1. A method comprising: processing one or more vertices of a geometric primitive within a vertex shader function, wherein processed vertices output from the vertex shader function are temporarily stored; retrieving the temporarily stored processed vertices by a geometry shader function; and generating new primitive information within the geometry shader function based upon the processed vertices, the generating emitting a single vertex associated with the new primitive information, wherein the vertex shader function and the geometry shader function are implemented in a merged shader, the merged shader providing access for the geometry shader to directly retrieve the vertex shader output.