Tracing ray differentials

摘要

Antialiasing of ray traced images is typically performed by supersampling the image plane.While this type of filtering works well for many algorthms,it is much more efficient to perform filtering locally on a surfae for algorithms such as texture mapping.In order to perform this type of filtering,one must not only trace the ray passing through the pixel,but also have osme approximation of the distane to neighboring rays hitting the surface (i.e.,a ray's footprint).In this paper,we present a fast,simple,robust scheme for tracking such a quantity based on ray differentialsm,derivtives of the ray with respect to the image plane.