Hi John, Have a look into discussion on osg-users about positional state. LightSource is what positions Light in the scene. You can't have one GL light in more than one place at a time, and the light has to be positioned by a specific modelview matrix, not one artificially inherited, so LightSource's role is to place the light.
Robert. On Mon, Mar 22, 2010 at 11:52 AM, PCJohn <[email protected]> wrote: > Gurus, > > What is the reason for keeping LightSource in OSG? > > I successfully removed all osg::LightSources from my scene graph and used > just osg::Light - it is well placed and follows the transformation of the > parent node (f.ex. locomotive) as it moves. Except absolute reference frame, > is there any reason for LightSource existence in OSG? I think yes, but > missing arguments. > > Thx for explanation, > John > > Thrall, Bryan wrote: >> >> You place the LightSource in the scene graph where you want the light to >> be positioned. I don't think it is necessary for directional lights (they >> are infinitely far away, so don't have a position), but say you want a >> spotlight attached to a train locomotive. You could update osg::Light's >> position every time the locomotive moves, or you could attach a LightSource >> to the locomotive's scene graph and have the light placed correctly >> automatically. >> > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
