1. A method for use a computer system, the method for processing an input gesture, the method comprising: accessing a generic scene graph, the generic scene graph defining behaviors for input gesture processing independent of any of a plurality of different platform specific sub-systems, the generic scene graph containing scene graph metadata that describes characteristics of the behaviors; receiving input gesture data from a specified platform specific sub-system, the specified platform specific sub-system selected from among the plurality of different platform specific sub-systems; recognizing an input gesture corresponding to the input gesture data by utilizing a gesture recognition technique available to the specified platform specific sub-system; adjusting the input gesture data for consistency with the generic scene graph based on the utilized gesture recognition technique and in view of the scene graph metadata; and routing the adjusted input gesture data to an appropriate behavior in the generic scene graph.