Applying Transformational Music Theory to Dynamic Music Composition for Game Soundtracks: A practice-based investigation

Dynamic music systems are often found in video games for interactively altering music as a result of player input and game events. Real-time recomposition of music is a ``holy grail'' of dynamic soundtracks. However, common approaches based on managing multi-track audio and sequenced segments face challenges in responding musically to events. Audio tracks are limited due to a lack of granularity and sequenced content is unwieldy due to the complexity of relationships. Many of these limitations can be addressed, in part, by the representation used for the musical material. In this thesis I engage with generative sequencing for dynamic soundtracks through application of algorithmic composition to manage complexity. In this practice, I utilise a novel representational model to situate musical material in spatial relationships, drawing on concepts from transformational music theory. I have implemented this model as a new software library, ScaleVec, which is also explained in detail in this research. This alternate approach to dynamic soundtracks addresses shortcomings in the granularity of contemporary stem-based approaches by generating and rendering a soundtrack in real-time. Furthermore, the spatial representation facilitates a path-based model which manages complex relationships by mapping out where the soundtrack has been, where it is planning to go and where it may diverge in response to events. Through a practice-led enquiry, I evaluate the quality of this approach by considering dynamic music for games according to four categories of adaptive behaviours: immediate (short-timescale), game-state (mid-timescale), plot (long-timescale) and variation (steady-state). These four timescales are applied as a conceptual framework for the contextualisation and discussion of two prototype soundtracks, Spaceship and Submarine. These two works utilise ScaleVec to control the musical output of the generative processes, presenting a parametric interface for the dynamic behaviours of the soundtrack. The reflection and discussion of my practice examines the perceived affordances, musical quality and the nature of my compositional process. The capacity for real-time recomposition through generative scoring, by managing musical spaces with ScaleVec, represents a paradigmatic shift which allows for deeper engagement with the interactive facets of video game music composition, thereby embracing the emergent nature of gameplay as an integral part of the soundtrack