1. A machine-implemented method of graphics processing, comprising: identifying visible surfaces of a scene for pixels of a frame of pixels; determining origins for casting rays from the visible surfaces for a plurality of the pixels towards a light; determining whether each of the rays is occluded from reaching the light; for each of the rays that are determined to be occluded from the light, recording a distance along the ray from the surface to its respective occlusion; for each of the rays that are determined to be not occluded from the light, searching for one or more pixels for which a ray is determined to be occluded from the light, and if at least one pixel is found in the search, determining a distance based on the distances recorded for the found pixels; and for each of the rays for which a distance is recorded: determining a blending region for a blending filter based on the recorded distance for the ray; transforming that blending region into the frame of pixels; blending shadow information for pixels in the frame of pixels that are within the transformed blending region; and using the blended shadow information to determine shadowing for one or more pixels corresponding to the ray.