Filter-based Real-time Single Scattering using Rectified Shadow

Figure 1. Our method needs only 2.2ms for single scattering using a 10242 shadow map and a 1920×1080 full-HD screen resolution. It has basically a constant cost per screen pixel, achieving speedups of a magnitude for similar quality compared to state-of-the-art methods whose performance is scene-dependent [Chen et al. 2011]. Light scattering due to participating media is a complex process and difficult to simulate in real time because light can be scattered towards the camera from everywhere in space. In this work, we replace the usually-employed ray-marching with an efficient ray-independent texture filtering process, which leads to a significant acceleration. Our algorithm assumes single scattering media and takes a rectified shadow map as input, which can also be efficiently rectified by a new scheme, which we propose in this work. Our method is fast and almost resolution independent, while producing near-reference results. For this reason, it is a good candidate for performance-critical applications, such as games. 1