Precomputed Radiance Transfer for X3D based Mixed Reality Applications

We present a lightweight framework composed of two extensions to introduce precomputed radiance transfer (PRT) to X3D. Depending on the basis function, PRT is used to simulate shading, complex light transfer and effects like subsurface scattering and caustics in real time by projecting incident light and transfer functions into frequency space, which allows the solution of the integration of the rendering equation through a simple dot product. Light transfer from incident to transferred radiance thus becomes a matter of solving dot products of coefficient vectors, which can be easily evaluated on the GPU. In this paper, we identify the minimal set of components needed for an X3D application to use spherical harmonic based PRT, and discuss how further enhancements to PRT can be implemented, like new basis functions and other features.

Real-Time Mixed Reality with GPU Techniques

In this paper, we propose a combination of modern GPU-based methods that are able to generate high-quality, interactive real-time rendering for augmented and mixed reality applications. We also present a new approach to estimate surface reflection functions and materials from images using genetic algorithms.

Enhancing X3D for advanced MR appliances

In this paper, we explore and discuss X3D as an application description language for advanced mixed reality environments. X3D has been established as an important platform for today's web-based visualization and VR applications. Yet, there are very few examples for augmented reality systems utilizing X3D beyond a simple geometric description format. In order to fulfill the image compositing and synthesis requests of today's augmented reality applications, we propose extensions to X3D, especially with a focus on lighting and realistic rendering.

Erweiterte Konzepte in C++: Multithreading

Der C++ ISO Standard von 1998 behandelt keine Nebenläufigkeit von Programmen und ist in diesem Punkt bisher Programmiersprachen wie Java, die Threads intern als Sprachmittel anbieten, unterlegen. Die Implementierung von Programmen, die Multithreading nutzen, wird somit vorerst zu einem meist unsicheren und vor allem unportablen Vorhaben. Aktuell ist jedoch gerade Multithreading ein gefragtes Thema, denn in Zeiten von Hyperthreading und Multi-Core Prozessoren wird der Anteil multithread-fähiger Programme weiter ansteigen. Um die Sicherheit und Korrektheit dieser Programme zu gewährleisten, ist auf Dauer eine Anpassung des Standards unerlässlich. Diese Ausarbeitung befasst sich mit aktuellen Lösungen und den vorgesehen Modifikationen für C++0x in Bezug auf Multithreading.

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Compiler extensions to catch security holes: Dissected

Programming errors that lead to unreliable and insecure programs are a problem that has been around since the very beginning of computer science. Most of these errors are caught via extensive testing and debugging. However, more serious bugs are often left in the code unnoticed, because either the interaction through which they can occur is too complex to understand, given a certain time section, or the testing phase is too expensive. This paper presents various automated methods, with a special focus on code analysis (both static and dynamic) to contain or isolate the damage.

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Static Terrain Shadowmaping

An old article about the shadowmapping technique. Easy to implement, and it looks pretty nice.

Terrain Texture Generation Redux

My first article, originally published on flipCode in 2001, about terrain textures and how to generate them with a set of different terrain attributes. Also very easy to implement and quick to set up. Working image loader required!