Coherent Hierarchical Culling: Hardware Occlusion Queries Made Useful

Jiří Bittner, Michael Wimmer, Harald Piringer, Werner Purgathofer
Coherent Hierarchical Culling: Hardware Occlusion Queries Made Useful
Computer Graphics Forum, 23(3):615-624, September 2004. [ Paper]
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Abstract

We present a simple but powerful algorithm for optimizing the usage of hardware occlusion queries in arbitrary complex scenes. Our method minimizes the number of issued queries and reduces the delays due to the latency of query results. We reuse the results of the occlusion queries from the last frame in order to initiate and schedule the queries in the next frame. This is done by processing nodes of a spatial hierarchy in front-to-back order, interleaving occlusion queries with the rendering of certain previously visible nodes. The proposed scheduling of the queries makes use of spatial and temporal coherence of visibility. Despite its simplicity, the algorithm achieves good culling efficiency for scenes of various characteristics. The implementation of the algorithm is straightforward, and it can be easily integrated in existing real-time rendering packages using various spatial data structures.

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@article{Bittner-2004-CHC,
  title =      "Coherent Hierarchical Culling: Hardware Occlusion Queries
               Made Useful",
  author =     "Ji{\v r}{\' i} Bittner and Michael Wimmer and Harald
               Piringer and Werner Purgathofer",
  year =       "2004",
  abstract =   "We present a simple but powerful algorithm for optimizing
               the usage of hardware occlusion queries in arbitrary complex
               scenes. Our method minimizes the number of issued queries
               and reduces the delays due to the latency of query results.
               We reuse the results of the occlusion queries from the last
               frame in order to initiate and schedule the queries in the
               next frame. This is done by processing nodes of a spatial
               hierarchy in front-to-back order, interleaving occlusion
               queries with the rendering of certain previously visible
               nodes. The proposed scheduling of the queries makes use of
               spatial and temporal coherence of visibility. Despite its
               simplicity, the algorithm achieves good culling efficiency
               for scenes of various characteristics. The implementation of
               the algorithm is straightforward, and it can be easily
               integrated in existing real-time rendering packages using
               various spatial data structures.",
  pages =      "615--624",
  month =      sep,
  number =     "3",
  note =       "Proceedings EUROGRAPHICS 2004",
  event =      "EUROGRAPHICS 2004",
  issn =       "0167-7055",
  journal =    "Computer Graphics Forum",
  volume =     "23",
  location =   "Grenoble, France",
  keywords =   "occlusion query, visibility, real-time rendering, occlusion
               culling",
  URL =        "http://www.cg.tuwien.ac.at/research/publications/2004/Bittner-2004-CHC/",
}