From David Callu, "Here an update of osg::Uniform :

- add non square matrix
- add double
- add all uniform type available in OpenGL 4.2
- backward compatibility for Matrixd to set/get an float uniform matrix
- update of IVE / Wrapper ReadWriter

implementation of AtomicCounterBuffer based on BufferIndexBinding

add example that use AtomicCounterBuffer and show rendering order of fragments,
original idea from geeks3d.com."

include/osg/BufferObject

@@ -1,4 +1,5 @@
 /* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
+ * Copyright (C) 2012 David Callu
  *
  * This library is open source and may be redistributed and/or modified under
  * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
@@ -829,6 +830,17 @@ class OSG_EXPORT UniformBufferObject : public BufferObject
     virtual ~UniformBufferObject();
 };
 
+class OSG_EXPORT AtomicCounterBufferObject : public BufferObject
+{
+ public:
+    AtomicCounterBufferObject();
+    AtomicCounterBufferObject(const AtomicCounterBufferObject& ubo, const CopyOp& copyop=CopyOp::SHALLOW_COPY);
+    META_Object(osg, AtomicCounterBufferObject);
+
+ protected:
+    virtual ~AtomicCounterBufferObject();
+};
+
 inline void GLBufferObject::bindBuffer()
 {
     _extensions->glBindBuffer(_profile._target,_glObjectID);