Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for shading computer graphics (CG) representations of materials. One of the methods includes obtaining data describing a physical material; receiving a shading request to shade a particular point in a CG representation of the physical material from a rendering engine, wherein the request identifies a mapping position of the particular point, a view direction at the mapping position, and a light direction at the mapping position; calculating a direct lighting color at the mapping position using a plurality of palettized images; calculating an indirect lighting color at the mapping position using the data describing the physical material; generating a final color at the mapping position by combining the direct lighting color and the indirect lighting color; and providing the final color to the rendering engine for use in rendering the CG representation of the physical material.