ABSTRACT
This chapter discusses only some of the basic physics behind lighting, as required for students to understand and appreciate computer graphics (CG) lighting. Light is a form of electromagnetic radiation. Visible light is only one small portion of a family of waves called electromagnetic radiation. Refraction refers to the process of bending of light that occurs when light travels from one medium into another. One of the most fundamental differences between CG lighting and real-world lighting is that students have relatively greater control with CG lights than the real-world lights. The position and orientation of a light influence the angle of incidence of the radiation on the scene objects, and this in turn influences the highlights and shadows. Directional lights are also known as infinite lights, and their intensity does not vary with distance. Color refers to the light reflected by an object and is defined in terms of hue, value, and intensity.
