Esteban Clua

Fluid Simulation with Two-Way Interaction Rigid Body Using a Heterogeneous GPU and CPU Environment

Simulation of natural phenomena, such as water and smoke, is a very important topic to increase real time scene realism in video-games. Besides the graphical aspect, in order to achieve realism, it is necessary to correctly simulate and solve its complex governing equations, requiring an intense computational work.Fluid simulation is achieved by solving the Navier-Stokes set of equations, using a numerical method in CPU or GPU, independently, as these equations do not have an analytical solution. The real time simulacraon also requires the simulation of interaction of the particles with objects in the scene, requiring many collision and contact forces calculation, which may drastically increase the computational time. In this paper we propose an heterogeneous multicore CPU and GPU hybrid architecture for fluid simulation with two-ways of interaction between them, and with a fine granularity control over rigid bodys shape collision. We also show the impact of this heterogeneous architecture over GPU and CPU bounded simulations, which is commonly used for this kind of application. The heterogeneous architecture developed in this work is developed to best fit the Single Instruction Multiple Thread (SIMT) model used by GPUs in all simulation stages, allowing a high level performance increase.

A progressive vector map browser for the web

With the increasing popularity of web-based map browsers, remotely obtaining a high quality depiction of cartographic information has become commonplace. Most web mapping systems, however, rely on high-capacity servers transmitting pre-rendered tiled maps in raster format. That approach is capable of producing good quality renderings on the client side while using limited bandwidth and exploiting the browser’s image cache. These goals are harder to achieve for maps in vector format. In this work, we present an alternative client-server architecture capable of progressively transmitting vector maps in levels-of-detail (LOD) by using techniques such as polygonal line simplification, spatial data structures and, most importantly, a customized memory management algorithm. A multiplatform implementation of this system is described, where the client application is written entirely in JavaScript and processed within the web browser, avoiding the need of external applications or plug-ins. Results of experiments aimed at gauging both the performance and the display quality obtained with the system are presented and explained. Extensions to the system are also discussed, including issues such as level-of-detail versus visual importance tradeoffs and the handling of closed polygonal lines.

Ginga Game: A Framework for Game Development for the Interactive Digital Television

With the implantation of Brazilian’s Digital Television System, a new software development platform has been created. Applications for the Digital TV are an important part of this new system, which aims, in addition to higher image and sound quality, the creation of an interactivity channel for the viewer. Among all possible applications for this new environment are the digital games, which every year attract a growing audience worldwide. However, game development isn’t a simple task, and doing so in a limited platform such as digital receivers could be a complicated process. So, this paper presents a framework for game development for the Digital TV, which allows the developer to focus on content creation only, without concerns about technical issues or common tasks related to game development.

A parallel fipa architecture based on GPU for games and real time simulations

The dynamic nature and common use of agents and agent paradigm motives the investigation on standardization of multi-agent systems (MAS). The main property of a MAS is to allow the sub-problems related to a constraint satisfaction issues to be subcontracted to different problem solving agents with their own interests and goals, being FIPA one of the most commonly collection of standards used nowadays. When dealing with a huge set of agents for real time applications, such as games and virtual reality solutions, it is hard to compute a massive crowd of agents due the computational restrictions in CPU. With the advent of parallel GPU architectures and the possibility to run general algorithms inside it, it became possible to model such massive applications. In this work we propose a novel standardization of agent applications based on FIPA using GPU architectures, making possible the modelling of more complex crowd behaviours. The obtained results in our simulations were very promising and show that GPUs may be a choice for massively agents applications. We also present restrictions and cases where GPU based agents may not be a good choice.

Architecture of Request Distributor for GPU Clusters

The advent of GPU computing has enabled development of many strategies for accelerating different kinds of simulations. Even further, instead of processing an application by just using one GPU, it is a common to use a collection of GPUs as a solution. These GPUs can be located in the same machine, network, or even across a wide area network. Unfortunately, distribution and management of GPUs requires additional efforts by the user such as deal with data transfer, connection and processing among GPUs. Request distributor for GPU clusters (RDGPUC) is a software architecture which allows companies, institutes and other users to share their GPU resources. By using this architecture, each cluster can have its own software to manage internal resources and they only need to develop small code to interact with RDGPUC. This novel design brings flexibility to the system and allows everyone to share their resources without need to change their GPU cluster tool. Another interesting part of system is to allow users to submit requests from all kind of devices and platforms. Admin of this system is able to specify resource groups and special schedules for using resources. On the other hand, end-users can just use a simple interface to submit their requests on RDGPUC without knowing about internal design and current status of GPU clusters.

A real-time game streaming optimization technique based on layer caching

Advances in cloud computing have enabled cloud gaming systems. In those systems, game logic and rendering is processed remotely in a cloud server and audio and video outputs are streamed to a thin client with limited computing capabilities, such as mobile phones, low-powered computers or even smart TVs. There are still many challenges involved in the task of providing cloud games, especially when trying to reduce server encoding time and video bitrate. In this work, we present a novel optimization technique based on image layers caching. Our technique allows that previously encoded layers are reused reducing encoding workload. In addition, only newly encoded layers are streamed, reducing the overall bitrate sent from server to client. We achieved around 23% stream size reduction with about 5% encoding time increase for cases where background cache usage is maximized.

Sound Wave Propagation Applied in Games

Many games and other interactive virtual environments are known for their focus in rendering natural phenomena, such as accurate visuals and physics, in the most believable manner. Several advances in the aforementioned fields took place during the last decade but, unfortunately, this effort has not been reflected in libraries for spatial audio. These libraries traditionally do not accurately simulate sound wave propagation through the virtual environment, never taking into consideration the speed of sound, reflection and absorbency by scene geometry, phenomena whose simulation could be used to render many interesting effects in real time. In this paper, we propose the use of a sound wave propagation simulation based on the finite difference method, running on the GPU, that can be used to compute how a sound pulse spreads through a virtual environment. In the prototypes implemented, the simulation data is interactively used to determine the perceived direction of a sound source in a closed building, and rendering a mimic of a shock-wave in an open scene