Foveated path tracing a literature review and a performance gain analysis

Abstract

Virtual Reality (VR) places demanding requirements on the rendering pipeline: the rendering is stereoscopic and the refresh rate should be as high as 95Hz to make VR immersive. One promising technique for making the final push to meet these requirements is foveated rendering, where the rendering effort is prioritized on the areas where the user’s gaze lies. This requires rapid adjustment of level of detail based on screen space coordinates. Path tracing allows this kind of changes without much extra work. However, real-time path tracing is fairly new concept. This paper is a literature review of techniques related to optimizing path tracing with foveated rendering. In addition, we provide a theoretical estimation of performance gains available and calculate that 94% of the paths could be omitted. For this reason we predict that path tracing can soon meet the demanding rendering requirements of VR.