Coarse-Z Filter: a Graphics Pipeline Unit to Reduce Depth Bandwidth

We proposed a graphics pipeline unit,namely Coarse-Z filter (CZF),for tile-level depth culling prior to per-pixel test,to reduce depth reading and thus reduce the pipeline bandwidth.CZF provides two modes,namely Single CZF,which employs a low-resolution Filter Buffer storing the maximum depth of a scan-converted tile;and Double CZF,which adds an auxiliary buffer and a bit mask plane to gain a higher culling ratio. Test results shows that CZF can reduce up to 30%~40% pipeline bandwidth in today's scenes being more complex.