Apparatus and method for foveated rendering, bin comparison and TBIMR memory-backed storage for virtual reality implementations

A virtual reality apparatus comprising:

• a graphics processing engine comprising a plurality of graphics processing stages, the graphics processing engine to render a plurality of image frames for left and right displays of a head mounted display (HMD);
• and
• foveation control hardware logic to independently control two or more of the plurality of graphics processing stages based on feedback received from an eye tracking module of the HMD, the feedback indicating a foveated region selected based on a current or anticipated direction of a user's gaze, the foveation control hardware logic to cause the two or more of the graphics processing stages to process the foveated region differently than other regions of the image frames,
• wherein the foveation control hardware logic, based on the feedback indicating the foveated region, reduces a threshold for path termination for the foveated region to cause a shader to generate additional secondary rays for the foveated region and reduces a number of secondary rays for non-foveated regions.