Subscribe

Issue No.09 - September (1986 vol.6)

pp: 6-16

Eric Haines , Cornell University

Donald Greenberg , Cornell University

ABSTRACT

In one area of computer graphics, realistic image synthesis, the ultimate goal is to produce a picture indistinguishable from a photograph of a real environment. A particularly powerful technique for simulating light reflection-an important element in creating this realism-is called ray tracing. This method produces images of excellent quality, but suffers from lengthy computation time that limits its practical use. This article presents a new method to reduce shadow testing time during ray tracing. The technique involves generating light buffers, each of which partition the environment with respect to an individual light source. These partition descriptions are then used during shadow testing to quickly determine a small subset of objects that may have to be tested for intersection. The results of timing tests illustrate the beneficial performance of these techniques. The tests compare the standard ray-tracing algorithm to light buffers of varying resolution.

INDEX TERMS

null

CITATION

Eric Haines, Donald Greenberg, "The Light Buffer: A Shadow-Testing Accelerator",

*IEEE Computer Graphics and Applications*, vol.6, no. 9, pp. 6-16, September 1986, doi:10.1109/MCG.1986.276832REFERENCES

- 1. A.Appel, "Some Techniques for Shading Machine Renderings of Solids,"
Proc. SJCC 1968pp. 37-45 Thompson Books - 2. R.Goldstein and R.Nagel,
Simulation , Jan. 1971pp. 25-31- 5. S.Rubin and T.Whitted, "Three-Dimensional Representation for Fast Rendering of Complex Scenes,"
Computer Graphics (Proc. SIGGRAPH 80) July 1980 Vol. 14, No. 3, pp. 110-116- 7. A.Glassner, "Space Subdivision for Fast Ray Tracing,"
IEEE CG&A Vol. 4, No. 10, pp. 15-22 Oct. 1984- 8. M.Kaplan,
course notes from tutorial "State of the Art in Image Synthesis,"- 9. M.Dippe and J.Swensen, "An Adaptive Subdivision Algorithm and Parallel Architecture for Realistic Image Synthesis,"
Computer Graphics (Proc. SIGGRAPH 84) July 1984 Vol. 18, No. 3, pp. 149-158- 11. E.Haines,
The Light Buffer: A Ray Tracer Shadow Testing Accelerator 1986- 12. W.Bouknight and K.Kelley, "An Algorithm for Producing Half-Tone Computer Graphics Presentations with Shadows and Movable Light Sources,"
Proc. SJCC 1970pp. 1-10 AFIPS Press - 14. M.Cohen and D.Greenberg, "The Hemi-Cube: A Radiosity Solution for Complex Environments,"
Computer Graphics (Proc. SIGGRAPH 85) July 1985 Vol. 19, No. 3, pp. 31-40- 15. W.Franklin, "A Linear Time Exact Hidden Surface Algorithm,"
Computer Graphics (Proc. SIGGRAPH 80) July 1980 Vol. 14, No. 3, pp. 117-123- 16. W.Newman and R.Sproull,
Principles of Interactive Computer Graphics , McGraw-Hill 1979- 17. J.Foley and A.van Dam,
Fundamentals of Interactive Computer Graphics , Addison-Wesley 1982- 18. J.Warnock,
TR 4-15 , Univ. of Utah, CS Dept. 1969- 19. M.Aono and T.Kunii, "Botanical Tree Image Generation,"
IEEE CG&A Vol. 4, No. 5, pp. 10-34 May 1984- 20. C.Verbeck,
A Comprehensive Light Source Description for Computer Graphics 1984 |