“Fast Phong shading” by Bishop and Weimer
Conference:
Type(s):
Title:
- Fast Phong shading
Presenter(s)/Author(s):
Abstract:
Computer image generation systems often represent curved surfaces as a mesh of planar polygons that are shaded to restore a smooth appearance. Phong shading is a well known algorithm for producing a realistic shading but it has not been used by real-time systems because of the 3 additions, 1 division, and 1 square-root required per pixel for its evaluation. We describe a new formulation for Phong shading that reduces the amount of computation per pixel to only 2 additions for simple Lambertian reflection and 5 additions and 1 memory reference for Phong’s complete reflection model. We also show how to extend our method to compute the specular component with the eye at a finite distance from the scene rather than at infinity as is usually assumed. The method can be implemented in hardware for real-time applications or in software to speed image generation for almost any system.
References:
- Duff, T. 1979. “Smoothly Shaded Renderings of Polyhedral Objects on Raster Displays,” ACM Computer Graphics, vol. 13, no. 2, pp. 270-275.
- Foley, J. D. and A. Van Darn. 1983. Fundamentals of Interactive Computer Graphics, Addison Wesley, Reading, MA.
- Gouraud, H. June 1971. “Continuous Shading of Curved Surfaces,” IEEE Transactions on Computers, vol. 20, no. 6, pp. 623-628.
- Newman, W. N. and R. F. Sproull. 1979. Principles of Interactive Computer Graphics, McGraw-Hill, New York, NY.
- Phong, B. T. July 1973. Illumination for Computer- Generated Images, Ph.D. Dissertation, Department of Computer Science, University of Utah, Salt Lake City. Gov. ordering no. AD-A008 786.
- Whitted, T. and D. Weimer. 1982. “A Software Testbed for the Development of 3D Raster Graphics Systems,~’ ACM Transactions on Graphics, vol. 1, no. 1, pp. 43-58.
