An adaptive spatial filter for early depth test

In this paper, we extend our previous work which is a new method for early depth test in a 3D rendering engine. We add a filter stage to the rasterizer in the 3D rendering engine, in an attempt to identify and avoid the occluded pixels. This filtering block determines if a pixel is hidden by a certain plane. The plane is a mask having the history of a pixel´s appearances in front of it. If a pixel is hidden by the plane, it can be removed. The filter adaptively updates its position from an initial position in order to find a maximum rejection ratio. The simulation results show that the filter reduces the number of pixels to the next stage up to 71.7%. As a result, 67% of memory bandwidth is saved with simple extra hardware in the 3D rendering engine.