FULLTEXT01.Pdf

Abstract This dissertation presents a study that explores the idea of implementing PCG in game bits. Procedural Content Generation (PCG) refers to content in games that is created by an algorithm rather than a human. Game bits is the part of game content that relates to graphics, audio and other elements that don’t directly affect gameplay. The goal was to find out what a PCG implementation in game bits needs to affect player behaviour. Qualitative play sessions with interviews were performed to examine potential ways this could occur. Results show that no noticeable behavioural differences appeared due to PCG in game bits, but three properties are set up detailing how implementations would increase the odds of affecting player behaviour. These properties are: PCG implementation changing visuals drastically, different visual elements matching and game space generation matching game bits repeatedly. Keywords: PCG, game bits, player behaviour, roguelike Table of Contents 1. Introduction……………………………………………………………………………....1 2. Background…………………….…………………….…………………………………..2 2.1 Procedural Content Generation…………………….……………………………………….. 2 2.1.1 Reasons to use PCG…………………….…………………….………………………………. 2 2.2 Different methods for PCG…………………….…………………….……………………….. 3 2.2.1 Search-based approach…………………….…………………….………………………….... 3 2.2.2 Agent-based dungeon growing…………………….…………………….…………………….4 2.3 Games that apply PCG…………………….…………………….………………………….... 4 2.4 Layers of Game Content…………………….…………………….…………………………. 7 2.5 Roguelike…………………….…………………….…………………….…………………….. 9 2.5.1 Roguelikes Over the Years…………………….…………………….………………………. 10 2.5.2 Roguelikes and Layers of Game Content…………………….……………………………..11 2.5.3 Game Bits in Roguelikes…………………….…………………….…………………………. 12 2.6 Player behaviour…………………….…………………….…………………………………. 15 3. Problem…………………….…………………….……………………………………...16 3.1 Method…………………….…………………….…………………….……………………....16 3.1.1 Artifact…………………….…………………….…………………….………………………... 17 3.1.2 Test procedure…………………….…………………….……………………………………..18 3.1.3 Data gathering and analysing…………………….…………………….…………………….18 4. Implementation…………………….…………………….……………………………. 21 4.1 Menu…………………….…………………….…………………….………………………... 21 4.2 Controls and HUD…………………….…………………….……………………………….. 22 4.3 Progression and content…………………….…………………….………………………... 23 4.4 Parts that use PCG…………………….…………………….……………………………… 24 5. Evaluation…………………….…………………….………………………………….. 26 5.1 Results…………………….…………………….…………………….……………………....26 5.1.1 General thoughts of the game…………………….…………………………………………. 26 5.1.2 Perceived differences…………………….…………………….…………………………….. 27 5.1.3 Behavioural differences…………………….…………………….…………………………...27 5.2 Analysis…………………….…………………….…………………….……………………...27 5.2.1 Commercial game sense…………………….…………………….………………………….27 5.2.2 Reasons for specific behaviour…………………….………………………………………... 28 5.2.3 Attention focus…………………….…………………….…………………………………….. 28 5.2.4 Connection with previous experiences…………………….……………………………….. 30 5.3 Conclusions…………………….…………………….………………………………………. 30 6. Concluding Discussions…………………….…………………………………….. 32 6.1 Summary…………………….…………………….…………………………………………. 32 6.2 Ethical Considerations…………………….…………………….…………………………...33 6.3 Discussion…………………….…………………….………………………………………... 34 6.3 Future Work…………………….…………………….……………………………………….35 References…………………….…………………….……………………………………..37 1. Introduction Procedural Content Generation (PCG) is content in games that is created by an algorithm, rather than a developer or player. Content itself can refer to many things, but often means graphics, audio, complete game components or levels. These algorithms often create content much faster than a human ever could, making it an efficient way to add a lot of content to a game. This can also be exploited to have games create unique content for every player while the game is running. A main reason to use PCG is then development efficiency, but it can also be used to increase replay value or create novel mechanics. PCG implementations can either be constructive or generate-and-test. As constructive methods only generate content once, it can be used during runtime. Generate-and-test methods instead repeatedly generate and evolve these results until something desirable comes up, making it more fitting to create content before play. While PCG can be implemented in most types of games, one genre that is closely connected to it is roguelike. Roguelikes were originally games very inspired by the game Rogue (1980, A.I. Design) and has since then become a way to distinguish games that use a specific combination of core mechanics. These mechanics are procedurally generated levels and permadeath. Permadeath refers to the player having to restart the entire game when they reach a failstate. This, combined with the fact that levels are generated when starting the game, means that every attempt in the game contains unique levels that are lost as soon as the player loses or wins. Roguelikes then becomes a very fitting genre to explore PCG further with. Game content can be divided into several layers. Two of these are game space and game bits. While game space refers to content that the player directly interacts with (ground, walls, enemies), game bits are the, mostly, aesthetical parts of content that don’t directly relate to gameplay, like environmental graphics, audio and effects. Roguelikes always apply PCG to game space, as generating levels is part of the genre. PCG is also occasionally applied in game bits, both in roguelikes and other genres. When it comes to applying PCG, not much is known on what effects it has when used in game bits, mostly because generating game space receives the most focus. Knowing how certain elements, mechanics or implementations affect how players behave is important since it allows developers to control the intended player behaviour and choose the most efficient methods, knowing it doesn’t disrupt these intentions. By letting players play through two different versions of a roguelike, one where PCG is applied to game bits and one where it isn’t, then following that with qualitative interviews, conclusions on how it potentially affects player behaviour and to what degree are drawn. The question is the following: Which properties of game bits using PCG changes player behaviour? Results show that no noticeable behavioural differences appeared due to PCG in game bits, but conditions are set up detailing how some ways of implementing it would increase the odds of affecting player behaviour. These conditions generally come down to how drastic the PCG implementation changes visuals and if certain results match up with other aesthetical or gameplay related elements to create false player assumptions. 1 2. Background 2.1 Procedural Content Generation Procedural Content Generation (PCG), as it is used in games, can refer to “the creation of game content automatically using algorithms” (Togelius, Kastbjerg, Schedl & Yannakakis, 2011, p. 1). Other definitions often point to the exact same meaning (Summerville et al., 2018). PCG is specific for digital games, as it requires the algorithm to be run by software. The content that is created is then what the player of the game experiences and interacts with. While creating content for a game manually is a more traditional and common method, using PCG will allow content to be made without developer input. Content created by players is, however, not included in this definition. Content itself can be many different things, and is likely defined differently between areas of game development, so what it means to apply PCG is very loosely defined. A variation of the definition can be found from Hendrikx et al. (2013): “the application of computers to generate game content, distinguish interesting instances among the ones generated, and select entertaining instances on behalf of the players” (p. 2). This definition implies a specific purpose with using PCG: to create entertaining content. There are, however, other possible motivations behind using the method. 2.1.1 Reasons to use PCG This section will go over common reasons to apply PCG in games. Time efficiency. PCG can be used to help level designers. (Smith & Bryson, 2014). A level designer can be tasked with creating content in the form of interactable environment geometry, placement of items or general structure of the area used for gameplay. PCG can then be used in this area for efficiency, as having an algorithm create this kind of content is generally much faster than making it manually. If the goal of the game is to provide a large amount of levels, then applying PCG can greatly benefit that game. It can even be that a development team doesn't need a level designer since they already have algorithms to make that content, making this a potentially cost efficient solution. Replay value. Another reason can be to increase a game’s replay value (Summerville et al. 2018). Replay value generally refers to how sparse the user experience is (Roth, Vermeulen, Vorderer & Klimmt, 2012). A game having a high replay value means that there is an incentive to replay the game, be it a complete restart or with some parameters carrying over. PCG helps in this regard as it can generate new content every time the player plays the game. In that way, the player always experiences new content which creates a reason to keep playing and/or keep replaying. Memory. All content in a game needs to be stored in a memory of some form. With manually created

Load more