EDBT 2026 Demo / reviewers in the wild / expert
Ahmed Khalifa 0001
dblp:26/10674-1
· DBLP profile ↗
41ranked-venue papers
11as first author
17since 2021 · last 2026
0000-0002-7839-9432ORCID · conflict
Domains — the database's venue-derived domains; a paper can count in several
Graphics, computer vision, multimedia, augmented reality and games · 27 · 6 first-author · 11 since 2021Human-computer interaction and ubiquitous computing · 27 · 6 first-author · 12 since 2021Artificial intelligence and machine learning · 14 · 5 first-author · 5 since 2021Applied, interdisciplinary, general and emerging computing · 2 · 1 first-author
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | ProFiT: Program Search for Financial TradingabstractThis paper presents a framework called Program Search for Financial Trading (ProFiT), a large-language-model-driven evolutionary algorithm for automated discovery and continual improvement of trading strategies in financial markets. These markets are inherently non-stationary and thus resist static modeling or prediction, suggesting the need for a more open-ended and adaptive evolutionary approach. ProFiT integrates code-level mutation on a complexifying representation, self-analysis, and walk-forward validation within a closed feedback loop, enabling trading strategies to autonomously evolve in response to changing market conditions. ProFiT consistently outperforms both Random and Buy-and-Hold strategies, which are used as both academic and industry-standard baselines, across seven futures assets. Specifically, it outperforms Random in 100% of cases and surpasses Buy-and-Hold in over 77% of all evolved strategy-asset combinations. Collectively, these results demonstrate that the ProFiT framework yields robust, statistically significant, and risk-adjusted gains across diverse types of financial assets and market dynamics, establishing a practical pathway toward open-ended self-improving algorithmic trading systems. Matthew Siper, Ahmed Khalifa 0001, Lisa B. Soros, Muhammad Umair Nasir, Juyan Azhang, Julian Togelius |
GECCO | 2 |
| 2025 | ScriptDoctor: Automatic Generation of PuzzleScript Games via Large Language Models and Tree SearchabstractThere is much interest in using large pre-trained models in Automatic Game Design (AGD), whether via the generation of code, assets, or more abstract conceptualization of design ideas. But so far, this interest largely stems from the ad hoc use of such generative models under persistent human supervision. Much work remains to show how these tools can be integrated into longer-time-horizon AGD pipelines, in which systems interface with game engines to test generated content autonomously. To this end, we introduce ScriptDoctor, a Large Language Model (LLM)-driven system for automatically generating and testing games in PuzzleScript, an expressive but highly constrained description language for turn-based puzzle games over 2D gridworlds. ScriptDoctor generates and tests game design ideas in an iterative loop, where human-authored examples are used to ground the system's output, compilation errors from the PuzzleScript engine are used to elicit functional code, and search-based agents play-test generated games. ScriptDoctor serves as a concrete example of the potential of automated, openended LLM-based workflows in generating novel game content. Sam Earle, Ahmed Khalifa 0001, Muhammad Umair Nasir, Zehua Jiang, Graham Todd, Andrzej Banburski-Fahey, Julian Togelius |
CoG | 2 |
| 2025 | The Procedural Content Generation Benchmark: An Open-source Testbed for Generative Challenges in GamesabstractThis paper introduces the Procedural Content Generation Benchmark for evaluating generative algorithms on different game content creation tasks.The benchmark comes with 12 game-related problems with multiple variants on each problem.Problems vary from creating levels of different kinds to creating rule sets for simple arcade games.Each problem has its own content representation, control parameters, and evaluation metrics for quality, diversity, and controllability.This benchmark is intended as a first step towards a standardized way of comparing generative algorithms.We use the benchmark to score three baseline algorithms: a random generator, an evolution strategy, and a genetic algorithm.Results show that some problems are easier to solve than others, as well as the impact the chosen objective has on quality, diversity, and controllability of the generated artifacts. Ahmed Khalifa 0001, Roberto Gallotta, Matthew Barthet, Antonios Liapis, Julian Togelius, Georgios N. Yannakakis |
FDG | 1 |
| 2024 | Closing the Affective Loop via Experience-Driven Reinforcement Learning DesignersabstractAutonomously tailoring content to a set of pre-determined affective patterns has long been considered the holy grail of affect-aware human-computer interaction at large. The experience-driven procedural content generation framework realises this vision by searching for content that elicits a certain experience pattern to a user. In this paper, we propose a novel reinforcement learning (RL) framework for generating affect-tailored content, and we test it in the domain of racing games. Specifically, the experience-driven RL (EDRL) framework is given a target arousal trace, and it then generates a racetrack that elicits the desired affective responses for a particular type of player. EDRL leverages a reward function that assesses the affective pattern of any generated racetrack from a corpus of arousal traces. Our findings suggest that EDRL can accurately generate affect-driven racing game levels according to a designer's style and outperforms search-based methods for personalised content generation. The method is not only directly applicable to game content generation tasks but also employable broadly to any domain that uses content for affective adaptation. Matthew Barthet, Diogo Branco, Roberto Gallotta, Ahmed Khalifa 0001, Georgios N. Yannakakis |
ACII | 4 |
| 2024 | Baba is Y'all 2.0: Design and Investigation of a Collaborative Mixed-Initiative SystemabstractThis article describes a new version of the mixed-initiative collaborative level-designing system, i.e.,Baba Is Y'all, as well as the results of a user study on the system.Baba is Y'allis a prototype for artificial intelligence (AI)-assisted game design in collaboration with others. The updated version includes a more user-friendly interface, a better level evolver and recommendation system, and extended site features. The system was evaluated via a user study where participants were required to play a previously submitted level from the site, and then create their own levels using the editor. They reported on their individual process creating the level and their overall experience interacting with the site. The results have shown both the benefits and limitations of this mixed-initiative system and how it can help with creating a diversity ofBaba is Youlevels that are both human and AI designed while maintaining their quality. M Charity, Isha Dave, Ahmed Khalifa 0001, Julian Togelius |
IEEE Trans. Games | 3 |
| 2023 | Controllable Path of DestructionabstractPath of Destruction (PoD) is a self-supervised method for learning iterative generators. The core idea is to produce a training set by destroying a set of artifacts, and for each destructive step create a training instance based on the corresponding repair action. A generator trained on this dataset can then generate new artifacts by "repairing" from arbitrary states. The PoD method is very data-efficient in terms of original training examples and well-suited to functional artifacts composed of categorical data, such as game levels and discrete 3D structures. In this paper, we extend the Path of Destruction method to allow designer control over aspects of the generated artifacts. Controllability is introduced by adding conditional inputs to the state-action pairs that make up the repair trajectories. We test the controllable PoD method in a 2D dungeon setting, as well as in the domain of small 3D Lego cars. Matthew Siper, Sam Earle, Zehua Jiang, Ahmed Khalifa 0001, Julian Togelius |
CoG | 4 |
| 2023 | Lode Enhancer: Level Co-creation Through ScalingabstractWe explore AI-powered upscaling as a design assistance tool in the context of creating 2D game levels. Deep neural networks are used to upscale artificially downscaled patches of levels from the puzzle platformer game Lode Runner. The trained networks are incorporated into a web-based editor, where the user can create and edit levels at three different levels of resolution: 4x4, 8x8, and 16x16. An edit at any resolution instantly transfers to the other resolutions. As upscaling requires inventing features that might not be present at lower resolutions, we train neural networks to reproduce these features. We introduce a neural network architecture that is capable of not only learning upscaling but also giving higher priority to less frequent tiles. To investigate the potential of this tool and guide further development, we conduct a qualitative study with 3 designers to understand how they use it. Designers enjoyed co-designing with the tool, liked its underlying concept, and provided feedback for further improvement. Debosmita Bhaumik, Julian Togelius, Georgios N. Yannakakis, Ahmed Khalifa 0001 |
FDG | 4 |
| 2022 | Play with Emotion: Affect-Driven Reinforcement LearningabstractThis paper introduces a paradigm shift by viewing the task of affect modeling as a reinforcement learning (RL) process. According to the proposed paradigm, RL agents learn a policy (i.e. affective interaction) by attempting to maximize a set of rewards (i.e. behavioral and affective patterns) via their experience with their environment (i.e. context). Our hypothesis is that RL is an effective paradigm for interweaving affect elicitation and manifestation with behavioral and affective demonstrations. Importantly, our second hypothesis-building on Damasio's so-matic marker hypothesis-is that emotion can be the facilitator of decision-making. We test our hypotheses in a racing game by training Go-Blend agents to model human demonstrations of arousal and behavior; Go-Blend is a modified version of the Go-Explore algorithm which has recently showcased supreme performance in hard exploration tasks. We first vary the arousal-based reward function and observe agents that can effectively display a palette of affect and behavioral patterns according to the specified reward. Then we use arousal-based state selection mechanisms in order to bias the strategies that Go-Blend explores. Our findings suggest that Go-Blend not only is an efficient affect modeling paradigm but, more importantly, affect-driven RL improves exploration and yields higher performing agents, validating Damasio's hypothesis in the domain of games. Matthew Barthet, Ahmed Khalifa 0001, Antonios Liapis, Georgios N. Yannakakis |
ACII | 2 |
| 2022 | Predicting Personas Using Mechanic Frequencies and Game State TracesabstractWe investigate how to efficiently predict play personas based on playtraces. Play personas can be computed by calculating the action agreement ratio between a player and a generative model of playing behavior, a so-called procedural persona. But this is computationally expensive and assumes that appropriate procedural personas are readily available. We present two methods for estimating play personas, one using regular supervised learning and aggregate measures of game mechanics initiated, and another based on sequence learning on a trace of closely cropped gameplay observations. While both of these methods achieve high accuracy when predicting play personas defined by agreement with procedural personas, they utterly fail to predict play style as defined by the players themselves using a questionnaire. This interesting result highlights the value of using computational methods in defining play personas. Michael Cerny Green, Ahmed Khalifa 0001, M Charity, Debosmita Bhaumik, Julian Togelius |
CEC | 2 |
| 2022 | Generative Personas That Behave and Experience Like HumansabstractUsing artificial intelligence (AI) to automatically test a game remains a critical challenge for the development of richer and more complex game worlds and for the advancement of AI at large. One of the most promising methods for achieving that long-standing goal is the use of generative AI agents, namely procedural personas, that attempt to imitate particular playing behaviors which are represented as rules, rewards, or human demonstrations. All research efforts for building those generative agents, however, have focused solely on playing behavior which is arguably a narrow perspective of what a player actually does in a game. Motivated by this gap in the existing state of the art, in this paper we extend the notion of behavioral procedural personas to cater for player experience, thus examining generative agents that can both behave and experience their game as humans would. For that purpose, we employ the Go-Explore reinforcement learning paradigm for training human-like procedural personas, and we test our method on behavior and experience demonstrations of more than 100 players of a racing game. Our findings suggest that the generated agents exhibit distinctive play styles and experience responses of the human personas they were designed to imitate. Importantly, it also appears that experience, which is tied to playing behavior, can be a highly informative driver for better behavioral exploration. Matthew Barthet, Ahmed Khalifa 0001, Antonios Liapis, Georgios N. Yannakakis |
FDG | 2 |
| 2022 | Persona-driven Dominant/Submissive Map (PDSM) Generation for TutorialsabstractIn this paper, we present a method for automated persona-driven video game tutorial level generation. Tutorial levels are scenarios in which the player can explore and discover different rules and game mechanics. Procedural personas can guide generators to create content which encourages or discourages certain playstyle behaviors. In this system, we use procedural personas to calculate the behavioral characteristics of levels which are evolved using the quality-diversity algorithm known as Constrained MAP-Elites. An evolved map’s quality is determined by its simplicity: the simpler it is, the better it is. Within this work, we show that the generated maps can strongly encourage or discourage different persona-like behaviors and range from simple solutions to complex puzzle-levels, making them perfect candidates for a tutorial generative system. Michael Cerny Green, Ahmed Khalifa 0001, M Charity, Julian Togelius |
FDG | 2 |
| 2022 | Mutation Models: Learning to Generate Levels by Imitating EvolutionabstractSearch-based procedural content generation (PCG) is a well-known method for level generation in games. Its key advantage is that it is generic and able to satisfy functional constraints. However, due to the heavy computational costs to run these algorithms online, search-based PCG is rarely utilized for real-time generation. In this paper, we introduce mutation models, a new type of iterative level generator based on machine learning. We train a model to imitate the evolutionary process and use the trained model to generate levels. This trained model is able to modify noisy levels sequentially to create better levels without the need for a fitness function during inference. We evaluate our trained models on a 2D maze generation task. We compare several different versions of the method: training the models either at the end of evolution (normal evolution) or every 100 generations (assisted evolution) and using the model as a mutation function during evolution. Using the assisted evolution process, the final trained models are able to generate mazes with a success rate of and high diversity of . The trained model is many times faster than the evolutionary process it was trained on. This work opens the door to a new way of learning level generators guided by an evolutionary process, meaning automatic creation of generators with specifiable constraints and objectives that are fast enough for runtime deployment in games. Ahmed Khalifa 0001, Julian Togelius, Michael Cerny Green |
FDG | 1 |
| 2021 | Illuminating Mario Scenes in the Latent Space of a Generative Adversarial NetworkabstractGenerative adversarial networks (GANs) are quickly becoming a ubiquitous approach to procedurally generating video game levels. While GAN generated levels are stylistically similar to human-authored examples, human designers often want to explore the generative design space of GANs to extract interesting levels. However, human designers find latent vectors opaque and would rather explore along dimensions the designer specifies, such as number of enemies or obstacles. We propose using state-of-the-art quality diversity algorithms designed to optimize continuous spaces, i.e. MAP-Elites with a directional variation operator and Covariance Matrix Adaptation MAP-Elites, to efficiently explore the latent space of a GAN to extract levels that vary across a set of specified gameplay measures. In the benchmark domain of Super Mario Bros, we demonstrate how designers may specify gameplay measures to our system and extract high-quality (playable) levels with a diverse range of level mechanics, while still maintaining stylistic similarity to human authored examples. An online user study shows how the different mechanics of the automatically generated levels affect subjective ratings of their perceived difficulty and appearance. Matthew C. Fontaine, Ahmed Khalifa 0001, Jignesh Modi, Julian Togelius, Amy K. Hoover, Stefanos Nikolaidis |
AAAI | 3 |
| 2021 | Lode Encoder: AI-constrained co-creativityabstractWe present Lode Encoder, a gamified mixed-initiative level creation system for the classic platform-puzzle game Lode Runner. The system is built around several autoen-coders which are trained on sets of Lode Runner levels. When fed with the user's design, each autoencoder produces a version of that design which is closer in style to the levels that it was trained on. The Lode Encoder interface allows the user to build and edit levels through “painting” from the suggestions provided by the autoencoders. Crucially, in order to encourage designers to explore new possibilities, the system does not include more traditional editing tools. We report on the system design and training procedure, as well as on the evolution of the system itself and user tests. Debosmita Bhaumik, Ahmed Khalifa 0001, Julian Togelius |
CoG | 2 |
| 2021 | Learning Controllable Content GeneratorsabstractIt has recently been shown that reinforcement learning can be used to train generators capable of producing high-quality game levels, with quality defined in terms of some user-specified heuristic. To ensure that these generators' output is sufficiently diverse (that is, not amounting to the reproduction of a single optimal level configuration), the generation process is constrained such that the initial seed results in some variance in the generator's output. However, this results in a loss of control over the generated content for the human user. We propose to train generators capable of producing controllably diverse output, by making them “goal-aware.” To this end, we add conditional inputs representing how close a generator is to some heuristic, and also modify the reward mechanism to incorporate that value. Testing on multiple domains, we show that the resulting level generators are capable of exploring the space of possible levels in a targeted, controllable manner, producing levels of comparable quality as their goal-unaware counterparts, that are diverse along designer-specified dimensions. Sam Earle, Maria Edwards, Ahmed Khalifa 0001, Philip Bontrager, Julian Togelius |
CoG | 3 |
| 2021 | Game Mechanic Alignment TheoryabstractWe present a new concept called Game Mechanic Alignment theory as a way to organize game mechanics through the lens of systemic rewards and agential motivations. By disentangling player and systemic influences, mechanics may be better identified for use in an automated tutorial generation system, which could tailor tutorials for a particular playstyle or player. Within, we apply this theory to several well-known games to demonstrate how designers can benefit from it, we describe a methodology for how to estimate “mechanic alignment”, and we apply this methodology on multiple games in the GVGAI framework. We discuss how effectively this estimation captures agential motivations and systemic rewards and how our theory could be used as an alternative way to find mechanics for tutorial generation. Michael Cerny Green, Ahmed Khalifa 0001, Rodrigo Canaan, Philip Bontrager, Julian Togelius |
FDG | 2 |
| 2021 | Deep learning for procedural content generation
Jialin Liu 0001, Sam Snodgrass, Ahmed Khalifa 0001, Sebastian Risi, Georgios N. Yannakakis, Julian Togelius |
Neural Comput. Appl. | 3 |
| 2020 | A Continuous Information Gain Measure to Find the Most Discriminatory Problems for AI BenchmarkingabstractThis paper introduces an information-theoretic method for selecting a subset of problems which gives the most information about a group of problem-solving algorithms. This method was tested on the games in the General Video Game AI (GVGAI) framework, allowing us to identify a smaller set of games that still gives a large amount of information about the abilities of different game-playing agents. This approach can be used to make agent testing more efficient. We can achieve almost as good discriminatory accuracy when testing on only a handful of games as when testing on more than a hundred games, something which is often computationally infeasible. Furthermore, this method can be extended to study the dimensions of the effective variance in game design between these games, allowing us to identify which games differentiate between agents in the most complementary ways. Matthew Stephenson 0001, Damien Anderson, Ahmed Khalifa 0001, John Levine, Jochen Renz, Julian Togelius, Christoph Salge |
CEC | 3 |
| 2020 | Baba is Y'all: Collaborative Mixed-Initiative Level DesignabstractWe present a collaborative mixed-initiative system for building levels for the puzzle game "Baba is You". Unlike previous mixed-initiative systems, Baba is Y'all is designed for collaborative asynchronous creation by multiple users over the internet. The system includes several AI-assisted features to help designers, including a level evolver and an automated player for playtesting. The level archives catalogues levels according to which mechanics are implemented and not implemented, allowing the system to ask users to design levels with specific combinations of mechanics. We describe the operation of the system and the results of small-scale informal user test, and discuss future development paths for this system as well as for collaborative mixed-initiative systems in general. M Charity, Ahmed Khalifa 0001, Julian Togelius |
CoG | 2 |
| 2020 | Mario Level Generation From Mechanics Using Scene StitchingabstractVideo game tutorials allow players to gain mastery over game skills and mechanics. To hone players' skills, it is beneficial from practicing in environments that promote individual player skill sets. However, automatically generating environments which are mechanically similar to one-another is a non-trivial problem. This paper presents a level generation method for Super Mario by stitching together pre-generated "scenes" that contain specific mechanics, using mechanic-sequences from agent playthroughs as input specifications. Given a sequence of mechanics, the proposed system uses an FI-2Pop algorithm and a corpus of scenes to perform automated level authoring. The proposed system outputs levels that can be beaten using a similar mechanical sequence to the target mechanic sequence but with a different playthrough experience. We compare the proposed system to a greedy method that selects scenes that maximize the number of matched mechanics. Unlike the greedy approach, the proposed system is able to maximize the number of matched mechanics while reducing emergent mechanics using the stitching process. Michael Cerny Green, Luvneesh Mugrai, Ahmed Khalifa 0001, Julian Togelius |
CoG | 3 |
| 2020 | Bootstrapping Conditional GANs for Video Game Level GenerationabstractGenerative Adversarial Networks (GANs) have shown impressive results for image generation. However, GANs face challenges in generating contents with certain types of constraints, such as game levels. Specifically, it is difficult to generate levels that have aesthetic appeal and are playable at the same time. Additionally, because training data usually is limited, it is challenging to generate unique levels with current GANs. In this paper, we propose a new GAN architecture named Conditional Embedding Self-Attention Generative Adversarial Net-work (CESAGAN) and a new bootstrapping training procedure. The CESAGAN is a modification of the self-attention GAN that incorporates an embedding feature vector input to condition the training of the discriminator and generator. This allows the network to model non-local dependency between game objects, and to count objects. Additionally, to reduce the number of levels necessary to train the GAN, we propose a bootstrapping mechanism in which playable generated levels are added to the training set. The results demonstrate that the new approach does not only generate a larger number of levels that are playable but also generates fewer duplicate levels compared to a standard GAN. Ruben Rodriguez Torrado, Ahmed Khalifa 0001, Michael Cerny Green, Niels Justesen, Sebastian Risi, Julian Togelius |
CoG | 2 |
| 2020 | Rotation, Translation, and Cropping for Zero-Shot GeneralizationabstractDeep Reinforcement Learning (DRL) has shown impressive performance on domains with visual inputs, in particular various games. However, the agent is usually trained on a fixed environment, e.g. a fixed number of levels. A growing mass of evidence suggests that these trained models fail to generalize to even slight variations of the environments they were trained on. This paper advances the hypothesis that the lack of generalization is partly due to the input representation, and explores how rotation, cropping and translation could increase generality. We show that a cropped, translated and rotated observation can get better generalization on unseen levels of two-dimensional arcade games from the GVGAI framework. The generality of the agents is evaluated on both human-designed and procedurally generated levels. Chang Ye, Ahmed Khalifa 0001, Philip Bontrager, Julian Togelius |
CoG | 2 |
| 2020 | Mech-Elites: Illuminating the Mechanic Space of GVG-AIabstractThis paper introduces a fully automatic method of mechanic illumination for general video game level generation. Using the Constrained MAP-Elites algorithm and the GVG-AI framework, this system generates the simplest tile based levels that contain specific sets of game mechanics and also satisfy playability constraints. We apply this method to illuminate the mechanic space for four different games in GVG-AI: Zelda, Solarfox, Plants, and RealPortals. With this system, we can generate playable levels that contain different combinations of most of the possible mechanics. These levels can later be used to populate game tutorials that teach players how to use the mechanics of the game. M Charity, Michael Cerny Green, Ahmed Khalifa 0001, Julian Togelius |
FDG | 3 |
| 2020 | Automatic Critical Mechanic Discovery Using Playtraces in Video GamesabstractWe present a new method of automatic critical mechanic discovery for video games using a combination of game description parsing and playtrace information. This method is applied to several games within the General Video Game Artificial Intelligence (GVG-AI) framework. In a user study, human-identified mechanics are compared against system-identified critical mechanics to verify alignment between humans and the system. The results of the study demonstrate that the new method is able to match humans with higher consistency than baseline. Our system is further validated by comparing MCTS agents augmented with critical mechanics and vanilla MCTS agents on 4 games from GVG-AI. Our new playtrace method shows a significant performance improvement over the baseline for all 4 tested games. The proposed method also shows either matched or improved performance over the old method, demonstrating that playtrace information is responsible for more complete critical mechanic discovery. Michael Cerny Green, Ahmed Khalifa 0001, Gabriella A. B. Barros, Tiago Machado, Julian Togelius |
FDG | 2 |
| 2020 | Multi-Objective level generator generation with MarahelabstractThis paper introduces a new system to design constructive level generators by searching the space of constructive level generators defined by Marahel language. We use NSGA-II, a multi-objective optimization algorithm, to search for generators for three different problems (Binary, Zelda, and Sokoban). We restrict the representation to a subset of Marahel language to push the evolution to find more efficient generators. The results show that the generated generators were able to achieve good performance on most of the fitness functions over these three problems. However, on Zelda and Sokoban they tend to depend on the initial state than modifying the map. Ahmed Khalifa 0001, Julian Togelius |
FDG | 1 |
| 2019 | Procedural Content Generation through Quality DiversityabstractQuality-diversity (QD) algorithms search for a set of good solutions which cover a space as defined by behavior metrics. This simultaneous focus on quality and diversity with explicit metrics sets QD algorithms apart from standard single- and multi-objective evolutionary algorithms, as well as from diversity preservation approaches such as niching. These properties open up new avenues for artificial intelligence in games, in particular for procedural content generation. Creating multiple systematically varying solutions allows new approaches to creative human-AI interaction as well as adaptivity. In the last few years, a handful of applications of QD to procedural content generation and game playing have been proposed; we discuss these and propose challenges for future work. Daniele Gravina, Ahmed Khalifa 0001, Antonios Liapis, Julian Togelius, Georgios N. Yannakakis |
CoG | 2 |
| 2019 | ELIMINATION from Design to AnalysisabstractElimination is a word puzzle game for browsers and mobile devices, where all levels are generated by a constrained evolutionary algorithm with no human intervention. This paper describes the design of the game and its level generation methods, and analysis of playtraces from almost a thousand players. The analysis corroborates that the level generator creates a sawtooth-shaped difficulty curve, as intended. The analysis also offers insights into player behavior in this game. Ahmed Khalifa 0001, Daniel Gopstein, Julian Togelius |
CoG | 1 |
| 2019 | Level Design Patterns in 2D GamesabstractVideogame designers use tips and tricks and tools of the trade to design levels. Some of these tips are based on their gut feeling and others have been known in the game industry for the last 30 years. In this work, we discuss six of common level design patterns present in 2D videogames. The patterns under discussion are the product of an exploratory analysis of over thirty 2D games. We choose to focus on patterns that are both common and impactful for the overall player experience. We discuss in detail the rationale for and advantages of each pattern, showing examples of games that make use of such. We conclude with a discussion of the usage and understanding of these patterns from the perspective of level design and how other technical approaches can benefit from them. Ahmed Khalifa 0001, Julian Togelius |
CoG | 1 |
| 2019 | Two-step constructive approaches for dungeon generationabstractThis paper presents a two-step generative approach for creating dungeons in the rogue-like puzzle game MiniDungeons 2. Generation is split into two steps, initially producing the architectural layout of the level as its walls and floor tiles, and then furnishing it with game objects representing the player's start and goal position, challenges and rewards. Three layout creators and three furnishers are introduced in this paper, which can be combined in different ways in the two-step generative process for producing diverse dungeons levels. Layout creators generate the floors and walls of a level, while furnishers populate it with monsters, traps, and treasures. We test the generated levels on several expressivity measures, and in simulations with procedural persona agents. Michael Cerny Green, Ahmed Khalifa 0001, Athoug Alsoughayer, Divyesh Surana, Antonios Liapis, Julian Togelius |
FDG | 2 |
| 2019 | Intentional computational level designabstractThe procedural generation of levels and content in video games is a challenging AI problem. Often such generation relies on an intelligent way of evaluating the content being generated so that constraints are satisfied and/or objectives maximized. In this work, we address the problem of creating levels that are not only playable but also revolve around specific mechanics in the game. We use constrained evolutionary algorithms and quality-diversity algorithms to generate small sections of Super Mario Bros levels called scenes, using three different simulation approaches: Limited Agents, Punishing Model, and Mechanics Dimensions. All three approaches are able to create scenes that give opportunity for a player to encounter or use targeted mechanics with different properties. We conclude by discussing the advantages and disadvantages of each approach and compare them to each other. Ahmed Khalifa 0001, Michael Cerny Green, Gabriella A. B. Barros, Julian Togelius |
GECCO | 1 |
| 2019 | Obstacle Tower: A Generalization Challenge in Vision, Control, and PlanningabstractThe rapid pace of recent research in AI has been driven in part by the presence of fast and challenging simulation environments. These environments often take the form of games; with tasks ranging from simple board games, to competitive video games. We propose a new benchmark - Obstacle Tower: a high fidelity, 3D, 3rd person, procedurally generated environment. An agent in Obstacle Tower must learn to solve both low-level control and high-level planning problems in tandem while learning from pixels and a sparse reward signal. Unlike other benchmarks such as the Arcade Learning Environment, evaluation of agent performance in Obstacle Tower is based on an agent's ability to perform well on unseen instances of the environment. In this paper we outline the environment and provide a set of baseline results produced by current state-of-the-art Deep RL methods as well as human players. These algorithms fail to produce agents capable of performing near human level. Arthur Juliani, Ahmed Khalifa 0001, Vincent-Pierre Berges, Jonathan Harper, Ervin Teng, Hunter Henry, Adam Crespi, Julian Togelius, Danny Lange |
IJCAI | 2 |
| 2019 | General Video Game AI: A Multitrack Framework for Evaluating Agents, Games, and Content Generation AlgorithmsabstractGeneral video game playing aims at designing an agent that is capable of playing multiple video games with no human intervention. In 2014, the General Video Game Artificial Intelligence (GVGAI) competition framework was created and released with the purpose of providing researchers a common open-source and easy-to-use platform for testing their artificial intelligence (AI) methods with potentially infinity of games created using the video game description language (VGDL). The framework has been expanded into several tracks during the last few years to meet the demands of different research directions. The agents are required either to play multiple unknown games with or without access to game simulations, or to design new game levels or rules. This survey paper presents the VGDL, the GVGAI framework, existing tracks, and reviews the wide use of GVGAI framework in research, education, and competitions five years after its birth. A future plan of framework improvements is also described. Diego Perez Liebana, Jialin Liu 0001, Ahmed Khalifa 0001, Raluca D. Gaina, Julian Togelius, Simon M. Lucas |
IEEE Trans. Games | 3 |
| 2018 | AtDELFI: automatically designing legible, full instructions for gamesabstractThis paper introduces a fully automatic method for generating video game tutorials. The AtDELFI system (Automatically DEsigning Legible, Full Instructions for games) was created to investigate procedural generation of instructions that teach players how to play video games. We present a representation of game rules and mechanics using a graph system as well as a tutorial generation method that uses said graph representation. We demonstrate the concept by testing it on games within the General Video Game Artificial Intelligence (GVG-AI) framework; the paper discusses tutorials generated for eight different games. Our findings suggest that a graph representation scheme works well for simple arcade style games such as Space Invaders and Pacman, but it appears that tutorials for more complex games might require higher-level understanding of the game than just single mechanics. Michael Cerny Green, Ahmed Khalifa 0001, Gabriella A. B. Barros, Tiago Machado, Andrew Nealen, Julian Togelius |
FDG | 2 |
| 2018 | Generating levels that teach mechanicsabstractThe automatic generation of game tutorials is a challenging AI problem. While it is possible to generate annotations and instructions that explain to the player how the game is played, this paper focuses on generating a gameplay experience that introduces the player to a game mechanic. It evolves small levels for the Mario AI Framework that can only be beaten by an agent that knows how to perform specific actions in the game. It uses variations of a perfect A* agent that are limited in various ways, such as not being able to jump high or see enemies, to test how failing to do certain actions can stop the player from beating the level. Michael Cerny Green, Ahmed Khalifa 0001, Gabriella A. B. Barros, Andrew Nealen, Julian Togelius |
FDG | 2 |
| 2018 | A hybrid search agent in pommermanabstractIn this paper, we explore the possibility of search-based agents in games with resource-intensive forward models. We implemented a player agent in the Pommerman framework and put it against the baseline agent to measure its performance. We implemented a heuristic agent and improved it by enabling depth-limited tree search in specific gameplay moments. We also compared different node selection methods during depth-limited tree search. Our result shows that depth-limited tree search is still viable when presented with inefficient forward models and exploitation-driven selection method is the most efficient in this specific domain. Hongwei Henry Zhou, Yichen Gong, Luvneesh Mugrai, Ahmed Khalifa 0001, Andrew Nealen, Julian Togelius |
FDG | 4 |
| 2018 | Talakat: bullet hell generation through constrained map-elitesabstractWe describe a search-based approach to generating new levels for bullet hell games, which are action games characterized by and requiring avoidance of a very large amount of projectiles. Levels are represented using a domain-specific description language, and search in the space defined by this language is performed by a novel variant of the Map-Elites algorithm which incorporates a feasible-infeasible approach to constraint satisfaction. Simulation-based evaluation is used to gauge the fitness of levels, using an agent based on best-first search. The performance of the agent can be tuned according to the two dimensions of strategy and dexterity, making it possible to search for level configurations that require a specific combination of both. As far as we know, this paper describes the first generator for this game genre, and includes several algorithmic innovations. Ahmed Khalifa 0001, Scott Lee, Andrew Nealen, Julian Togelius |
GECCO | 1 |
| 2017 | Multi-objective Adaptation of a Parameterized GVGAI Agent Towards Several Games
Ahmed Khalifa 0001, Mike Preuss, Julian Togelius |
EMO | 1 |
| 2017 | Evolving Game-Specific UCB Alternatives for General Video Game Playing
Ivan Bravi, Ahmed Khalifa 0001, Christoffer Holmgård, Julian Togelius |
EvoApplications (1) | 2 |
| 2017 | DeepTingle
Ahmed Khalifa 0001, Gabriella A. B. Barros, Julian Togelius |
ICCC | 1 |
| 2016 | General Video Game Level GenerationabstractThis paper presents a framework and an initial study in general video game level generation, the problem of generating levels for not only a single game but for any game within a specified range. While existing level generators are tailored to a particular game, this new challenge requires generators to take into account the constraints and affordances of games that might not even have been designed when the generator was constructed. The framework presented here builds on the General Video Game AI framework (GVG-AI) and the Video Game Description Language (VGDL), in order to reap synergies from research activities connected to the General Video Game Playing Competition. The framework will also form the basis for a new track of this competition. In addition to the framework, the paper presents three general level generators and an empirical comparison of their qualities. Ahmed Khalifa 0001, Diego Perez Liebana, Simon M. Lucas, Julian Togelius |
GECCO | 1 |
| 2016 | Modifying MCTS for Human-Like General Video Game Playing
Ahmed Khalifa 0001, Aaron Isaksen, Julian Togelius, Andrew Nealen |
IJCAI | 1 |