Hi Jan, I am glad you like many of the improvements i made to osgexport. Allow me to reassure you that you'll like the rest of them as well:
> -----Original Message----- > From: Jan Ciger > Sent: Tuesday, August 22, 2006 4:56 AM > > > 2. Exposed the diffuse+ambient values of textured materials > > as a user option in the GUI. > > Objects can be textured and lit at the same time from Blender > already >From osgexport 2.41, not consistently lit, only by accident :) The textured Geodes were written with no Material, just a naked Texture2D. Depending on the arrangement of your scene, you might have a Geode with a Material above your textured object in the graph, in which case it could conceivably inherit. Otherwise, 2.41 doesn't give the artist any control of the lighting properties of textured surfaces. If you feel strongly about it, i could add a Checkbox to the exporter so that people who want the old uncontrolled behavior could still get it. > The only thing that remains is the ambient lighting - I do > not have much use for that, though. Just FYI, many if not most people do use ambient. I understand if you've got projects which deal purely with diffuse, or don't use traditional materials at all (e.g. shader code, etc.) But the common case is that an artist does want/need to set ambient-diffuse-specular. > > 4. Write an ambient component for each material (equal to half the > > diffuse) which is a better behavior than defaulting to OSG grey. > > Well, no - this is a bad idea, IMHO. I would rather export NO > ambient lighting or set it to (0,0,0), since I didn't specify > any in Blender. If that case, you won't like the previous osgexport behavior either, which is to omit ambient which produces OSG's default (grey). Which seems more correct to you: A. Green and black objects which are both grey on their unlit sides. B. Green and black objects which are dark green and black on their unlit sides. (A) is the old behavior and (B) is the new behavior. > Otherwise you will get a surprise if you set the color to be > some shade of e.g. blue You mean set the Diffuse to be some shade of blue. There is no surprise, because the Diffuse is indeed set to exactly that shade of blue. > and the object will look different > (lighter) due to the contributing ambient lighting in OpenGL > which you didn't have in Blender. Not a surprise if you read the documentation on the exporter. Then if becomes a valuable feature, in fact essential for normal lighting behavior (for those of us who are in fact using OpenGL materials). The traditional approach is A+D=1, so ambient and diffuse sum to 1 in the OpenGL lighting model, which is additive. If an artist wants an object to be [0 0 1] when fully illuminated, they can set Diffuse to [0 0 .666] so that A+D=[0 0 1] at runtime. In light of your feedback, i will add one more slider (0..1, default 0.5) for A/D ratio. Then users like you who want no ambient at all can just set it to 0, and get the ambient=0 that osgexport 2.41 isn't giving you: C. Green and black objects which are both black on their unlit sides. -Ben _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
