Cache-efficient processor and method of rendering indirect illumination using interleaving and sub-image blur

A method of rendering indirect illumination for a full-resolution image of a scene, comprising:

• rendering said scene into a reflective shadow map (RSM) in light-space and a camera-view G-buffer;
• restructuring said RSM into sub-RSMs and said camera-view G-buffer into camera-view sub-buffers representing sub-images of said full-resolution image;
• employing interleaved sampling on said sub-RSMs and said camera-view sub-buffers to compute indirect illumination for each pixel in each of said sub-images, thereby generating indirect illumination sub-images;
• blurring said indirect illumination sub-images;
• and
• interleaving blurred indirect illumination sub-images into a higher-resolution indirect illumination image, wherein said restructuring said RSM into said sub-RSMs comprises assigning each pixel of said RSM to a single sub-RSM so that each sub-RSM has a same resolution and number of said sub-RSM pixels as all other sub-RSMs.

A graphics processing subsystem, comprising:

• a memory configured to store a light-space reflective shadow map (RSM) data structure according to which a RSM rendered with respect to a light source is organized into a plurality of unique reduced-resolution sub-RSMs;
• and
• a processor configured to gain access to said memory via a data bus and operable to:
• employ said plurality of unique reduced-resolution sub-RSMs to compute a plurality of reduced-resolution indirect illumination sub-images,
• apply a blurring effect to each of said plurality of reduced-resolution indirect illumination sub-images, and
• interleave said plurality of reduced-resolution indirect illumination sub-images into a higher-resolution indirect illumination image, wherein said organizing said RSM into said plurality of unique sub-RSMs comprises assigning each pixel of said RSM to a single sub-RSM so that each sub-RSM has a same resolution and number of said sub-RSM pixels as all other sub-RSMs.