Lighting

Lighting in computer graphics

Now, we introduce the constructs needed to add lighting to a scene. Like many topics in the wide world of computer graphics, lighting is quite complex, and many different approaches have been taken by artists and engineers seeking to achieve specific styles and aesthetics.

The simplest kind of lighting is purely emissive lighting. With this lighting model, the polygons of objects are self-lighting and do not interact with external materials at all. They appear the same regardless of the view angle, their position in the world, or occlusions from other nearby objects. The shading process simply takes the diffuse appearance of the polygon and renders it to the camera. However, emissive lighting is also referred to as unlit shading since no actual lighting is involved. Historically, this technique has been used in real-time rendering contexts such as video games from the 1990s. It is highly performant but quite unrealistic in appearance.

A brief introduction to light physics

What we call visible light is a specific band of wavelengths in the electromagnetic spectrum. This band consists of radiation with roughly the wavelength of $400-700$ nanometers, with deep violets at the lower $400$ range and deep reds at the upper $700$ ...