Generate Accurate Soft Shadows Using Complete Occluder Buffer

In this paper, we propose a novel approach to generate accurate soft shadows for complex virtual scenes in real time. A Multi-Layer Occluder buffer (MLO-buffer) is used in our algorithm, and it is determined by rendering the scene from the center of area light source. MLO-buffer records all the potential occluders in the scene. When calculating shadow factors, area light source is represented by a set of point samples, and MLO-buffer is traversed to figure out the visibility relations between an occludee and each light sample. Finally, the accurate soft shadows can be produced. The experimental results show that our algorithm can generate high-quality soft shadows in real time without making any assumption, like shape orientation or density distribution, on the area light source.