by Sheng Guo, Cage Lu, Xiaochang Wu
Clouds play an important role in creating images of outdoor scenery. Most games render clouds with the planar cloud textures mapping to the sky dome. This method is suitable when the viewpoint is close to the ground, but is not visually convincing when the viewpoint approaches or passes through the clouds. For a realistic experience in flying games, players should see clouds that appear to be three-dimensional with irregular shapes and realistic illumination. Implementing these features requires using volumetric techniques to model, illuminate, and render clouds. However, due to the inherent computational intensity of volumetric cloud techniques, it can be a challenge to apply these techniques in games. Although there have been some cloud systems that support real-time rendering of large-scale volumetric clouds in games, based on performance considerations, these systems generally must abandon the realistic dynamic features of clouds at run-time.
Currently, multi-core platforms are the PC market mainstream. However, because traditional game architectures are not designed for multi-core systems, most games based on multi-core processors are not able to make full use of the power of all cores. Using all cores would provide performance headroom for games and flight simulators to render more realistic volumetric clouds. This article presents a technique for games running on mainstream multi-core platforms to render dynamic volumetric clouds.
