Fast Intensity Distribution Functions for Soft and Hard Edged Spotlights



Anders Hast
University of Gävle
Creative Media Lab.
801 76 Gävle




Keywords: Spotlights, Beam Angle, Field Angle, Luminous intensity distribution.


The purpose of this paper is twofold: to propose two fast distribution functions for spotlights and to use terminology used in stage lighting to model these luminaries. In OpenGL and other API’s the original Warn model is used where the light distribution is computed using a power function. In professional modeling tools, a linear or a cubic function is often used. We propose the use of two different quadratic functions instead that will make the computation involved faster than using the power function or a cubic function. Moreover it will be more flexible than using a linear function. These functions can be used to model both hard and soft edged spotlights.