Abstract: Elementary geometries for rendering objects of a 3D scene are generated from input geometry data sets. Instructions of a source program are transformed into a code executable in a rendering pipeline by at least one graphics processor, by segmenting the source program into sub-programs, each adapted to process the input data sets, and by ordering the sub-programs in function of the instructions. Each ordered sub-program is configured in the executable code for being executed only after the preceding sub-program has been executed for all input data sets. Launching the execution of instructions to generate elementary geometries includes determining among the sub-programs a starting sub-program, deactivating all sub-programs preceding it and activating it as well as all sub-programs following it. Modularity is thereby introduced in generating elementary geometries, allowing time-efficient lazy execution of grammar rules.