Ajuste dinâmico de dificuldade híbrido em um jogo do gênero plataforma

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2019.Conforme a indústria de videogames cresce, novos cenários surgem e os jogos devem se manter divertidos para distintos perfis de consumidor, com variados níveis de habilidades e preferências. Assim, surge um campo de pesquisa a partir da percepção e de mecanismos de ajuste da dificuldade nos jogos eletrônicos. Ou seja, um jogo pode ser tedioso quando muito fácil ou frustrante quando muito difícil, precisando oferecer um desafio contínuo e condizente ao jogador para mantê-lo motivado. A implementação de um sistema de dificuldade, ao se adaptar automaticamente à performance do jogador, pode melhorar a experiência geral do jogador com o jogo. Esses sistemas são comumente lineares, seguindo um padrão médio do público almejado. No entanto, a dificuldade pode ser adaptada de acordo com o desempenho do jogador, com seu estado afetivo ou a conjunção de ambos os modelos. No âmbito deste trabalho, objetiva-se investigar um método de estimação da dificuldade de níveis de jogos do gênero plataforma e se um mecanismo híbrido do Ajuste Dinâmico de Dificuldade (ADD) possibilita adequar a dificuldade ao jogador e mantê-lo em estado de fluxo, além de comparar sua eficiência com os outros modelos. Para isso, um jogo foi desenvolvido para se adaptar com base aos dados extraídos por algoritmos de análise de desempenho do jogador correlacionados aos obtidos por um sensor de captura de dados fisiológicos, mais especificamente pela Atividade Eletrodérmica (EDA). Além de jogar com os distintos modelos de ADD, cada participante respondeu questionários e teve seus dados coletados para averiguação dos objetos de pesquisa. O modelo híbrido demonstrou-se capaz de manter o jogador em estado de fluxo e adequar a dificuldade ao jogador, com resultados superiores aos demais modelos.As the video game industry grows, new scenarios arise and games should be entertaining for different consumer profiles with varying skill levels and preferences. Thus, a field of research emerges from the perception and mechanisms of adjustment of the difficulty in electronic games. That is, a game can be tedious when very easy or frustrating when very difficult, needing to offer a continuous and appropriate challenge to the player to keep him motivated. The implementation of a difficulty system, when adapting automatically to the performance of the player, can improve the overall experience of the player in the game. These systems are commonly linear, following the average pattern of the target audience. However, the difficulty can be adapted according to the player’s performance, his affective state or the conjunction of both models. In the scope of this work, the objective is to investigate a method that estimates the difficulty of game levels of the platform genre and if a hybrid Dynamic Difficulty Adjustment (DDA) mechanism makes it possible to adapt the difficulty to the player and keep him in a state of flow, besides comparing its efficiency with the other models. For this, a game was developed to adapt based on the data extracted by analysis algorithms of the player’s performance correlated to those obtained by a sensor that captures physiological data, more specifically by the Electrodermal Activity (EDA). In addition to playing with the different DDA models, each participant answered questionnaires and had their data collected for inquiry purposes. The hybrid model was able to keep the player in a state of flow and to adapt the difficulty to the player, with superior results compared to other models

Probabilistic Modeling for Game Content Creation and Adaption

Dynamic Difficulty Adjustment studies how games can adapt content totheir users’ skill level, aiming to keep them in flow. Most of these methodsmaximize engagement or minimize churn by adapting factors like the opponentAI or the availability of resources. However, such methods do notmaintain a model of the player, and use technologies that are highly specificto the games in which they are tested (e.g. requiring forward modelsfor enemy AIs based on planning agents). Designers may also intend tofind content that is more difficult/easier on purpose, and current methodsdo not allow for such targeting.This thesis proposes and tests a framework for adapting game content tousers based on Bayesian Optimization, giving designers flexibility whenchoosing which skill level to target. Starting with a design space, a metricto be measured, a prior over this metric, and a target value, our frameworkquickly searches possible levels/tasks for one with ideal difficulty (i.e. closeto the specified target). In the process, our framework maintains a simpledata-driven model of the player, which could be used for further decisionmakingand analysis.We test this framework in two settings: adapting content to planning agentsbased on search algorithms likeMonte Carlo Tree Search and Rolling HorizonEvolution in a dungeon crawler-type game, and adapting both Sudokupuzzles and dungeon crawler levels to players. Our framework successfullyadapts content to planning agents as long as their skill level is not extreme,and takes roughly 7 iterations to find an appropriate Sudoku puzzle.Additionally, instead of relying on designers to specify a real-valued encodingof the content (e.g. the number of pre-filled cells in a Sudoku puzzle),we investigate learning this encoding automatically usingDeep GenerativeModels. In other words, we explore design spaces learned as latent spacesof Variational Autoencoders using tile-based representations of games likeSuperMario Bros and The Legend of Zelda.Our final contribution is a novel way of interpolating, sampling and optimizingin the playable regions of latent spaces of Variational Autoencoders,and addresses the challenge that generative models are not always guaranteedto decode playable content. This contribution, based on differentialgeometry, is inspired by recent advancements in domains like robotics andproteinmodeling. We combine these ideas of safe generation with contentoptimization and propose a restricted version of Bayesian Optimization,which optimizes content inside playable regions. We see a clear trade-off:restricting the latent space to playable regions decreases the diversity ofthe generated content, as well as the quality of the optimal values in theoptimization.In summary, this thesis studies applications of Bayesian Optimization andDeep Generative Models to the problem of creating and adapting gamecontent to users. We develop a framework that quickly finds relevant levelsin settings varying from corpora of levels to the latent spaces of generativemodels, and we show in experiments involving both human and artificialplayers that this framework finds appropriate game content in a few iterations.This framework is readily applicable, and could be used to creategames that learn and adapt to their players.<br/