Hi Gulianzhang, We had a long thread discussing a similar problem a while ago. As a result I have been using shaders to apply different lights to different parts of a scene, and it is working quite well:
http://www.mail-archive.com/[email protected]/msg05683.html - Terry > > Message: 4 > Date: Thu, 28 Aug 2008 09:14:40 +0100 > From: "Robert Osfield" <[EMAIL PROTECTED]> > Subject: Re: [osg-users] How does each object set its own light > parameters? > To: "OpenSceneGraph Users" <[email protected]> > Message-ID: > <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=ISO-8859-1 > > Hi Gulianzhang (BTW, do you have a shorted name we could use?) > > Management of lights is complicated by the fact the lights are > positional state i.e. they rely on specific values of the modelview > matrix to position them in the right place so you can't them apply > arbitrary times with arbitrary modelview matrices as they jump around > in your scene. The OSG solves this problem by handling positional > state differently than the rest of OpenGL state - and positions it via > the osg::LightSource, and once positioned you can only have one > position for a whole stage in rendering (implemented via the > osgUtil::RenderStage in the rendering backend). This does mean that > one light source can only be in one place at a time - you can't just > reassign it as you wish. > > If you want to do the reassignment then you'll need to create a > multiple stage rendering setup, and place objects you wish to > associate with a particular light source into the same rendering > stage. In scene graph terms this would mean dividing your scene up so > that you have a series of subgraphs each with the LightSource for that > subgraph, and a callback above each subgraph that setups up the > rendering backend. > > Robert. > > On Thu, Aug 28, 2008 at 8:01 AM, guilianzhang <[EMAIL PROTECTED]> wrote: >> Hi, >> I build a scene using osg which is composed of many objects and many lights, >> I want to traverse each object to find the nearest light away from it and >> associate the light with GL_LIGHT0, so each object has its own GL_LIGHT0 >> parameters. >> The problem is that the light is added to the scene by adding a >> osg::LightSource, and the LightSource node then is added to the scene graph, >> Must I add LightSources for each object to set its own light parameters? Is >> there any better method? >> >> Thanks very much! >> >> ________________________________ >> guilianzhang >> 2008-08-28 >> _______________________________________________ >> 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
