Old video games, especially those for personal computers, used to treat the game screen as if it were a game board in a tabletop game. Today we use a cinematic analogy and talk about the main view on the screen as if it displayed the output of a movie camera looking at the game world. This is the source of the terms virtual camera and camera model.
To define the camera model, you will make a number of design decisions about how you want the player to view the game world, what the camera focuses on, and how the camera behaves. Certain camera models work best with particular interaction models; the next few sections introduce the most common camera models and discuss the appropriate interaction models for them.
The game industry has adopted a number of terms from filmmaking to describe certain kinds of camera movements. When a camera moves forward or back through the environment, it is said to dolly, as in the camera dollies to follow the avatar. When it moves laterally, as it would to keep the avatar in view in a side-scrolling game, it trucks. When it moves vertically, it cranes. When a camera swivels about its vertical axis but does not move, it pans. When it swivels to look up or down, it tilts. When it rotates around an imaginary axis running lengthwise through the lens, it is said to roll. Games almost never roll their cameras except in flight simulators; as in movies, the player normally expects the horizon to be level.