1. A computer-implemented process for tone mapping a sub-image of a wide angle, high dynamic range (HDR) image for display, comprising using a computer to perform the following process actions: computing, in advance of rendering the sub-image, a global tone map of the image; using the global tone map during rendering of the sub-image to compute a local tone map for the sub-image based on an average luminance and a contrast of the pixels of the sub-image.