The reason you need GL_RESCALE_NORMAL is because you have scaled your terrain. OpenGL by default does NOT scale normal on a scale matrix because the act of rescale requires the use of sqr roots and this is expensive. when you have a lot of them every frame ( see any good OpenGL book for details) I would recommend that you create your terrain to the correct size and not scale at run time,
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ümit Uzun Sent: Saturday, July 19, 2008 9:06 AM To: OpenSceneGraph Users Subject: Re: [osg-users] osg::Light Simple Question ? Hi Jean, Thanks for reply. You are right, my model hasn't normals :) So "terrainScaleMAT->getOrCreateStateSet()->setMode( GL_RESCALE_NORMAL, osg::StateAttribute::ON );" pattern doesn't work on terrain lightening. Like your advice I can use osgUtil::SmoothingVisitor but I choose easier way which is gathering model which has normals in it. So I use new model with adding GL_RESCALE_NORMAL control and result is perfect like added screenshot:) I have a last question about why my model's lightening operation related with normals rescaling process? I can't understand backgroud of this command. Thanks for helps Jean and Gordon :) Best Regards. Ümit UZUN 2008/7/19 Jean-Sébastien Guay <[EMAIL PROTECTED]>: Hello Ümit, I have tried "terrainScaleMAT->getOrCreateStateSet()->setMode( GL_RESCALE_NORMAL, osg::StateAttribute::ON );" pattern but the result is same. There is no light effect on the terrain. I don't understand why? As Gordon said, check if your terrain has normals in the first place... Rescaling non-existing normals won't do anything :-) In your .osg file, check for normalArray under your Geometry, and check that normalBinding is set to PER_VERTEX. If the model has no normals, you can generate them with a modeling tool or use the osgUtil::SmoothingVisitor to create smooth normals across the surface. And BTW, yes you're right that the two suggestions I gave before were mutually exclusive, i.e. if you checked your model and changed the TexEnv in it you don't need a NodeVisitor to do the same thing... Oh, just another little thing, are you sure you're reloading the .osg model and not the original one without your changes? J-S -- ______________________________________________________ Jean-Sebastien Guay [EMAIL PROTECTED] http://www.cm-labs.com/ http://whitestar02.webhop.org/ _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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