Paul, Thanks for pointing that out. I failed to mention the winding rule dependency...
-Shayne -----Original Message----- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Paul Martz Sent: Thursday, March 14, 2013 1:44 PM To: OpenSceneGraph Users Subject: Re: [osg-users] [forum] Rendering backface like front face There are a couple different scenarios. If a surface is composed of triangles that all have a normal consistent with the winding order, but some of the triangles are facing the wrong way, then two-sided lighting will address the issue. That's why I asked the OP if he had tried this. If your surface has normals that are not consistent with vertex winding order, then you might be able to fix this in a shader by flipping the normal only when the dot product is negative, but I've never tried this. I've always just called it a modeling bug. :-) On Thu, Mar 14, 2013 at 12:27 PM, Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC <shayne.tuel...@hill.af.mil> wrote: If you enable two-sided lighting, the driver flips the lighting normals so that the back side of the polygon is lit correctly. There should be no need to do this in a shader (with OGL that supports fixed functionality...). -----Original Message----- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Christian Buchner Sent: Thursday, March 14, 2013 10:46 AM To: OpenSceneGraph Users Subject: Re: [osg-users] [forum] Rendering backface like front face The front and back material properties were set to same values, it's just that when doing the calculations for the back side, the normal vector is not pointing towards the light source but away from it. I only looked at this issue briefly, and concluded that it would take some GLSL to fix it. Christian _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.or g -- Paul Martz Skew Matrix Software LLC _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
