Abstract: Samples of a volume are lighted in a rendering pipeline by having a first arithmetic unit combine a modulated emissive coefficient with a modulated diffuse coefficient and a modulated diffuse intensity. A second arithmetic logic unit combines a specular coefficient with a modulated specular intensity and an opacity component of the sample. A third arithmetic unit combines the output of the second arithmetic logic unit and specular colors of the sample. A fourth arithmetic logic unit combines the output of the first arithmetic unit with colors of the sample, and a fifth arithmetic logic unit combines the output of the third and fourth arithmetic units to illuminate the sample.