A renderer for realtime soft shadow casting on the basis of a two-pass z buffer (shadow mapping) has been developed, embedded within an ASIC. Functions for erosive and penumbra effects, along with a filtering method for shadow polygons to generate soft shadows and shadows from transparent objects, are newly defined. The renderer consists purely of hardware modules, including multiple shadow buffers, bi-directional IIR filters, and intensity modulation circuits, involving textured and bump-mapped light-reflection shaders. It produces a shadowed pixel at 0.8ns per pixel (1.2 billion pixels), comprising a fully unidirectional pipeline architecture