The OpenRT Application Programming Interface - Towards A Common API for Interactive Ray Tracing -

Andreas Dietrich, Ingo Wald and Philipp Slusallek
Proceedings of the 2003 OpenSG Symposium,
Darmstadt, Germany, April 1-2, 2003, pages 23-31,
Published by the Eurographics Association

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For more than a decade now, interactive graphics has been shaped by triangle rasterization technology and the corresponding OpenGL graphics API. Since recently, however, interactive ray tracing is becoming a reality, and is slowly becoming available on several different hardware platforms. Due to its superior scalability, usability and efficiency, it is likely to play an increasingly important role in future interactive graphics applications.

Though it would be desirable to drive this technology with a well-known API such as todays quasi-standard OpenGL interface, this would be complicated due to OpenGL's tight coupling to rasterization technology, which makes it less suitable for ray tracing. In this paper, we propose a new application programming interface called OpenRT. This new API is designed to be as similar to OpenGL as possible, while emphasizing the strength of interactive ray tracing. While being as simple to learn and use as OpenGL, OpenRT offers all the advantages of ray tracing, like implicit visibility culling, instantiation, the freedom to shoot arbitrary rays, and fully programmable shading.