How do I share a shader between a number of shared nodes? The shaders need some uniforms to be set each frame with node specific information. Since the GLSLShaderDataLogic only has a reference to the geometry, I cannot use it to set my uniforms (the parent reference of shared meshes is pointing wrong). How do I solve this? What have I missed?
/Robert
I actually bumped into this same problem myself… I don't think there's an actual solution, except maybe not to use shared nodes at all. 
I did an ugly change in the SharedMesh:
### Eclipse Workspace Patch 1.0
#P jME2
Index: src/com/jme/scene/SharedMesh.java
===================================================================
--- src/com/jme/scene/SharedMesh.java (revision 4105)
+++ src/com/jme/scene/SharedMesh.java (working copy)
@Override
public void draw(Renderer r) {
@@ -612,6 +623,10 @@
target.getWorldRotation().set(getWorldRotation());
target.getWorldScale().set(getWorldScale());
target.setDefaultColor(getDefaultColor());
+
+ // first parent of target is the shared node (if using one), second is the one to set
+ target.getParent().setParent(this.getParent());
+
System.arraycopy(this.states, 0, target.states, 0, states.length);
r.draw(target);
So now, I can do this:
sharedShader.setShaderDataLogic(new GLSLShaderDataLogic() {
public void applyData(GLSLShaderObjectsState shader, Geometry geom) {
shader.setUniform("animationMatrix", ((MyNode)geom.getParent().getParent().getParent()).animationController.getAnimationMatrix(),true);
shader.setUniform("skinShade", ((MyNode)geom.getParent().getParent().getParent()).skinShade);
}
});
Maybe something similar should be in jME?
OK, that's sad. I will try to solve it in some other way then… Thanks for answering.
Anyway sharing shader can be done without modifying SharedMesh, I think.
Because each geometry can have its own UserData,
you can get and use it in applyData()
Yes, you can share a shader without shared mesh and that works fine in jME. The problem is when you want to share a shader between shared meshes (so you have both shared vertices and shader).
I don't use that UserData actually, so I know nothing of it…