Shadow and Environment Maps

Shadows and complex lighting are an essential part of realistic rendering, however they can be computationally expensive (such as path tracing shadows). Therefore image-based methods, Shadow and Environment Mapping (See figure 1), are used to accelerate and approximate these effects in interactive real-time rendering. Shadow mapping is an old technique [Williams 78], but very widely used and developed with many extensions and implementations (Renderman). Environment mapping is also a very old technique [Blinn and Newell 76], but has only seen more use and development in recent times due to previous hardware limitations.