Data structure for texture data, computer program product, and texture mapping method

Abstract

The present invention has as an object to propose a texture mapping method which enables smooth shading, and is also appropriate for conserving memory resources. In order to achieve this object, in this invention, data regions with different color tones are set so as to form density gradients in the U coordinate direction and in the V coordinate direction of the texture data. If the brightness of the surface of the object to which texture mapping is performed is I, then among the coordinates to be read to access texture data, the U coordinate is calculated as U=a*I+b, and the V coordinate is determined from V=d. The value of the dynamic variable d can be set appropriately according to the application. Because the texture data is such that color tone density gradients are formed in two mutually orthogonal directions, smooth shading is possible, and a plurality of texture memory areas can be consolidated to conserve memory usage.