Real-time soft shadows for large-scale virtual environments

Shadow mapping is a widely used shadowing technique in real-time rendering because of its generality and efficiency. In this paper, a practical shadow-mapping-based method called PSPCSS is presented to generate real-time soft shadows in large-scale virtual environments. In PSPCSS, the view frustum is subdivided into several parts along the z-axis, each of which is corresponding to a shadow map with different resolution, and then percentage-closer soft shadows are adaptively applied in each of the shadow maps. The method focuses soft shadows on visual-important area and reduces the waste of shadow map resolution and the cost the adaptive filtering procedure takes. The experiments show plausible real-time soft shadow effect in large-scale virtual environments.