JP is right. I dug into this a little more. Basically if your st coordinates map linearly to the xyz vertices, then breaking the poly into triangles to scan convert will produce consistent and correct results. However, if your st coordinates map non-linearly, then tessellating into triangles will produce different results depending on screen orientation of the geometry.
JP's suggestions are sound, either tessellate the poly yourself at a high enough resolution s that the visual artifacts are insignificant, or use a fragment shader to compensate for the artifacts. Note that with the latter solution, you'll probably want to tessellate into triangles on the host so that you have a consistent triangulation across all architectures (the OpenGL spec doesn't dictate polygon triangulation, so different hardware could produce different triangles for the same input poly). Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com +1 303 859 9466 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
