Accelerated single source 3d lighting mechanism

Abstract

A system for determining the lighting conditions of objects illuminated by light sources. The system is adapted for use in a three-dimensional graphics system in which a scene is provided having one or more objects. Each object is made up of one or more polygons comprising one or more surfaces. Each surface is delimited by a plurality of vertices. One or more light sources are disposed within the scene. The inventive system determines lighting conditions such as color and intensity for each surface of each object taking into account ambient lighting conditions and each of the light sources in an accelerated manner relative to conventional approaches. In the illustrative embodiment, the inventive system first pre-computes a lighting condition for a vertex and provides a first value representative thereof. This value is stored to avoid the computational expense of re-computing same for each subsequent lighting condition evaluated for the vertex. The system next determines a direction of a light source relative to a direction of the vertex and provides a first indication with respect thereto if the light source is directed toward the vertex and a second indication otherwise. The first value is output as a lighting condition of the vertex if the second indication is provided. If not, reflections from the light source with respect to the vertex are evaluated if the first indication is provided and a second value representative thereof is generated. Thereafter, the first and second values are combined and output as a lighting condition of the vertex.