Virtual Area Light for Dynamic and Spatially-Varying Area Lighting

We describe a technique for interactively rendering diffuse scenes with near-field area lighting by introducing a new light type called VAL (Virtual area light). The VALs are generated via the subdivision of the primary planar luminaire, and near-field area lighting effects can be simulated directly from the geometric and radiometric information of these VALs. To ensure a high fidelity of soft shadows, we propose the multi-PCF (Percentage closer filter) algorithm which evaluates visibility through several PCF values of each VAL. Experimental results reveal that our approach can render visually convincing near-field area lighting effects as well as soft shadows without any precomputation. Our strategy also enables high-quality direct illumination results in fully dynamic scenes under both time-varying and spatially-varying area lighting conditions in the order of milliseconds.