Evaluating the perceived immersion of procedurally generated game levels Taura J. Greig A thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Creative Technologies Table of Contents Table of Contents ............................................................................................................... i List of Figures ................................................................................................................... iii Attestation of Authorship ................................................................................................ iv Acknowledgements ........................................................................................................... v Abstract ........................................................................................................................... vii 1 Introduction .............................................................................................................. 1 2 Literature Review ...................................................................................................... 4 2.1 Games and Design ............................................................................................. 4 2.1.1 Mechanics Dynamics, Aesthetics Framework ............................................... 5 2.2 Artificial Intelligence and Games ...................................................................... 7 2.2.1 AI in commercial games ................................................................................ 8 2.2.2 AI Assisted Game Design ............................................................................. 11 2.3 Procedural Content Generation ...................................................................... 13 2.3.1 Search Based PCG........................................................................................ 16 2.3.2 Experience-Driven PCG and user evaluation .............................................. 20 2.4 Summary ......................................................................................................... 21 3 Methodology ........................................................................................................... 22 3.1 Research Objective .......................................................................................... 22 3.2 Research Methodology ................................................................................... 22 3.3 Experimental Design ....................................................................................... 23 3.3.1 MDA Framework and the use of PCG ......................................................... 23 3.3.2 Game Immersion Questionnaire ................................................................. 27 3.3.3 Hypothesis ................................................................................................... 30 3.3.4 Experimental Structure ............................................................................... 31 4 Implementation ...................................................................................................... 35 4.1 Vektor .............................................................................................................. 35 4.1.1 Objective of the game ................................................................................. 36 4.1.2 Player ........................................................................................................... 37 4.1.3 Hostile NPCs ................................................................................................ 40 4.1.4 Game Design and PCG evaluation ............................................................... 42 4.1.5 Vektor and MDA .......................................................................................... 44 4.2 Genetic Algorithm Implementation ................................................................ 44 4.2.1 Chromosome Representation ..................................................................... 44 4.2.2 Population Generation ................................................................................ 46 4.2.3 Fitness Function and Selection ................................................................... 49 4.2.4 Crossover Function ...................................................................................... 58 4.2.5 Mutation Function ...................................................................................... 60 4.2.6 GA Gameplay elements ............................................................................... 64 4.2.7 GA in PCG Taxonomy................................................................................... 65 4.3 Human Designed Levels .................................................................................. 66 4.4 Summary ......................................................................................................... 67 5 Results ..................................................................................................................... 68 5.1 Participants ..................................................................................................... 68 5.2 Playtesting groups ........................................................................................... 71 5.3 Total Immersion Analysis ................................................................................ 74 5.4 Detailed Questionnaire Analysis ..................................................................... 76 5.5 Discussion of Results ....................................................................................... 80 i 5.5.1 Genetic Algorithm ....................................................................................... 80 5.5.2 Observation of differences between PCG content and Human content .... 81 5.5.3 Individual Questions .................................................................................... 82 6 Conclusion ............................................................................................................... 84 6.1 Potential Limitations ....................................................................................... 84 6.1.1 Play test experiment ................................................................................... 85 6.1.2 Limitation in the GA .................................................................................... 85 6.1.3 Clarity of game design ................................................................................. 86 6.1.4 Game Design understanding across variants .............................................. 86 6.2 Future Work .................................................................................................... 87 6.2.1 Design of the GA ......................................................................................... 87 6.2.2 Game Design Schema and PCG ................................................................... 88 6.2.3 AI assisted game design with GA method ................................................... 89 6.2.4 Further testing............................................................................................. 90 6.3 Summary ......................................................................................................... 90 6.4 References ....................................................................................................... 91 Appendix A: Evolved Levels and Human Levels .............................................................. 97 A.1 Human Designed Level Maps .......................................................................... 97 A.2 Procedurally Generated Level Maps ............................................................. 101 Appendix B: Questionnaires .......................................................................................... 105 B.1 Pre-Participation Questionnaire ................................................................... 105 B.2 Participation Questionnaire .......................................................................... 107 Appendix C: ANOVA Results for individual questions ................................................... 112 ii List of Figures Figure 1: Screenshot of the game Vektor ....................................................................... 36 Figure 2: Image of the player in the game ...................................................................... 37 Figure 3: Image of weapons from the game ................................................................... 39 Figure 4: Examples of different Weapons being fired .................................................... 39 Figure 5: Images of Key and Ammo pickups in the game ............................................... 40 Figure 6: Image of enemies in the game ......................................................................... 41 Figure 7: Level generated by a genetic algorithm ........................................................... 45 Figure 8: An example of the mapping between the chromosome and a level .............. 46 Figure 9: Level with main space highlighted ................................................................... 51 Figure 10: Level with the start (green) and end (red) spaces highlighted ...................... 52 Figure 11: The levels longest possible distance .............................................................. 52 Figure 12: The shortest distance between the start/end and the main space .............. 53 Figure 13: Start