Priority rendering with a virtual reality address recalculation pipeline

Abstract

Virtual reality systems are placing never before seen demands on computer graphics hardware, yet few graphics systems are designed specifically for virtural reality. An address recalculation pipeline is a graphics display controller specifically designed for use with head mounted virtual reality systems, it performs orientation viewport mapping after rendering which means the users head orientation does not need to be known accurately until less than a microsecond before the first pixel of an update frame is actually sent to the head mounted display device. As a result the user perceived latency to head rotations is minimal. Using such a controller with image composition it is possible to render different objects within the world at different rate, thus it is possible to concentrate the available rendering power on the sections of the scene that change the most. The concentration of rendering power is known as priority rendering. Reductions of one order of magnitude in the number of objects rendered for an entire scene have been observed when using priority rendering. When non interactive background scenes which are rendered with a high quality rendering algorithm such as ray tracing are added to the world, highly realistic virtual worlds are possible with little or no latency.