Method and apparatus for applying specular highlighting with specular components included with texture maps

Abstract

A graphics processor is disclosed that renders polygons with specular highlighting (glare) based on specular fractional values included in a texture map as components of each texel in the texure map. Each texel in the texture map includes red, green, and blue color values and the specular fractional component. The specular fractional component determines the proportion or percentage of a specular color value that is to be combined with the texel color values. The graphics processor preferably comprises a texture map engine that includes multiplier logic and adder logic. The texture map engine receives three values preferably from a video memory device—the texel color value, the specular fractional component value, and the specular color value. The multiplier multiplies the specular fraction by the specular color value and the resulting product is added to the texel color value. The output value from the adder is then used to render a screen pixel or is provided to another lighting stage. The result is that the texture map itself can influence how much specular highlighting is applied to an object on the screen.