Patent ID: 8941660
Filing Date: 2015-01-27
Classification: G06T,G09G

Abstract:
1. A graphics processing unit which generates a graphics image by rendering a polygon according to a rendering instruction from a central processing unit, said graphics processing unit comprising: a coordinate processing unit configured to load, from a memory, coordinate data indicating a position of each of vertices of the polygon and perform coordinate transform on the loaded coordinate data to generate transformed coordinate data, the coordinate data being included in vertex data that indicates information of the vertices of the polygon; a determining unit configured to determine whether or not the polygon is a rendering object, using the transformed coordinate data generated by said coordinate processing unit, and, when the polygon is determined to be the rendering object, generate a vertex list indicating the vertices of the polygon; a shape data cache for storing, for each of the vertices, shape data that is included in the vertex data and other than the coordinate data; a shape data processing unit configured to (i) determine whether or not the shape data for each of the vertices indicated in the vertex list generated by said determining unit is stored in said shape data cache and (ii) when the shape data for each of the vertices indicated in the vertex list is not yet stored in said shape data cache, load the shape data from the memory and store the loaded shape data for each of the vertices indicated in the vertex list in said shape data cache in association with the vertices indicated in the vertex list; and a polygon rendering processing unit configured to render the polygon using the transformed coordinate data generated by said coordinate processing unit and the shape data stored in said shape data cache, wherein modified shape data generated by modifying the shape data is stored in said shape data cache, wherein said shape data processing unit includes: wherein said shape data cache includes a plurality of cache lines, wherein each of said cache lines includes: wherein said shape data check unit is configured to judge, for each of said cache lines, whether or not the ID of the one of the vertices indicated in the vertex list is already stored in said cache tag corresponding to said flag indicating that the modified shape data is valid, wherein said shape data loading unit is configured to load, for each of said cache lines, the shape data for the one of the vertices from the memory when said shape data check unit judges that the ID of the one of the vertices is not yet stored in said cache tag, and wherein each of said cache lines includes a reference counter for counting the number of times the modified shape data stored in said line memory is referred to.