Hi Roger,
I would like to render a scene that has some nodes in it that should not
receive a shadow, and also some nodes that should neither cast nor
receive a shadow but still be rendered.
Not that I want to curb your enthusiasm to fix a percieved problem, but
there are ways to achieve what you want without changing the shadow
technique code.
(Note that I will only speak from experience with osgShadow::ShadowMap
and the new ViewDependentShadow techniques - the others I know less
about but it might be similar)
First of all, ShadowMap and the new ViewDependentShadow classes
(LightSpacePerspectiveShadowMap being the one you probably want) will
honor the castsShadow traversal mask. So if you flag a node like so:
unsigned int castsShadow = shadowedScene->getCastsShadowTraversalMask();
node->setNodeMask(node->getNodeMask() & ~castsShadow);
it will not cast shadows (and its volume will not be considered when
calculating the shadow casting volume, which is good for reducing shadow
aliasing in the case of ShadowMap).
Second, no shadow technique right now honors the receivesShadow
traversal mask. But you can work around this by putting the node you
don't want to receive shadows outside the shadowedScene in your scene
graph. So for example, your actual scene root would be an ordinary
osg::Group, which would have as children all the nodes you don't want to
receive shadows, and also the ShadowedScene under which all nodes will
receive shadows.
You can also add control for receiving shadows in your shadow shader.
Both ShadowMap and LightSpacePerspectiveShadowMap allow you to replace
the shaders by ones you would write yourself. In my case, I have a
single shader pair (vertex + fragment) for the whole scene, where I have
a uniform that controls if the object is shadowed (so if this uniform is
false, no shadow map lookup will be performed for the current
vertex/fragment). Then I just set that uniform to the desired value on
the nodes. This might slow down your rendering a bit, but it gives you
better control over shadow application in your scene.
So with those suggestions I think you can get the result you want. If
not, perhaps I've misunderstood what you were trying to accomplish.
Hope this helps,
J-S
--
______________________________________________________
Jean-Sebastien Guay [EMAIL PROTECTED]
http://www.cm-labs.com/
http://whitestar02.webhop.org/
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