Moka: Designing a Simple Scene Graph Library for Cluster-Based Virtual Reality Systems.

Clusters of PCs are widely employed in multi-screen immersive virtual reality systems. While this allows reducing the realization costs, it leds to an increase of complexity on the software side, since they require the development of distributed applications. Over the years, many frameworks supporting cluster rendering have been proposed, but none has established itself as the defacto standard for immersive virtual reality application development. A new trend that is taking place consists in adding cluster-rendering support to one of the many freely available 3D engines. In this paper, we propose a convenient method to develop a lightweight distributed scene graph on top of a generic graphics engine. In particular, we describe the main mechanisms and design choices behind "Moka", a library for the development for cluster-based virtual reality applications. We also present "Caffeine", a virtual reality molecular visualizer based on the Moka library.