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SPEC CPU2000 Benchmark Description File

Benchmark Name


Benchmark Author

Peter Shirley, Ken Chiu, Kurt Zimmerman, and Steve Marschner

Benchmark Program General Category

Computer Visualization

Benchmark Description

Eon is a probabilistic ray tracer based on Kajiya's 1986 ACM SIGGRAPH conference paper. It sends a number of 3D lines (rays) into a 3D polygonal model. Intersections between the lines and the polygons are computed, and new lines are generated to compute light incident at these intersection points. The final result of the computation is an image as seen by camera. The computational demands of the program are much like a traditional deterministic ray tracer as described in basic computer graphics texts, but it has less memory coherence because many of the random rays generated in the same part of the code traverse very different parts of 3D space.

Input Description

252.eon renders a 150x150 pixel image of a chair sitting in front of a corner in a room. The input files define the objects in the space being rendered by specifying their positions, sizes, reflectivity, and luminance. 252.eon is run three times, each time rendering the same scene using a different rendering algorithm. The rendering algorithms used are Kajiya, Cook, and Rushmeier.

Output Description

Three of the output files contain the ppm formatted images corresponding to the three algorithms specified in the inputsets. These files can be viewed using xv or your favorite image viewer:


The other three output files contain the greyscale values for each pixel. These values are printed out as floating-point values. These files are created solely for verification of results for the SPEC CPU2000 benchmarks and are not normally created by the Eon application when used for non-benchmarking purposes:


Programming Language


Known portability issues

  • -DSPEC_CPU2000_LP64 If you are running in a 64-bit environment and using a compiler that supports an LP64 programming model (where "long" and pointers are 64-bits in size).
  • -DFMAX_IS_DOUBLE If your compiler won't automatically cast return values to the explicitly declared size for a function, you may need this flag. The HP compiler is the only one (so far) that requires this.
  • -DNEED_EXPLICIT_SPECIALIZATION If your compiler requires explicit specialization for templatized functions you may need to use this flag.


K. Zimmerman and P. Shirley,
A Two-Pass Realistic Image Synthesis Method for Complex Scenes.
Eurographics Rendering Workshop, 1995, pp. 284-295.

G. Spencer, P. Shirley, K. Zimmerman, and D. Greenberg,
Physically-Based Glare Effects for Digital Images.
SIGGRAPH '95, pp. 325-334.

P. Shirley, C. Wang, K. and Zimmerman, Monte Carlo Techniques for Direct
Lighting Calculations. ACM Transactions on Graphics, 1996, pp. 1-36.

K. Chiu, K. Zimmerman and P. Shirley, The Light Volume: an Aid for
Rendering Complex Scenes. Eurographics Rendering Workshop, 1996, pp. 1-10.

J. Ferwerda, S. Pattanaik, P. Shirley, and D. Greenberg, An Adaptation
Model for Realistic Image Synthesis. SIGGRAPH '96, pp. 249-258.

S. Marschner and D. Greenberg. Inverse Lighting for Photography.
IS&T/SID Fifth Color Imaging Conference,
pages 262-265, November 1997

P. Shirley, H. Hu, B. Smits, E. Lafortune,
A Practitioners' Assessment of Light Reflection Models.
Pacific Graphics 97, pp. 40-49.

J. Ferwerda, S. Pattanaik, P. Shirley, and D. Greenberg, A Model of
Visual Masking for Computer Graphics. SIGGRAPH 97, pp. 91-100.

S. Premoze, W. Thompson, P. Shirley, Geospecific Rendering of Alpine Terrain.
Eurographics Rendering Workshop, 1999.

A. J. Preetham, P. Shirley, B Smits.
A Practical Analytic Model for Daylight, SIGGRAPH 99, pp.

Last updated: 6 October 1999