ABSTRACT
The most popular methods of composing music for games are the two provided by many audio middleware engines right out of the box: "horizontal" and "vertical" composition. Horizontally composed music plays one piece of music at a time. When the state of the game changes, a new piece of music is swapped in, usually with a transition stinger in between. Vertically composed music fades in and out a collection of stems—groups of instruments mixed to a single audio file—in response to game state changes. Note-based music systems open up all kinds of new interaction and reaction possibilities for music in games. A set of tools is created to allow the composers to get their hands on the behavior of music as well as the sound. And building on it to create new behavior is quick and easy, leaving time and energy for thinking about the creative possibilities.
