Hi Miguel, This is a standard issue with rendering shapes with depth buffer hardware - if the front faces are drawn before ones at the back then the depth buffer is written to and when it comes to drawing the back faces the depth test rejects the fragment. Go look in online literature/books on the topic of drawing transparent objects, or even the osg-users forum/mailing and you'll background on it.
Techniques to solve issue range from : Disabling the depth write for the transparent objects Breaking the transparent objects into smaller segments that can indivually be sorted in depth (the OSG sorts it's transparent bin on drawable bounding box). Drawing the object twice, the first time drawing the back faces, the second time drawing the front faces. You can use glFrontFace/osg::FrontFace to do this trick, or just create a single osg::Geometry that contains the both passes, and manually changing the winding of the triangles between passes. This later approach is typically the most efficient. Robert. On Fri, Sep 11, 2009 at 8:02 AM, Miguel Lokida <[email protected]> wrote: > Hi, > > Here 's my problem. I have an osg::Cone (inherit from shape) and I would > like it to be transparent. I have used some example using blendFunction but > the problem is that the cone is a little transparent but some slices all > along the cone appear. > If someone know how to make it fully transparent that would be great. > > Thank you. > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=17263#17263 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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