From Art Trevs, "File Changes:

- GL2Extensions, Program and Program.cpp

Features:
- Support for fragment output binding. (e.g. You can now specify in the fragment shader varying out vec3 fragOut; fragOut = vec3(1,0,1); to write to the fragOut variable. In your program you call glBindFragDataLocation(program, 1, "fragOut") to bind the fragOut variable with the MRT 1 - GL_COLOR_ATTACHMENT1_EXT)

- new methods Program::add/removeBindFragDataLocation Program::getFragDataBindingList

"

include/osg/GL2Extensions

@@ -267,6 +267,11 @@ class OSG_EXPORT GL2Extensions : public osg::Referenced
         bool getProgramInfoLog( GLuint program, std::string& result ) const;
         bool getShaderInfoLog( GLuint shader, std::string& result ) const;
         bool getAttribLocation( const char* attribName, GLuint& slot ) const;
+        bool getFragDataLocation( const char* fragDataName, GLuint& slot) const;
+
+        //EXT_gpu_shader4 to support frag data binding
+        void glBindFragDataLocation(GLuint program, GLuint colorNumber, const GLchar *name) const;
+        GLint glGetFragDataLocation(GLuint program, const GLchar *name) const;
 
     protected:
         ~GL2Extensions() {}
@@ -377,6 +382,9 @@ class OSG_EXPORT GL2Extensions : public osg::Referenced
         void* _glGetObjectParameterivARB;
         void* _glDeleteObjectARB;
         void* _glGetHandleARB;
+
+        void* _glBindFragDataLocation;
+        void* _glGetFragDataLocation;
 };
 
 }

include/osg/Program

@@ -2,7 +2,7 @@
  * Copyright (C) 2003-2005 3Dlabs Inc. Ltd.
  * Copyright (C) 2004-2005 Nathan Cournia
  *
- * This application is open source and may be redistributed and/or modified   
+ * This application is open source and may be redistributed and/or modified
  * freely and without restriction, both in commericial and non commericial
  * applications, as long as this copyright notice is maintained.
  * 
@@ -94,12 +94,20 @@ class OSG_EXPORT Program : public osg::StateAttribute
         /** Add an attribute location binding. */
         void addBindAttribLocation( const std::string& name, GLuint index );
         
-        /** Add an attribute location binding. */
+        /** Remove an attribute location binding. */
         void removeBindAttribLocation( const std::string& name );
 
+        /** Add an frag data location binding. See EXT_gpu_shader4 for BindFragDataLocationEXT */
+        void addBindFragDataLocation( const std::string& name, GLuint index );
+
+        /** Remove an frag data location binding. */
+        void removeBindFragDataLocation( const std::string& name );
+
         typedef std::map<std::string,GLuint> AttribBindingList;
+        typedef std::map<std::string,GLuint> FragDataBindingList;
 
         const AttribBindingList& getAttribBindingList() const { return _attribBindingList; }
+        const FragDataBindingList& getFragDataBindingList() const { return _fragDataBindingList; }
 
         /** Return true if this Program represents "fixed-functionality" rendering */
         bool isFixedFunction() const;
@@ -234,6 +242,7 @@ class OSG_EXPORT Program : public osg::StateAttribute
 
         mutable osg::buffered_value< osg::ref_ptr<PerContextProgram> > _pcpList;
         AttribBindingList _attribBindingList;
+        FragDataBindingList _fragDataBindingList;
 
         typedef std::vector< ref_ptr<Shader> > ShaderList;
         ShaderList _shaderList;