Adaptive Music

"An adaptive score is a game-driven interchange between musical states, junctures and segments." (Bajakian, 2010)

Ristar

Ristar is a 2D platform game released on the Sega Mega Drive/Genesis in 1995.

Music: Tomoko Sasaki

The fourth level of the game 'Planet Sonata' is a music themed level that incorporates an element of interactivity in the music.

Music plays directly to the player as a soundtrack throughout play in the game. The music track in the fourth level is adapted every time the player progresses beyond one of the four sections. In each section a metronome must be carried to the end and given to a songbird. The process of giving the metronome to the bird acts as an in- game switch. The music in the level begins with an 8 bar loop of chord tones. As each switch is activated, two of the bars in the loop are replaced by a melody line. Once the player has activated the final switch the soundtrack has entirely changed into a melodic piece.

Adaptive Method

Horizontal re-sequencing (Sweet, 2016): The new, melodic bars entirely replace the chord tones that were previously playing. They do not play over the chords as a new layer in the way that a parallel form of music may allow. A 'parallel form' of music, "consists of several tracks or stems playing in sync and in parallel." (Stevens, Raybould, 2016). Once a switch has been activated the soundtrack immediately plays the new melody line and continues to loop the music from that point regardless of the position of the music in terms of beats or phrases, before the switch was activated.

Problems

The music design cannot account for the varying time the player takes to activate each switch. The switch can be reached at any point during the playback of the current form of the soundtrack. Jumping to the new section of music regardless of the currently playing section of the soundtrack can create an un-musical result. This problem can be prevented in modern releases by delaying the switch in soundtrack until the begging of a beat or until the music has reached the end of a bar or phrase. We can also cross-fade between tracks in some circumstances though this would not have been suitable for this example in Ristar. Another method may be to have the chords continuing to play alongside the added melody line creating a soundtrack that uses a parallel form of musical composition.

References

Sweet, M (2016). Top 6 Adaptive Music Techniques in Games – Pros and Cons. [Online] DesigningMusicNow. Available at: http://www.designingmusicnow.com/2016/06/13/advantages-disadvantages-common- interactive-music-techniques-used-video-games/ [Accessed 15th Nov. 2016]

Sega Retro (2016). Tomoko Sasaki. [Online] Available at: http://segaretro.org/Tomoko_Sasaki [Accessed 15th Nov. 2016]

Bajakian, C (2010). Adaptive Music: The Secret Lies Within Music Itself. In: Game Developer's Conference. San Francisco, CA. Available at: http://www.gdcvault.com/play/1012601/Adaptive-Music-The-Secret-Lies [Accessed: 15th Nov. 2016]

Stevens, R. and Raybould D. (2016). Game Audio Implementation, CRC Press, pp. 130 - 133, 173 - 195