Quests are a fundamental storytelling mechanism used by computer role-playing games (RPGs) to engage and involve players in the game's narrative. Although RPGs have evolved in many ways in the last years, their basic narrative structure is still based on static plots manually created by game designers. This project explores the generation of dynamic and interactive quests for games using hierarchical task decomposition, planning under nondeterminism, player modeling, and genetic algorithms.

Fear is a basic human emotion that can be triggered by different situations, which vary from person to person. However, game developers usually design horror games based on a general knowledge about what most players fear, which does not guarantee a satisfying horror experience for everyone. When a horror game aims at intensifying the fear evoked in individual players, having useful information about the fears of the current player is vital to promote more frightening experiences. This project explores new methods to create adaptive horror games by using player modeling techniques to identify what individual players fear and adapt the content of the game to intensify the fear evoked in players.

In almost all forms of storytelling, the background and the current state of mind of the audience members predispose them to experience a given story from a uniquely personal perspective. However, traditional story writers usually construct their narratives based on the average preferences of their audience, which does not guarantee satisfying narrative experiences for its members. This project explores user modeling and adaptive storytelling to generate individualized interactive narratives based on the preferences of users.

An intriguing phenomenon in human storytelling - inexhaustible source of inspiration for digital storytelling - is our ability to still recognize a story that the narrator has felt free to change to a considerable extent. However, observing how folktales have appeared and been disseminated through different countries along the centuries, we shall notice that our favorite stories have evolved no less dramatically in the course of the oral storytelling tradition. Founded on the classification of types and motifs contained in the Index of Antti Aarne and Stith Thompson, this research project attempts to understand how narrative variants emerge in order to create new narrative generation methods.

The generation of engaging visual representations for interactive storytelling represents a key challenge for the evolution and popularization of interactive narratives. Usually, interactive storytelling systems adopt computer graphics to represent the virtual story worlds, which facilitates the dynamic generation of visual content. Although animation is a powerful storytelling medium, live-action films are still attracting more attention from the general public. This project explores a new approach to create more engaging interactive narratives, denominated "Video-Based Interactive Storytelling", where characters and virtual environments are replaced by real actors and settings.

In this project, we explore the use of an augmented reality visualization interface combined with a sketch-based interaction interface. We present a storytelling system able to dramatize interactive narratives in augmented reality over a conventional sheet of paper. The system allows users to freely interact with virtual characters by sketching objects on the paper. The system recognizes the hand-drawn sketches and converts the drawings into virtual objects in the 3D story world.

In recent years, interactive narratives emerged as a new form of digital entertainment, allowing users to interact and change stories according to their own desires. However, designing an interaction model for an interactive storytelling system involves several challenges, including the need for natural interaction interfaces and the ability to handle multi-user interactions. This project explores the development and evaluation of several interaction methods for interactive storytelling systems.

Many of the challenges that today are faced during the development of interactive storytelling systems have been treated before by filmmakers. Over the years, cinema has evolved and established various principles and rules to be adopted during the creation of a film. However, unlike movies, where every scene is carefully planned, interactive storytelling does not have this freedom. The dramatization of stories, whose sequence of events is unknown, depends on a robust dramatization system, which adapts itself appropriately to any type of scene. This project explores the use autonomous agents inspired on cinematography to dramatize interactive narratives.

Krimson and Warped Metal are two games that I have created to participate of an indie game development festival at the SBGames 2010. Krimson tells the story of a dragon, named Krimson, who was prisoned by people many years ago. Now the dragon has awakened and wants revenge! Warped Metal is a car battle game where the only think that matter is survive and destroy the opponents' cars. The game include several cars, weapons and power-ups.

This was my final undergraduate project in computer science. The goal of the project was to create a 3D game engine to make easy to people without experience in programming languages to create their own 3D games. The 3D game engine created, called 3D Game Builder, became a success in the Brazilian independent game development community and had more that 5.000 downloads in the first week after the release of the first version. Now, this number already reached over that 700.000 downloads. More details about the 3D Game Builder can be found in the official web page: https://edirlei.com/3dgamebuilder/pt/index.php