Geometry shadow maps with per-fragment atomics

A system for constructing advanced shadow maps, the system comprising:

• a display device;
• a memory device;
• and
• a processing unit configured to execute a fragment shader and operable to determine an occluded area in a graphical scene depicting a plurality of objects graphically rendered as a plurality of polygons and comprising a plurality of pixels, to compute a corresponding list of polygons from the plurality of polygons for each pixel of the plurality of pixels comprised in the occluded area with the fragment shader, to store the list of polygons in the memory device, to perform shadow rendering for polygons in the list of polygons in the occluded area with the advanced shadow map, and to display the graphical scene in the display device, wherein said list of polygons comprises more than one polygon from the plurality of polygons.

A non-transitory computer readable medium comprising having computer executable instructions for causing a computer system to perform a method for performing shadow mapping, the instructions comprising:

• instructions to determine an occluded area in a graphical scene comprising a plurality of pixels, the graphical scene depicting a plurality of objects graphically rendered as a plurality of polygons;
• instructions to compute, for each pixel of the plurality of pixels comprised in the occluded area, a corresponding list of polygons from the plurality of polygons that intersect the pixel, wherein said list of polygons comprises more than one polygon from the plurality of polygons;
• instructions to store an advanced shadow map comprising the list of polygons for each pixel in the occluded area in a memory device;
• and
• instructions to perform shadow rendering for the list of polygons with the advanced shadow map,
• wherein the computing the list of polygons for each pixel is performed by a shader executed by a graphics processing system.