Real-time Subsurface Control Variates

Real-time adaptive sampling is a new technique recently proposed for efficient importance in realtime Monte Carlo subsurface scattering. It adaptively places samples based on variance tracking to help escape the uncanny valley of rendering. However, occasional performance drop due temporal lighting dynamics (e.g., guns or lights turning and off) could hinder adoption games other applications where smooth high frame rate preferred. In this paper we propose novel usage Control Variates (CV) sample domain instead shading maintain consistent low pass time. Our algorithm seamlessly reduces diffuse with zero scattering sub-pixel We joint-optimization count CV coefficient estimation. The main enabler our time-variant covariance updating method that helps remove effect recent from tracking. Since bandwidth critical real-time rendering, solution without adding any extra textures also provided.