Diploma and Master Theses (authored and supervised):
"A caching system for a dependency-aware scene graph";
Supervisor: W. Purgathofer, R.F. Tobler;
Institut für Computergraphik und Algorithmen,
Scene graphs are a common way of representing 3-dimensional scenes for graphical applications. A scene is represented as a hierarchical structure of nodes which represent 3D geometry, spatial transformations, surface properties, and other-possibly application specific-aspects. Scene graph systems can be designed to be very generic and flexible, e.g. by allowing users to implement custom node types and traversals or by providing facilities to dynamically create subgraphs during a traversal. This flexibility comes at the cost of increased time spent in pure traversal logic. Especially for CPU-bound applications this causes a performance drop. This thesis proposes a scene graph caching system that automatically creates an alternative representation of selected subgraphs. This alternative representation poses a render cache in the form of a so-called instruction stream which allows to render the cached subgraph at lower CPU cost and thus more quickly than with a regular render traversal. In order to be able to update render caches incrementally in reaction to certain scene graph changes, a dependency system was developed. This system provides a model for describing and tracking changes in the scene graph and enables the scene graph caching system to update only those parts of the render cache that needs to be updated. The actual performance characteristics of the scene graph caching system were investigated using a number of synthetic test scenes in different configurations. These tests showed that the caching system is most useful in scenes with a high structural complexity (high geometry count and/or deep scene graph hierarchies) and moderate primitive count per geometry.
Electronic version of the publication:
Created from the Publication Database of the Vienna University of Technology.