Towards a Video Game Description Language

Abstract

As participants in this Dagstuhl session address the challenge of General Video Game Playing (GVGP), we have recognised the need to create a Video Game Description Language (VGDL). Unlike General Game Playing, we have envisioned GVGP will not require a prescribed language to facilitate understanding of the logic of the game: requiring the computational agent to ascertain these facts for itself. However, we would still require means to define the wide range of problems the GVGP agents may face for the purpose of classification. Not only would such a language provide means to encapsulate the features and mechanics of a game for the purposes of human understanding, but also provide context for the evaluation of GVGP agents having completed playing. Outside of the issues of classification, there is also the opportunity for automatic game generation. Given the intent of the GVGP group to work within a framework akin to the one of the Physical Travelling Salesman Problem (PTSP), we aim to attach a code-base to the VGDL compiler that derives implementations of these games from the definition that can be used in conjunction with GVGP. Implementing such a compiler could provide numerous opportunities; users could modify existing games very quickly, or have a library of existing implementations defined within the language (e.g. an Asteroids ship or a Mario avatar) that have pre-existing, parameterised behaviours that can be customised for the users specific purposes. Provided the language is fit for purpose, automatic game creation could be explored further through experimentation with machine learning algorithms, furthering research in game creation and design. In order for both of these perceived functions to be realised and to ensure it is suitable for a large user base we recognise that the language carries several key requirements. Not only must it be human-readable, but retain the capability to be both expressive and extensible whilst equally simple as it is general. In our preliminary discussions, we sought to define the key requirements and challenges in constructing a new VGDL that will become part of the GVGP process. From this we have proposed an initial design to the semantics of the language and the components required to define a given game. Furthermore, we applied this approach to represent classic games such as Space Invaders, Lunar Lander and Frogger in an attempt to identify potential problems that may come to light. In summary, our group has agreed on a series of preliminary language components and started to experiment with forms of implementation for both the language and the attached framework. In future we aim to realise the potential of the VGDL for the purposes of Procedural Content Generation, Automatic Game Design and Transfer Learning and how the roadmap for GVGP can provide opportunities for these areas.