ABSTRACT
Most games still make use of conventional uniform shadow filters. This means that the importance of all shadow map based visibility results (e.g., is the light
visible) is equal. In order to achieve soft shadow to light transitions, as a minimal solution four visibility samples, e.g., a 2×2 neighborhood of shadow map samples, are taken into account. These four samples are bi-linearly weighted using sub-texel coordinates to generate a smooth result. This approach is called percentage closer filtering (PCF), and is supported by all Direct3D 10.0 class hardware and some Direct3D 9.x class hardware.
