Single Scattering in Heterogeneous Participating Media
Abstract
The interaction between light and light-transmitting objects, known as participating media, involves complex physical phenomena such as light absorption and scattering. Media such as clouds, smoke and translucent materials often feature heterogeneous scattering properties. Hence the radiance transmitted by the medium potentially depends on such varying properties on the entire light paths, yielding soft light shafts and opacity variations. Computing light scattering in these media usually requires complex offline computations [Cerezo et al. 2005]. Real-time applications are either based on heavy precomputations [Zhou et al. 2008], limited to homogeneous media [Gautron et al. 2009] or relying on simplistic rendering techniques such as billboards. We propose a generic method for fast estimation of single scattering within heterogeneous participating media. Introducing the concept of attenuation function maps, our method leverages graphics hardware to support dynamic light sources, viewpoints and participating media interactively. Our method also accounts for the shadows cast from solid objects, providing a full-featured solution for fast rendering of participating media which potentially embrace the entire world.