1. A computer-implemented method of rendering an image having a plurality of objects, executing on electronic hardware, comprising: generating an adjusted z-position by randomly adjusting the original z-position of each object in each sample of a series of samples, wherein the adjustments corresponding to each sample are independent of the adjustments corresponding to the other samples; and for each sample: sorting the objects in the sample according to the adjusted z-position of each object in the sample; and rendering each object in the sample to generate a resulting image, wherein the order of said rendering for the sample is based on the sorted order of the objects in the sample, and each object in the sample is rendered at its original z-position.