Updating depth related graphics data is described. Geometric primitives are processed. Pixels are generated from the primitives based on the processing, each of which has at least one corresponding depth value. Culling is performed on a first group of the pixels, based on a representation of the at least one depth related value corresponding to each. Pixels may be discarded based on the culling and upon which a second group of pixels remain. A depth related raster operations function is performed, in which data is transacted with a depth buffer. The culling function is updated in relation to the transacting. The updating is performed on the basis of a granularity, which characterizes the culling function.