Dynamic selection of lighting coordinates in a computer graphics system

Abstract

A computer graphics system includes a lighting system that performs lighting efficiently by selecting dynamically the lighting space in which lighting calculations are to be performed to thereby minimize resources required to be expended to perform lighting. A particular preferred lighting coordinate system is then selected, based upon particular criteria, and the light source information is transformed to the selected coordinate system (if necessary) where lighting is performed. The dynamic selection can take many objective indicia into account, such as whether functions other than lighting must be performed in either of the coordinate systems, whether transformation of the lighting information is possible and the relative efficiencies of performing lighting in one coordinate system verses the other coordinate system. In another aspect, a lighting subsystem for use in a computer graphics system includes a dynamic light space selector for selecting dynamically a lighting space for performing lighting, a lighting processor for performing lighting and at least one switch operatively associated with and controlled by the dynamic light space selector to selectively enable the transformation of data from a first coordinate space to a second coordinate space prior to being input into the lighting processor. The dynamic light space selector thus controls the switch to operatively determine which coordinate system will be used to perform lighting in the lighting processor.