An apparatus for texture mapping in a computer graphics system, using a predetermined set of standardized textures. Each texture of the standardized set is a procedural texture, and is supplied to the apparatus as one or a sequence of program commands the execution of which will result in the generation of the respective procedural texture. In a preferred embodiment, the means for processing the program commands comprises a processor operable to implement only those input program commands or sequences of input program commands as are required to generate the procedural textures of the standardized set.