models that come to my application are already > > prepared by people that do not (and unfortunately won't) think about > > normals issues, so maybe the best thing to do would be to really > > render both front and back faces, I'm not an expert, but the only > > approach I can think is to double the geometry so to have both faces, > > but it would be really a waste (not to mention performace problems > > that may arise..and other unexpected visualization problems I cannot > > think of..) Regards. > > Alessandro > > > > On Mon, Jan 26, 2009 at 1:37 PM, Tomlinson, Gordon < > > gtomlin...@overwatch.textron.com> wrote: > > > > > your triangles all need to be wound the same way (anticlockwise by > > > default for OSG & Opengl), whether or not your normal's are correct > > > > > > The easiest fix would be to ensure that your modeling package sets > > > up correct normal's before you get to OSG > > > > > > Assuming your triangles are wound the same way ( if not you will > > > have to fix that ) try using the SmoothingVistor on the data see > > > > > > include\osgUtil\SmoothingVisitor > > > > > > > > > *Gordon* > > > > > > __________________________________________________________ > > > *Gordon Tomlinson* > > > > > > *Product Manager 3D > > > **Email * : gtomlinson @ overwatch.textron.com > > > __________________________________________________________ > > > *(C): (+1) 571-265-2612 > > > (W)**: (+1) 703-437-7651* > > > > > > "Self defence is not a function of learning tricks but is a function > > > of how quickly and intensely one can arouse one's instinct for > > > survival" > > > - *Master Tambo Tetsura* > > > > > > > > > > > > ------------------------------ > > > *From:* osg-users-boun...@lists.openscenegraph.org [mailto: > > > osg-users-boun...@lists.openscenegraph.org] *On Behalf Of > > > *alessandro terenzi > > > *Sent:* Monday, January 26, 2009 7:09 AM > > > *To:* OpenSceneGraph Users > > > *Subject:* [osg-users] Rendering double-sided surfaces. > > > > > > Sometimes my application has to load models that have normals not > > > always oriented in the same coherent way, so it is not always > > > possible to say that a surface is oriented in a way or in another > > > and my renderings do not look correct. > > > > > > I'd like to fix this problem in some way...so I was thinking about > > > rendering both front and back faces, but how do I ask OSG do this? > > > Or perhaps, is there another way/technique to achive the same result? > (ie. > > > orient a surface in a coherent way: all faces inward XOR outward) > > > > > > Thank you. > > > Alessandro > > > > > > _______________________________________________ > > > osg-users mailing list > > > osg-users@lists.openscenegraph.org > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegrap > > > h.org > > > > > > > > > _______________________________________________ > > osg-users mailing list > > osg-users@lists.openscenegraph.org > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph. > > org > > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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