  We propose a quantum optical device to experimentally realize quantum
processes, which perform the regularization of the---in general highly
singular---Glauber-Sudarshan $P$~functions of arbitrary quantum states before
their application and/or measurement. This allows us to produce a broad class
of nonclassical states with regular $P$~functions, also called nonclassicality
quasiprobabilities. For this purpose, the input states are combined on highly
transmissive beam splitters with specific Gaussian or non-Gaussian classical
states. We study both balanced and unbalanced homodyne detections for the
direct sampling of the output states of the implemented processes, which
requires no further regularization or state-reconstruction. By numerical
simulations we demonstrate the feasibility of our approach and we outline the
generalization to multimode light.
