Fast and Exact Direct Illumination

Rendering high quality soft shadows from area light sources is necessary to increase the level of realism. Quality soft shadows are closely related to the visibility computation. An accurate visibility information will improve the shadows realism. However, this remains a challenging problem since even small visibility approximations can lead to unacceptable errors in a picture. We propose a new approach to this problem, based on an exact visibility pre-computation, done in the Pl"{u}cker space. It takes advantage of this first step to provide an exact from-point visibility query algorithm. We propose several results in a ray tracing application, where the direct illumination at any given point is provided with a fast computation, and with a high degree of quality.