From Terry Welsh, added copy texture support to TextureRectangle

include/osg/TextureRectangle

@@ -106,6 +106,21 @@ class OSG_EXPORT TextureRectangle : public Texture
         SubloadCallback* getSubloadCallback() { return _subloadCallback.get(); }
         const SubloadCallback* getSubloadCallback() const { return _subloadCallback.get(); }
 
+        /** Copies pixels into a 2D texture image, as per glCopyTexImage2D.
+          * Creates an OpenGL texture object from the current OpenGL background
+          * framebuffer contents at position \a x, \a y with width \a width and
+          * height \a height. \a width and \a height must be a power of two. */
+        void copyTexImage2D(State& state, int x, int y, int width, int height );
+
+        /** Copies a two-dimensional texture subimage, as per
+          * glCopyTexSubImage2D. Updates a portion of an existing OpenGL
+          * texture object from the current OpenGL background framebuffer
+          * contents at position \a x, \a y with width \a width and height
+          * \a height. Loads framebuffer data into the texture using offsets
+          * \a xoffset and \a yoffset. \a width and \a height must be powers
+          * of two. */
+        void copyTexSubImage2D(State& state, int xoffset, int yoffset, int x, int y, int width, int height );
+
         /** On first apply (unless already compiled), create and bind the 
           * texture, subsequent apply will simply bind to texture.
         */