Image shader using two-tiered lookup table for implementing style attribute references

Abstract

A graphics or image rendering system, such as a map image rendering system, receives image data from an image database, such as a map database, in the form of vector data having image features defined as sets of vertex data. The vertex data includes location data as well as an attribute reference pointer variable value that references a first lookup table, in the form of a texture map, which is sent to or generated in the image rendering system. The attribute reference variable value stored in the first lookup table is then used to reference a second lookup table, which may also be in the form of a texture map, to determine the specific values for a plurality of vertex attributes or properties, as stored in the second look up table. The image rendering system thus processes the vector data in a manner that allows for minimal data to be sent to the image rendering system from the image database or between processors of the image rendering device, as this system enables multiple vertex properties to be specified and easily changed by changing a single attribute reference pointer variable value for each vertex data point.