1. A computer graphics system for generating a pixel value for a pixel in an image, the pixel being representative of a point in a scene, the computer graphics system generating the pixel value to provide a soft shadow that is represented by an evaluation of an integral of a selected function over a finite extent of a light source, the computer graphics system comprising: A. a sample point generator for generating a set of sample points representing points on the finite extent of the light source, the sample point generator using a predetermined strictly-deterministic low-discrepancy sequence to generate the sample points; B. a function evaluator for generating a plurality of function values each representing an evaluation of said selected function at one of the sample points generated by said sample point generator; C. an illumination value generator for generating an illumination level value for the point in the scene as the average of said function values generated by said function evaluator; and D. a pixel value generator for using the illumination level value generated for the point in the scene in generating the pixel value.