1. A computer-implemented method for rendering an image sequence, comprising: fully calculating or reconstructing a first image in the image sequence; and for each of a plurality of subsequent images in the image sequence: determining a subset of pixels in the image to be calculated, the subset of pixels being less than all pixels in the image, calculating image data for the determined subset of pixels, and propagating calculated image data from one or more neighboring images to each pixel in the image that is not calculated.