The virtual discontinuity principle of diffraction (VDPD), which gives the representation of a sound field that satisfies both the wave equation and boundary conditions [J. Acoust. Soc. Am. 95, 2354--2362 (1994)], is applied to the analysis of diffracted waves from a rigid wedge in 2-D space. According to VDPD, diffracted waves from the wedge can be expressed as an integral of particle velocity along a half-line that starts from a corner point of the wedge and would pass through an observation point if it was drawn in the reverse direction. Since the particle velocity normal to the line is expressed as the sum of geometrical-optics and near-field components, diffracted waves are also expressed as the sum of waves contributed by the geometrical-optics and near-field components of particle velocity. In this presentation, simple relations expressing the two contributions of diffracted waves are derived and it is shown that the sum of the two contributions agrees well with the rigorous solution of diffracted waves.