Luis Valente

Automatic Dynamic Task Distribution between CPU and GPU for Real-Time Systems

The increase of computational power of programmable GPU (graphics processing unit) brings new concepts for using these devices for generic processing. Hence, with the use of the CPU and the GPU for data processing come new ideas that deals with distribution of tasks among CPU and GPU, such as automatic distribution. The importance of the automatic distribution of tasks between CPU and GPU lies in three facts. First, automatic task distribution enables the applications to use the best of both processors. Second, the developer does not have to decide which processor will do the work, allowing the automatic task distribution system to choose the best option for the moment. And third, sometimes, the application can be slowed down by other processes if the CPU or GPU is already overloaded. Based on these facts, this paper presents new schemes for efficient automatic task distribution between CPU and GPU. This paper also includes tests and results of implementing those schemes with a test case and with a real-time system.

An adaptative game loop architecture with automatic distribution of tasks between CPU and GPU

This article presents a new architecture to implement all game loop models for games and real-time applications that use the GPU as a mathematics and physics coprocessor, working in parallel processing mode with the CPU. The presented model applies automatic task distribution concepts. The architecture can apply a set of heuristics defined in Lua scripts in order to get acquainted with the best processor for handling a given task. The model applies the GPGPU (general-purpose computation on GPUs) paradigm. In this article we propose an architecture that acquires knowledge about the hardware by running tasks in each processor and, by studying their performance over time, finding the best processor for a group of tasks.

A game loop architecture for the GPU used as a math coprocessor in real-time applications

This article concerns the use of a graphics processor unit (GPU) as a math co-processor in real-time applications in special games and physics simulations. To validate this approach, we present a new game loop architecture that employs GPUs for general-purpose computations (GPGPUs). A critical issue here is the process distribution between the CPU and the GPU. The architecture consists of a model for distribution, and our implementation offers many advantages in comparison to other approaches without the GPGPU stage. This architecture can be used either by a general-purpose language such as the Compute Unified Device Architecture (CUDA), or shader languages such as the High-Level Shader Language (HLSL) and the OpenGL Shading Language (GLSL). Although the architecture proposed here aims at supporting mathematics and physics on the GPU, it is possible to adapt any kind of generic computation. This article discusses the model implementation in an open-source game engine and presents the results of using this platform.

Mapping quality requirements for pervasive mobile games

Games have not received the full attention of the requirements engineering community. This scenario is becoming more critical as we move towards newer forms of games, such as pervasive games. Pervasiveness (the quality that distinguishes pervasive games from traditional digital games) holds several meanings, including being ubiquitous, permeating something, or spreading something, somewhere, in a physical space. Pervasiveness can be recognized in by the boundaries of the game expanding every time it is played, from the virtual (or fictional) world to the real world. Pervasive games are a new form of digital entertainment that has evolved in different forms, such as alternate reality games, transmedia games, and crossmedia games. Sensor technologies, networking capabilities, augmented reality systems, computer vision technology, the internet, and, especially, mobile devices have been responsible for the rapid evolution of this new form of digital product. This paper is focused on “pervasive mobile games”, which we define as context-aware games that use mobile devices. We bear in mind that mobile devices are currently the main driver for fulfilling the promises of pervasive game playing. Our investigations and experiments on this class of games led us to study the quality requirements for pervasive mobile games. Using different information sources, we gathered a set of interrelated characteristics that are crucial to the success of these games. In this paper, we begin to clarify the definition and scope of pervasive mobile games, which are controversial issues in the literature. Using these fundamentals, we propose a two-level conceptual map of non-functional requirements that helps to realize pervasiveness in pervasive mobile games. These non-functional requirements are then associated with a set of questions that help the designers in verifying tasks and operationalizing the requirements of a game. We also propose a dependence matrix for pervasive game qualities that enhances the insight into pervasiveness and reveals important guidelines for the game designers.

Turn off the graphics: designing non-visual interfaces for mobile phone games

Mobile phones are a widespread platform for ICT applications because they are highly pervasive in contemporary society. Hence, we can think of mobile gaming as a serious candidate to being a prominent form of entertainment in the near future. However, most games (for computers, console and mobile devices) make extensive use of the visual medium, which tends to exclude visually-impaired users from the play. While mobile gaming could potentially reach many visually-impaired users, who are very familiar with this technology, currently there seems to be only very few alternatives for this community. In an attempt to explore new interactive possibilities for such users, this work presents an initial study on non-visual interfaces for mobile phone games. It is based on Semiotic Engineering principles, emphasizing communication through aural, tactile and gestural signs, and deliberately excluding visual information. Results include a number of issues that can be incorporated to a wider research agenda on mobile gaming accessibility, both for the visually-impaired and sighted.

An Architecture with Automatic Load Balancing and Distribution for Digital Games

Distributed computing is being used in several fields to solve many computation intensive problems. In digital games, it is used mainly in multi-player games, where the majority of the game logic is processed in a mainframe or cluster. Single player games could also use distributed computing to process the game logic, devoting host processing to renderization, which is usually the task that digital games spend most of its processing time. By using distributed computing, games could need softer system requirements, since the game loop would be distributed. This paper presents a game loop that can be applied in both multi-player and single-player games, using automatic load balancing and distributing game logic computation among several computers.

Minimizing cyber sickness in head mounted display systems: Design guidelines and applications

We are experiencing an upcoming trend of using head mounted display systems in games and serious games, which is likely to become an established practice in the near future. While these systems provide highly immersive experiences, many users have been reporting discomfort symptoms, such as nausea, sickness, and headaches, among others. When using VR for health applications, this is more critical, since the discomfort may interfere a lot in treatments. In this work we discuss possible causes of these issues, and present possible solutions as design guidelines that may mitigate them. In this context, we go deeper within a dynamic focus solution to reduce discomfort in immersive virtual environments, when using first-person navigation. This solution applies an heuristic model of visual attention that works in real time. This work also discusses a case study (as a first-person spatial shooter demo) that applies this solution and the proposed design guidelines.

A Distributed Architecture for Mobile Digital Games Based on Cloud Computing

Several fields in Computer Science use distributed computing to solve many intensive computational problems. Digital games use this approach mainly in multiplayer games, where a mainframe or cluster processes the majority of game logic. Single player games can also use distribute computing to process game logic and visualization algorithms, usually the tasks where digital games spend most of the processing time. By applying an approach based on distributed computing, games would have softer requirements regarding hardware, since the network cluster would be responsible for processing parts of game loop tasks. With the concept of cloud computing, games could rely on other computers to aid in processing their tasks. This work presents game-loop architecture for single-player or multiplayer games, using automatic load balancing and distributing game logic computation among several computers.

Extending Use Cases to Support Activity Design in Pervasive Mobile Games

Computer games are creative projects thatrequire the input of professionals with very diversebackgrounds, including game designers, artists, and softwaredevelopers. Game development frequently is a complex processdue to different expectations of the involved stakeholders. Withpervasive games, this situation becomes more chaotic as thereare not specific processes devoted to the design anddevelopment of this type of game. In this paper, we propose atemplate-based language to design activities in pervasivemobile games in the conceptual design phase, helping to fill agap between the preproduction and production stages of thistype of game. We define a template for activity specificationbased on an extension of traditional use case templates. Thisextension helps in fulfilling a set of general goals that theactivity modeling should address. We also present examples ofusing the proposed modeling approach in a real game.

The Concept of Pervasive Virtuality and Its Application in Digital Entertainment Systems

Virtual reality has received a lot of attention lately due to a new wave of affordable HMD devices arriving in the consumer market. These new display devices – along with the availability of fast wireless networking, comprehensive wearable technologies, and robust context-aware devices – are enabling the emergence of a new type of mixed-reality system for games and digital entertainment. In this paper we name this new situation as “pervasive virtuality”, which we define as being a virtual environment that is extended by incorporating physical environments, physical objects as “proxy” elements, and context information. This new mixed reality paradigm is not well understood by both industry and academia. Therefore, we propose an extension to the well-known Milgram and Colquhoun’s taxonomy to cope with this new mixed-reality situation. Furthermore, we identify fundamental aspects and features that help designers and developers of this new type of application. We present these features as a two-level map of conceptual characteristics (i.e. quality requirements). This paper also presents a brief case study using these characteristics.