Virtual Camera System - Implementation

Implementation

There is a large body of research on how to implement a camera system. The role of a constraint solver software is to generate the best possible shot given a set of visual constraints. In other words, the constraint solver is given a requested shot composition such as "show this character and ensure that he covers at least 30 percent of the screen space". The solver will then use various methods to try creating a shot that would satisfy this request. Once a suitable shot is found, the solver outputs the coordinates and rotation of the camera, which can then be used by the graphic engine renderer to display the view.

In some camera systems, if no solution can be found, constraints are relaxed. For example, if the solver cannot generate a shot where the character occupies 30 percent of the screen space, it might ignore the screen space constraint and simply ensure that the character is visible at all. Such methods include zooming out.

Some camera systems use predefined scripts to decide how to select the current shot. Typically, the script is going to be triggered as a result of an action. For instance, when the player's character initiates a conversation with another character, the "conversation" script is going to be triggered. This script will contain instructions on how to "shoot" a two-character conversation. Thus the shots will be a combination of, for instance, over the shoulder shots and close-up shots. Such script-based approaches usually rely on a constraint solver to generate the camera coordinates.

Bill Tomlinson used a more original approach to the problem. He devised a system in which the camera is an autonomous agent with its own personality. The style of the shots and their rhythm will be affected by its mood. Thus a happy camera will "cut more frequently, spend more time in close-up shots, move with a bouncy, swooping motion, and brightly illuminate the scene".