GRAPHICS PROCESSING SYSTEMS

• Main Author: HAZEL GRAHAM
• Format: Patent
• Language: English
• Published: 11.11.2015
• Subjects: CALCULATING; COMPUTING; COUNTING; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; PHYSICS

In a tile-based graphics processing system, to simulate the effect of shadows in an image being rendered a light source bounding frustum 34 is produced for a tile for a light source , and used to determine a set of geometry 37 for the tile that could cast a shadow in the tile. The determined set of geometry 37 is then used to determine a light source visibility parameter for each sampling position in the tile by determining for each tile screen space sampling position, whether rays cast between the tile sampling position and a set of sampling positions representing the light source would intersect occluding geometry or not. The determined number of visible light source sampling positions for each tile sampling position is used to determine a light source visibility parameter value for each tile sampling position, and the determined light source visibility parameters are then used to modulate the light source when shading the geometry in the tile to produce the rendered output image 51 for the tile.