Sort-First Parallelism for Image-Based Rendering

Voicu Popescu,  Anselmo Lastra, John Eyles


Rendering from images with depth (Image-Based Rendering by Warping, IBRW) is an appealing 3D-computer-graphics technique since it alleviates the modeling bottleneck and promises photorealism at interactive rates. Current, and probably near future silicon technology cannot produce single-chip IBRW renderers that are powerful enough. Thus a high-level parallelism scheme needs to be employed that divides the rendering task among several nodes.
We show that sort-first is the technique best suited for parallel IBRW since it takes advantage of the locality characteristic of depth images. One can easily determine the output-image region to which a contiguous set of depth samples warps. Thus the nodes get the samples pertinent to their region which they fully render independently, eliminating the need of very high bandwidth node-to-node communication paths for sorting the warped samples.
We previously presented the WarpEngine, a sort-first architecture for IBRW. In this paper we will measure the performance of sort-first by analyzing the efficiency of the parallelization scheme, the communication costs, and the load balancing for various system configurations and output-image resolutions.

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