Abstract. This paper describes a series of algorithms that allow the unconstrained walkthrough of static scenes shaded with the results of precomputed global illumination. The global illumination includes specular as well as diffuse terms, and intermediate results are cached as surface light fields. The compression of such light fields is examined, and a lazy decompression scheme is presented which allows for high-quality compression by making use of block-coding techniques. This scheme takes advantage of spatial coherence within the light field to aid compression, and also makes use of temporal coherence to accelerate decompression. Finally the techniques are extended to a certain type of dynamic scene.
This paper describes the design and implementation of an architecture for interactively viewing static light fields with very low latency. The system was deliberately over engineered to specifications much tighter than expected necessary to eliminate perceptible latency. This allowed us to relax the specifications to the point at which human users began to detect latency artifacts. We found empirically that when interacting with a light field, human users began to notice latency artifacts when the total system latency is approximately 15 ms. Although the architecture may not be used in practice, this result should prove fundamental for designers of future interactive graphics systems.
Hierarchical representationsof 3-dimensional objects are both time and space efficient. They typically consist of trees whose branches represent bounding volumes and whose terminal nodes represent primitive object elements (usually polygons).This paper describes a method whereby the object space is represented entirely by a hierarchical data structure consisting of bounding volumes, with no other form of representation. This homogeneity allows the visible surface rendering to be performed simply and efficiently.The bounding volumes selected for this algorithm are parallelepipeds oriented to minimize their size. With this representation, any surface can be rendered since in the limit the bounding volumes make up a point representation of the object. The advantage is that the visibility calculations consist only of a search through the data structure to determine the correspondence between terminal level bounding volumes and the current pixel. For ray tracing algorithms, this means that a simplified operation will produce the point of intersection of each ray with the bounding volumes.Memory requirements are minimized by expanding or fetching the lower levels of the hierarchy only when required. Because the viewing process has a single operation and primitive type, the software or hardware chosen to implement the search can be highly optimized for very fast execution.
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