On 09/15/2011 04:33 PM, Paul Martz wrote:
You're free to put whatever transform you want in either matrix as long as transform by the two produces clip coords, but for correct FFP lighting computations, your modelview matrix *must* produce eye coordinates. OpenGL FFP lighting is computed in eye space. So, if you did something crazy like have an identity modelview, but a full object-to-clip transform in the projection, then vertices would be transformed correctly, but your lighting would be way wrong.
You're right, Paul, I neglected the FFP lighting issue. There is a fundamental difference between the projection and modelview transforms for this purpose, and since lights are in eye space, there is an inherent coordinate system as well, so I stand corrected on those points.
Still, in OpenGL 3.1+, that's all out the window :-) --"J" _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
