Hello Joel,
It seems apparent that I need to multiply the osg_Vertex vector in my vertex
shader with the model matrix for that geometry (via a uniform updated every
frame, or at least whenever the geometry is transformed). The only function
that I've found that may get the model matrix is getModelMatrix() in the
IntersectionVisitor class.
You need to accumulate the matrices from the root of your graph to the
drawables, and provide this to your vertex shader so it can transform
your vertices.
There are many ways you could do this. One would be to subclass the
osgUtil::CullVisitor class, and whenever your custom CullVisitor gets to
a Transform node, instead of applying the accumulated matrix to the
fixed pipeline state, it would set a Uniform so that the accumulated
matrix is available to your shader. You then set an instance of your
custom CullVisitor on your viewer (I think), and it will use it in the
cull traversal instead of the stock CullVisitor.
There are other, perhaps less intrusive but potentially slower ways:
putting callbacks on all Transform nodes, or creating another visitor
that runs each frame after the update traversal, or something like that.
But I think the custom CullVisitor way is the cleanest. Others (Robert?)
can correct me if I'm wrong.
Hope this helps,
J-S
--
______________________________________________________
Jean-Sebastien Guay jean-sebastien.g...@cm-labs.com
http://www.cm-labs.com/
http://whitestar02.dyndns-web.com/
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