Interactive Relighting of Virtual Objects under Environment Lighting

Current relighting applications often constrain one or several factors of the rendering equation to keep the rendering speed real-time. For example, visibility is often precalculated and animations are not allowed, changes in lighting are limited to simple rotation or the lighting is not very detailed. Other techniques compromise on quality and often coarsely tabulate BRDF functions. In order to solve these problems, some techniques have started to use spherical radial basis functions. However, solving the triple product integral does not guarantee interactivity. In order to dynamically change lighting conditions or alter scene geometry and materials, these three factors need to be converted to the SRBF representation in a fast manner. This paper presents a method to perform the SRBF data construction and rendering in real-time. To support dynamic high-frequency lighting, a multiscale residual transformation algorithm is applied. Area lights are detected through a peak detection algorithm. By using voxel cone tracing and a subsampling scheme, animated geometry casts soft shadows dynamically. We demonstrate the effectiveness of our method with a real-time application. Users can shine with multiple light sources onto a camera and the animated virtual scene is relit accordingly.